* PDKIM - a RFC4871 (DKIM) implementation
*
* Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net>
- * Copyright (C) 2016 Jeremy Harris <jgh@exim.org>
+ * Copyright (C) 2016 - 2018 Jeremy Harris <jgh@exim.org>
*
* http://duncanthrax.net/pdkim/
*
#ifndef DISABLE_DKIM /* entire file */
-#ifndef SUPPORT_TLS
-# error Need SUPPORT_TLS for DKIM
+#ifdef DISABLE_TLS
+# error Must not DISABLE_TLS, for DKIM
#endif
#include "crypt_ver.h"
-#ifdef RSA_OPENSSL
+#ifdef SIGN_OPENSSL
# include <openssl/rsa.h>
# include <openssl/ssl.h>
# include <openssl/err.h>
-#elif defined(RSA_GNUTLS)
+#elif defined(SIGN_GNUTLS)
# include <gnutls/gnutls.h>
# include <gnutls/x509.h>
#endif
#include "pdkim.h"
-#include "rsa.h"
+#include "signing.h"
#define PDKIM_SIGNATURE_VERSION "1"
#define PDKIM_PUB_RECORD_VERSION US "DKIM1"
#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 {
US"dns/txt",
NULL
};
-const uschar * pdkim_algos[] = {
- US"rsa-sha256",
- US"rsa-sha1",
- NULL
-};
const uschar * pdkim_canons[] = {
US"simple",
US"relaxed",
NULL
};
-const uschar * pdkim_hashes[] = {
- US"sha256",
- US"sha1",
- NULL
+
+const pdkim_hashtype pdkim_hashes[] = {
+ { US"sha1", HASH_SHA1 },
+ { US"sha256", HASH_SHA2_256 },
+ { US"sha512", HASH_SHA2_512 }
};
+
const uschar * pdkim_keytypes[] = {
- US"rsa",
- NULL
+ [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 uschar * 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[] = {
};
+static blob lineending = {.data = US"\r\n", .len = 2};
+
/* -------------------------------------------------------------------------- */
+uschar *
+dkim_sig_to_a_tag(const pdkim_signature * sig)
+{
+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);
+}
+
+
+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;
+}
+
+int
+pdkim_hashname_to_hashtype(const uschar * s, unsigned len)
+{
+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;
+}
+
+void
+pdkim_cstring_to_canons(const uschar * s, unsigned len,
+ int * canon_head, int * canon_body)
+{
+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;
+ }
+}
+
+
const char *
pdkim_verify_status_str(int status)
{
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";
}
}
-const char *
+const uschar *
pdkim_errstr(int status)
{
switch(status)
{
- case PDKIM_OK: return "OK";
- case PDKIM_FAIL: return "FAIL";
- case PDKIM_ERR_RSA_PRIVKEY: return "RSA_PRIVKEY";
- case PDKIM_ERR_RSA_SIGNING: return "RSA SIGNING";
- case PDKIM_ERR_LONG_LINE: return "RSA_LONG_LINE";
- case PDKIM_ERR_BUFFER_TOO_SMALL: return "BUFFER_TOO_SMALL";
- case PDKIM_SIGN_PRIVKEY_WRAP: return "PRIVKEY_WRAP";
- case PDKIM_SIGN_PRIVKEY_B64D: return "PRIVKEY_B64D";
- default: return "(unknown)";
+ 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)";
}
}
/* -------------------------------------------------------------------------- */
/* Print debugging functions */
-static void
+void
pdkim_quoteprint(const uschar *data, int len)
{
-int i;
-for (i = 0; i < len; i++)
+for (int i = 0; i < len; i++)
{
const int c = data[i];
switch (c)
debug_printf("\n");
}
-static void
+void
pdkim_hexprint(const uschar *data, int len)
{
-int i;
-for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+if (data) for (int i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+else debug_printf("<NULL>");
debug_printf("\n");
}
static pdkim_stringlist *
pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str)
{
-pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist));
+pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), FALSE);
memset(new_entry, 0, sizeof(pdkim_stringlist));
new_entry->value = string_copy(str);
/* Trim whitespace fore & aft */
static void
-pdkim_strtrim(uschar * str)
+pdkim_strtrim(gstring * str)
{
-uschar * p = str;
-uschar * q = str;
-while (*p == '\t' || *p == ' ') p++; /* skip whitespace */
-while (*p) {*q = *p; q++; p++;} /* dump the leading whitespace */
-*q = '\0';
-while (q != str && ( (*q == '\0') || (*q == '\t') || (*q == ' ') ) )
- { /* dump trailing whitespace */
- *q = '\0';
- q--;
- }
+uschar * p = str->s;
+uschar * q;
+
+while (*p == '\t' || *p == ' ') /* dump the leading whitespace */
+ { str->size--; str->ptr--; str->s++; }
+
+while ( str->ptr > 0
+ && ((q = str->s + str->ptr - 1), (*q == '\t' || *q == ' '))
+ )
+ str->ptr--; /* dump trailing whitespace */
+
+(void) string_from_gstring(str);
}
/* -------------------------------------------------------------------------- */
/* Matches the name of the passed raw "header" against
the passed colon-separated "tick", and invalidates
- the entry in tick. Returns OK or fail-code */
-/*XXX might be safer done using a pdkim_stringlist for "tick" */
+ the entry in tick. Entries can be prefixed for multi- or over-signing,
+ in which case do not invalidate.
+
+ Returns OK for a match, or fail-code
+*/
static int
header_name_match(const uschar * header, uschar * tick)
{
-uschar * hname;
-uschar * lcopy;
-uschar * p;
-uschar * q;
+const uschar * ticklist = tick;
+int sep = ':';
+BOOL multisign;
+uschar * hname, * p, * ele;
uschar * hcolon = Ustrchr(header, ':'); /* Get header name */
if (!hcolon)
/* 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 */
-p = lcopy = string_copy(tick);
-
-for (q = Ustrchr(p, ':'); q; q = Ustrchr(p, ':'))
+while (p = US ticklist, ele = string_nextinlist(&ticklist, &sep, NULL, 0))
{
- *q = '\0';
- if (strcmpic(p, hname) == 0)
- goto found;
-
- p = q+1;
+ switch (*ele)
+ {
+ case '=': case '+': multisign = TRUE; ele++; break;
+ default: multisign = FALSE; break;
}
-if (strcmpic(p, hname) == 0)
- goto found;
-
+ if (strcmpic(ele, hname) == 0)
+ {
+ if (!multisign)
+ *p = '_'; /* Invalidate this header name instance in tick-off list */
+ return PDKIM_OK;
+ }
+ }
return PDKIM_FAIL;
-
-found:
- /* Invalidate header name instance in tick-off list */
- tick[p-lcopy] = '_';
- return PDKIM_OK;
}
/* -------------------------------------------------------------------------- */
/* Performs "relaxed" canonicalization of a header. */
-static uschar *
-pdkim_relax_header(const uschar * 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;
-const uschar * p;
-uschar * relaxed = store_get(Ustrlen(header)+3);
+uschar * relaxed = store_get(len+3, TRUE); /* tainted */
uschar * q = relaxed;
-for (p = header; *p; p++)
+for (const uschar * p = header; p - header < len; p++)
{
uschar c = *p;
- /* Ignore CR & LF */
- if (c == '\r' || c == '\n')
+
+ 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 */
-if (crlf) { *q++ = '\r'; *q++ = '\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 uschar *
-pdkim_decode_qp_char(uschar *qp_p, int *c)
+static const uschar *
+pdkim_decode_qp_char(const uschar *qp_p, int *c)
{
-uschar *initial_pos = qp_p;
+const uschar *initial_pos = qp_p;
/* Advance one char */
qp_p++;
/* -------------------------------------------------------------------------- */
static uschar *
-pdkim_decode_qp(uschar * str)
+pdkim_decode_qp(const uschar * str)
{
int nchar = 0;
uschar * q;
-uschar * p = str;
-uschar * n = store_get(Ustrlen(str)+1);
+const uschar * p = str;
+uschar * n = store_get(Ustrlen(str)+1, TRUE);
*n = '\0';
q = n;
/* -------------------------------------------------------------------------- */
-static void
-pdkim_decode_base64(uschar *str, blob * b)
+void
+pdkim_decode_base64(const uschar * str, blob * b)
{
-int dlen;
-dlen = b64decode(str, &b->data);
+int dlen = b64decode(str, &b->data);
if (dlen < 0) b->data = NULL;
b->len = dlen;
}
-static uschar *
+uschar *
pdkim_encode_base64(blob * b)
{
-return b64encode(b->data, b->len);
+return b64encode(CUS b->data, b->len);
}
#define PDKIM_HDR_VALUE 2
static pdkim_signature *
-pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr)
+pdkim_parse_sig_header(pdkim_ctx * ctx, uschar * raw_hdr)
{
-pdkim_signature *sig ;
-uschar *p, *q;
-uschar * cur_tag = NULL; int ts = 0, tl = 0;
-uschar * cur_val = NULL; int vs = 0, vl = 0;
+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;
-sig = store_get(sizeof(pdkim_signature));
+sig = store_get(sizeof(pdkim_signature), FALSE);
memset(sig, 0, sizeof(pdkim_signature));
sig->bodylength = -1;
/* Set so invalid/missing data error display is accurate */
-sig->algo = -1;
sig->version = 0;
+sig->keytype = -1;
+sig->hashtype = -1;
-q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1);
+q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, TRUE); /* tainted */
-for (p = raw_hdr; ; p++)
+for (uschar * p = raw_hdr; ; p++)
{
char c = *p;
if (where == PDKIM_HDR_TAG)
{
if (c >= 'a' && c <= 'z')
- cur_tag = string_catn(cur_tag, &ts, &tl, p, 1);
+ cur_tag = string_catn(cur_tag, p, 1);
if (c == '=')
{
- cur_tag[tl] = '\0';
- if (Ustrcmp(cur_tag, "b") == 0)
+ if (Ustrcmp(string_from_gstring(cur_tag), "b") == 0)
{
*q++ = '=';
in_b_val = TRUE;
if (c == ';' || c == '\0')
{
- if (tl && vl)
+ /* 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')
+ )
{
- cur_val[vl] = '\0';
+ (void) string_from_gstring(cur_val);
pdkim_strtrim(cur_val);
- DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val);
+ DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->s, cur_val->s);
- switch (*cur_tag)
+ switch (*cur_tag->s)
{
- case 'b':
- if (cur_tag[1] == 'h')
- pdkim_decode_base64(cur_val, &sig->bodyhash);
- else
- pdkim_decode_base64(cur_val, &sig->sigdata);
+ 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. */
sig->version =
- Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1;
- break;
- case 'a':
- for (i = 0; pdkim_algos[i]; i++)
- if (Ustrcmp(cur_val, pdkim_algos[i]) == 0)
- {
- sig->algo = i;
- break;
- }
+ Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1;
break;
- case 'c':
- for (i = 0; pdkim_combined_canons[i].str; i++)
- if (Ustrcmp(cur_val, 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 (Ustrcmp(cur_val, 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 = string_copy(cur_val); break;
- case 'd':
- sig->domain = string_copy(cur_val); break;
- case 'i':
- sig->identity = pdkim_decode_qp(cur_val); break;
- case 't':
- sig->created = strtoul(CS cur_val, NULL, 10); break;
- case 'x':
- sig->expires = strtoul(CS cur_val, NULL, 10); break;
- case 'l':
- sig->bodylength = strtol(CS cur_val, NULL, 10); break;
- case 'h':
- sig->headernames = string_copy(cur_val); break;
- case 'z':
- sig->copiedheaders = pdkim_decode_qp(cur_val); 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;
}
}
- tl = 0;
- vl = 0;
+ cur_tag = cur_val = NULL;
in_b_val = FALSE;
where = PDKIM_HDR_LIMBO;
}
else
- cur_val = string_catn(cur_val, &vs, &vl, p, 1);
+ cur_val = string_catn(cur_val, p, 1);
}
NEXT_CHAR:
*q++ = c;
}
+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. */
while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n'))
DEBUG(D_acl)
{
debug_printf(
- "PDKIM >> Raw signature w/o b= tag value >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ "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: %4u bits\n", (unsigned) sig->sigdata.len*8);
+ "DKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8);
debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-exim_sha_init(&sig->body_hash, sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256);
+if (!pdkim_set_sig_bodyhash(ctx, sig))
+ return NULL;
+
return sig;
}
/* -------------------------------------------------------------------------- */
-static pdkim_pubkey *
-pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record)
+pdkim_pubkey *
+pdkim_parse_pubkey_record(const uschar *raw_record)
{
-pdkim_pubkey *pub;
-const uschar *p;
-uschar * cur_tag = NULL; int ts = 0, tl = 0;
-uschar * cur_val = NULL; int vs = 0, vl = 0;
-int where = PDKIM_HDR_LIMBO;
+const uschar * ele;
+int sep = ';';
+pdkim_pubkey * pub;
-pub = store_get(sizeof(pdkim_pubkey));
+pub = store_get(sizeof(pdkim_pubkey), TRUE); /* 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;
+ const uschar * val;
- where = PDKIM_HDR_TAG;
- }
-
- if (where == PDKIM_HDR_TAG)
+ if ((val = Ustrchr(ele, '=')))
{
- if (c >= 'a' && c <= 'z')
- cur_tag = string_catn(cur_tag, &ts, &tl, p, 1);
+ int taglen = val++ - ele;
- if (c == '=')
+ DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val);
+ switch (ele[0])
{
- cur_tag[tl] = '\0';
- where = PDKIM_HDR_VALUE;
- goto NEXT_CHAR;
- }
- }
-
- if (where == PDKIM_HDR_VALUE)
- {
- if (c == ';' || c == '\0')
- {
- if (tl && vl)
- {
- cur_val[vl] = '\0';
- pdkim_strtrim(cur_val);
- DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag, cur_val);
-
- switch (cur_tag[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':
- case 'k':
- pub->hashes = string_copy(cur_val); break;
- case 'g':
- pub->granularity = string_copy(cur_val); break;
- case 'n':
- pub->notes = pdkim_decode_qp(cur_val); break;
- case 'p':
- pdkim_decode_base64(US cur_val, &pub->key);
- break;
- case 's':
- pub->srvtype = string_copy(cur_val); break;
- case 't':
- if (Ustrchr(cur_val, 'y') != NULL) pub->testing = 1;
- if (Ustrchr(cur_val, 's') != NULL) pub->no_subdomaining = 1;
- break;
- default:
- DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
- break;
- }
- }
- tl = 0;
- vl = 0;
- 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
- cur_val = string_catn(cur_val, &vs, &vl, p, 1);
}
-
-NEXT_CHAR:
- if (c == '\0') break;
}
/* Set fallback defaults */
-if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
-if (!pub->granularity) pub->granularity = string_copy(US"*");
-if (!pub->keytype ) pub->keytype = string_copy(US"rsa");
-if (!pub->srvtype ) pub->srvtype = string_copy(US"*");
+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.data)
return pub;
+DEBUG(D_acl) debug_printf(" Missing p= field\n");
return NULL;
}
/* -------------------------------------------------------------------------- */
-static 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, blob * orig_data, blob * relaxed_data)
{
-pdkim_signature *sig = ctx->sig;
-/* Cache relaxed version of data */
-uschar *relaxed_data = NULL;
-int relaxed_len = 0;
+blob * canon_data = orig_data;
+/* Defaults to simple canon (no further treatment necessary) */
-/* Traverse all signatures, updating their hashes. */
-while (sig)
+if (b->canon_method == PDKIM_CANON_RELAXED)
{
- /* Defaults to simple canon (no further treatment necessary) */
- const uschar *canon_data = CUS data;
- int canon_len = len;
-
- if (sig->canon_body == 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;
- /* 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(). */
+ /* 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(). */
- relaxed_data = store_malloc(len+1);
+ relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1);
+ relaxed_data->data = US (relaxed_data+1);
- 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;
+ 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)
- {
- exim_sha_update(&sig->body_hash, CUS canon_data, canon_len);
- sig->signed_body_bytes += canon_len;
- DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len);
- }
+/* Make sure we don't exceed the to-be-signed body length */
+if ( b->bodylength >= 0
+ && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength
+ )
+ canon_data->len = b->bodylength - b->signed_body_bytes;
- sig = sig->next;
+if (canon_data->len > 0)
+ {
+ exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, canon_data->len);
+ b->signed_body_bytes += canon_data->len;
+ DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len);
}
-if (relaxed_data) store_free(relaxed_data);
-return PDKIM_OK;
+return relaxed_data;
}
/* -------------------------------------------------------------------------- */
static void
-pdkim_finish_bodyhash(pdkim_ctx *ctx)
+pdkim_finish_bodyhash(pdkim_ctx * ctx)
{
-pdkim_signature *sig;
+for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) /* Finish hashes */
+ {
+ DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %d/%d/%ld len %ld\n",
+ b->hashtype, b->canon_method, b->bodylength, b->signed_body_bytes);
+ exim_sha_finish(&b->body_hash_ctx, &b->bh);
+ }
/* Traverse all signatures */
-for (sig = ctx->sig; sig; sig = sig->next)
- { /* Finish hashes */
- blob bh;
-
- exim_sha_finish(&sig->body_hash, &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(CUS bh.data, bh.len);
+ debug_printf("DKIM [%s] Body bytes (%s) hashed: %lu\n"
+ "DKIM [%s] Body %s computed: ",
+ sig->domain, pdkim_canons[b->canon_method], b->signed_body_bytes,
+ sig->domain, pdkim_hashes[b->hashtype].dkim_hashname);
+ pdkim_hexprint(CUS b->bh.data, b->bh.len);
}
/* SIGNING -------------------------------------------------------------- */
if (ctx->flags & PDKIM_MODE_SIGN)
{
- sig->bodyhash = bh;
-
/* 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.data, sig->bodyhash.data, bh.len) == 0)
+ /* VERIFICATION --------------------------------------------------------- */
+ /* Be careful that the header sig included a bodyash */
+
+ if ( sig->bodyhash.data
+ && 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.data,
- exim_sha_hashlen(&sig->body_hash));
- 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;
}
- }
}
}
-static int
+static void
pdkim_body_complete(pdkim_ctx * ctx)
{
-pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */
-
/* 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);
+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;
-return PDKIM_OK;
}
/* -------------------------------------------------------------------------- */
/* 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->flags & PDKIM_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 (ctx->flags & PDKIM_DOT_TERM)
{
- if ( memcmp(p, ".\r\n", 3) == 0)
- return pdkim_body_complete(ctx);
+ if (memcmp(line.data, ".\r\n", 3) == 0)
+ { pdkim_body_complete(ctx); return; }
/* Unstuff dots */
- if (memcmp(p, "..", 2) == 0)
- {
- p++;
- n--;
- }
+ 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;
- if (c != '\t' && c != ' ')
- goto PROCESS;
- check++;
+ while ((c = *cp))
+ {
+ if (c == '\r' && cp[1] == '\n') break;
+ if (c != ' ' && c != '\t') goto hash_process;
+ cp++;
+ }
+
+ 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;
}
#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
static int
-pdkim_header_complete(pdkim_ctx *ctx)
+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[(ctx->cur_header_len)-1] == '\r') )
- --ctx->cur_header_len;
-ctx->cur_header[ctx->cur_header_len] = '\0';
+if ( (ctx->cur_header->ptr > 1) &&
+ (ctx->cur_header->s[ctx->cur_header->ptr-1] == '\r') )
+ --ctx->cur_header->ptr;
+(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->flags & PDKIM_MODE_SIGN)
- {
- pdkim_signature *sig;
-
- for (sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */
+ for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next) /* Traverse all signatures */
/* Add header to the signed headers list (in reverse order) */
- sig->headers = pdkim_prepend_stringlist(sig->headers,
- ctx->cur_header);
- }
+ sig->headers = pdkim_prepend_stringlist(sig->headers, ctx->cur_header->s);
/* VERIFICATION ----------------------------------------------------------- */
/* DKIM-Signature: headers are added to the verification list */
else
{
- if (strncasecmp(CCS ctx->cur_header,
+#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,
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");
+
+ sig = pdkim_parse_sig_header(ctx, ctx->cur_header->s);
- if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header)))
+ 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;
+ }
+
+ if (--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;
}
- else
- DEBUG(D_acl) debug_printf(
- "Error while parsing signature header\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
- /* every other header is stored for signature verification */
- else
- ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header);
+ /* all headers are stored for signature verification */
+ ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s);
}
BAIL:
-*ctx->cur_header = '\0';
-ctx->cur_header_len = 0; /* leave buffer for reuse */
+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);
-else for (p = 0; p<len; p++)
+else for (int p = 0; p < len; p++)
{
uschar c = data[p];
+ int rc;
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->flags & PDKIM_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->flags = ctx->flags & ~PDKIM_SEEN_LF | PDKIM_PAST_HDRS;
- DEBUG(D_acl) debug_printf(
- "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>\n");
- continue;
- }
- else
- ctx->flags |= PDKIM_SEEN_LF;
- }
- else if (ctx->flags & PDKIM_SEEN_LF)
- {
- if (!(c == '\t' || c == ' '))
- {
- int rc = pdkim_header_complete(ctx); /* End of header */
- if (rc != PDKIM_OK) return rc;
- }
- ctx->flags &= ~PDKIM_SEEN_LF;
+ 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_len < PDKIM_MAX_HEADER_LEN)
- ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size,
- &ctx->cur_header_len, CUS &data[p], 1);
+ 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 grwong header with a continuation-linebreak */
-static uschar *
-pdkim_hdr_cont(uschar * str, int * size, int * ptr, int * col)
+/* Extend a growing header with a continuation-linebreak */
+static gstring *
+pdkim_hdr_cont(gstring * str, int * col)
{
*col = 1;
-return string_catn(str, size, ptr, US"\r\n\t", 3);
+return string_catn(str, US"\r\n\t", 3);
}
*
* col: this int holds and receives column number (octets since last '\n')
* str: partial string to append to
- * size: current buffer size for str
- * ptr: current tail-pointer for str
* pad: padding, split line or space after before or after eg: ";"
* intro: - must join to payload eg "h=", usually the tag name
* payload: eg base64 data - long data can be split arbitrarily.
* names longer than 78, or bogus col. Input is assumed to be free of line breaks.
*/
-static uschar *
-pdkim_headcat(int * col, uschar * str, int * size, int * ptr,
+static gstring *
+pdkim_headcat(int * col, gstring * str,
const uschar * pad, const uschar * intro, const uschar * payload)
{
size_t l;
{
l = Ustrlen(pad);
if (*col + l > 78)
- str = pdkim_hdr_cont(str, size, ptr, col);
- str = string_catn(str, size, ptr, pad, l);
+ str = pdkim_hdr_cont(str, col);
+ str = string_catn(str, pad, l);
*col += l;
}
if (*col + l > 78)
{ /*can't fit intro - start a new line to make room.*/
- str = pdkim_hdr_cont(str, size, ptr, col);
+ str = pdkim_hdr_cont(str, col);
l = intro?Ustrlen(intro):0;
}
{ /* this fragment will not fit on a single line */
if (pad)
{
- str = string_catn(str, size, ptr, US" ", 1);
+ str = string_catn(str, US" ", 1);
*col += 1;
pad = NULL; /* only want this once */
l--;
{
size_t sl = Ustrlen(intro);
- str = string_catn(str, size, ptr, intro, sl);
+ str = string_catn(str, intro, sl);
*col += sl;
l -= sl;
intro = NULL; /* only want this once */
size_t sl = Ustrlen(payload);
size_t chomp = *col+sl < 77 ? sl : 78-*col;
- str = string_catn(str, size, ptr, payload, chomp);
+ str = string_catn(str, payload, chomp);
*col += chomp;
payload += chomp;
l -= chomp-1;
}
/* the while precondition tells us it didn't fit. */
- str = pdkim_hdr_cont(str, size, ptr, col);
+ str = pdkim_hdr_cont(str, col);
}
if (*col + l > 78)
{
- str = pdkim_hdr_cont(str, size, ptr, col);
+ str = pdkim_hdr_cont(str, col);
pad = NULL;
}
if (pad)
{
- str = string_catn(str, size, ptr, US" ", 1);
+ str = string_catn(str, US" ", 1);
*col += 1;
pad = NULL;
}
{
size_t sl = Ustrlen(intro);
- str = string_catn(str, size, ptr, intro, sl);
+ str = string_catn(str, intro, sl);
*col += sl;
l -= sl;
intro = NULL;
{
size_t sl = Ustrlen(payload);
- str = string_catn(str, size, ptr, payload, sl);
+ str = string_catn(str, payload, sl);
*col += sl;
}
/* -------------------------------------------------------------------------- */
+/* Signing: create signature header
+*/
static uschar *
-pdkim_create_header(pdkim_signature *sig, BOOL final)
+pdkim_create_header(pdkim_signature * sig, BOOL final)
{
uschar * base64_bh;
uschar * base64_b;
int col = 0;
-uschar * hdr; int hdr_size = 0, hdr_len = 0;
-uschar * canon_all; int can_size = 0, can_len = 0;
+gstring * hdr;
+gstring * canon_all;
-canon_all = string_cat (NULL, &can_size, &can_len,
- pdkim_canons[sig->canon_headers]);
-canon_all = string_catn(canon_all, &can_size, &can_len, US"/", 1);
-canon_all = string_cat (canon_all, &can_size, &can_len,
- pdkim_canons[sig->canon_body]);
-canon_all[can_len] = '\0';
+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, &hdr_size, &hdr_len,
- US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
-col = hdr_len;
+hdr = string_cat(NULL, US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION);
+col = hdr->ptr;
/* Required and static bits */
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=",
- pdkim_algos[sig->algo]);
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=",
- pdkim_querymethods[sig->querymethod]);
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"c=",
- canon_all);
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"d=",
- sig->domain);
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"s=",
- sig->selector);
+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. */
{
if (c) *c ='\0';
if (!i)
- hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, NULL, US":");
+ hdr = pdkim_headcat(&col, hdr, NULL, NULL, US":");
- hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, s, i, n);
+ hdr = pdkim_headcat(&col, hdr, s, i, n);
if (!c)
break;
}
}
-base64_bh = pdkim_encode_base64(&sig->bodyhash);
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"bh=", base64_bh);
+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, &hdr_size, &hdr_len, US";", US"i=", sig->identity);
+ hdr = pdkim_headcat(&col, hdr, US";", US"i=", sig->identity);
if (sig->created > 0)
{
uschar minibuf[20];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created);
- hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"t=", minibuf);
+ hdr = pdkim_headcat(&col, hdr, US";", US"t=", minibuf);
}
if (sig->expires > 0)
uschar minibuf[20];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires);
- hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"x=", minibuf);
+ hdr = pdkim_headcat(&col, hdr, US";", US"x=", minibuf);
}
if (sig->bodylength >= 0)
uschar minibuf[20];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength);
- hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"l=", minibuf);
+ hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf);
}
/* Preliminary or final version? */
-base64_b = final ? pdkim_encode_base64(&sig->sigdata) : US"";
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"b=", base64_b);
+if (final)
+ {
+ base64_b = pdkim_encode_base64(&sig->sighash);
+ hdr = pdkim_headcat(&col, hdr, US";", US"b=", base64_b);
+
+ /* 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 string_from_gstring(hdr);
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+/* 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)
+{
+int excess = p->key.len - 32;
+if (excess > 0)
+ {
+ DEBUG(D_acl) debug_printf("DKIM: unexpected pubkey len %lu\n", p->key.len);
+ p->key.data += excess; p->key.len = 32;
+ }
+}
+
+
+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;
+
+/* Fetch public key for signing domain, from DNS */
+
+dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain);
+
+if ( !(dns_txt_reply = ctx->dns_txt_callback(dns_txt_name))
+ || dns_txt_reply[0] == '\0'
+ )
+ {
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
+ return NULL;
+ }
+
+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 ( !(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;
+
+ 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");
+
+/* Import public key */
+
+/* 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->keytype < 0)
+ if ((sig->keytype = pdkim_keyname_to_keytype(p->keytype)) < 0)
+ {
+ 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);
+
+if ((*errstr = exim_dkim_verify_init(&p->key,
+ sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER,
+ vctx)))
+ {
+ 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;
+ }
+
+vctx->keytype = sig->keytype;
+return p;
+}
+
+
+/* -------------------------------------------------------------------------- */
+/* Sort and filter the sigs developed from the message */
+
+static pdkim_signature *
+sort_sig_methods(pdkim_signature * siglist)
+{
+pdkim_signature * yield, ** ss;
+const uschar * prefs;
+uschar * ele;
+int sep;
+
+if (!siglist) return NULL;
-/* add trailing semicolon: I'm not sure if this is actually needed */
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US"");
+/* 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)
+ {
+ next = s->next;
+ if (s->hashtype == i)
+ { *prev = next; s->next = NULL; *ss = s; ss = &s->next; }
+ else
+ prev = &s->next;
+ }
+ }
-hdr[hdr_len] = '\0';
-return hdr;
+/* 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;
+ }
+ }
+
+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;
+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. Do this even if no DKIM sigs, in case we
+have a hash to do for ARC. */
-/* Build (and/or evaluate) body hash */
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)
+ {
+ DEBUG(D_acl) debug_printf("DKIM: no signatures\n");
+ *return_signatures = NULL;
+ return PDKIM_OK;
+ }
+
+for (pdkim_signature * sig = ctx->sig; sig; sig = sig->next)
{
- BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1;
hctx hhash_ctx;
uschar * sig_hdr = US"";
blob hhash;
- blob hdata;
- int hdata_alloc = 0;
+ gstring * hdata = NULL;
+ es_ctx sctx;
- hdata.data = NULL;
- hdata.len = 0;
+ 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;
+ }
- exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256);
+ 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
if (ctx->flags & PDKIM_MODE_SIGN)
{
- uschar * headernames = NULL; /* Collected signed header names */
- int hs = 0, hl = 0;
- pdkim_stringlist *p;
+ gstring * g = NULL;
const uschar * l;
uschar * s;
int sep = 0;
- for (p = sig->headers; p; p = p->next)
- if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK)
+ /* Import private key, including the keytype which we need for building
+ the signature header */
+
+ if ((*err = exim_dkim_signing_init(CUS sig->privkey, &sctx)))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing_init: %s", *err);
+ return PDKIM_ERR_RSA_PRIVKEY;
+ }
+ sig->keytype = sctx.keytype;
+
+ 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)
{
- uschar * rh;
/* Collect header names (Note: colon presence is guaranteed here) */
- uschar * q = Ustrchr(p->value, ':');
-
- headernames = string_catn(headernames, &hs, &hl,
- p->value, (q - US p->value) + (p->next ? 1 : 0));
+ g = string_append_listele_n(g, ':', rh, Ustrchr(rh, ':') - rh);
- rh = sig->canon_headers == PDKIM_CANON_RELAXED
- ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
- : string_copy(CUS p->value); /* just copy it for simple canon */
+ 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(&hhash_ctx, CUS rh, Ustrlen(rh));
/* Remember headers block for signing (when the library cannot do incremental) */
- (void) exim_rsa_data_append(&hdata, &hdata_alloc, rh);
+ /*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 != '_')
- { /*SSS string_append_listele() */
- if (hl > 0 && headernames[hl-1] != ':')
- headernames = string_catn(headernames, &hs, &hl, US":", 1);
-
- headernames = string_cat(headernames, &hs, &hl, s);
- }
- headernames[hl] = '\0';
-
- /* Copy headernames to signature struct */
- sig->headernames = headernames;
+ {
+ 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);
{
uschar * p = sig->headernames;
uschar * q;
- pdkim_stringlist * hdrs;
if (p)
{
/* clear tags */
- for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+ for (pdkim_stringlist * hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
hdrs->tag = 0;
p = string_copy(p);
*q = '\0';
/*XXX walk the list of headers in same order as received. */
- for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next)
+ 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, 1)
+ ? pdkim_relax_header(hdrs->value, TRUE)
: string_copy(CUS hdrs->value);
/* Feed header to the hash algorithm */
}
DEBUG(D_acl) debug_printf(
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+
+ DEBUG(D_acl)
+ {
+ debug_printf(
+ "DKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n");
+ pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
+ debug_printf(
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ }
/* Relax header if necessary */
if (sig->canon_headers == PDKIM_CANON_RELAXED)
- sig_hdr = pdkim_relax_header(sig_hdr, 0);
+ sig_hdr = pdkim_relax_header(sig_hdr, FALSE);
DEBUG(D_acl)
{
- debug_printf(
- "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
+ 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 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
/* Finalize header hash */
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] hh computed: ", sig->domain);
+ debug_printf("DKIM [%s] Header %s computed: ",
+ sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname);
pdkim_hexprint(hhash.data, hhash.len);
}
- /* Remember headers block for signing (when the library cannot do incremental) */
+ /* Remember headers block for signing (when the signing library cannot do
+ incremental) */
if (ctx->flags & PDKIM_MODE_SIGN)
- (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr);
+ hdata = exim_dkim_data_append(hdata, US sig_hdr);
/* SIGNING ---------------------------------------------------------------- */
if (ctx->flags & PDKIM_MODE_SIGN)
{
- es_ctx sctx;
- const uschar * errstr;
-
- /* Import private key */
- if ((errstr = exim_rsa_signing_init(US sig->rsa_privkey, &sctx)))
- {
- DEBUG(D_acl) debug_printf("signing_init: %s\n", errstr);
- return PDKIM_ERR_RSA_PRIVKEY;
- }
+ hashmethod hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+ ? HASH_NULL
+#else
+ ? HASH_SHA2_512
+#endif
+ : pdkim_hashes[sig->hashtype].exim_hashmethod;
- /* Do signing. With OpenSSL we are signing the hash of headers just
- calculated, with GnuTLS we have to sign an entire block of headers
- (due to available interfaces) and it recalculates the hash internally. */
+#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 defined(RSA_OPENSSL) || defined(RSA_GCRYPT)
- hdata = hhash;
+ if (sig->keytype != KEYTYPE_ED25519)
#endif
+ {
+ hhash.data = hdata->s;
+ hhash.len = hdata->ptr;
+ }
- if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sigdata)))
+ if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash)))
{
- DEBUG(D_acl) debug_printf("signing: %s\n", errstr);
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err);
return PDKIM_ERR_RSA_SIGNING;
}
DEBUG(D_acl)
{
- debug_printf( "PDKIM [%s] b computed: ", sig->domain);
- pdkim_hexprint(sig->sigdata.data, sig->sigdata.len);
+ debug_printf( "DKIM [%s] b computed: ", sig->domain);
+ pdkim_hexprint(sig->sighash.data, sig->sighash.len);
}
sig->signature_header = pdkim_create_header(sig, TRUE);
else
{
ev_ctx vctx;
- const uschar * errstr;
-
- uschar *dns_txt_name, *dns_txt_reply;
+ 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->sigdata.data
- && sig->algo > -1
+ && sig->sighash.data
+ && sig->keytype >= 0
+ && sig->hashtype >= 0
&& sig->version
) )
{
sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR;
DEBUG(D_acl) debug_printf(
- " Error in DKIM-Signature header: tags missing or invalid\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ " 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;
}
DEBUG(D_acl) debug_printf(
" Error in DKIM-Signature header: unsupported DKIM version\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
- goto NEXT_VERIFY;
- }
-
- /* Fetch public key for signing domain, from DNS */
-
- dns_txt_name = string_sprintf("%s._domainkey.%s.",
- sig->selector, sig->domain);
-
- dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN);
- memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN);
-
- if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK
- || dns_txt_reply[0] == '\0')
- {
- sig->verify_status = PDKIM_VERIFY_INVALID;
- sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE;
+ "DKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
goto NEXT_VERIFY;
}
DEBUG(D_acl)
{
- debug_printf(
- "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"
- " Raw record: ");
- pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply));
+ 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, CUS 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_DNSRECORD;
-
- 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 */
- /* Import public key */
- if ((errstr = exim_rsa_verify_init(&sig->pubkey->key, &vctx)))
+ if (sig->pubkey->hashes)
{
- 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;
- 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 ((errstr = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sigdata)))
+
+ if ((*err = exim_dkim_verify(&vctx, hm, &hhash, &sig->sighash)))
{
- DEBUG(D_acl) debug_printf("headers verify: %s\n", errstr);
+ 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;
}
- /* 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));
debug_printf("\n");
}
}
-
- 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 *), BOOL dot_stuffing)
+pdkim_init_verify(uschar * (*dns_txt_callback)(const uschar *), BOOL dot_stuffing)
{
pdkim_ctx * ctx;
-ctx = store_get(sizeof(pdkim_ctx));
+ctx = store_get(sizeof(pdkim_ctx), FALSE);
memset(ctx, 0, sizeof(pdkim_ctx));
if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM;
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN);
+/* The line-buffer is for message data, hence tainted */
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE);
ctx->dns_txt_callback = dns_txt_callback;
return ctx;
/* -------------------------------------------------------------------------- */
-DLLEXPORT pdkim_ctx *
-pdkim_init_sign(char *domain, char *selector, char *rsa_privkey, int algo,
- BOOL dot_stuffed)
+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;
-ctx = store_get(sizeof(pdkim_ctx));
-memset(ctx, 0, sizeof(pdkim_ctx));
+/* Allocate & init one signature struct */
-ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN);
-
-sig = store_get(sizeof(pdkim_signature));
+sig = store_get(sizeof(pdkim_signature), FALSE);
memset(sig, 0, sizeof(pdkim_signature));
sig->bodylength = -1;
-ctx->sig = sig;
sig->domain = string_copy(US domain);
sig->selector = string_copy(US selector);
-sig->rsa_privkey = string_copy(US rsa_privkey);
-sig->algo = algo;
+sig->privkey = string_copy(US privkey);
+sig->keytype = -1;
-exim_sha_init(&sig->body_hash, algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256);
-return ctx;
+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))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "DKIM: unrecognised hashname '%s'", hashname);
+ return NULL;
+ }
+
+DEBUG(D_acl)
+ {
+ 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");
+ }
+return sig;
}
/* -------------------------------------------------------------------------- */
-DLLEXPORT int
-pdkim_set_optional(pdkim_ctx *ctx,
- char *sign_headers,
- char *identity,
+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)
{
-pdkim_signature * sig = ctx->sig;
-
if (identity)
sig->identity = string_copy(US identity);
sig->created = created;
sig->expires = expires;
-return PDKIM_OK;
+return;
+}
+
+
+
+/* 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 %d/%d/%ld\n",
+ hashtype, canon_method, bodylength);
+ return b;
+ }
+
+DEBUG(D_receive) debug_printf("DKIM: new bodyhash %d/%d/%ld\n",
+ hashtype, canon_method, bodylength);
+b = store_get(sizeof(pdkim_bodyhash), FALSE);
+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;
+}
+
+
+/* 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;
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+
+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, TRUE);
+DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback;
}
void
pdkim_init(void)
{
-exim_rsa_init();
+exim_dkim_init();
}
git://git.exim.org / users / jgh / exim.git / blobdiff