X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/b9df1829d6afa37ef6576d04fc8845c1d20269b0..9e70917d0aa5e51f584b2af69ce80df458ac5c79:/src/src/pdkim/pdkim.c diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c index 5fc6045d0..f107a5948 100644 --- a/src/src/pdkim/pdkim.c +++ b/src/src/pdkim/pdkim.c @@ -32,17 +32,17 @@ #include "crypt_ver.h" -#ifdef RSA_OPENSSL +#ifdef SIGN_OPENSSL # include # include # include -#elif defined(RSA_GNUTLS) +#elif defined(SIGN_GNUTLS) # include # include #endif #include "pdkim.h" -#include "rsa.h" +#include "signing.h" #define PDKIM_SIGNATURE_VERSION "1" #define PDKIM_PUB_RECORD_VERSION US "DKIM1" @@ -73,24 +73,24 @@ const uschar * pdkim_querymethods[] = { 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 { @@ -110,7 +110,20 @@ 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); +} + + const char * pdkim_verify_status_str(int status) @@ -132,6 +145,7 @@ 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"; @@ -155,7 +169,7 @@ switch(status) 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 "(unknown)"; + default: return US"(unknown)"; } } @@ -288,7 +302,7 @@ 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; @@ -299,8 +313,8 @@ 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 == ' ') { @@ -312,8 +326,8 @@ 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 @@ -326,7 +340,7 @@ 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; } @@ -335,10 +349,10 @@ 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++; @@ -361,11 +375,11 @@ 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'; @@ -393,7 +407,7 @@ 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); @@ -414,7 +428,7 @@ return b64encode(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; @@ -430,8 +444,9 @@ 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); @@ -504,13 +519,18 @@ for (p = raw_hdr; ; p++) 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) @@ -582,10 +602,12 @@ DEBUG(D_acl) "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); } +/*XXX hash method: extend for sha512 */ if (!exim_sha_init(&sig->body_hash_ctx, - sig->algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) + pdkim_hashes[sig->hashtype].exim_hashmethod)) { - DEBUG(D_acl) debug_printf("PDKIM: hash init internal error\n"); + DEBUG(D_acl) + debug_printf("PDKIM: hash init error, possibly nonhandled hashtype\n"); return NULL; } return sig; @@ -597,190 +619,145 @@ 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; } /* -------------------------------------------------------------------------- */ -static int -pdkim_update_bodyhash(pdkim_ctx * ctx, const char * data, int len) +/* Update the bodyhash for one sig, with some additional data. +If we have to relax the data for this sig, return our copy of it. */ + +/*XXX Currently we calculate a hash for each sig. But it is possible +that multi-signing will be wanted using different signing algos +(rsa, ec) using the same hash and canonicalization. Consider in future +hanging the hash+cacnon from the ctx and only referencing from the sig, +so that it can be calculated only once - being over the body this +caould be meagbytes, hence expensive. */ + +static blob * +pdkim_update_sig_bodyhash(pdkim_signature * sig, blob * orig_data, blob * relaxed_data) { -pdkim_signature * sig; -uschar * relaxed_data = NULL; /* Cache relaxed version of data */ -int relaxed_len = 0; +blob * canon_data = orig_data; +/* Defaults to simple canon (no further treatment necessary) */ -/* Traverse all signatures, updating their hashes. */ -for (sig = ctx->sig; sig; sig = sig->next) +if (sig->canon_body == 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; + const char *p; + 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 (p = orig_data->data; *p; 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; +/* Make sure we don't exceed the to-be-signed body length */ +if ( sig->bodylength >= 0 + && sig->signed_body_bytes + (unsigned long)canon_data->len > sig->bodylength + ) + canon_data->len = sig->bodylength - sig->signed_body_bytes; - if (canon_len > 0) - { - 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); - } +if (canon_data->len > 0) + { + exim_sha_update(&sig->body_hash_ctx, CUS canon_data->data, canon_data->len); + sig->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; +pdkim_signature * sig; /* Traverse all signatures */ for (sig = ctx->sig; sig; sig = sig->next) @@ -792,8 +769,9 @@ for (sig = ctx->sig; sig; sig = sig->next) DEBUG(D_acl) { debug_printf("PDKIM [%s] Body bytes hashed: %lu\n" - "PDKIM [%s] Body hash computed: ", - sig->domain, sig->signed_body_bytes, sig->domain); + "PDKIM [%s] Body %s computed: ", + sig->domain, sig->signed_body_bytes, + sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname); pdkim_hexprint(CUS bh.data, bh.len); } @@ -832,10 +810,10 @@ for (sig = ctx->sig; sig; sig = sig->next) -static int +static void pdkim_body_complete(pdkim_ctx * ctx) { -pdkim_signature * sig = ctx->sig; /*XXX assumes only one sig */ +pdkim_signature * sig; /* In simple body mode, if any empty lines were buffered, replace with one. rfc 4871 3.4.3 */ @@ -843,15 +821,15 @@ replace with one. rfc 4871 3.4.3 */ 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 (sig = ctx->sig; sig; sig = sig->next) + if ( sig->canon_body == PDKIM_CANON_SIMPLE + && sig->signed_body_bytes == 0 + && sig->num_buffered_blanklines > 0 + ) + (void) pdkim_update_sig_bodyhash(sig, &lineending, NULL); ctx->flags |= PDKIM_SEEN_EOD; ctx->linebuf_offset = 0; -return PDKIM_OK; } @@ -859,70 +837,78 @@ return PDKIM_OK; /* -------------------------------------------------------------------------- */ /* Call from pdkim_feed below for processing complete body lines */ -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}; +pdkim_signature * sig; +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 (sig = ctx->sig; sig; sig = sig->next) sig->num_buffered_blanklines++; + goto all_skip; } -if (sig && sig->canon_body == PDKIM_CANON_RELAXED) +/* Process line for each sig separately */ +for (sig = ctx->sig; sig; sig = sig->next) { - /* Lines with just spaces need to be buffered too */ - char *check = p; - while (memcmp(check, "\r\n", 2) != 0) + if (sig->canon_body == PDKIM_CANON_RELAXED) { - char c = *check; + /* Lines with just spaces need to be buffered too */ + char * cp = line.data; + char c; + + while ((c = *cp)) + { + if (c == '\r' && cp[1] == '\n') break; + if (c != ' ' && c != '\t') goto sig_process; + cp++; + } - if (c != '\t' && c != ' ') - goto PROCESS; - check++; + sig->num_buffered_blanklines++; + goto sig_skip; } - ctx->num_buffered_crlf++; - goto BAIL; -} +sig_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 (sig->num_buffered_blanklines) + { + rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl); + sig->num_buffered_blanklines--; + } + + rline = pdkim_update_sig_bodyhash(sig, &line, rline); +sig_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; } @@ -999,7 +985,7 @@ 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, rc; @@ -1027,8 +1013,7 @@ else for (p = 0; pflags &= ~PDKIM_SEEN_CR; - if ((rc = pdkim_bodyline_complete(ctx)) != PDKIM_OK) - return rc; + pdkim_bodyline_complete(ctx); } if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) @@ -1208,7 +1193,7 @@ return str; /* -------------------------------------------------------------------------- */ static uschar * -pdkim_create_header(pdkim_signature *sig, BOOL final) +pdkim_create_header(pdkim_signature * sig, BOOL final) { uschar * base64_bh; uschar * base64_b; @@ -1229,7 +1214,7 @@ col = hdr_len; /* 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=", @@ -1297,11 +1282,23 @@ if (sig->bodylength >= 0) } /* Preliminary or final version? */ -base64_b = final ? pdkim_encode_base64(&sig->sighash) : 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; @@ -1337,7 +1334,9 @@ DEBUG(D_acl) { debug_printf( "PDKIM >> Parsing public key record >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n" - " Raw record: "); + " %s\n" + " Raw record: ", + dns_txt_name); pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply)); } @@ -1364,7 +1363,7 @@ 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); sig->verify_status = PDKIM_VERIFY_INVALID; @@ -1382,16 +1381,22 @@ DLLEXPORT int pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures, const uschar ** err) { -pdkim_signature *sig = ctx->sig; +pdkim_signature * sig; /* 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 '' */ if (ctx->cur_header && ctx->cur_header_len) { - 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 (sig = ctx->sig; sig; sig = sig->next) + rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl); + if (rnl) store_free(rnl); } else DEBUG(D_acl) debug_printf( @@ -1400,9 +1405,8 @@ else /* Build (and/or evaluate) body hash */ pdkim_finish_bodyhash(ctx); -while (sig) +for (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; @@ -1412,14 +1416,22 @@ while (sig) hdata.data = NULL; hdata.len = 0; - if (!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: hask setup internal error\n"); + DEBUG(D_acl) + debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n"); break; } + if (ctx->flags & PDKIM_MODE_SIGN) + DEBUG(D_acl) debug_printf( + "PDKIM >> Headers to be signed: >>>>>>>>>>>>\n" + " %s\n", + sig->sign_headers); + 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 @@ -1429,49 +1441,43 @@ while (sig) if (ctx->flags & PDKIM_MODE_SIGN) { - uschar * headernames = NULL; /* Collected signed header names */ int hs = 0, hl = 0; pdkim_stringlist *p; const uschar * l; uschar * s; int sep = 0; + sig->headernames = NULL; /* Collected signed header names */ + for (p = sig->headers; p; p = p->next) - if (header_name_match(p->value, sig->sign_headers) == PDKIM_OK) + { + 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)); + sig->headernames = string_append_listele_n(sig->headernames, &hs, &hl, + ':', 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); + (void) exim_dkim_data_append(&hdata, &hdata_alloc, rh); DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); } + } + /* Any headers we wanted to sign but were not present must also be listed */ 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; + sig->headernames = string_append_listele(sig->headernames, &hs, &hl, ':', s); + sig->headernames[hl] = '\0'; /* Create signature header with b= omitted */ sig_hdr = pdkim_create_header(sig, FALSE); @@ -1508,7 +1514,7 @@ 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 */ @@ -1530,9 +1536,18 @@ while (sig) DEBUG(D_acl) debug_printf( "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + DEBUG(D_acl) + { + debug_printf( + "PDKIM >> Signed DKIM-Signature header, pre-canonicalized >>>>>>>>>>>>>\n"); + pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); + debug_printf( + "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\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) { @@ -1549,21 +1564,24 @@ while (sig) DEBUG(D_acl) { - debug_printf("PDKIM [%s] Header hash computed: ", sig->domain); + debug_printf("PDKIM [%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); + (void) exim_dkim_data_append(&hdata, &hdata_alloc, US sig_hdr); /* SIGNING ---------------------------------------------------------------- */ if (ctx->flags & PDKIM_MODE_SIGN) { es_ctx sctx; - /* Import private key */ - if ((*err = 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", *err); return PDKIM_ERR_RSA_PRIVKEY; @@ -1573,11 +1591,14 @@ while (sig) 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 ((*err = exim_rsa_sign(&sctx, is_sha1, &hdata, &sig->sighash))) +/*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", *err); return PDKIM_ERR_RSA_SIGNING; @@ -1596,7 +1617,6 @@ while (sig) else { ev_ctx vctx; - pdkim_pubkey * p; /* Make sure we have all required signature tags */ if (!( sig->domain && *sig->domain @@ -1604,7 +1624,8 @@ while (sig) && sig->headernames && *sig->headernames && sig->bodyhash.data && sig->sighash.data - && sig->algo > -1 + && sig->keytype >= 0 + && sig->hashtype >= 0 && sig->version ) ) { @@ -1629,11 +1650,41 @@ while (sig) goto NEXT_VERIFY; } + DEBUG(D_acl) + { + debug_printf( "PDKIM [%s] b from mail: ", sig->domain); + pdkim_hexprint(sig->sighash.data, sig->sighash.len); + } + 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 ((*err = exim_rsa_verify(&vctx, is_sha1, &hhash, &sig->sighash))) +/*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", *err); sig->verify_status = PDKIM_VERIFY_FAIL; @@ -1659,8 +1710,6 @@ NEXT_VERIFY: debug_printf("\n"); } } - - sig = sig->next; } /* If requested, set return pointer to signature(s) */ @@ -1691,40 +1740,45 @@ return ctx; /* -------------------------------------------------------------------------- */ -DLLEXPORT pdkim_ctx * -pdkim_init_sign(char * domain, char * selector, char * rsa_privkey, int algo, - BOOL dot_stuffed, int(*dns_txt_callback)(char *, char *), - const uschar ** errstr) +/*XXX ? needs extension to cover non-RSA algo? */ + +DLLEXPORT pdkim_signature * +pdkim_init_sign(pdkim_ctx * ctx, + uschar * domain, uschar * selector, uschar * privkey, + uschar * hashname, const uschar ** errstr) { -pdkim_ctx * ctx; +int hashtype; 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)); -memset(ctx, 0, sizeof(pdkim_ctx)); - -ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; -ctx->linebuf = CS (ctx+1); - -DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; +/* Allocate & init one signature struct */ -sig = (pdkim_signature *)(ctx->linebuf + PDKIM_MAX_BODY_LINE_LEN); +sig = store_get(sizeof(pdkim_signature)); 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); +/*XXX no keytype yet; comes from privkey */ -if (!exim_sha_init(&sig->body_hash_ctx, - algo == PDKIM_ALGO_RSA_SHA1 ? HASH_SHA1 : HASH_SHA256)) +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; + } + +if (!exim_sha_init(&sig->body_hash_ctx, pdkim_hashes[hashtype].exim_hashmethod)) { - DEBUG(D_acl) debug_printf("PDKIM: hash setup internal error\n"); + DEBUG(D_acl) + debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n"); return NULL; } @@ -1733,29 +1787,27 @@ DEBUG(D_acl) pdkim_signature s = *sig; ev_ctx vctx; - debug_printf("PDKIM (checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); + 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; +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); @@ -1768,14 +1820,26 @@ sig->bodylength = bodylength; sig->created = created; sig->expires = expires; -return PDKIM_OK; +return; +} + + + +void +pdkim_init_context(pdkim_ctx * ctx, BOOL dot_stuffed, + int(*dns_txt_callback)(char *, char *)) +{ +memset(ctx, 0, sizeof(pdkim_ctx)); +ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN; +ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); +DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback; } void pdkim_init(void) { -exim_rsa_init(); +exim_dkim_init(); }