/*
* PDKIM - a RFC4871 (DKIM) implementation
*
- * Copyright (C) 2009 - 2015 Tom Kistner <tom@duncanthrax.net>
+ * Copyright (c) The Exim Maintainers 2021 - 2022
+ * Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net>
+ * Copyright (C) 2016 - 2020 Jeremy Harris <jgh@exim.org>
+ * SPDX-License-Identifier: GPL-2.0-or-later
*
* http://duncanthrax.net/pdkim/
*
*/
#include "../exim.h"
-#include "pdkim.h"
-#include "pdkim-rsa.h"
-#include "polarssl/sha1.h"
-#include "polarssl/sha2.h"
-#include "polarssl/rsa.h"
-#include "polarssl/base64.h"
+
+#ifndef DISABLE_DKIM /* entire file */
+
+#ifdef DISABLE_TLS
+# error Must not DISABLE_TLS, for DKIM
+#endif
+
+#include "crypt_ver.h"
+
+#ifdef SIGN_OPENSSL
+# include <openssl/rsa.h>
+# include <openssl/ssl.h>
+# include <openssl/err.h>
+#elif defined(SIGN_GNUTLS)
+# include <gnutls/gnutls.h>
+# include <gnutls/x509.h>
+#endif
+
+#include "pdkim.h"
+#include "signing.h"
#define PDKIM_SIGNATURE_VERSION "1"
-#define PDKIM_PUB_RECORD_VERSION "DKIM1"
+#define PDKIM_PUB_RECORD_VERSION US "DKIM1"
#define PDKIM_MAX_HEADER_LEN 65536
#define PDKIM_MAX_HEADERS 512
#define PDKIM_MAX_BODY_LINE_LEN 16384
#define PDKIM_DNS_TXT_MAX_NAMELEN 1024
-#define PDKIM_DEFAULT_SIGN_HEADERS "From:Sender:Reply-To:Subject:Date:"\
- "Message-ID:To:Cc:MIME-Version:Content-Type:"\
- "Content-Transfer-Encoding:Content-ID:"\
- "Content-Description:Resent-Date:Resent-From:"\
- "Resent-Sender:Resent-To:Resent-Cc:"\
- "Resent-Message-ID:In-Reply-To:References:"\
- "List-Id:List-Help:List-Unsubscribe:"\
- "List-Subscribe:List-Post:List-Owner:List-Archive"
/* -------------------------------------------------------------------------- */
struct pdkim_stringlist {
- char *value;
- int tag;
- void *next;
-};
-
-#define PDKIM_STR_ALLOC_FRAG 256
-struct pdkim_str {
- char *str;
- unsigned int len;
- unsigned int allocated;
+ uschar * value;
+ int tag;
+ void * next;
};
/* -------------------------------------------------------------------------- */
/* A bunch of list constants */
-const char *pdkim_querymethods[] = {
- "dns/txt",
- NULL
-};
-const char *pdkim_algos[] = {
- "rsa-sha256",
- "rsa-sha1",
+const uschar * pdkim_querymethods[] = {
+ US"dns/txt",
NULL
};
-const char *pdkim_canons[] = {
- "simple",
- "relaxed",
+const uschar * pdkim_canons[] = {
+ US"simple",
+ US"relaxed",
NULL
};
-const char *pdkim_hashes[] = {
- "sha256",
- "sha1",
- NULL
+
+const pdkim_hashtype pdkim_hashes[] = {
+ { US"sha1", HASH_SHA1 },
+ { US"sha256", HASH_SHA2_256 },
+ { US"sha512", HASH_SHA2_512 }
};
-const char *pdkim_keytypes[] = {
- "rsa",
- NULL
+
+const uschar * pdkim_keytypes[] = {
+ [KEYTYPE_RSA] = US"rsa",
+#ifdef SIGN_HAVE_ED25519
+ [KEYTYPE_ED25519] = US"ed25519", /* Works for 3.6.0 GnuTLS, OpenSSL 1.1.1 */
+#endif
+
+#ifdef notyet_EC_dkim_extensions /* https://tools.ietf.org/html/draft-srose-dkim-ecc-00 */
+ US"eccp256",
+ US"eccp348",
+ US"ed448",
+#endif
};
typedef struct pdkim_combined_canon_entry {
- const char *str;
- int canon_headers;
- int canon_body;
+ const uschar * str;
+ int canon_headers;
+ int canon_body;
} pdkim_combined_canon_entry;
+
pdkim_combined_canon_entry pdkim_combined_canons[] = {
- { "simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE },
- { "simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED },
- { "relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE },
- { "relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED },
- { "simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE },
- { "relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE },
- { NULL, 0, 0 }
+ { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE },
+ { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED },
+ { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE },
+ { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED },
+ { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE },
+ { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE },
+ { NULL, 0, 0 }
};
-const char *pdkim_verify_status_str(int status) {
- switch(status) {
- case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE";
- case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID";
- case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL";
- case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS";
- default: return "PDKIM_VERIFY_UNKNOWN";
- }
-}
-const char *pdkim_verify_ext_status_str(int ext_status) {
- switch(ext_status) {
- case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY";
- case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE";
- case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE";
- case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
- case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: return "PDKIM_VERIFY_INVALID_PUBKEY_PARSING";
- default: return "PDKIM_VERIFY_UNKNOWN";
- }
-}
-
+static const blob lineending = {.data = US"\r\n", .len = 2};
/* -------------------------------------------------------------------------- */
-/* Print debugging functions */
-void
-pdkim_quoteprint(const char *data, int len, int lf)
+uschar *
+dkim_sig_to_a_tag(const pdkim_signature * sig)
{
-int i;
-const unsigned char *p = (const unsigned char *)data;
-
-for (i = 0; i < len; i++)
- {
- const int c = p[i];
- switch (c)
- {
- case ' ' : debug_printf("{SP}"); break;
- case '\t': debug_printf("{TB}"); break;
- case '\r': debug_printf("{CR}"); break;
- case '\n': debug_printf("{LF}"); break;
- case '{' : debug_printf("{BO}"); break;
- case '}' : debug_printf("{BC}"); break;
- default:
- if ( (c < 32) || (c > 127) )
- debug_printf("{%02x}", c);
- else
- debug_printf("%c", c);
- break;
- }
- }
-if (lf)
- debug_printf("\n");
+if ( sig->keytype < 0 || sig->keytype > nelem(pdkim_keytypes)
+ || sig->hashtype < 0 || sig->hashtype > nelem(pdkim_hashes))
+ return US"err";
+return string_sprintf("%s-%s",
+ pdkim_keytypes[sig->keytype], pdkim_hashes[sig->hashtype].dkim_hashname);
}
-void
-pdkim_hexprint(const char *data, int len, int lf)
-{
-int i;
-const unsigned char *p = (const unsigned char *)data;
-for (i = 0 ; i < len; i++)
- debug_printf("%02x", p[i]);
-if (lf)
- debug_printf("\n");
+static int
+pdkim_keyname_to_keytype(const uschar * s)
+{
+for (int i = 0; i < nelem(pdkim_keytypes); i++)
+ if (Ustrcmp(s, pdkim_keytypes[i]) == 0) return i;
+return -1;
}
-
-/* -------------------------------------------------------------------------- */
-/* Simple string list implementation for convinience */
-pdkim_stringlist *
-pdkim_append_stringlist(pdkim_stringlist *base, char *str)
+int
+pdkim_hashname_to_hashtype(const uschar * s, unsigned len)
{
-pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
-
-if (!new_entry) return NULL;
-memset(new_entry, 0, sizeof(pdkim_stringlist));
-if (!(new_entry->value = strdup(str))) return NULL;
-if (base)
- {
- pdkim_stringlist *last = base;
- while (last->next != NULL) { last = last->next; }
- last->next = new_entry;
- return base;
- }
-else
- return new_entry;
+if (!len) len = Ustrlen(s);
+for (int i = 0; i < nelem(pdkim_hashes); i++)
+ if (Ustrncmp(s, pdkim_hashes[i].dkim_hashname, len) == 0)
+ return i;
+return -1;
}
-pdkim_stringlist *
-pdkim_prepend_stringlist(pdkim_stringlist *base, char *str)
+void
+pdkim_cstring_to_canons(const uschar * s, unsigned len,
+ int * canon_head, int * canon_body)
{
-pdkim_stringlist *new_entry = malloc(sizeof(pdkim_stringlist));
-
-if (!new_entry) return NULL;
-memset(new_entry, 0, sizeof(pdkim_stringlist));
-if (!(new_entry->value = strdup(str))) return NULL;
-if (base)
- new_entry->next = base;
-return new_entry;
+if (!len) len = Ustrlen(s);
+for (int i = 0; pdkim_combined_canons[i].str; i++)
+ if ( Ustrncmp(s, pdkim_combined_canons[i].str, len) == 0
+ && len == Ustrlen(pdkim_combined_canons[i].str))
+ {
+ *canon_head = pdkim_combined_canons[i].canon_headers;
+ *canon_body = pdkim_combined_canons[i].canon_body;
+ break;
+ }
}
-/* -------------------------------------------------------------------------- */
-/* A small "growing string" implementation to escape malloc/realloc hell */
-pdkim_str *
-pdkim_strnew (const char *cstr)
+const char *
+pdkim_verify_status_str(int status)
{
-unsigned int len = cstr ? strlen(cstr) : 0;
-pdkim_str *p = malloc(sizeof(pdkim_str));
-
-if (!p) return NULL;
-memset(p, 0, sizeof(pdkim_str));
-if (!(p->str = malloc(len+1)))
+switch(status)
{
- free(p);
- return NULL;
+ case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE";
+ case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID";
+ case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL";
+ case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS";
+ default: return "PDKIM_VERIFY_UNKNOWN";
}
-p->allocated = len+1;
-p->len = len;
-if (cstr)
- strcpy(p->str, cstr);
-else
- p->str[p->len] = '\0';
-return p;
}
-char *
-pdkim_strncat(pdkim_str *str, const char *data, int len)
+const char *
+pdkim_verify_ext_status_str(int ext_status)
{
-if ((str->allocated - str->len) < (len+1))
+switch(ext_status)
{
- /* Extend the buffer */
- int num_frags = ((len+1)/PDKIM_STR_ALLOC_FRAG)+1;
- char *n = realloc(str->str,
- (str->allocated+(num_frags*PDKIM_STR_ALLOC_FRAG)));
- if (n == NULL) return NULL;
- str->str = n;
- str->allocated += (num_frags*PDKIM_STR_ALLOC_FRAG);
+ case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY";
+ case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE";
+ case PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH: return "PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH";
+ case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE";
+ case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
+ case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD";
+ case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT";
+ case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: return "PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE";
+ case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR";
+ case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION";
+ default: return "PDKIM_VERIFY_UNKNOWN";
}
-strncpy(&(str->str[str->len]), data, len);
-str->len += len;
-str->str[str->len] = '\0';
-return str->str;
}
-char *
-pdkim_strcat(pdkim_str *str, const char *cstr)
+const uschar *
+pdkim_errstr(int status)
{
-return pdkim_strncat(str, cstr, strlen(cstr));
+switch(status)
+ {
+ case PDKIM_OK: return US"OK";
+ case PDKIM_FAIL: return US"FAIL";
+ case PDKIM_ERR_RSA_PRIVKEY: return US"PRIVKEY";
+ case PDKIM_ERR_RSA_SIGNING: return US"SIGNING";
+ case PDKIM_ERR_LONG_LINE: return US"LONG_LINE";
+ case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL";
+ case PDKIM_ERR_EXCESS_SIGS: return US"EXCESS_SIGS";
+ case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP";
+ case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D";
+ default: return US"(unknown)";
+ }
}
-char *
-pdkim_numcat(pdkim_str *str, unsigned long num)
-{
-char minibuf[20];
-snprintf(minibuf, 20, "%lu", num);
-return pdkim_strcat(str, minibuf);
-}
-char *
-pdkim_strtrim(pdkim_str *str)
+/* -------------------------------------------------------------------------- */
+/* Print debugging functions */
+void
+pdkim_quoteprint(const uschar *data, int len)
{
-char *p = str->str;
-char *q = str->str;
-while ( (*p != '\0') && ((*p == '\t') || (*p == ' ')) ) p++;
-while (*p != '\0') {*q = *p; q++; p++;}
-*q = '\0';
-while ( (q != str->str) && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) )
+for (int i = 0; i < len; i++)
{
- *q = '\0';
- q--;
+ const int c = data[i];
+ switch (c)
+ {
+ case ' ' : debug_printf("{SP}"); break;
+ case '\t': debug_printf("{TB}"); break;
+ case '\r': debug_printf("{CR}"); break;
+ case '\n': debug_printf("{LF}"); break;
+ case '{' : debug_printf("{BO}"); break;
+ case '}' : debug_printf("{BC}"); break;
+ default:
+ if ( (c < 32) || (c > 127) )
+ debug_printf("{%02x}", c);
+ else
+ debug_printf("%c", c);
+ break;
+ }
}
-str->len = strlen(str->str);
-return str->str;
-}
-
-char *
-pdkim_strclear(pdkim_str *str)
-{
-str->str[0] = '\0';
-str->len = 0;
-return str->str;
+debug_printf("\n");
}
void
-pdkim_strfree(pdkim_str *str)
+pdkim_hexprint(const uschar *data, int len)
{
-if (!str) return;
-if (str->str) free(str->str);
-free(str);
+if (data) for (int i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+else debug_printf("<NULL>");
+debug_printf("\n");
}
-/* -------------------------------------------------------------------------- */
-
-void
-pdkim_free_pubkey(pdkim_pubkey *pub)
+static pdkim_stringlist *
+pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str)
{
-if (pub)
- {
- if (pub->version ) free(pub->version);
- if (pub->granularity) free(pub->granularity);
- if (pub->hashes ) free(pub->hashes);
- if (pub->keytype ) free(pub->keytype);
- if (pub->srvtype ) free(pub->srvtype);
- if (pub->notes ) free(pub->notes);
- if (pub->key ) free(pub->key);
- free(pub);
- }
+pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), GET_UNTAINTED);
+
+memset(new_entry, 0, sizeof(pdkim_stringlist));
+new_entry->value = string_copy(str);
+if (base) new_entry->next = base;
+return new_entry;
}
-/* -------------------------------------------------------------------------- */
-void
-pdkim_free_sig(pdkim_signature *sig)
+/* Trim whitespace fore & aft */
+
+static void
+pdkim_strtrim(gstring * str)
{
-if (sig)
- {
- pdkim_signature *next = (pdkim_signature *)sig->next;
+uschar * p = str->s;
+uschar * q;
- pdkim_stringlist *e = sig->headers;
- while(e)
- {
- pdkim_stringlist *c = e;
- if (e->value) free(e->value);
- e = e->next;
- free(c);
- }
+while (*p == '\t' || *p == ' ') /* dump the leading whitespace */
+ { str->size--; str->ptr--; str->s++; }
- if (sig->sigdata ) free(sig->sigdata);
- if (sig->bodyhash ) free(sig->bodyhash);
- if (sig->selector ) free(sig->selector);
- if (sig->domain ) free(sig->domain);
- if (sig->identity ) free(sig->identity);
- if (sig->headernames ) free(sig->headernames);
- if (sig->copiedheaders ) free(sig->copiedheaders);
- if (sig->rsa_privkey ) free(sig->rsa_privkey);
- if (sig->sign_headers ) free(sig->sign_headers);
- if (sig->signature_header) free(sig->signature_header);
- if (sig->sha1_body ) free(sig->sha1_body);
- if (sig->sha2_body ) free(sig->sha2_body);
-
- if (sig->pubkey) pdkim_free_pubkey(sig->pubkey);
-
- free(sig);
- if (next) pdkim_free_sig(next);
- }
+while ( str->ptr > 0
+ && ((q = str->s + str->ptr - 1), (*q == '\t' || *q == ' '))
+ )
+ str->ptr--; /* dump trailing whitespace */
+
+(void) string_from_gstring(str);
}
+
/* -------------------------------------------------------------------------- */
DLLEXPORT void
pdkim_free_ctx(pdkim_ctx *ctx)
{
-if (ctx)
- {
- pdkim_stringlist *e = ctx->headers;
- while(e)
- {
- pdkim_stringlist *c = e;
- if (e->value) free(e->value);
- e = e->next;
- free(c);
- }
- pdkim_free_sig(ctx->sig);
- pdkim_strfree(ctx->cur_header);
- free(ctx);
- }
}
/* -------------------------------------------------------------------------- */
/* Matches the name of the passed raw "header" against
- the passed colon-separated "list", starting at entry
- "start". Returns the position of the header name in
- the list. */
+ the passed colon-separated "tick", and invalidates
+ the entry in tick. Entries can be prefixed for multi- or over-signing,
+ in which case do not invalidate.
-int
-header_name_match(const char *header,
- char *tick,
- int do_tick)
-{
-char *hname;
-char *lcopy;
-char *p;
-char *q;
-int rc = PDKIM_FAIL;
+ Returns OK for a match, or fail-code
+*/
-/* Get header name */
-char *hcolon = strchr(header, ':');
+static int
+header_name_match(const uschar * header, uschar * tick)
+{
+const uschar * ticklist = tick;
+int sep = ':';
+BOOL multisign;
+uschar * hname, * p, * ele;
+uschar * hcolon = Ustrchr(header, ':'); /* Get header name */
-if (!hcolon) return rc; /* This isn't a header */
+if (!hcolon)
+ return PDKIM_FAIL; /* This isn't a header */
-if (!(hname = malloc((hcolon-header)+1)))
- return PDKIM_ERR_OOM;
-memset(hname, 0, (hcolon-header)+1);
-strncpy(hname, header, (hcolon-header));
+/* if we had strncmpic() we wouldn't need this copy */
+hname = string_copyn(header, hcolon-header);
-/* Copy tick-off list locally, so we can punch zeroes into it */
-if (!(lcopy = strdup(tick)))
+while (p = US ticklist, ele = string_nextinlist(&ticklist, &sep, NULL, 0))
{
- free(hname);
- return PDKIM_ERR_OOM;
- }
-p = lcopy;
-q = strchr(p, ':');
-while (q)
+ switch (*ele)
{
- *q = '\0';
+ case '=': case '+': multisign = TRUE; ele++; break;
+ default: multisign = FALSE; break;
+ }
- if (strcasecmp(p, hname) == 0)
+ if (strcmpic(ele, hname) == 0)
{
- rc = PDKIM_OK;
- /* Invalidate header name instance in tick-off list */
- if (do_tick) tick[p-lcopy] = '_';
- goto BAIL;
+ if (!multisign)
+ *p = '_'; /* Invalidate this header name instance in tick-off list */
+ return PDKIM_OK;
}
-
- p = q+1;
- q = strchr(p, ':');
- }
-
-if (strcasecmp(p, hname) == 0)
- {
- rc = PDKIM_OK;
- /* Invalidate header name instance in tick-off list */
- if (do_tick) tick[p-lcopy] = '_';
}
-
-BAIL:
-free(hname);
-free(lcopy);
-return rc;
+return PDKIM_FAIL;
}
/* -------------------------------------------------------------------------- */
-/* Performs "relaxed" canonicalization of a header. The returned pointer needs
- to be free()d. */
+/* Performs "relaxed" canonicalization of a header. */
-char *
-pdkim_relax_header (char *header, int crlf)
+uschar *
+pdkim_relax_header_n(const uschar * header, int len, BOOL append_crlf)
{
BOOL past_field_name = FALSE;
BOOL seen_wsp = FALSE;
-char *p;
-char *q;
-char *relaxed = malloc(strlen(header)+3);
+uschar * relaxed = store_get(len+3, GET_TAINTED);
+uschar * q = relaxed;
-if (!relaxed) return NULL;
-
-q = relaxed;
-for (p = header; *p != '\0'; p++)
+for (const uschar * p = header; p - header < len; p++)
{
- int c = *p;
- /* Ignore CR & LF */
- if (c == '\r' || c == '\n')
+ uschar c = *p;
+
+ if (c == '\r' || c == '\n') /* Ignore CR & LF */
continue;
if (c == '\t' || c == ' ')
{
else
if (!past_field_name && c == ':')
{
- if (seen_wsp) q--; /* This removes WSP before the colon */
- seen_wsp = TRUE; /* This removes WSP after the colon */
+ if (seen_wsp) q--; /* This removes WSP immediately before the colon */
+ seen_wsp = TRUE; /* This removes WSP immediately after the colon */
past_field_name = TRUE;
}
else
}
if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */
-*q = '\0';
-if (crlf) strcat(relaxed, "\r\n");
+if (append_crlf) { *q++ = '\r'; *q++ = '\n'; }
+*q = '\0';
return relaxed;
}
+uschar *
+pdkim_relax_header(const uschar * header, BOOL append_crlf)
+{
+return pdkim_relax_header_n(header, Ustrlen(header), append_crlf);
+}
+
+
/* -------------------------------------------------------------------------- */
#define PDKIM_QP_ERROR_DECODE -1
-static char *
-pdkim_decode_qp_char(char *qp_p, int *c)
+static const uschar *
+pdkim_decode_qp_char(const uschar *qp_p, int *c)
{
-char *initial_pos = qp_p;
+const uschar *initial_pos = qp_p;
/* Advance one char */
qp_p++;
/* -------------------------------------------------------------------------- */
-char *
-pdkim_decode_qp(char *str)
+static uschar *
+pdkim_decode_qp(const uschar * str)
{
int nchar = 0;
-char *q;
-char *p = str;
-char *n = malloc(strlen(p)+1);
-
-if (!n) return NULL;
+uschar * q;
+const uschar * p = str;
+uschar * n = store_get(Ustrlen(str)+1, GET_TAINTED);
*n = '\0';
q = n;
-while (*p != '\0')
+while (*p)
{
if (*p == '=')
{
/* -------------------------------------------------------------------------- */
-char *
-pdkim_decode_base64(char *str, int *num_decoded)
+void
+pdkim_decode_base64(const uschar * str, blob * b)
{
-int dlen = 0;
-char *res;
-
-base64_decode(NULL, &dlen, (unsigned char *)str, strlen(str));
-
-if (!(res = malloc(dlen+1)))
- return NULL;
-if (base64_decode((unsigned char *)res, &dlen, (unsigned char *)str, strlen(str)) != 0)
- {
- free(res);
- return NULL;
- }
-
-if (num_decoded) *num_decoded = dlen;
-return res;
+int dlen = b64decode(str, &b->data, str);
+if (dlen < 0) b->data = NULL;
+b->len = dlen;
}
-
-/* -------------------------------------------------------------------------- */
-
-char *
-pdkim_encode_base64(char *str, int num)
+uschar *
+pdkim_encode_base64(blob * b)
{
-int dlen = 0;
-char *res;
-
-base64_encode(NULL, &dlen, (unsigned char *)str, num);
-
-if (!(res = malloc(dlen+1)))
- return NULL;
-if (base64_encode((unsigned char *)res, &dlen, (unsigned char *)str, num) != 0)
- {
- free(res);
- return NULL;
- }
-return res;
+return b64encode(CUS b->data, b->len);
}
#define PDKIM_HDR_TAG 1
#define PDKIM_HDR_VALUE 2
-pdkim_signature *
-pdkim_parse_sig_header(pdkim_ctx *ctx, char *raw_hdr)
+static pdkim_signature *
+pdkim_parse_sig_header(pdkim_ctx * ctx, uschar * raw_hdr)
{
-pdkim_signature *sig ;
-char *p, *q;
-pdkim_str *cur_tag = NULL;
-pdkim_str *cur_val = NULL;
+pdkim_signature * sig;
+uschar *q;
+gstring * cur_tag = NULL;
+gstring * cur_val = NULL;
BOOL past_hname = FALSE;
BOOL in_b_val = FALSE;
int where = PDKIM_HDR_LIMBO;
-int i;
-if (!(sig = malloc(sizeof(pdkim_signature)))) return NULL;
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
memset(sig, 0, sizeof(pdkim_signature));
sig->bodylength = -1;
-if (!(sig->rawsig_no_b_val = malloc(strlen(raw_hdr)+1)))
- {
- free(sig);
- return NULL;
- }
+/* Set so invalid/missing data error display is accurate */
+sig->version = 0;
+sig->keytype = -1;
+sig->hashtype = -1;
-q = sig->rawsig_no_b_val;
+q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, GET_TAINTED);
-for (p = raw_hdr; ; p++)
+for (uschar * p = raw_hdr; ; p++)
{
char c = *p;
if (where == PDKIM_HDR_TAG)
{
- if (!cur_tag)
- cur_tag = pdkim_strnew(NULL);
-
if (c >= 'a' && c <= 'z')
- pdkim_strncat(cur_tag, p, 1);
+ cur_tag = string_catn(cur_tag, p, 1);
if (c == '=')
{
- if (strcmp(cur_tag->str, "b") == 0)
+ if (Ustrcmp(string_from_gstring(cur_tag), "b") == 0)
{
- *q = '='; q++;
+ *q++ = '=';
in_b_val = TRUE;
}
where = PDKIM_HDR_VALUE;
if (where == PDKIM_HDR_VALUE)
{
- if (!cur_val)
- cur_val = pdkim_strnew(NULL);
-
if (c == '\r' || c == '\n' || c == ' ' || c == '\t')
goto NEXT_CHAR;
if (c == ';' || c == '\0')
{
- if (cur_tag->len > 0)
+ /* We must have both tag and value, and tags must be one char except
+ for the possibility of "bh". */
+
+ if ( cur_tag && cur_val
+ && (cur_tag->ptr == 1 || *cur_tag->s == 'b')
+ )
{
+ (void) string_from_gstring(cur_val);
pdkim_strtrim(cur_val);
- DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->str, cur_val->str);
+ DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->s, cur_val->s);
- switch (cur_tag->str[0])
+ switch (*cur_tag->s)
{
- case 'b':
- if (cur_tag->str[1] == 'h')
- sig->bodyhash = pdkim_decode_base64(cur_val->str,
- &sig->bodyhash_len);
- else
- sig->sigdata = pdkim_decode_base64(cur_val->str,
- &sig->sigdata_len);
+ case 'b': /* sig-data or body-hash */
+ switch (cur_tag->s[1])
+ {
+ case '\0': pdkim_decode_base64(cur_val->s, &sig->sighash); break;
+ case 'h': if (cur_tag->ptr == 2)
+ pdkim_decode_base64(cur_val->s, &sig->bodyhash);
+ break;
+ default: break;
+ }
break;
- case 'v':
+ case 'v': /* version */
/* We only support version 1, and that is currently the
only version there is. */
- if (strcmp(cur_val->str, PDKIM_SIGNATURE_VERSION) == 0)
- sig->version = 1;
- break;
- case 'a':
- for (i = 0; pdkim_algos[i]; i++)
- if (strcmp(cur_val->str, pdkim_algos[i]) == 0)
- {
- sig->algo = i;
- break;
- }
+ sig->version =
+ Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1;
break;
- case 'c':
- for (i = 0; pdkim_combined_canons[i].str; i++)
- if (strcmp(cur_val->str, pdkim_combined_canons[i].str) == 0)
- {
- sig->canon_headers = pdkim_combined_canons[i].canon_headers;
- sig->canon_body = pdkim_combined_canons[i].canon_body;
- break;
- }
+ case 'a': /* algorithm */
+ {
+ const uschar * list = cur_val->s;
+ int sep = '-';
+ uschar * elem;
+
+ if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+ sig->keytype = pdkim_keyname_to_keytype(elem);
+ if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+ for (int i = 0; i < nelem(pdkim_hashes); i++)
+ if (Ustrcmp(elem, pdkim_hashes[i].dkim_hashname) == 0)
+ { sig->hashtype = i; break; }
+ }
+
+ case 'c': /* canonicalization */
+ pdkim_cstring_to_canons(cur_val->s, 0,
+ &sig->canon_headers, &sig->canon_body);
break;
- case 'q':
- for (i = 0; pdkim_querymethods[i]; i++)
- if (strcmp(cur_val->str, pdkim_querymethods[i]) == 0)
+ case 'q': /* Query method (for pubkey)*/
+ for (int i = 0; pdkim_querymethods[i]; i++)
+ if (Ustrcmp(cur_val->s, pdkim_querymethods[i]) == 0)
{
- sig->querymethod = i;
+ sig->querymethod = i; /* we never actually use this */
break;
}
break;
- case 's':
- sig->selector = strdup(cur_val->str); break;
- case 'd':
- sig->domain = strdup(cur_val->str); break;
- case 'i':
- sig->identity = pdkim_decode_qp(cur_val->str); break;
- case 't':
- sig->created = strtoul(cur_val->str, NULL, 10); break;
- case 'x':
- sig->expires = strtoul(cur_val->str, NULL, 10); break;
- case 'l':
- sig->bodylength = strtol(cur_val->str, NULL, 10); break;
- case 'h':
- sig->headernames = strdup(cur_val->str); break;
- case 'z':
- sig->copiedheaders = pdkim_decode_qp(cur_val->str); break;
+ case 's': /* Selector */
+ sig->selector = string_copyn(cur_val->s, cur_val->ptr); break;
+ case 'd': /* SDID */
+ sig->domain = string_copyn(cur_val->s, cur_val->ptr); break;
+ case 'i': /* AUID */
+ sig->identity = pdkim_decode_qp(cur_val->s); break;
+ case 't': /* Timestamp */
+ sig->created = strtoul(CS cur_val->s, NULL, 10); break;
+ case 'x': /* Expiration */
+ sig->expires = strtoul(CS cur_val->s, NULL, 10); break;
+ case 'l': /* Body length count */
+ sig->bodylength = strtol(CS cur_val->s, NULL, 10); break;
+ case 'h': /* signed header fields */
+ sig->headernames = string_copyn(cur_val->s, cur_val->ptr); break;
+ case 'z': /* Copied headfields */
+ sig->copiedheaders = pdkim_decode_qp(cur_val->s); break;
+/*XXX draft-ietf-dcrup-dkim-crypto-05 would need 'p' tag support
+for rsafp signatures. But later discussion is dropping those. */
default:
DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
break;
}
}
- pdkim_strclear(cur_tag);
- pdkim_strclear(cur_val);
+ cur_tag = cur_val = NULL;
in_b_val = FALSE;
where = PDKIM_HDR_LIMBO;
}
else
- pdkim_strncat(cur_val, p, 1);
+ cur_val = string_catn(cur_val, p, 1);
}
NEXT_CHAR:
*q++ = c;
}
-/* Make sure the most important bits are there. */
-if (!(sig->domain && (*(sig->domain) != '\0') &&
- sig->selector && (*(sig->selector) != '\0') &&
- sig->headernames && (*(sig->headernames) != '\0') &&
- sig->bodyhash &&
- sig->sigdata &&
- sig->version))
- {
- pdkim_free_sig(sig);
+if (sig->keytype < 0 || sig->hashtype < 0) /* Cannot verify this signature */
return NULL;
- }
*q = '\0';
/* Chomp raw header. The final newline must not be added to the signature. */
-q--;
-while (q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n'))
- *q = '\0'; q--; /*XXX questionable code layout; possible bug */
+while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n'))
+ *q = '\0';
DEBUG(D_acl)
{
debug_printf(
- "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
- pdkim_quoteprint(sig->rawsig_no_b_val, strlen(sig->rawsig_no_b_val), 1);
+ "DKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ pdkim_quoteprint(US sig->rawsig_no_b_val, Ustrlen(sig->rawsig_no_b_val));
debug_printf(
- "PDKIM >> Sig size: %4d bits\n", sig->sigdata_len*8);
+ "DKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8);
debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-if ( !(sig->sha1_body = malloc(sizeof(sha1_context)))
- || !(sig->sha2_body = malloc(sizeof(sha2_context)))
- )
- {
- pdkim_free_sig(sig);
+if (!pdkim_set_sig_bodyhash(ctx, sig))
return NULL;
- }
-
-sha1_starts(sig->sha1_body);
-sha2_starts(sig->sha2_body, 0);
return sig;
}
/* -------------------------------------------------------------------------- */
pdkim_pubkey *
-pdkim_parse_pubkey_record(pdkim_ctx *ctx, char *raw_record)
+pdkim_parse_pubkey_record(const uschar *raw_record)
{
-pdkim_pubkey *pub;
-char *p;
-pdkim_str *cur_tag = NULL;
-pdkim_str *cur_val = NULL;
-int where = PDKIM_HDR_LIMBO;
+const uschar * ele;
+int sep = ';';
+pdkim_pubkey * pub;
-if (!(pub = malloc(sizeof(pdkim_pubkey)))) return NULL;
+pub = store_get(sizeof(pdkim_pubkey), GET_TAINTED);
memset(pub, 0, sizeof(pdkim_pubkey));
-for (p = raw_record; ; p++)
+while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
{
- char c = *p;
-
- /* Ignore FWS */
- if (c == '\r' || c == '\n')
- goto NEXT_CHAR;
-
- if (where == PDKIM_HDR_LIMBO)
- {
- /* In limbo, just wait for a tag-char to appear */
- if (!(c >= 'a' && c <= 'z'))
- goto NEXT_CHAR;
-
- where = PDKIM_HDR_TAG;
- }
-
- if (where == PDKIM_HDR_TAG)
- {
- if (!cur_tag)
- cur_tag = pdkim_strnew(NULL);
-
- if (c >= 'a' && c <= 'z')
- pdkim_strncat(cur_tag, p, 1);
+ const uschar * val;
- if (c == '=')
- {
- where = PDKIM_HDR_VALUE;
- goto NEXT_CHAR;
- }
- }
-
- if (where == PDKIM_HDR_VALUE)
+ if ((val = Ustrchr(ele, '=')))
{
- if (!cur_val)
- cur_val = pdkim_strnew(NULL);
+ int taglen = val++ - ele;
- if (c == '\r' || c == '\n')
- goto NEXT_CHAR;
-
- if (c == ';' || c == '\0')
+ DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val);
+ switch (ele[0])
{
- if (cur_tag->len > 0)
- {
- pdkim_strtrim(cur_val);
- DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->str, cur_val->str);
-
- switch (cur_tag->str[0])
- {
- case 'v':
- /* This tag isn't evaluated because:
- - We only support version DKIM1.
- - Which is the default for this value (set below)
- - Other versions are currently not specified. */
- break;
- case 'h':
- pub->hashes = strdup(cur_val->str); break;
- case 'g':
- pub->granularity = strdup(cur_val->str); break;
- case 'n':
- pub->notes = pdkim_decode_qp(cur_val->str); break;
- case 'p':
- pub->key = pdkim_decode_base64(cur_val->str, &(pub->key_len)); break;
- case 'k':
- pub->hashes = strdup(cur_val->str); break;
- case 's':
- pub->srvtype = strdup(cur_val->str); break;
- case 't':
- if (strchr(cur_val->str, 'y') != NULL) pub->testing = 1;
- if (strchr(cur_val->str, 's') != NULL) pub->no_subdomaining = 1;
- break;
- default:
- DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
- break;
- }
- }
- pdkim_strclear(cur_tag);
- pdkim_strclear(cur_val);
- where = PDKIM_HDR_LIMBO;
+ case 'v': pub->version = val; break;
+ case 'h': pub->hashes = val; break;
+ case 'k': pub->keytype = val; break;
+ case 'g': pub->granularity = val; break;
+ case 'n': pub->notes = pdkim_decode_qp(val); break;
+ case 'p': pdkim_decode_base64(val, &pub->key); break;
+ case 's': pub->srvtype = val; break;
+ case 't': if (Ustrchr(val, 'y')) pub->testing = 1;
+ if (Ustrchr(val, 's')) pub->no_subdomaining = 1;
+ break;
+ default: DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); break;
}
- else
- pdkim_strncat(cur_val, p, 1);
}
-
-NEXT_CHAR:
- if (c == '\0') break;
}
/* Set fallback defaults */
-if (!pub->version ) pub->version = strdup(PDKIM_PUB_RECORD_VERSION);
-if (!pub->granularity) pub->granularity = strdup("*");
-if (!pub->keytype ) pub->keytype = strdup("rsa");
-if (!pub->srvtype ) pub->srvtype = strdup("*");
+if (!pub->version)
+ pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
+else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0)
+ {
+ DEBUG(D_acl) debug_printf(" Bad v= field\n");
+ return NULL;
+ }
+
+if (!pub->granularity) pub->granularity = US"*";
+if (!pub->keytype ) pub->keytype = US"rsa";
+if (!pub->srvtype ) pub->srvtype = US"*";
/* p= is required */
-if (pub->key)
+if (pub->key.data)
return pub;
-pdkim_free_pubkey(pub);
+DEBUG(D_acl) debug_printf(" Missing p= field\n");
return NULL;
}
/* -------------------------------------------------------------------------- */
-int
-pdkim_update_bodyhash(pdkim_ctx *ctx, const char *data, int len)
+/* Update one bodyhash with some additional data.
+If we have to relax the data for this sig, return our copy of it. */
+
+static blob *
+pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, const blob * orig_data, blob * relaxed_data)
{
-pdkim_signature *sig = ctx->sig;
-/* Cache relaxed version of data */
-char *relaxed_data = NULL;
-int relaxed_len = 0;
+const blob * canon_data = orig_data;
+size_t left;
-/* Traverse all signatures, updating their hashes. */
-while (sig)
- {
- /* Defaults to simple canon (no further treatment necessary) */
- const char *canon_data = data;
- int canon_len = len;
+/* Defaults to simple canon (no further treatment necessary) */
- if (sig->canon_body == PDKIM_CANON_RELAXED)
+if (b->canon_method == PDKIM_CANON_RELAXED)
+ {
+ /* Relax the line if not done already */
+ if (!relaxed_data)
{
- /* Relax the line if not done already */
- if (!relaxed_data)
- {
- BOOL seen_wsp = FALSE;
- const char *p;
- int q = 0;
+ BOOL seen_wsp = FALSE;
+ int q = 0;
- if (!(relaxed_data = malloc(len+1)))
- return PDKIM_ERR_OOM;
+ /* We want to be able to free this else we allocate
+ for the entire message which could be many MB. Since
+ we don't know what allocations the SHA routines might
+ do, not safe to use store_get()/store_reset(). */
- for (p = data; *p; p++)
- {
- char c = *p;
- if (c == '\r')
- {
- if (q > 0 && relaxed_data[q-1] == ' ')
- q--;
- }
- else if (c == '\t' || c == ' ')
- {
- c = ' '; /* Turns WSP into SP */
- if (seen_wsp)
- continue;
- seen_wsp = TRUE;
- }
- else
- seen_wsp = FALSE;
- relaxed_data[q++] = c;
+ relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1);
+ relaxed_data->data = US (relaxed_data+1);
+
+ for (const uschar * p = orig_data->data, * r = p + orig_data->len; p < r; p++)
+ {
+ char c = *p;
+ if (c == '\r')
+ {
+ if (q > 0 && relaxed_data->data[q-1] == ' ')
+ q--;
}
- relaxed_data[q] = '\0';
- relaxed_len = q;
+ else if (c == '\t' || c == ' ')
+ {
+ c = ' '; /* Turns WSP into SP */
+ if (seen_wsp)
+ continue;
+ seen_wsp = TRUE;
+ }
+ else
+ seen_wsp = FALSE;
+ relaxed_data->data[q++] = c;
}
- canon_data = relaxed_data;
- canon_len = relaxed_len;
+ relaxed_data->data[q] = '\0';
+ relaxed_data->len = q;
}
+ canon_data = relaxed_data;
+ }
- /* Make sure we don't exceed the to-be-signed body length */
- if ( sig->bodylength >= 0
- && sig->signed_body_bytes + (unsigned long)canon_len > sig->bodylength
- )
- canon_len = sig->bodylength - sig->signed_body_bytes;
-
- if (canon_len > 0)
- {
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- sha1_update(sig->sha1_body, (unsigned char *)canon_data, canon_len);
- else
- sha2_update(sig->sha2_body, (unsigned char *)canon_data, canon_len);
-
- sig->signed_body_bytes += canon_len;
- DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len, 1);
- }
+/* Make sure we don't exceed the to-be-signed body length */
+left = canon_data->len;
+if ( b->bodylength >= 0
+ && left > (unsigned long)b->bodylength - b->signed_body_bytes
+ )
+ left = (unsigned long)b->bodylength - b->signed_body_bytes;
- sig = sig->next;
+if (left > 0)
+ {
+ exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, left);
+ b->signed_body_bytes += left;
+ DEBUG(D_acl) pdkim_quoteprint(canon_data->data, left);
}
-if (relaxed_data) free(relaxed_data);
-return PDKIM_OK;
+return relaxed_data;
}
/* -------------------------------------------------------------------------- */
-int
-pdkim_finish_bodyhash(pdkim_ctx *ctx)
+static void
+pdkim_finish_bodyhash(pdkim_ctx * ctx)
{
-pdkim_signature *sig = ctx->sig;
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) /* Finish hashes */
+ {
+ DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %s/%s/%ld len %ld\n",
+ pdkim_hashes[b->hashtype].dkim_hashname, pdkim_canons[b->canon_method],
+ b->bodylength, b->signed_body_bytes);
+ exim_sha_finish(&b->body_hash_ctx, &b->bh);
+ }
/* Traverse all signatures */
-while (sig)
- { /* Finish hashes */
- unsigned char bh[32]; /* SHA-256 = 32 Bytes, SHA-1 = 20 Bytes */
-
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- sha1_finish(sig->sha1_body, bh);
- else
- sha2_finish(sig->sha2_body, bh);
+for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)
+ {
+ pdkim_bodyhash * b = sig->calc_body_hash;
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] Body bytes hashed: %lu\n"
- "PDKIM [%s] bh computed: ",
- sig->domain, sig->signed_body_bytes, sig->domain);
- pdkim_hexprint((char *)bh, sig->algo == PDKIM_ALGO_RSA_SHA1 ? 20 : 32, 1);
+ debug_printf("DKIM [%s]%s Body bytes (%s) hashed: %lu\n"
+ "DKIM [%s]%s Body %s computed: ",
+ sig->domain, sig->selector, pdkim_canons[b->canon_method], b->signed_body_bytes,
+ sig->domain, sig->selector, pdkim_hashes[b->hashtype].dkim_hashname);
+ pdkim_hexprint(CUS b->bh.data, b->bh.len);
}
/* SIGNING -------------------------------------------------------------- */
- if (ctx->mode == PDKIM_MODE_SIGN)
+ if (ctx->flags & PDKIM_MODE_SIGN)
{
- sig->bodyhash_len = (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32;
-
- if (!(sig->bodyhash = malloc(sig->bodyhash_len)))
- return PDKIM_ERR_OOM;
- memcpy(sig->bodyhash, bh, sig->bodyhash_len);
-
/* If bodylength limit is set, and we have received less bytes
than the requested amount, effectively remove the limit tag. */
- if (sig->signed_body_bytes < sig->bodylength)
+ if (b->signed_body_bytes < sig->bodylength)
sig->bodylength = -1;
}
- /* VERIFICATION --------------------------------------------------------- */
else
- {
- /* Compare bodyhash */
- if (memcmp(bh, sig->bodyhash,
- (sig->algo == PDKIM_ALGO_RSA_SHA1)?20:32) == 0)
+ /* VERIFICATION --------------------------------------------------------- */
+ /* Be careful that the header sig included a bodyash */
+
+ if (sig->bodyhash.data && sig->bodyhash.len == b->bh.len
+ && memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0)
{
- DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain);
+ DEBUG(D_acl) debug_printf("DKIM [%s] Body hash compared OK\n", sig->domain);
}
else
{
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] bh signature: ", sig->domain);
- pdkim_hexprint(sig->bodyhash,
- sig->algo == PDKIM_ALGO_RSA_SHA1 ? 20 : 32, 1);
- debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain);
+ debug_printf("DKIM [%s] Body hash signature from headers: ", sig->domain);
+ pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len);
+ debug_printf("DKIM [%s] Body hash did NOT verify\n", sig->domain);
}
sig->verify_status = PDKIM_VERIFY_FAIL;
sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
}
- }
-
- sig = sig->next;
}
+}
-return PDKIM_OK;
+
+
+static void
+pdkim_body_complete(pdkim_ctx * ctx)
+{
+/* In simple body mode, if any empty lines were buffered,
+replace with one. rfc 4871 3.4.3 */
+/*XXX checking the signed-body-bytes is a gross hack; I think
+it indicates that all linebreaks should be buffered, including
+the one terminating a text line */
+
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+ if ( b->canon_method == PDKIM_CANON_SIMPLE
+ && b->signed_body_bytes == 0
+ && b->num_buffered_blanklines > 0
+ )
+ (void) pdkim_update_ctx_bodyhash(b, &lineending, NULL);
+
+ctx->flags |= PDKIM_SEEN_EOD;
+ctx->linebuf_offset = 0;
}
/* -------------------------------------------------------------------------- */
-/* Callback from pdkim_feed below for processing complete body lines */
+/* Call from pdkim_feed below for processing complete body lines */
+/* NOTE: the line is not NUL-terminated; but we have a count */
-static int
-pdkim_bodyline_complete(pdkim_ctx *ctx)
+static void
+pdkim_bodyline_complete(pdkim_ctx * ctx)
{
-char *p = ctx->linebuf;
-int n = ctx->linebuf_offset;
-pdkim_signature *sig = ctx->sig; /*XXX assumes only one sig */
+blob line = {.data = ctx->linebuf, .len = ctx->linebuf_offset};
+blob * rnl = NULL;
+blob * rline = NULL;
/* Ignore extra data if we've seen the end-of-data marker */
-if (ctx->seen_eod) goto BAIL;
+if (ctx->flags & PDKIM_SEEN_EOD) goto all_skip;
/* We've always got one extra byte to stuff a zero ... */
-ctx->linebuf[ctx->linebuf_offset] = '\0';
+ctx->linebuf[line.len] = '\0';
/* Terminate on EOD marker */
-if (memcmp(p, ".\r\n", 3) == 0)
+if (ctx->flags & PDKIM_DOT_TERM)
{
- /* In simple body mode, if any empty lines were buffered,
- replace with one. rfc 4871 3.4.3 */
- /*XXX checking the signed-body-bytes is a gross hack; I think
- it indicates that all linebreaks should be buffered, including
- the one terminating a text line */
- if ( sig && sig->canon_body == PDKIM_CANON_SIMPLE
- && sig->signed_body_bytes == 0
- && ctx->num_buffered_crlf > 0
- )
- pdkim_update_bodyhash(ctx, "\r\n", 2);
+ if (memcmp(line.data, ".\r\n", 3) == 0)
+ { pdkim_body_complete(ctx); return; }
- ctx->seen_eod = TRUE;
- goto BAIL;
- }
-/* Unstuff dots */
-if (memcmp(p, "..", 2) == 0)
- {
- p++;
- n--;
+ /* Unstuff dots */
+ if (memcmp(line.data, "..", 2) == 0)
+ { line.data++; line.len--; }
}
/* Empty lines need to be buffered until we find a non-empty line */
-if (memcmp(p, "\r\n", 2) == 0)
+if (memcmp(line.data, "\r\n", 2) == 0)
{
- ctx->num_buffered_crlf++;
- goto BAIL;
+ for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+ b->num_buffered_blanklines++;
+ goto all_skip;
}
-if (sig && sig->canon_body == PDKIM_CANON_RELAXED)
+/* Process line for each bodyhash separately */
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
{
- /* Lines with just spaces need to be buffered too */
- char *check = p;
- while (memcmp(check, "\r\n", 2) != 0)
+ if (b->canon_method == PDKIM_CANON_RELAXED)
{
- char c = *check;
+ /* Lines with just spaces need to be buffered too */
+ uschar * cp = line.data;
+ char c;
+
+ while ((c = *cp))
+ {
+ if (c == '\r' && cp[1] == '\n') break;
+ if (c != ' ' && c != '\t') goto hash_process;
+ cp++;
+ }
- if (c != '\t' && c != ' ')
- goto PROCESS;
- check++;
+ b->num_buffered_blanklines++;
+ goto hash_skip;
}
- ctx->num_buffered_crlf++;
- goto BAIL;
-}
+hash_process:
+ /* At this point, we have a non-empty line, so release the buffered ones. */
-PROCESS:
-/* At this point, we have a non-empty line, so release the buffered ones. */
-while (ctx->num_buffered_crlf)
- {
- pdkim_update_bodyhash(ctx, "\r\n", 2);
- ctx->num_buffered_crlf--;
+ while (b->num_buffered_blanklines)
+ {
+ rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
+ b->num_buffered_blanklines--;
+ }
+
+ rline = pdkim_update_ctx_bodyhash(b, &line, rline);
+hash_skip: ;
}
-pdkim_update_bodyhash(ctx, p, n);
+if (rnl) store_free(rnl);
+if (rline) store_free(rline);
+
+all_skip:
-BAIL:
ctx->linebuf_offset = 0;
-return PDKIM_OK;
+return;
}
/* Callback from pdkim_feed below for processing complete headers */
#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
-int
-pdkim_header_complete(pdkim_ctx *ctx)
+static int
+pdkim_header_complete(pdkim_ctx * ctx)
{
-/* Special case: The last header can have an extra \r appended */
-if ( (ctx->cur_header->len > 1) &&
- (ctx->cur_header->str[(ctx->cur_header->len)-1] == '\r') )
- {
- ctx->cur_header->str[(ctx->cur_header->len)-1] = '\0';
- ctx->cur_header->len--;
- }
+if (ctx->cur_header->ptr > 1)
+ gstring_trim_trailing(ctx->cur_header, '\r');
+(void) string_from_gstring(ctx->cur_header);
+
+#ifdef EXPERIMENTAL_ARC
+/* Feed the header line to ARC processing */
+(void) arc_header_feed(ctx->cur_header, !(ctx->flags & PDKIM_MODE_SIGN));
+#endif
-ctx->num_headers++;
-if (ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
+if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
/* SIGNING -------------------------------------------------------------- */
-if (ctx->mode == PDKIM_MODE_SIGN)
- {
- pdkim_signature *sig;
+if (ctx->flags & PDKIM_MODE_SIGN)
+ for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */
- for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */
- if (header_name_match(ctx->cur_header->str,
- sig->sign_headers?
- sig->sign_headers:
- PDKIM_DEFAULT_SIGN_HEADERS, 0) == PDKIM_OK)
- {
- pdkim_stringlist *list;
-
- /* Add header to the signed headers list (in reverse order) */
- if (!(list = pdkim_prepend_stringlist(sig->headers,
- ctx->cur_header->str)))
- return PDKIM_ERR_OOM;
- sig->headers = list;
- }
- }
+ /* Add header to the signed headers list (in reverse order) */
+ sig->headers = pdkim_prepend_stringlist(sig->headers, ctx->cur_header->s);
/* VERIFICATION ----------------------------------------------------------- */
/* DKIM-Signature: headers are added to the verification list */
-if (ctx->mode == PDKIM_MODE_VERIFY)
+else
{
- if (strncasecmp(ctx->cur_header->str,
+#ifdef notdef
+ DEBUG(D_acl)
+ {
+ debug_printf("DKIM >> raw hdr: ");
+ pdkim_quoteprint(CUS ctx->cur_header->s, ctx->cur_header->ptr);
+ }
+#endif
+ if (strncasecmp(CCS ctx->cur_header->s,
DKIM_SIGNATURE_HEADERNAME,
- strlen(DKIM_SIGNATURE_HEADERNAME)) == 0)
+ Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0)
{
- pdkim_signature *new_sig;
+ pdkim_signature * sig, * last_sig;
+ /* Create and chain new signature block. We could error-check for all
+ required tags here, but prefer to create the internal sig and expicitly
+ fail verification of it later. */
- /* Create and chain new signature block */
DEBUG(D_acl) debug_printf(
- "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ "DKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
- if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header->str)))
+ sig = pdkim_parse_sig_header(ctx, ctx->cur_header->s);
+
+ if (!(last_sig = ctx->sig))
+ ctx->sig = sig;
+ else
{
- pdkim_signature *last_sig = ctx->sig;
- if (!last_sig)
- ctx->sig = new_sig;
- else
- {
- while (last_sig->next) last_sig = last_sig->next;
- last_sig->next = new_sig;
- }
+ while (last_sig->next) last_sig = last_sig->next;
+ last_sig->next = sig;
}
- else
- DEBUG(D_acl) debug_printf(
- "Error while parsing signature header\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
- }
-
- /* every other header is stored for signature verification */
- else
- {
- pdkim_stringlist *list;
- if (!(list = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->str)))
- return PDKIM_ERR_OOM;
- ctx->headers = list;
+ if (dkim_collect_input && --dkim_collect_input == 0)
+ {
+ ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s);
+ ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0';
+ return PDKIM_ERR_EXCESS_SIGS;
+ }
}
+
+ /* all headers are stored for signature verification */
+ ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s);
}
BAIL:
-pdkim_strclear(ctx->cur_header); /* Re-use existing pdkim_str */
+ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0'; /* leave buffer for reuse */
return PDKIM_OK;
}
#define HEADER_BUFFER_FRAG_SIZE 256
DLLEXPORT int
-pdkim_feed (pdkim_ctx *ctx, char *data, int len)
+pdkim_feed(pdkim_ctx * ctx, uschar * data, int len)
{
-int p;
+/* Alternate EOD signal, used in non-dotstuffing mode */
+if (!data)
+ pdkim_body_complete(ctx);
-for (p = 0; p<len; p++)
+else for (int p = 0; p < len; p++)
{
- char c = data[p];
+ uschar c = data[p];
+ int rc;
- if (ctx->past_headers)
+ if (ctx->flags & PDKIM_PAST_HDRS)
{
+ if (c == '\n' && !(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */
+ {
+ ctx->linebuf[ctx->linebuf_offset++] = '\r';
+ if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1)
+ return PDKIM_ERR_LONG_LINE;
+ }
+
/* Processing body byte */
ctx->linebuf[ctx->linebuf_offset++] = c;
- if (c == '\n')
+ if (c == '\r')
+ ctx->flags |= PDKIM_SEEN_CR;
+ else if (c == '\n')
{
- int rc = pdkim_bodyline_complete(ctx); /* End of line */
- if (rc != PDKIM_OK) return rc;
+ ctx->flags &= ~PDKIM_SEEN_CR;
+ pdkim_bodyline_complete(ctx);
}
- if (ctx->linebuf_offset == (PDKIM_MAX_BODY_LINE_LEN-1))
+
+ if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1)
return PDKIM_ERR_LONG_LINE;
}
else
{
/* Processing header byte */
- if (c != '\r')
+ if (c == '\r')
+ ctx->flags |= PDKIM_SEEN_CR;
+ else if (c == '\n')
{
- if (c == '\n')
- {
- if (ctx->seen_lf)
- {
- int rc = pdkim_header_complete(ctx); /* Seen last header line */
- if (rc != PDKIM_OK) return rc;
+ if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */
+ ctx->cur_header = string_catn(ctx->cur_header, CUS "\r", 1);
- ctx->past_headers = TRUE;
- ctx->seen_lf = 0;
- DEBUG(D_acl) debug_printf(
- "PDKIM >> Hashed body data, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
- continue;
- }
- else
- ctx->seen_lf = TRUE;
- }
- else if (ctx->seen_lf)
- {
- if (!(c == '\t' || c == ' '))
- {
- int rc = pdkim_header_complete(ctx); /* End of header */
- if (rc != PDKIM_OK) return rc;
- }
- ctx->seen_lf = FALSE;
+ if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */
+ {
+ if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
+ return rc;
+
+ ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS;
+ DEBUG(D_acl) debug_printf(
+ "DKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ continue;
}
+ else
+ ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | PDKIM_SEEN_LF;
+ }
+ else if (ctx->flags & PDKIM_SEEN_LF)
+ {
+ if (!(c == '\t' || c == ' ')) /* End of header */
+ if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
+ return rc;
+ ctx->flags &= ~PDKIM_SEEN_LF;
}
- if (!ctx->cur_header)
- if (!(ctx->cur_header = pdkim_strnew(NULL)))
- return PDKIM_ERR_OOM;
-
- if (ctx->cur_header->len < PDKIM_MAX_HEADER_LEN)
- if (!pdkim_strncat(ctx->cur_header, &data[p], 1))
- return PDKIM_ERR_OOM;
+ if (!ctx->cur_header || ctx->cur_header->ptr < PDKIM_MAX_HEADER_LEN)
+ ctx->cur_header = string_catn(ctx->cur_header, CUS &data[p], 1);
}
}
return PDKIM_OK;
}
+
+
+/* Extend a growing header with a continuation-linebreak */
+static gstring *
+pdkim_hdr_cont(gstring * str, int * col)
+{
+*col = 1;
+return string_catn(str, US"\r\n\t", 3);
+}
+
+
+
/*
* RFC 5322 specifies that header line length SHOULD be no more than 78
- * lets make it so!
* pdkim_headcat
- * returns char*
+ *
+ * Returns gstring (not nul-terminated) appending to one supplied
*
* col: this int holds and receives column number (octets since last '\n')
* str: partial string to append to
- * pad: padding, split line or space after before or after eg: ";"
+ * pad: padding, split line or space after before or after eg: ";".
+ * Only the initial charater is used.
* intro: - must join to payload eg "h=", usually the tag name
* payload: eg base64 data - long data can be split arbitrarily.
*
* pairs and inside long values. it also always spaces or breaks after the
* "pad"
*
- * no guarantees are made for output given out-of range input. like tag
- * names loinger than 78, or bogus col. Input is assumed to be free of line breaks.
+ * No guarantees are made for output given out-of range input. like tag
+ * names longer than 78, or bogus col. Input is assumed to be free of line breaks.
*/
-static char *
-pdkim_headcat(int *col, pdkim_str *str, const char * pad,
- const char *intro, const char *payload)
+static gstring *
+pdkim_headcat(int * col, gstring * str,
+ const uschar * pad, const uschar * intro, const uschar * payload)
{
-size_t l;
+int len, chomp, padded = 0;
+
+/* If we can fit at least the pad at the end of current line, do it now.
+Otherwise, wrap if there is a pad. */
if (pad)
- {
- l = strlen(pad);
- if (*col + l > 78)
+ if (*col + 1 <= 78)
{
- pdkim_strcat(str, "\r\n\t");
- *col = 1;
+ str = string_catn(str, pad, 1);
+ (*col)++;
+ pad = NULL;
+ padded = 1;
}
- pdkim_strncat(str, pad, l);
- *col += l;
+ else
+ str = pdkim_hdr_cont(str, col);
+
+/* Special case: if the whole addition does not fit at the end of the current
+line, but could fit on a new line, wrap to give it its full, dedicated line. */
+
+len = (pad ? 2 : padded)
+ + (intro ? Ustrlen(intro) : 0)
+ + (payload ? Ustrlen(payload) : 0);
+if (len <= 77 && *col+len > 78)
+ {
+ str = pdkim_hdr_cont(str, col);
+ padded = 0;
}
-l = (pad?1:0) + (intro?strlen(intro):0);
+/* Either we already dealt with the pad or we know there is room */
-if (*col + l > 78)
- { /*can't fit intro - start a new line to make room.*/
- pdkim_strcat(str, "\r\n\t");
- *col = 1;
- l = intro?strlen(intro):0;
+if (pad)
+ {
+ str = string_catn(str, pad, 1);
+ str = string_catn(str, US" ", 1);
+ *col += 2;
}
+else if (padded && *col < 78)
+ {
+ str = string_catn(str, US" ", 1);
+ (*col)++;
+ }
+
+/* Call recursively with intro as payload: it gets the same, special treatment
+(that is, not split if < 78). */
-l += payload ? strlen(payload):0 ;
+if (intro)
+ str = pdkim_headcat(col, str, NULL, NULL, intro);
-while (l>77)
- { /* this fragment will not fit on a single line */
- if (pad)
+if (payload)
+ for (len = Ustrlen(payload); len; len -= chomp)
{
- pdkim_strcat(str, " ");
- *col += 1;
- pad = NULL; /* only want this once */
- l--;
+ if (*col >= 78)
+ str = pdkim_hdr_cont(str, col);
+ chomp = *col+len > 78 ? 78 - *col : len;
+ str = string_catn(str, payload, chomp);
+ *col += chomp;
+ payload += chomp;
}
- if (intro)
- {
- size_t sl = strlen(intro);
+return str;
+}
- pdkim_strncat(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL; /* only want this once */
- }
- if (payload)
+/* -------------------------------------------------------------------------- */
+
+/* Signing: create signature header
+*/
+static uschar *
+pdkim_create_header(pdkim_signature * sig, BOOL final)
+{
+uschar * base64_bh;
+uschar * base64_b;
+int col = 0;
+gstring * hdr;
+gstring * canon_all;
+
+canon_all = string_cat (NULL, pdkim_canons[sig->canon_headers]);
+canon_all = string_catn(canon_all, US"/", 1);
+canon_all = string_cat (canon_all, pdkim_canons[sig->canon_body]);
+(void) string_from_gstring(canon_all);
+
+hdr = string_cat(NULL, US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
+col = hdr->ptr;
+
+/* Required and static bits */
+hdr = pdkim_headcat(&col, hdr, US";", US"a=", dkim_sig_to_a_tag(sig));
+hdr = pdkim_headcat(&col, hdr, US";", US"q=", pdkim_querymethods[sig->querymethod]);
+hdr = pdkim_headcat(&col, hdr, US";", US"c=", canon_all->s);
+hdr = pdkim_headcat(&col, hdr, US";", US"d=", sig->domain);
+hdr = pdkim_headcat(&col, hdr, US";", US"s=", sig->selector);
+
+/* list of header names can be split between items. */
+ {
+ uschar * n = string_copy(sig->headernames);
+ uschar * i = US"h=";
+ uschar * s = US";";
+
+ while (*n)
{
- size_t sl = strlen(payload);
- size_t chomp = *col+sl < 77 ? sl : 78-*col;
+ uschar * c = Ustrchr(n, ':');
- pdkim_strncat(str, payload, chomp);
- *col += chomp;
- payload += chomp;
- l -= chomp-1;
- }
+ if (c) *c ='\0';
+
+ if (!i)
+ hdr = pdkim_headcat(&col, hdr, NULL, NULL, US":");
+
+ hdr = pdkim_headcat(&col, hdr, s, i, n);
- /* the while precondition tells us it didn't fit. */
- pdkim_strcat(str, "\r\n\t");
- *col = 1;
+ if (!c)
+ break;
+
+ n = c+1;
+ s = NULL;
+ i = NULL;
+ }
}
-if (*col + l > 78)
+base64_bh = pdkim_encode_base64(&sig->calc_body_hash->bh);
+hdr = pdkim_headcat(&col, hdr, US";", US"bh=", base64_bh);
+
+/* Optional bits */
+if (sig->identity)
+ hdr = pdkim_headcat(&col, hdr, US";", US"i=", sig->identity);
+
+if (sig->created > 0)
{
- pdkim_strcat(str, "\r\n\t");
- *col = 1;
- pad = NULL;
- }
+ uschar minibuf[21];
-if (pad)
+ snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created);
+ hdr = pdkim_headcat(&col, hdr, US";", US"t=", minibuf);
+}
+
+if (sig->expires > 0)
{
- pdkim_strcat(str, " ");
- *col += 1;
- pad = NULL;
+ uschar minibuf[21];
+
+ snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires);
+ hdr = pdkim_headcat(&col, hdr, US";", US"x=", minibuf);
}
-if (intro)
+if (sig->bodylength >= 0)
{
- size_t sl = strlen(intro);
+ uschar minibuf[21];
- pdkim_strncat(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL;
+ snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength);
+ hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf);
}
-if (payload)
+/* Preliminary or final version? */
+if (final)
{
- size_t sl = strlen(payload);
+ base64_b = pdkim_encode_base64(&sig->sighash);
+ hdr = pdkim_headcat(&col, hdr, US";", US"b=", base64_b);
- pdkim_strncat(str, payload, sl);
- *col += sl;
+ /* add trailing semicolon: I'm not sure if this is actually needed */
+ hdr = pdkim_headcat(&col, hdr, NULL, US";", US"");
+ }
+else
+ {
+ /* To satisfy the rule "all surrounding whitespace [...] deleted"
+ ( RFC 6376 section 3.7 ) we ensure there is no whitespace here. Otherwise
+ the headcat routine could insert a linebreak which the relaxer would reduce
+ to a single space preceding the terminating semicolon, resulting in an
+ incorrect header-hash. */
+ hdr = pdkim_headcat(&col, hdr, US";", US"b=;", US"");
}
-return str->str;
+return string_from_gstring(hdr);
}
/* -------------------------------------------------------------------------- */
-char *
-pdkim_create_header(pdkim_signature *sig, int final)
+/* According to draft-ietf-dcrup-dkim-crypto-07 "keys are 256 bits" (referring
+to DNS, hence the pubkey). Check for more than 32 bytes; if so assume the
+alternate possible representation (still) being discussed: a
+SubjectPublickeyInfo wrapped key - and drop all but the trailing 32-bytes (it
+should be a DER, with exactly 12 leading bytes - but we could accept a BER also,
+which could be any size). We still rely on the crypto library for checking for
+undersize.
+
+When the RFC is published this should be re-addressed. */
+
+static void
+check_bare_ed25519_pubkey(pdkim_pubkey * p)
{
-char *rc = NULL;
-char *base64_bh = NULL;
-char *base64_b = NULL;
-int col = 0;
-pdkim_str *hdr;
-pdkim_str *canon_all;
+int excess = p->key.len - 32;
+if (excess > 0)
+ {
+ DEBUG(D_acl)
+ debug_printf("DKIM: unexpected pubkey len %lu\n", (unsigned long) p->key.len);
+ p->key.data += excess; p->key.len = 32;
+ }
+}
-if (!(hdr = pdkim_strnew("DKIM-Signature: v="PDKIM_SIGNATURE_VERSION)))
- return NULL;
-if (!(canon_all = pdkim_strnew(pdkim_canons[sig->canon_headers])))
- goto BAIL;
+static pdkim_pubkey *
+pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx,
+ const uschar ** errstr)
+{
+uschar * dns_txt_name, * dns_txt_reply;
+pdkim_pubkey * p;
-if (!(base64_bh = pdkim_encode_base64(sig->bodyhash, sig->bodyhash_len)))
- goto BAIL;
+/* Fetch public key for signing domain, from DNS */
-col = strlen(hdr->str);
+dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain);
-/* Required and static bits */
-if ( pdkim_headcat(&col, hdr, ";", "a=", pdkim_algos[sig->algo])
- && pdkim_headcat(&col, hdr, ";", "q=", pdkim_querymethods[sig->querymethod])
- && pdkim_strcat(canon_all, "/")
- && pdkim_strcat(canon_all, pdkim_canons[sig->canon_body])
- && pdkim_headcat(&col, hdr, ";", "c=", canon_all->str)
- && pdkim_headcat(&col, hdr, ";", "d=", sig->domain)
- && pdkim_headcat(&col, hdr, ";", "s=", sig->selector)
+if ( !(dns_txt_reply = ctx->dns_txt_callback(dns_txt_name))
+ || dns_txt_reply[0] == '\0'
)
{
- /* list of eader names can be split between items. */
- {
- char *n = strdup(sig->headernames);
- char *f = n;
- char *i = "h=";
- char *s = ";";
-
- if (!n) goto BAIL;
- while (*n)
- {
- char *c = strchr(n, ':');
-
- if (c) *c ='\0';
-
- if (!i)
- if (!pdkim_headcat(&col, hdr, NULL, NULL, ":"))
- {
- free(f);
- goto BAIL;
- }
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
+ return NULL;
+ }
- if (!pdkim_headcat(&col, hdr, s, i, n))
- {
- free(f);
- goto BAIL;
- }
+DEBUG(D_acl)
+ {
+ debug_printf(
+ "DKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
+ " %s\n"
+ " Raw record: ",
+ dns_txt_name);
+ pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply));
+ }
- if (!c)
- break;
+if ( !(p = pdkim_parse_pubkey_record(CUS dns_txt_reply))
+ || (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0)
+ )
+ {
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD;
- n = c+1;
- s = NULL;
- i = NULL;
- }
- free(f);
+ DEBUG(D_acl)
+ {
+ if (p)
+ debug_printf(" Invalid public key service type '%s'\n", p->srvtype);
+ else
+ debug_printf(" Error while parsing public key record\n");
+ debug_printf(
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
+ return NULL;
+ }
+
+DEBUG(D_acl) debug_printf(
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
- if(!pdkim_headcat(&col, hdr, ";", "bh=", base64_bh))
- goto BAIL;
+/* Import public key */
- /* Optional bits */
- if (sig->identity)
- if(!pdkim_headcat(&col, hdr, ";", "i=", sig->identity))
- goto BAIL;
+/* Normally we use the signature a= tag to tell us the pubkey format.
+When signing under debug we do a test-import of the pubkey, and at that
+time we do not have a signature so we must interpret the pubkey k= tag
+instead. Assume writing on the sig is ok in that case. */
- if (sig->created > 0)
+if (sig->keytype < 0)
+ if ((sig->keytype = pdkim_keyname_to_keytype(p->keytype)) < 0)
{
- char minibuf[20];
+ DEBUG(D_acl) debug_printf("verify_init: unhandled keytype %s\n", p->keytype);
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT;
+ return NULL;
+ }
+
+if (sig->keytype == KEYTYPE_ED25519)
+ check_bare_ed25519_pubkey(p);
- snprintf(minibuf, 20, "%lu", sig->created);
- if(!pdkim_headcat(&col, hdr, ";", "t=", minibuf))
- goto BAIL;
+if ((*errstr = exim_dkim_verify_init(&p->key,
+ sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER,
+ vctx, &sig->keybits)))
+ {
+ DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr);
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT;
+ return NULL;
}
- if (sig->expires > 0)
- {
- char minibuf[20];
+vctx->keytype = sig->keytype;
+return p;
+}
- snprintf(minibuf, 20, "%lu", sig->expires);
- if(!pdkim_headcat(&col, hdr, ";", "x=", minibuf))
- goto BAIL;
- }
- if (sig->bodylength >= 0)
- {
- char minibuf[20];
+/* -------------------------------------------------------------------------- */
+/* Sort and filter the sigs developed from the message */
- snprintf(minibuf, 20, "%lu", sig->bodylength);
- if(!pdkim_headcat(&col, hdr, ";", "l=", minibuf))
- goto BAIL;
- }
+static pdkim_signature *
+sort_sig_methods(pdkim_signature * siglist)
+{
+pdkim_signature * yield, ** ss;
+const uschar * prefs;
+uschar * ele;
+int sep;
+
+if (!siglist) return NULL;
- /* Preliminary or final version? */
- if (final)
+/* first select in order of hashtypes */
+DEBUG(D_acl) debug_printf("DKIM: dkim_verify_hashes '%s'\n", dkim_verify_hashes);
+for (prefs = dkim_verify_hashes, sep = 0, yield = NULL, ss = &yield;
+ ele = string_nextinlist(&prefs, &sep, NULL, 0); )
+ {
+ int i = pdkim_hashname_to_hashtype(CUS ele, 0);
+ for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s;
+ s = next)
{
- if (!(base64_b = pdkim_encode_base64(sig->sigdata, sig->sigdata_len)))
- goto BAIL;
- if (!pdkim_headcat(&col, hdr, ";", "b=", base64_b))
- goto BAIL;
+ next = s->next;
+ if (s->hashtype == i)
+ { *prev = next; s->next = NULL; *ss = s; ss = &s->next; }
+ else
+ prev = &s->next;
+ }
}
- else
- if(!pdkim_headcat(&col, hdr, ";", "b=", ""))
- goto BAIL;
- /* add trailing semicolon: I'm not sure if this is actually needed */
- if (!pdkim_headcat(&col, hdr, NULL, ";", ""))
- goto BAIL;
+/* then in order of keytypes */
+siglist = yield;
+DEBUG(D_acl) debug_printf("DKIM: dkim_verify_keytypes '%s'\n", dkim_verify_keytypes);
+for (prefs = dkim_verify_keytypes, sep = 0, yield = NULL, ss = &yield;
+ ele = string_nextinlist(&prefs, &sep, NULL, 0); )
+ {
+ int i = pdkim_keyname_to_keytype(CUS ele);
+ for (pdkim_signature * s = siglist, * next, ** prev = &siglist; s;
+ s = next)
+ {
+ next = s->next;
+ if (s->keytype == i)
+ { *prev = next; s->next = NULL; *ss = s; ss = &s->next; }
+ else
+ prev = &s->next;
+ }
}
-rc = strdup(hdr->str);
-
-BAIL:
-pdkim_strfree(hdr);
-if (canon_all) pdkim_strfree(canon_all);
-if (base64_bh) free(base64_bh);
-if (base64_b ) free(base64_b);
-return rc;
+DEBUG(D_acl) for (pdkim_signature * s = yield; s; s = s->next)
+ debug_printf(" retain d=%s s=%s a=%s\n",
+ s->domain, s->selector, dkim_sig_to_a_tag(s));
+return yield;
}
/* -------------------------------------------------------------------------- */
DLLEXPORT int
-pdkim_feed_finish(pdkim_ctx *ctx, pdkim_signature **return_signatures)
+pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures,
+ const uschar ** err)
{
-pdkim_signature *sig = ctx->sig;
-pdkim_str *headernames = NULL; /* Collected signed header names */
+BOOL verify_pass = FALSE;
/* Check if we must still flush a (partial) header. If that is the
case, the message has no body, and we must compute a body hash
out of '<CR><LF>' */
-if (ctx->cur_header && ctx->cur_header->len)
+if (ctx->cur_header && ctx->cur_header->ptr > 0)
{
- int rc = pdkim_header_complete(ctx);
- if (rc != PDKIM_OK) return rc;
- pdkim_update_bodyhash(ctx, "\r\n", 2);
+ blob * rnl = NULL;
+ int rc;
+
+ if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
+ return rc;
+
+ for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next)
+ rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
+ if (rnl) store_free(rnl);
}
else
DEBUG(D_acl) debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
-/* Build (and/or evaluate) body hash */
-if (pdkim_finish_bodyhash(ctx) != PDKIM_OK)
- return PDKIM_ERR_OOM;
+/* Build (and/or evaluate) body hash. Do this even if no DKIM sigs, in case we
+have a hash to do for ARC. */
-/* SIGNING -------------------------------------------------------------- */
-if (ctx->mode == PDKIM_MODE_SIGN)
- if (!(headernames = pdkim_strnew(NULL)))
- return PDKIM_ERR_OOM;
-/* ---------------------------------------------------------------------- */
+pdkim_finish_bodyhash(ctx);
-while (sig)
+/* Sort and filter the recived signatures */
+
+if (!(ctx->flags & PDKIM_MODE_SIGN))
+ ctx->sig = sort_sig_methods(ctx->sig);
+
+if (!ctx->sig)
{
- sha1_context sha1_headers;
- sha2_context sha2_headers;
- char *sig_hdr;
- char headerhash[32];
+ DEBUG(D_acl) debug_printf("DKIM: no signatures\n");
+ *return_signatures = NULL;
+ return PDKIM_OK;
+ }
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- sha1_starts(&sha1_headers);
- else
- sha2_starts(&sha2_headers, 0);
+for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)
+ {
+ hctx hhash_ctx;
+ uschar * sig_hdr = US"";
+ blob hhash;
+ gstring * hdata = NULL;
+ es_ctx sctx;
+
+ if ( !(ctx->flags & PDKIM_MODE_SIGN)
+ && sig->verify_status == PDKIM_VERIFY_FAIL)
+ {
+ DEBUG(D_acl)
+ debug_printf("DKIM: [%s] abandoning this signature\n", sig->domain);
+ continue;
+ }
+
+ /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA
+ signing only, as it happens) and for either GnuTLS and OpenSSL when we are
+ signing with EC (specifically, Ed25519). The former is because the GCrypt
+ signing operation is pure (does not do its own hash) so we must hash. The
+ latter is because we (stupidly, but this is what the IETF draft is saying)
+ must hash with the declared hash method, then pass the result to the library
+ hash-and-sign routine (because that's all the libraries are providing. And
+ we're stuck with whatever that hidden hash method is, too). We may as well
+ do this hash incrementally.
+ We don't need the hash we're calculating here for the GnuTLS and OpenSSL
+ cases of RSA signing, since those library routines can do hash-and-sign.
+
+ Some time in the future we could easily avoid doing the hash here for those
+ cases (which will be common for a long while. We could also change from
+ the current copy-all-the-headers-into-one-block, then call the hash-and-sign
+ implementation - to a proper incremental one. Unfortunately, GnuTLS just
+ cannot do incremental - either signing or verification. Unsure about GCrypt.
+ */
+
+ /*XXX The header hash is also used (so far) by the verify operation */
+
+ if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "DKIM: hash setup error, possibly nonhandled hashtype");
+ break;
+ }
+
+ if (ctx->flags & PDKIM_MODE_SIGN)
+ DEBUG(D_acl) debug_printf(
+ "DKIM >> Headers to be signed: >>>>>>>>>>>>\n"
+ " %s\n",
+ sig->sign_headers);
DEBUG(D_acl) debug_printf(
- "PDKIM >> Hashed header data, canonicalized, in sequence >>>>>>>>>>>>>>\n");
+ "DKIM >> Header data for hash, canonicalized (%-7s), in sequence >>\n",
+ pdkim_canons[sig->canon_headers]);
+
/* SIGNING ---------------------------------------------------------------- */
/* When signing, walk through our header list and add them to the hash. As we
- go, construct a list of the header's names to use for the h= parameter. */
+ go, construct a list of the header's names to use for the h= parameter.
+ Then append to that list any remaining header names for which there was no
+ header to sign. */
- if (ctx->mode == PDKIM_MODE_SIGN)
+ if (ctx->flags & PDKIM_MODE_SIGN)
{
- pdkim_stringlist *p;
+ gstring * g = NULL;
+ const uschar * l;
+ uschar * s;
+ int sep = 0;
+
+ /* Import private key, including the keytype which we need for building
+ the signature header */
- for (p = sig->headers; p; p = p->next)
+ if ((*err = exim_dkim_signing_init(CUS sig->privkey, &sctx)))
{
- char *rh = NULL;
- /* Collect header names (Note: colon presence is guaranteed here) */
- char *q = strchr(p->value, ':');
-
- if (!(pdkim_strncat(headernames, p->value,
- (q-(p->value)) + (p->next ? 1 : 0))))
- return PDKIM_ERR_OOM;
-
- rh = sig->canon_headers == PDKIM_CANON_RELAXED
- ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
- : strdup(p->value); /* just copy it for simple canon */
- if (!rh)
- return PDKIM_ERR_OOM;
-
- /* Feed header to the hash algorithm */
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- sha1_update(&(sha1_headers), (unsigned char *)rh, strlen(rh));
- else
- sha2_update(&(sha2_headers), (unsigned char *)rh, strlen(rh));
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing_init: %s", *err);
+ return PDKIM_ERR_RSA_PRIVKEY;
+ }
+ sig->keytype = sctx.keytype;
- DEBUG(D_acl) pdkim_quoteprint(rh, strlen(rh), 1);
- free(rh);
+ sig->headernames = NULL; /* Collected signed header names */
+ for (pdkim_stringlist * p = sig->headers; p; p = p->next)
+ {
+ uschar * rh = p->value;
+
+ if (header_name_match(rh, sig->sign_headers) == PDKIM_OK)
+ {
+ /* Collect header names (Note: colon presence is guaranteed here) */
+ g = string_append_listele_n(g, ':', rh, Ustrchr(rh, ':') - rh);
+
+ if (sig->canon_headers == PDKIM_CANON_RELAXED)
+ rh = pdkim_relax_header(rh, TRUE); /* cook header for relaxed canon */
+
+ /* Feed header to the hash algorithm */
+ exim_sha_update_string(&hhash_ctx, CUS rh);
+
+ /* Remember headers block for signing (when the library cannot do incremental) */
+ /*XXX we could avoid doing this for all but the GnuTLS/RSA case */
+ hdata = exim_dkim_data_append(hdata, rh);
+
+ DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
+ }
}
+
+ /* Any headers we wanted to sign but were not present must also be listed.
+ Ignore elements that have been ticked-off or are marked as never-oversign. */
+
+ l = sig->sign_headers;
+ while((s = string_nextinlist(&l, &sep, NULL, 0)))
+ {
+ if (*s == '+') /* skip oversigning marker */
+ s++;
+ if (*s != '_' && *s != '=')
+ g = string_append_listele(g, ':', s);
+ }
+ sig->headernames = string_from_gstring(g);
+
+ /* Create signature header with b= omitted */
+ sig_hdr = pdkim_create_header(sig, FALSE);
}
/* VERIFICATION ----------------------------------------------------------- */
add the headers to the hash in that order. */
else
{
- char *b = strdup(sig->headernames);
- char *p = b;
- char *q = NULL;
- pdkim_stringlist *hdrs;
+ uschar * p = sig->headernames;
+ uschar * q;
- if (!b) return PDKIM_ERR_OOM;
+ if (p)
+ {
+ /* clear tags */
+ for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+ hdrs->tag = 0;
- /* clear tags */
- for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
- hdrs->tag = 0;
+ p = string_copy(p);
+ while(1)
+ {
+ if ((q = Ustrchr(p, ':')))
+ *q = '\0';
+
+ /*XXX walk the list of headers in same order as received. */
+ for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+ if ( hdrs->tag == 0
+ && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0
+ && (hdrs->value)[Ustrlen(p)] == ':'
+ )
+ {
+ /* cook header for relaxed canon, or just copy it for simple */
+
+ uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED
+ ? pdkim_relax_header(hdrs->value, TRUE)
+ : string_copy(CUS hdrs->value);
+
+ /* Feed header to the hash algorithm */
+ exim_sha_update_string(&hhash_ctx, CUS rh);
+
+ DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
+ hdrs->tag = 1;
+ break;
+ }
- while(1)
- {
- if ((q = strchr(p, ':')))
- *q = '\0';
-
- for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
- if ( hdrs->tag == 0
- && strncasecmp(hdrs->value, p, strlen(p)) == 0
- && (hdrs->value)[strlen(p)] == ':'
- )
- {
- char *rh;
-
- rh = sig->canon_headers == PDKIM_CANON_RELAXED
- ? pdkim_relax_header(hdrs->value, 1) /* cook header for relaxed canon */
- : strdup(hdrs->value); /* just copy it for simple canon */
- if (!rh)
- return PDKIM_ERR_OOM;
-
- /* Feed header to the hash algorithm */
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- sha1_update(&sha1_headers, (unsigned char *)rh, strlen(rh));
- else
- sha2_update(&sha2_headers, (unsigned char *)rh, strlen(rh));
-
- DEBUG(D_acl) pdkim_quoteprint(rh, strlen(rh), 1);
- free(rh);
- hdrs->tag = 1;
- break;
- }
+ if (!q) break;
+ p = q+1;
+ }
- if (!q) break;
- p = q+1;
+ sig_hdr = string_copy(sig->rawsig_no_b_val);
}
- free(b);
}
DEBUG(D_acl) debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
- /* SIGNING ---------------------------------------------------------------- */
- if (ctx->mode == PDKIM_MODE_SIGN)
+ DEBUG(D_acl)
{
- /* Copy headernames to signature struct */
- sig->headernames = strdup(headernames->str);
- pdkim_strfree(headernames);
-
- /* Create signature header with b= omitted */
- sig_hdr = pdkim_create_header(ctx->sig, 0);
+ debug_printf(
+ "DKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n");
+ pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
+ debug_printf(
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
- /* VERIFICATION ----------------------------------------------------------- */
- else
- sig_hdr = strdup(sig->rawsig_no_b_val);
- /* ------------------------------------------------------------------------ */
-
- if (!sig_hdr)
- return PDKIM_ERR_OOM;
-
/* Relax header if necessary */
if (sig->canon_headers == PDKIM_CANON_RELAXED)
- {
- char *relaxed_hdr = pdkim_relax_header(sig_hdr, 0);
-
- free(sig_hdr);
- if (!relaxed_hdr)
- return PDKIM_ERR_OOM;
- sig_hdr = relaxed_hdr;
- }
+ sig_hdr = pdkim_relax_header(sig_hdr, FALSE);
DEBUG(D_acl)
{
+ debug_printf("DKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n",
+ pdkim_canons[sig->canon_headers]);
+ pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
debug_printf(
- "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
- pdkim_quoteprint(sig_hdr, strlen(sig_hdr), 1);
- debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
/* Finalize header hash */
- if (sig->algo == PDKIM_ALGO_RSA_SHA1)
- {
- sha1_update(&sha1_headers, (unsigned char *)sig_hdr, strlen(sig_hdr));
- sha1_finish(&sha1_headers, (unsigned char *)headerhash);
+ exim_sha_update_string(&hhash_ctx, CUS sig_hdr);
+ exim_sha_finish(&hhash_ctx, &hhash);
- DEBUG(D_acl)
- {
- debug_printf( "PDKIM [%s] hh computed: ", sig->domain);
- pdkim_hexprint(headerhash, 20, 1);
- }
- }
- else
+ DEBUG(D_acl)
{
- sha2_update(&sha2_headers, (unsigned char *)sig_hdr, strlen(sig_hdr));
- sha2_finish(&sha2_headers, (unsigned char *)headerhash);
-
- DEBUG(D_acl)
- {
- debug_printf("PDKIM [%s] hh computed: ", sig->domain);
- pdkim_hexprint(headerhash, 32, 1);
- }
+ debug_printf("DKIM [%s] Header %s computed: ",
+ sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname);
+ pdkim_hexprint(hhash.data, hhash.len);
}
- free(sig_hdr);
+ /* Remember headers block for signing (when the signing library cannot do
+ incremental) */
+ if (ctx->flags & PDKIM_MODE_SIGN)
+ hdata = exim_dkim_data_append(hdata, US sig_hdr);
/* SIGNING ---------------------------------------------------------------- */
- if (ctx->mode == PDKIM_MODE_SIGN)
+ if (ctx->flags & PDKIM_MODE_SIGN)
{
- rsa_context rsa;
-
- rsa_init(&rsa, RSA_PKCS_V15, 0);
-
- /* Perform private key operation */
- if (rsa_parse_key(&rsa, (unsigned char *)sig->rsa_privkey,
- strlen(sig->rsa_privkey), NULL, 0) != 0)
- return PDKIM_ERR_RSA_PRIVKEY;
-
- sig->sigdata_len = mpi_size(&(rsa.N));
- if (!(sig->sigdata = malloc(sig->sigdata_len)))
- return PDKIM_ERR_OOM;
+ hashmethod hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+ ? HASH_NULL
+#else
+ ? HASH_SHA2_512
+#endif
+ : pdkim_hashes[sig->hashtype].exim_hashmethod;
+
+#ifdef SIGN_HAVE_ED25519
+ /* For GCrypt, and for EC, we pass the hash-of-headers to the signing
+ routine. For anything else we just pass the headers. */
+
+ if (sig->keytype != KEYTYPE_ED25519)
+#endif
+ {
+ hhash.data = hdata->s;
+ hhash.len = hdata->ptr;
+ }
- if (rsa_pkcs1_sign( &rsa, RSA_PRIVATE,
- ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
- SIG_RSA_SHA1:SIG_RSA_SHA256),
- 0,
- (unsigned char *)headerhash,
- (unsigned char *)sig->sigdata ) != 0)
+ if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash)))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err);
return PDKIM_ERR_RSA_SIGNING;
-
- rsa_free(&rsa);
+ }
DEBUG(D_acl)
{
- debug_printf( "PDKIM [%s] b computed: ", sig->domain);
- pdkim_hexprint(sig->sigdata, sig->sigdata_len, 1);
+ debug_printf( "DKIM [%s] b computed: ", sig->domain);
+ pdkim_hexprint(sig->sighash.data, sig->sighash.len);
}
- if (!(sig->signature_header = pdkim_create_header(ctx->sig, 1)))
- return PDKIM_ERR_OOM;
+ sig->signature_header = pdkim_create_header(sig, TRUE);
}
/* VERIFICATION ----------------------------------------------------------- */
else
{
- rsa_context rsa;
- char *dns_txt_name, *dns_txt_reply;
-
- rsa_init(&rsa, RSA_PKCS_V15, 0);
-
- if (!(dns_txt_name = malloc(PDKIM_DNS_TXT_MAX_NAMELEN)))
- return PDKIM_ERR_OOM;
-
- if (!(dns_txt_reply = malloc(PDKIM_DNS_TXT_MAX_RECLEN)))
+ ev_ctx vctx;
+ hashmethod hm;
+
+ /* Make sure we have all required signature tags */
+ if (!( sig->domain && *sig->domain
+ && sig->selector && *sig->selector
+ && sig->headernames && *sig->headernames
+ && sig->bodyhash.data
+ && sig->sighash.data
+ && sig->keytype >= 0
+ && sig->hashtype >= 0
+ && sig->version
+ ) )
{
- free(dns_txt_name);
- return PDKIM_ERR_OOM;
- }
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR;
- memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN);
- memset(dns_txt_name , 0, PDKIM_DNS_TXT_MAX_NAMELEN);
-
- if (snprintf(dns_txt_name, PDKIM_DNS_TXT_MAX_NAMELEN,
- "%s._domainkey.%s.",
- sig->selector, sig->domain) >= PDKIM_DNS_TXT_MAX_NAMELEN)
- {
- sig->verify_status = PDKIM_VERIFY_INVALID;
- sig->verify_ext_status = PDKIM_VERIFY_INVALID_BUFFER_SIZE;
+ DEBUG(D_acl) debug_printf(
+ " Error in DKIM-Signature header: tags missing or invalid (%s)\n"
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n",
+ !(sig->domain && *sig->domain) ? "d="
+ : !(sig->selector && *sig->selector) ? "s="
+ : !(sig->headernames && *sig->headernames) ? "h="
+ : !sig->bodyhash.data ? "bh="
+ : !sig->sighash.data ? "b="
+ : sig->keytype < 0 || sig->hashtype < 0 ? "a="
+ : "v="
+ );
goto NEXT_VERIFY;
}
- if ( ctx->dns_txt_callback(dns_txt_name, dns_txt_reply) != PDKIM_OK
- || dns_txt_reply[0] == '\0')
+ /* Make sure sig uses supported DKIM version (only v1) */
+ if (sig->version != 1)
{
- sig->verify_status = PDKIM_VERIFY_INVALID;
- sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION;
+
+ DEBUG(D_acl) debug_printf(
+ " Error in DKIM-Signature header: unsupported DKIM version\n"
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
goto NEXT_VERIFY;
}
DEBUG(D_acl)
{
- debug_printf(
- "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
- " Raw record: ");
- pdkim_quoteprint(dns_txt_reply, strlen(dns_txt_reply), 1);
+ debug_printf( "DKIM [%s] b from mail: ", sig->domain);
+ pdkim_hexprint(sig->sighash.data, sig->sighash.len);
}
- if (!(sig->pubkey = pdkim_parse_pubkey_record(ctx, dns_txt_reply)))
+ if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err)))
{
- sig->verify_status = PDKIM_VERIFY_INVALID;
- sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
-
- DEBUG(D_acl) debug_printf(
- " Error while parsing public key record\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ log_write(0, LOG_MAIN, "DKIM: %s%s %s%s [failed key import]",
+ sig->domain ? "d=" : "", sig->domain ? sig->domain : US"",
+ sig->selector ? "s=" : "", sig->selector ? sig->selector : US"");
goto NEXT_VERIFY;
}
- DEBUG(D_acl) debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ /* If the pubkey limits to a list of specific hashes, ignore sigs that
+ do not have the hash part of the sig algorithm matching */
- if (rsa_parse_public_key(&rsa,
- (unsigned char *)sig->pubkey->key,
- sig->pubkey->key_len) != 0)
+ if (sig->pubkey->hashes)
{
- sig->verify_status = PDKIM_VERIFY_INVALID;
- sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_PARSING;
- goto NEXT_VERIFY;
+ const uschar * list = sig->pubkey->hashes, * ele;
+ int sep = ':';
+ while ((ele = string_nextinlist(&list, &sep, NULL, 0)))
+ if (Ustrcmp(ele, pdkim_hashes[sig->hashtype].dkim_hashname) == 0) break;
+ if (!ele)
+ {
+ DEBUG(D_acl) debug_printf("pubkey h=%s vs. sig a=%s_%s\n",
+ sig->pubkey->hashes,
+ pdkim_keytypes[sig->keytype],
+ pdkim_hashes[sig->hashtype].dkim_hashname);
+ sig->verify_status = PDKIM_VERIFY_FAIL;
+ sig->verify_ext_status = PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH;
+ goto NEXT_VERIFY;
+ }
}
+ hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+ ? HASH_NULL
+#else
+ ? HASH_SHA2_512
+#endif
+ : pdkim_hashes[sig->hashtype].exim_hashmethod;
+
/* Check the signature */
- if (rsa_pkcs1_verify(&rsa,
- RSA_PUBLIC,
- ((sig->algo == PDKIM_ALGO_RSA_SHA1)?
- SIG_RSA_SHA1:SIG_RSA_SHA256),
- 0,
- (unsigned char *)headerhash,
- (unsigned char *)sig->sigdata) != 0)
+
+ if ((*err = exim_dkim_verify(&vctx, hm, &hhash, &sig->sighash)))
{
+ DEBUG(D_acl) debug_printf("headers verify: %s\n", *err);
sig->verify_status = PDKIM_VERIFY_FAIL;
sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE;
goto NEXT_VERIFY;
}
+ if (*dkim_verify_min_keysizes)
+ {
+ unsigned minbits;
+ uschar * ss = expand_getkeyed(US pdkim_keytypes[sig->keytype],
+ dkim_verify_min_keysizes);
+ if (ss && (minbits = atoi(CS ss)) > sig->keybits)
+ {
+ DEBUG(D_acl) debug_printf("Key too short: Actual: %s %u Minima '%s'\n",
+ pdkim_keytypes[sig->keytype], sig->keybits, dkim_verify_min_keysizes);
+ sig->verify_status = PDKIM_VERIFY_FAIL;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE;
+ }
+ }
+
- /* We have a winner! (if bodydhash was correct earlier) */
+ /* We have a winner! (if bodyhash was correct earlier) */
if (sig->verify_status == PDKIM_VERIFY_NONE)
+ {
sig->verify_status = PDKIM_VERIFY_PASS;
+ verify_pass = TRUE;
+ if (dkim_verify_minimal) break;
+ }
NEXT_VERIFY:
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] signature status: %s",
- sig->domain, pdkim_verify_status_str(sig->verify_status));
+ debug_printf("DKIM [%s] %s signature status: %s",
+ sig->domain, dkim_sig_to_a_tag(sig),
+ pdkim_verify_status_str(sig->verify_status));
if (sig->verify_ext_status > 0)
debug_printf(" (%s)\n",
pdkim_verify_ext_status_str(sig->verify_ext_status));
else
debug_printf("\n");
}
-
- rsa_free(&rsa);
- free(dns_txt_name);
- free(dns_txt_reply);
}
-
- sig = sig->next;
}
/* If requested, set return pointer to signature(s) */
if (return_signatures)
*return_signatures = ctx->sig;
-return PDKIM_OK;
+return ctx->flags & PDKIM_MODE_SIGN || verify_pass
+ ? PDKIM_OK : PDKIM_FAIL;
}
/* -------------------------------------------------------------------------- */
DLLEXPORT pdkim_ctx *
-pdkim_init_verify(int(*dns_txt_callback)(char *, char *))
+pdkim_init_verify(uschar * (*dns_txt_callback)(const uschar *), BOOL dot_stuffing)
{
-pdkim_ctx *ctx = malloc(sizeof(pdkim_ctx));
+pdkim_ctx * ctx;
-if (!ctx)
- return NULL;
+ctx = store_get(sizeof(pdkim_ctx), GET_UNTAINTED);
memset(ctx, 0, sizeof(pdkim_ctx));
-if (!(ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN)))
- {
- free(ctx);
- return NULL;
- }
-
-ctx->mode = PDKIM_MODE_VERIFY;
+if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM;
+/* The line-buffer is for message data, hence tainted */
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
ctx->dns_txt_callback = dns_txt_callback;
+ctx->cur_header = string_get_tainted(36, GET_TAINTED);
return ctx;
}
/* -------------------------------------------------------------------------- */
-DLLEXPORT pdkim_ctx *
-pdkim_init_sign(char *domain, char *selector, char *rsa_privkey)
+DLLEXPORT pdkim_signature *
+pdkim_init_sign(pdkim_ctx * ctx,
+ uschar * domain, uschar * selector, uschar * privkey,
+ uschar * hashname, const uschar ** errstr)
{
-pdkim_ctx *ctx;
-pdkim_signature *sig;
+int hashtype;
+pdkim_signature * sig;
-if (!domain || !selector || !rsa_privkey)
+if (!domain || !selector || !privkey)
return NULL;
-if (!(ctx = malloc(sizeof(pdkim_ctx))))
- return NULL;
-memset(ctx, 0, sizeof(pdkim_ctx));
+/* Allocate & init one signature struct */
-if (!(ctx->linebuf = malloc(PDKIM_MAX_BODY_LINE_LEN)))
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
+memset(sig, 0, sizeof(pdkim_signature));
+
+sig->bodylength = -1;
+
+sig->domain = string_copy(US domain);
+sig->selector = string_copy(US selector);
+sig->privkey = string_copy(US privkey);
+sig->keytype = -1;
+
+for (hashtype = 0; hashtype < nelem(pdkim_hashes); hashtype++)
+ if (Ustrcmp(hashname, pdkim_hashes[hashtype].dkim_hashname) == 0)
+ { sig->hashtype = hashtype; break; }
+if (hashtype >= nelem(pdkim_hashes))
{
- free(ctx);
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "DKIM: unrecognised hashname '%s'", hashname);
return NULL;
}
-if (!(sig = malloc(sizeof(pdkim_signature))))
+DEBUG(D_acl)
{
- free(ctx->linebuf);
- free(ctx);
- return NULL;
+ pdkim_signature s = *sig;
+ ev_ctx vctx;
+
+ debug_printf("DKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr))
+ debug_printf("WARNING: bad dkim key in dns\n");
+ debug_printf("DKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-memset(sig, 0, sizeof(pdkim_signature));
+return sig;
+}
-sig->bodylength = -1;
-ctx->mode = PDKIM_MODE_SIGN;
-ctx->sig = sig;
+/* -------------------------------------------------------------------------- */
-ctx->sig->domain = strdup(domain);
-ctx->sig->selector = strdup(selector);
-ctx->sig->rsa_privkey = strdup(rsa_privkey);
+DLLEXPORT void
+pdkim_set_optional(pdkim_signature * sig,
+ char * sign_headers,
+ char * identity,
+ int canon_headers,
+ int canon_body,
+ long bodylength,
+ unsigned long created,
+ unsigned long expires)
+{
+if (identity)
+ sig->identity = string_copy(US identity);
-if (!ctx->sig->domain || !ctx->sig->selector || !ctx->sig->rsa_privkey)
- goto BAIL;
+sig->sign_headers = string_copy(sign_headers
+ ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS);
-if (!(ctx->sig->sha1_body = malloc(sizeof(sha1_context))))
- goto BAIL;
-sha1_starts(ctx->sig->sha1_body);
+sig->canon_headers = canon_headers;
+sig->canon_body = canon_body;
+sig->bodylength = bodylength;
+sig->created = created;
+sig->expires = expires;
-if (!(ctx->sig->sha2_body = malloc(sizeof(sha2_context))))
- goto BAIL;
-sha2_starts(ctx->sig->sha2_body, 0);
+return;
+}
-return ctx;
-BAIL:
- pdkim_free_ctx(ctx);
+
+/* Set up a blob for calculating the bodyhash according to the
+given needs. Use an existing one if possible, or create a new one.
+
+Return: hashblob pointer, or NULL on error
+*/
+pdkim_bodyhash *
+pdkim_set_bodyhash(pdkim_ctx * ctx, int hashtype, int canon_method,
+ long bodylength)
+{
+pdkim_bodyhash * b;
+
+if (hashtype == -1 || canon_method == -1) return NULL;
+
+for (b = ctx->bodyhash; b; b = b->next)
+ if ( hashtype == b->hashtype
+ && canon_method == b->canon_method
+ && bodylength == b->bodylength)
+ {
+ DEBUG(D_receive) debug_printf("DKIM: using existing bodyhash %s/%s/%ld\n",
+ pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
+ return b;
+ }
+
+DEBUG(D_receive) debug_printf("DKIM: new bodyhash %s/%s/%ld\n",
+ pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
+b = store_get(sizeof(pdkim_bodyhash), GET_UNTAINTED);
+b->next = ctx->bodyhash;
+b->hashtype = hashtype;
+b->canon_method = canon_method;
+b->bodylength = bodylength;
+if (!exim_sha_init(&b->body_hash_ctx, /*XXX hash method: extend for sha512 */
+ pdkim_hashes[hashtype].exim_hashmethod))
+ {
+ DEBUG(D_acl)
+ debug_printf("DKIM: hash init error, possibly nonhandled hashtype\n");
return NULL;
+ }
+b->signed_body_bytes = 0;
+b->num_buffered_blanklines = 0;
+ctx->bodyhash = b;
+return b;
}
-/* -------------------------------------------------------------------------- */
-DLLEXPORT int
-pdkim_set_optional(pdkim_ctx *ctx,
- char *sign_headers,
- char *identity,
- int canon_headers,
- int canon_body,
- long bodylength,
- int algo,
- unsigned long created,
- unsigned long expires)
+/* Set up a blob for calculating the bodyhash according to the
+needs of this signature. Use an existing one if possible, or
+create a new one.
+
+Return: hashblob pointer, or NULL on error (only used as a boolean).
+*/
+pdkim_bodyhash *
+pdkim_set_sig_bodyhash(pdkim_ctx * ctx, pdkim_signature * sig)
{
+pdkim_bodyhash * b = pdkim_set_bodyhash(ctx,
+ sig->hashtype, sig->canon_body, sig->bodylength);
+sig->calc_body_hash = b;
+return b;
+}
-if (identity)
- if (!(ctx->sig->identity = strdup(identity)))
- return PDKIM_ERR_OOM;
-if (sign_headers)
- if (!(ctx->sig->sign_headers = strdup(sign_headers)))
- return PDKIM_ERR_OOM;
+/* -------------------------------------------------------------------------- */
-ctx->sig->canon_headers = canon_headers;
-ctx->sig->canon_body = canon_body;
-ctx->sig->bodylength = bodylength;
-ctx->sig->algo = algo;
-ctx->sig->created = created;
-ctx->sig->expires = expires;
-return PDKIM_OK;
+void
+pdkim_init_context(pdkim_ctx * ctx, BOOL dot_stuffed,
+ uschar * (*dns_txt_callback)(const uschar *))
+{
+memset(ctx, 0, sizeof(pdkim_ctx));
+ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;
+/* The line buffer is for message data, hence tainted */
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
+DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback;
}
+void
+pdkim_init(void)
+{
+exim_dkim_init();
+}
+
+
+
+#endif /*DISABLE_DKIM*/
git://git.exim.org / exim.git / blobdiff