* 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 - 2017 Jeremy Harris <jgh@exim.org>
*
* http://duncanthrax.net/pdkim/
*
#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"
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
+
+typedef struct {
+ const uschar * dkim_hashname;
+ hashmethod exim_hashmethod;
+} pdkim_hashtype;
+static 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
+ US"rsa"
};
typedef struct pdkim_combined_canon_entry {
/* -------------------------------------------------------------------------- */
+uschar *
+dkim_sig_to_a_tag(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);
+}
+
+
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"RSA_PRIVKEY";
+ case PDKIM_ERR_RSA_SIGNING: return US"RSA SIGNING";
+ case PDKIM_ERR_LONG_LINE: return US"RSA_LONG_LINE";
+ case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL";
+ case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP";
+ case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D";
+ default: return US"(unknown)";
}
}
pdkim_hexprint(const uschar *data, int len)
{
int i;
-for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]);
+else debug_printf("<NULL>");
debug_printf("\n");
}
/* Performs "relaxed" canonicalization of a header. */
static uschar *
-pdkim_relax_header(const uschar * header, int crlf)
+pdkim_relax_header(const uschar * header, BOOL append_crlf)
{
BOOL past_field_name = FALSE;
BOOL seen_wsp = FALSE;
for (p = header; *p; 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;
}
/* -------------------------------------------------------------------------- */
#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;
+const uschar * p = str;
uschar * n = store_get(Ustrlen(str)+1);
*n = '\0';
/* -------------------------------------------------------------------------- */
static void
-pdkim_decode_base64(uschar *str, blob * b)
+pdkim_decode_base64(const uschar * str, blob * b)
{
int dlen;
dlen = b64decode(str, &b->data);
static pdkim_signature *
pdkim_parse_sig_header(pdkim_ctx *ctx, uschar * raw_hdr)
{
-pdkim_signature *sig ;
+pdkim_signature * sig;
uschar *p, *q;
uschar * cur_tag = NULL; int ts = 0, tl = 0;
uschar * cur_val = NULL; int vs = 0, vl = 0;
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);
switch (*cur_tag)
{
case 'b':
- if (cur_tag[1] == 'h')
- pdkim_decode_base64(cur_val, &sig->bodyhash);
- else
- pdkim_decode_base64(cur_val, &sig->sigdata);
+ pdkim_decode_base64(cur_val,
+ cur_tag[1] == 'h' ? &sig->bodyhash : &sig->sighash);
break;
case 'v':
/* We only support version 1, and that is currently the
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;
- }
+ {
+ uschar * s = Ustrchr(cur_val, '-');
+
+ for(i = 0; i < nelem(pdkim_keytypes); i++)
+ if (Ustrncmp(cur_val, pdkim_keytypes[i], s - cur_val) == 0)
+ { sig->keytype = i; break; }
+ for (++s, i = 0; i < nelem(pdkim_hashes); i++)
+ if (Ustrcmp(s, pdkim_hashes[i].dkim_hashname) == 0)
+ { sig->hashtype = i; break; }
break;
+ }
+
case 'c':
for (i = 0; pdkim_combined_canons[i].str; i++)
if (Ustrcmp(cur_val, pdkim_combined_canons[i].str) == 0)
"PDKIM >> 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);
+ "PDKIM >> Sig size: %4u bits\n", (unsigned) sig->sighash.len*8);
debug_printf(
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-exim_sha_init(&sig->body_hash, sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256);
+/*XXX hash method: extend for sha512 */
+if (!exim_sha_init(&sig->body_hash_ctx,
+ pdkim_hashes[sig->hashtype].exim_hashmethod))
+ {
+ DEBUG(D_acl)
+ debug_printf("PDKIM: hash init error, possibly nonhandled hashtype\n");
+ return NULL;
+ }
return sig;
}
static pdkim_pubkey *
pdkim_parse_pubkey_record(pdkim_ctx *ctx, 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));
memset(pub, 0, sizeof(pdkim_pubkey));
-for (p = raw_record; ; p++)
+while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
+ {
+ const uschar * val;
+
+ if ((val = Ustrchr(ele, '=')))
{
- uschar c = *p;
+ int taglen = val++ - ele;
- /* Ignore FWS */
- if (c != '\r' && c != '\n') switch (where)
+ DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val);
+ switch (ele[0])
{
- case PDKIM_HDR_LIMBO: /* In limbo, just wait for a tag-char to appear */
- if (!(c >= 'a' && c <= 'z'))
- break;
- where = PDKIM_HDR_TAG;
- /*FALLTHROUGH*/
-
- case PDKIM_HDR_TAG:
- if (c >= 'a' && c <= 'z')
- cur_tag = string_catn(cur_tag, &ts, &tl, p, 1);
-
- if (c == '=')
- {
- cur_tag[tl] = '\0';
- where = PDKIM_HDR_VALUE;
- }
- break;
-
- case 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':
- pub->version = string_copy(cur_val); break;
- case 'h':
- case 'k':
-/* This field appears to never be used. Also, unclear why
-a 'k' (key-type_ would go in this field name. There is a field
-"keytype", also never used.
- pub->hashes = string_copy(cur_val);
-*/
+ case 'v': pub->version = val; break;
+ case 'h': pub->hashes = val; break;
+ case 'k': 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;
- 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;
- }
- else
- cur_val = string_catn(cur_val, &vs, &vl, p, 1);
- break;
+ default: DEBUG(D_acl) debug_printf(" Unknown tag encountered\n"); break;
}
-
- if (c == '\0') break;
}
+ }
/* Set fallback defaults */
if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
-else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0) return NULL;
+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 = string_copy(US"*");
+if (!pub->granularity) pub->granularity = US"*";
/*
-if (!pub->keytype ) pub->keytype = string_copy(US"rsa");
+if (!pub->keytype ) pub->keytype = US"rsa";
*/
-if (!pub->srvtype ) pub->srvtype = string_copy(US"*");
+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)
+pdkim_update_bodyhash(pdkim_ctx * ctx, const char * data, int len)
{
-pdkim_signature *sig = ctx->sig;
-/* Cache relaxed version of data */
-uschar *relaxed_data = NULL;
-int relaxed_len = 0;
+pdkim_signature * sig;
+uschar * relaxed_data = NULL; /* Cache relaxed version of data */
+int relaxed_len = 0;
/* Traverse all signatures, updating their hashes. */
-while (sig)
+for (sig = ctx->sig; sig; sig = sig->next)
{
/* Defaults to simple canon (no further treatment necessary) */
const uschar *canon_data = CUS data;
if (canon_len > 0)
{
- exim_sha_update(&sig->body_hash, CUS canon_data, canon_len);
+ exim_sha_update(&sig->body_hash_ctx, CUS canon_data, canon_len);
sig->signed_body_bytes += canon_len;
DEBUG(D_acl) pdkim_quoteprint(canon_data, canon_len);
}
-
- sig = sig->next;
}
if (relaxed_data) store_free(relaxed_data);
{ /* Finish hashes */
blob bh;
- exim_sha_finish(&sig->body_hash, &bh);
+ exim_sha_finish(&sig->body_hash_ctx, &bh);
DEBUG(D_acl)
{
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(bh.data, sig->bodyhash.data, bh.len) == 0)
{
DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain);
}
DEBUG(D_acl)
{
debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain);
- pdkim_hexprint(sig->bodyhash.data,
- exim_sha_hashlen(&sig->body_hash));
+ pdkim_hexprint(sig->bodyhash.data, sig->bodyhash.len);
debug_printf("PDKIM [%s] Body hash did NOT verify\n", sig->domain);
}
sig->verify_status = PDKIM_VERIFY_FAIL;
sig->verify_ext_status = PDKIM_VERIFY_FAIL_BODY;
}
- }
}
}
#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:"
static int
-pdkim_header_complete(pdkim_ctx *ctx)
+pdkim_header_complete(pdkim_ctx * ctx)
{
+pdkim_signature * sig, * last_sig;
+
/* 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';
-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 */
/* Add header to the signed headers list (in reverse order) */
sig->headers = pdkim_prepend_stringlist(sig->headers,
ctx->cur_header);
- }
/* VERIFICATION ----------------------------------------------------------- */
/* DKIM-Signature: headers are added to the verification list */
else
{
+#ifdef notdef
DEBUG(D_acl)
{
debug_printf("PDKIM >> raw hdr: ");
- pdkim_quoteprint(CUS ctx->cur_header, Ustrlen(ctx->cur_header));
+ pdkim_quoteprint(CUS ctx->cur_header, ctx->cur_header_len);
}
+#endif
if (strncasecmp(CCS ctx->cur_header,
DKIM_SIGNATURE_HEADERNAME,
Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0)
{
- pdkim_signature *new_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");
- if ((new_sig = pdkim_parse_sig_header(ctx, ctx->cur_header)))
+ 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;
}
- else
- DEBUG(D_acl) debug_printf(
- "Error while parsing signature header\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
/* all headers are stored for signature verification */
}
BAIL:
-*ctx->cur_header = '\0';
-ctx->cur_header_len = 0; /* leave buffer for reuse */
+ctx->cur_header[ctx->cur_header_len = 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;
+int p, rc;
/* Alternate EOD signal, used in non-dotstuffing mode */
if (!data)
ctx->flags |= PDKIM_SEEN_CR;
else if (c == '\n')
{
- int rc;
ctx->flags &= ~PDKIM_SEEN_CR;
if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK)
return rc;
ctx->cur_header = string_catn(ctx->cur_header, &ctx->cur_header_size,
&ctx->cur_header_len, CUS "\r", 1);
- if (ctx->flags & PDKIM_SEEN_LF)
+ if (ctx->flags & PDKIM_SEEN_LF) /* Seen last header line */
{
- int rc = pdkim_header_complete(ctx); /* Seen last header line */
- if (rc != PDKIM_OK) return rc;
+ if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
+ return rc;
- ctx->flags = ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR) | PDKIM_PAST_HDRS;
+ ctx->flags = (ctx->flags & ~(PDKIM_SEEN_LF|PDKIM_SEEN_CR)) | PDKIM_PAST_HDRS;
DEBUG(D_acl) debug_printf(
- "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>\n");
+ "PDKIM >> Body data for hash, canonicalized >>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
continue;
}
else
- ctx->flags = ctx->flags & ~PDKIM_SEEN_CR | PDKIM_SEEN_LF;
+ ctx->flags = (ctx->flags & ~PDKIM_SEEN_CR) | 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;
- }
+ if (!(c == '\t' || c == ' ')) /* End of header */
+ if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
+ return rc;
ctx->flags &= ~PDKIM_SEEN_LF;
}
/* Required and static bits */
hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=",
- pdkim_algos[sig->algo]);
+ dkim_sig_to_a_tag(sig));
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=",
}
/* 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, &hdr_size, &hdr_len, US";", US"b=", base64_b);
-/* add trailing semicolon: I'm not sure if this is actually needed */
-hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, NULL, US";", US"");
+ /* add trailing semicolon: I'm not sure if this is actually needed */
+ hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, 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, &hdr_size, &hdr_len, US";", US"b=;", US"");
+ }
hdr[hdr_len] = '\0';
return hdr;
/* -------------------------------------------------------------------------- */
static pdkim_pubkey *
-pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx)
+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;
-const uschar * errstr;
/* Fetch public key for signing domain, from DNS */
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
/* Import public key */
-if ((errstr = exim_rsa_verify_init(&p->key, vctx)))
+if ((*errstr = exim_dkim_verify_init(&p->key, vctx)))
{
- DEBUG(D_acl) debug_printf("verify_init: %s\n", errstr);
+ 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;
/* -------------------------------------------------------------------------- */
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;
while (sig)
{
- BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1;
hctx hhash_ctx;
uschar * sig_hdr = US"";
blob hhash;
hdata.data = NULL;
hdata.len = 0;
- exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256);
+ if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+ {
+ DEBUG(D_acl)
+ debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+ break;
+ }
DEBUG(D_acl) debug_printf(
- "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>>>\n");
+ "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>\n");
/* SIGNING ---------------------------------------------------------------- */
/* When signing, walk through our header list and add them to the hash. As we
p->value, (q - US p->value) + (p->next ? 1 : 0));
rh = sig->canon_headers == PDKIM_CANON_RELAXED
- ? pdkim_relax_header(p->value, 1) /* cook header for relaxed canon */
+ ? pdkim_relax_header(p->value, TRUE) /* cook header for relaxed canon */
: string_copy(CUS p->value); /* just copy it for simple 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);
+ (void) exim_dkim_data_append(&hdata, &hdata_alloc, rh);
DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
}
/* 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 */
/* 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)
{
}
/* Remember headers block for signing (when the library cannot do incremental) */
+/*XXX is this assuing algo == RSA? */
if (ctx->flags & PDKIM_MODE_SIGN)
- (void) exim_rsa_data_append(&hdata, &hdata_alloc, US sig_hdr);
+ (void) exim_dkim_data_append(&hdata, &hdata_alloc, 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)))
+ /* Import private key, including the keytype */
+/*XXX extend for non-RSA algos */
+ if ((*err = exim_dkim_signing_init(US sig->privkey, &sctx)))
{
- DEBUG(D_acl) debug_printf("signing_init: %s\n", errstr);
+ DEBUG(D_acl) debug_printf("signing_init: %s\n", *err);
return PDKIM_ERR_RSA_PRIVKEY;
}
calculated, with GnuTLS we have to sign an entire block of headers
(due to available interfaces) and it recalculates the hash internally. */
-#if defined(RSA_OPENSSL) || defined(RSA_GCRYPT)
+#if defined(SIGN_OPENSSL) || defined(SIGN_GCRYPT)
hdata = hhash;
#endif
- if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sigdata)))
+/*XXX extend for non-RSA algos */
+ if ((*err = exim_dkim_sign(&sctx,
+ pdkim_hashes[sig->hashtype].exim_hashmethod,
+ &hdata, &sig->sighash)))
{
- DEBUG(D_acl) debug_printf("signing: %s\n", errstr);
+ DEBUG(D_acl) debug_printf("signing: %s\n", *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);
+ pdkim_hexprint(sig->sighash.data, sig->sighash.len);
}
sig->signature_header = pdkim_create_header(sig, TRUE);
else
{
ev_ctx vctx;
- const uschar * errstr;
- pdkim_pubkey * p;
/* 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
) )
{
goto NEXT_VERIFY;
}
- if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx)))
+ if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err)))
goto NEXT_VERIFY;
+ /* 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 (sig->pubkey->hashes)
+ {
+ 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;
+ }
+ }
+
/* Check the signature */
- if ((errstr = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sigdata)))
+/*XXX needs extension for non-RSA */
+ if ((*err = exim_dkim_verify(&vctx,
+ pdkim_hashes[sig->hashtype].exim_hashmethod,
+ &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;
/* -------------------------------------------------------------------------- */
+/*XXX ? needs extension to cover non-RSA algo? */
+
DLLEXPORT pdkim_ctx *
-pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo,
- BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *))
+pdkim_init_sign(uschar * domain, uschar * selector, uschar * privkey,
+ uschar * hashname, BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *),
+ const uschar ** errstr)
{
+int hashtype;
pdkim_ctx * ctx;
pdkim_signature * sig;
-if (!domain || !selector || !rsa_privkey)
+if (!domain || !selector || !privkey)
return NULL;
ctx = store_get(sizeof(pdkim_ctx) + PDKIM_MAX_BODY_LINE_LEN + sizeof(pdkim_signature));
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);
+/*XXX no keytype yet; comes from privkey */
+
+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))
+ {
+ DEBUG(D_acl)
+ debug_printf("PDKIM: unrecognised hashname '%s'\n", hashname);
+ return NULL;
+ }
-exim_sha_init(&sig->body_hash, algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256);
+if (!exim_sha_init(&sig->body_hash_ctx, pdkim_hashes[hashtype].exim_hashmethod))
+ {
+ DEBUG(D_acl)
+ debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+ return NULL;
+ }
DEBUG(D_acl)
{
pdkim_signature s = *sig;
ev_ctx vctx;
- debug_printf("PDKIM (checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
- if (!pdkim_key_from_dns(ctx, &s, &vctx))
+ debug_printf("PDKIM (checking verify key)>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ if (!pdkim_key_from_dns(ctx, &s, &vctx, errstr))
debug_printf("WARNING: bad dkim key in dns\n");
- debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-
return ctx;
}
void
pdkim_init(void)
{
-exim_rsa_init();
+exim_dkim_init();
}