X-Git-Url: https://vcs.fsf.org/?p=exim.git;a=blobdiff_plain;f=src%2Fsrc%2Fpdkim%2Fpdkim.c;h=441f96cb55b2217cac5c4b54fa8aedfad65e6d23;hp=4309675e6d86f48bc55b297cd5388a2895ac26af;hb=9b2583c440ab9104070054dfa02e8611799f777b;hpb=1137f3a6938882cc81a1fcd7dc15530e8fae9e32 diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c index 4309675e6..441f96cb5 100644 --- a/src/src/pdkim/pdkim.c +++ b/src/src/pdkim/pdkim.c @@ -2,7 +2,7 @@ * PDKIM - a RFC4871 (DKIM) implementation * * Copyright (C) 2009 - 2016 Tom Kistner - * Copyright (C) 2016 Jeremy Harris + * Copyright (C) 2016 - 2017 Jeremy Harris * * http://duncanthrax.net/pdkim/ * @@ -42,7 +42,7 @@ #endif #include "pdkim.h" -#include "rsa.h" +#include "signing.h" #define PDKIM_SIGNATURE_VERSION "1" #define PDKIM_PUB_RECORD_VERSION US "DKIM1" @@ -83,11 +83,13 @@ const uschar * pdkim_canons[] = { US"relaxed", NULL }; +/*XXX currently unused */ const uschar * pdkim_hashes[] = { US"sha256", US"sha1", NULL }; +/*XXX currently unused */ const uschar * pdkim_keytypes[] = { US"rsa", NULL @@ -132,6 +134,7 @@ switch(ext_status) { case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; + case PDKIM_VERIFY_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"; @@ -142,20 +145,20 @@ switch(ext_status) } } -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)"; } } @@ -192,7 +195,8 @@ static void 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(""); debug_printf("\n"); } @@ -287,7 +291,7 @@ found: /* 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; @@ -298,8 +302,8 @@ uschar * q = relaxed; 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 == ' ') { @@ -311,8 +315,8 @@ for (p = header; *p; p++) 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 @@ -325,7 +329,7 @@ for (p = header; *p; p++) 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; } @@ -334,10 +338,10 @@ 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++; @@ -360,11 +364,11 @@ return initial_pos; /* -------------------------------------------------------------------------- */ 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'; @@ -392,7 +396,7 @@ return n; /* -------------------------------------------------------------------------- */ static void -pdkim_decode_base64(uschar *str, blob * b) +pdkim_decode_base64(const uschar * str, blob * b) { int dlen; dlen = b64decode(str, &b->data); @@ -415,7 +419,7 @@ return b64encode(b->data, b->len); 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; @@ -493,10 +497,8 @@ for (p = raw_hdr; ; p++) 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 @@ -505,6 +507,7 @@ for (p = raw_hdr; ; p++) Ustrcmp(cur_val, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; break; case 'a': +/*XXX this searches a list of combined (algo + hash-method)s */ for (i = 0; pdkim_algos[i]; i++) if (Ustrcmp(cur_val, pdkim_algos[i]) == 0) { @@ -578,12 +581,18 @@ DEBUG(D_acl) "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, + sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash init internal error\n"); + return NULL; + } return sig; } @@ -593,103 +602,58 @@ 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); -*/ - 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; + 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; - 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; } @@ -697,15 +661,14 @@ 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; @@ -761,12 +724,10 @@ while (sig) 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); @@ -786,7 +747,7 @@ for (sig = ctx->sig; sig; sig = sig->next) { /* Finish hashes */ blob bh; - exim_sha_finish(&sig->body_hash, &bh); + exim_sha_finish(&sig->body_hash_ctx, &bh); DEBUG(D_acl) { @@ -807,11 +768,11 @@ for (sig = ctx->sig; sig; sig = sig->next) 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); } @@ -820,14 +781,12 @@ for (sig = ctx->sig; sig; sig = sig->next) 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; } - } } } @@ -932,73 +891,65 @@ return PDKIM_OK; #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"); } - /* 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); } 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; } @@ -1008,9 +959,9 @@ 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) @@ -1035,7 +986,6 @@ else for (p = 0; pflags |= PDKIM_SEEN_CR; else if (c == '\n') { - int rc; ctx->flags &= ~PDKIM_SEEN_CR; if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) return rc; @@ -1055,26 +1005,24 @@ else for (p = 0; pcur_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; } @@ -1241,6 +1189,7 @@ col = hdr_len; /* Required and static bits */ hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"a=", +/*XXX this is a combo of algo and hash-method */ pdkim_algos[sig->algo]); hdr = pdkim_headcat(&col, hdr, &hdr_size, &hdr_len, US";", US"q=", pdkim_querymethods[sig->querymethod]); @@ -1309,11 +1258,23 @@ if (sig->bodylength >= 0) } /* 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; @@ -1323,11 +1284,11 @@ 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 */ @@ -1376,9 +1337,9 @@ DEBUG(D_acl) debug_printf( "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; @@ -1391,7 +1352,8 @@ return p; /* -------------------------------------------------------------------------- */ 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; @@ -1413,6 +1375,7 @@ pdkim_finish_bodyhash(ctx); while (sig) { +/*XXX bool probably not enough */ BOOL is_sha1 = sig->algo == PDKIM_ALGO_RSA_SHA1; hctx hhash_ctx; uschar * sig_hdr = US""; @@ -1423,10 +1386,14 @@ while (sig) hdata.data = NULL; hdata.len = 0; - exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256); + if (!exim_sha_init(&hhash_ctx, is_sha1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hask setup internal error\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 @@ -1454,14 +1421,14 @@ while (sig) 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)); } @@ -1515,7 +1482,7 @@ while (sig) /* 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 */ @@ -1539,7 +1506,7 @@ while (sig) /* 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) { @@ -1561,19 +1528,20 @@ while (sig) } /* 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))) +/*XXX extend for non-RSA algos */ + if ((*err = exim_dkim_signing_init(US sig->rsa_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; } @@ -1585,16 +1553,20 @@ while (sig) hdata = hhash; #endif - if ((errstr = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sigdata))) +/*XXX extend for non-RSA algos */ +/*XXX oddly the dkim rfc does _not_ say what variant (sha1 or sha256) of +RSA signing should be done. We use the same variant as the hash-method. */ + + if ((*err = exim_dkim_sign(&sctx, is_sha1, &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); @@ -1604,15 +1576,13 @@ while (sig) 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->sighash.data && sig->algo > -1 && sig->version ) ) @@ -1638,13 +1608,33 @@ while (sig) 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_algos[sig->algo] + 4) == 0) break; + if (!ele) + { + DEBUG(D_acl) debug_printf("pubkey h=%s vs sig a=%s\n", + sig->pubkey->hashes, pdkim_algos[sig->algo]); + 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, is_sha1, &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; @@ -1700,9 +1690,13 @@ return ctx; /* -------------------------------------------------------------------------- */ +/*XXX ? needs extension to cover non-RSA algo? Currently the "algo" is actually +the combo of algo and hash-method */ + DLLEXPORT pdkim_ctx * pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, - BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *)) + BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *), + const uschar ** errstr) { pdkim_ctx * ctx; pdkim_signature * sig; @@ -1729,19 +1723,24 @@ sig->selector = string_copy(US selector); sig->rsa_privkey = string_copy(US rsa_privkey); sig->algo = algo; -exim_sha_init(&sig->body_hash, algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256); +/*XXX extend for sha512 */ +if (!exim_sha_init(&sig->body_hash_ctx, + algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + { + DEBUG(D_acl) debug_printf("PDKIM: hash setup internal error\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; } @@ -1779,7 +1778,7 @@ return PDKIM_OK; void pdkim_init(void) { -exim_rsa_init(); +exim_dkim_init(); }