X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/d64f251592db09252ac0584adbe72a2eeb9ca122..HEAD:/src/src/pdkim/pdkim.c diff --git a/src/src/pdkim/pdkim.c b/src/src/pdkim/pdkim.c deleted file mode 100644 index 2a66909ba..000000000 --- a/src/src/pdkim/pdkim.c +++ /dev/null @@ -1,1997 +0,0 @@ -/* - * PDKIM - a RFC4871 (DKIM) implementation - * - * Copyright (C) 2009 - 2016 Tom Kistner - * Copyright (C) 2016 - 2018 Jeremy Harris - * - * http://duncanthrax.net/pdkim/ - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License along - * with this program; if not, write to the Free Software Foundation, Inc., - * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. - */ - -#include "../exim.h" - - -#ifndef DISABLE_DKIM /* entire file */ - -#ifndef SUPPORT_TLS -# error Need SUPPORT_TLS for DKIM -#endif - -#include "crypt_ver.h" - -#ifdef SIGN_OPENSSL -# include -# include -# include -#elif defined(SIGN_GNUTLS) -# include -# include -#endif - -#include "pdkim.h" -#include "signing.h" - -#define PDKIM_SIGNATURE_VERSION "1" -#define PDKIM_PUB_RECORD_VERSION US "DKIM1" - -#define PDKIM_MAX_HEADER_LEN 65536 -#define PDKIM_MAX_HEADERS 512 -#define PDKIM_MAX_BODY_LINE_LEN 16384 -#define PDKIM_DNS_TXT_MAX_NAMELEN 1024 - -/* -------------------------------------------------------------------------- */ -struct pdkim_stringlist { - uschar * value; - int tag; - void * next; -}; - -/* -------------------------------------------------------------------------- */ -/* A bunch of list constants */ -const uschar * pdkim_querymethods[] = { - US"dns/txt", - NULL -}; -const uschar * pdkim_canons[] = { - US"simple", - US"relaxed", - NULL -}; - -const pdkim_hashtype pdkim_hashes[] = { - { US"sha1", HASH_SHA1 }, - { US"sha256", HASH_SHA2_256 }, - { US"sha512", HASH_SHA2_512 } -}; - -const uschar * pdkim_keytypes[] = { - [KEYTYPE_RSA] = US"rsa", -#ifdef SIGN_HAVE_ED25519 - [KEYTYPE_ED25519] = US"ed25519", /* Works for 3.6.0 GnuTLS */ -#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; -} pdkim_combined_canon_entry; - -pdkim_combined_canon_entry pdkim_combined_canons[] = { - { US"simple/simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { US"simple/relaxed", PDKIM_CANON_SIMPLE, PDKIM_CANON_RELAXED }, - { US"relaxed/simple", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { US"relaxed/relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_RELAXED }, - { US"simple", PDKIM_CANON_SIMPLE, PDKIM_CANON_SIMPLE }, - { US"relaxed", PDKIM_CANON_RELAXED, PDKIM_CANON_SIMPLE }, - { NULL, 0, 0 } -}; - - -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); -} - - -int -pdkim_hashname_to_hashtype(const uschar * s, unsigned len) -{ -int i; -if (!len) len = Ustrlen(s); -for (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) -{ -int i; -if (!len) len = Ustrlen(s); -for (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) -{ -switch(status) - { - case PDKIM_VERIFY_NONE: return "PDKIM_VERIFY_NONE"; - case PDKIM_VERIFY_INVALID: return "PDKIM_VERIFY_INVALID"; - case PDKIM_VERIFY_FAIL: return "PDKIM_VERIFY_FAIL"; - case PDKIM_VERIFY_PASS: return "PDKIM_VERIFY_PASS"; - default: return "PDKIM_VERIFY_UNKNOWN"; - } -} - -const char * -pdkim_verify_ext_status_str(int ext_status) -{ -switch(ext_status) - { - case PDKIM_VERIFY_FAIL_BODY: return "PDKIM_VERIFY_FAIL_BODY"; - case PDKIM_VERIFY_FAIL_MESSAGE: return "PDKIM_VERIFY_FAIL_MESSAGE"; - case PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH: return "PDKIM_VERIFY_FAIL_SIG_ALGO_MISMATCH"; - case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: return "PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE"; - case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE"; - case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD"; - case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT"; - case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR"; - case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION"; - default: return "PDKIM_VERIFY_UNKNOWN"; - } -} - -const uschar * -pdkim_errstr(int status) -{ -switch(status) - { - case PDKIM_OK: return US"OK"; - case PDKIM_FAIL: return US"FAIL"; - case PDKIM_ERR_RSA_PRIVKEY: return US"PRIVKEY"; - case PDKIM_ERR_RSA_SIGNING: return US"SIGNING"; - case PDKIM_ERR_LONG_LINE: return US"LONG_LINE"; - case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL"; - case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP"; - case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D"; - default: return US"(unknown)"; - } -} - - -/* -------------------------------------------------------------------------- */ -/* Print debugging functions */ -void -pdkim_quoteprint(const uschar *data, int len) -{ -int i; -for (i = 0; i < len; i++) - { - const int c = data[i]; - switch (c) - { - case ' ' : debug_printf("{SP}"); break; - case '\t': debug_printf("{TB}"); break; - case '\r': debug_printf("{CR}"); break; - case '\n': debug_printf("{LF}"); break; - case '{' : debug_printf("{BO}"); break; - case '}' : debug_printf("{BC}"); break; - default: - if ( (c < 32) || (c > 127) ) - debug_printf("{%02x}", c); - else - debug_printf("%c", c); - break; - } - } -debug_printf("\n"); -} - -void -pdkim_hexprint(const uschar *data, int len) -{ -int i; -if (data) for (i = 0 ; i < len; i++) debug_printf("%02x", data[i]); -else debug_printf(""); -debug_printf("\n"); -} - - - -static pdkim_stringlist * -pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str) -{ -pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist)); - -memset(new_entry, 0, sizeof(pdkim_stringlist)); -new_entry->value = string_copy(str); -if (base) new_entry->next = base; -return new_entry; -} - - - -/* Trim whitespace fore & aft */ - -static void -pdkim_strtrim(gstring * str) -{ -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); -} - - - -/* -------------------------------------------------------------------------- */ - -DLLEXPORT void -pdkim_free_ctx(pdkim_ctx *ctx) -{ -} - - -/* -------------------------------------------------------------------------- */ -/* Matches the name of the passed raw "header" against - the passed colon-separated "tick", and invalidates - the entry in tick. Entries can be prefixed for multi- or over-signing, - in which case do not invalidate. - - Returns OK for a match, or fail-code -*/ - -static int -header_name_match(const uschar * header, uschar * tick) -{ -const uschar * ticklist = tick; -int sep = ':'; -BOOL multisign; -uschar * hname, * p, * ele; -uschar * hcolon = Ustrchr(header, ':'); /* Get header name */ - -if (!hcolon) - return PDKIM_FAIL; /* This isn't a header */ - -/* if we had strncmpic() we wouldn't need this copy */ -hname = string_copyn(header, hcolon-header); - -while (p = US ticklist, ele = string_nextinlist(&ticklist, &sep, NULL, 0)) - { - switch (*ele) - { - case '=': case '+': multisign = TRUE; ele++; break; - default: multisign = FALSE; break; - } - - if (strcmpic(ele, hname) == 0) - { - if (!multisign) - *p = '_'; /* Invalidate this header name instance in tick-off list */ - return PDKIM_OK; - } - } -return PDKIM_FAIL; -} - - -/* -------------------------------------------------------------------------- */ -/* Performs "relaxed" canonicalization of a header. */ - -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(len+3); -uschar * q = relaxed; - -for (p = header; p - header < len; p++) - { - uschar c = *p; - - if (c == '\r' || c == '\n') /* Ignore CR & LF */ - continue; - if (c == '\t' || c == ' ') - { - if (seen_wsp) - continue; - c = ' '; /* Turns WSP into SP */ - seen_wsp = TRUE; - } - else - if (!past_field_name && c == ':') - { - 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 - seen_wsp = FALSE; - - /* Lowercase header name */ - if (!past_field_name) c = tolower(c); - *q++ = c; - } - -if (q > relaxed && q[-1] == ' ') q--; /* Squash eventual trailing SP */ - -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 const uschar * -pdkim_decode_qp_char(const uschar *qp_p, int *c) -{ -const uschar *initial_pos = qp_p; - -/* Advance one char */ -qp_p++; - -/* Check for two hex digits and decode them */ -if (isxdigit(*qp_p) && isxdigit(qp_p[1])) - { - /* Do hex conversion */ - *c = (isdigit(*qp_p) ? *qp_p - '0' : toupper(*qp_p) - 'A' + 10) << 4; - *c |= isdigit(qp_p[1]) ? qp_p[1] - '0' : toupper(qp_p[1]) - 'A' + 10; - return qp_p + 2; - } - -/* Illegal char here */ -*c = PDKIM_QP_ERROR_DECODE; -return initial_pos; -} - - -/* -------------------------------------------------------------------------- */ - -static uschar * -pdkim_decode_qp(const uschar * str) -{ -int nchar = 0; -uschar * q; -const uschar * p = str; -uschar * n = store_get(Ustrlen(str)+1); - -*n = '\0'; -q = n; -while (*p) - { - if (*p == '=') - { - p = pdkim_decode_qp_char(p, &nchar); - if (nchar >= 0) - { - *q++ = nchar; - continue; - } - } - else - *q++ = *p; - p++; - } -*q = '\0'; -return n; -} - - -/* -------------------------------------------------------------------------- */ - -void -pdkim_decode_base64(const uschar * str, blob * b) -{ -int dlen = b64decode(str, &b->data); -if (dlen < 0) b->data = NULL; -b->len = dlen; -} - -uschar * -pdkim_encode_base64(blob * b) -{ -return b64encode(b->data, b->len); -} - - -/* -------------------------------------------------------------------------- */ -#define PDKIM_HDR_LIMBO 0 -#define PDKIM_HDR_TAG 1 -#define PDKIM_HDR_VALUE 2 - -static pdkim_signature * -pdkim_parse_sig_header(pdkim_ctx * ctx, uschar * raw_hdr) -{ -pdkim_signature * sig; -uschar *p, *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)); -memset(sig, 0, sizeof(pdkim_signature)); -sig->bodylength = -1; - -/* Set so invalid/missing data error display is accurate */ -sig->version = 0; -sig->keytype = -1; -sig->hashtype = -1; - -q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1); - -for (p = raw_hdr; ; p++) - { - char c = *p; - - /* Ignore FWS */ - if (c == '\r' || c == '\n') - goto NEXT_CHAR; - - /* Fast-forward through header name */ - if (!past_hname) - { - if (c == ':') past_hname = TRUE; - goto NEXT_CHAR; - } - - if (where == PDKIM_HDR_LIMBO) - { - /* In limbo, just wait for a tag-char to appear */ - if (!(c >= 'a' && c <= 'z')) - goto NEXT_CHAR; - - where = PDKIM_HDR_TAG; - } - - if (where == PDKIM_HDR_TAG) - { - if (c >= 'a' && c <= 'z') - cur_tag = string_catn(cur_tag, p, 1); - - if (c == '=') - { - if (Ustrcmp(string_from_gstring(cur_tag), "b") == 0) - { - *q++ = '='; - in_b_val = TRUE; - } - where = PDKIM_HDR_VALUE; - goto NEXT_CHAR; - } - } - - if (where == PDKIM_HDR_VALUE) - { - if (c == '\r' || c == '\n' || c == ' ' || c == '\t') - goto NEXT_CHAR; - - if (c == ';' || c == '\0') - { - /* We must have both tag and value, and tags must be one char except - for the possibility of "bh". */ - - if ( cur_tag && cur_val - && (cur_tag->ptr == 1 || *cur_tag->s == 'b') - ) - { - (void) string_from_gstring(cur_val); - pdkim_strtrim(cur_val); - - DEBUG(D_acl) debug_printf(" %s=%s\n", cur_tag->s, cur_val->s); - - switch (*cur_tag->s) - { - 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': /* version */ - /* We only support version 1, and that is currently the - only version there is. */ - sig->version = - Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1; - break; - case 'a': /* algorithm */ - { - uschar * s = Ustrchr(cur_val->s, '-'); - - for(i = 0; i < nelem(pdkim_keytypes); i++) - if (Ustrncmp(cur_val->s, pdkim_keytypes[i], s - cur_val->s) == 0) - { sig->keytype = i; break; } - if (sig->keytype < 0) - log_write(0, LOG_MAIN, - "DKIM: ignoring signature due to nonhandled keytype in a=%s", - cur_val->s); - - sig->hashtype = pdkim_hashname_to_hashtype(++s, 0); - break; - } - - case 'c': /* canonicalization */ - pdkim_cstring_to_canons(cur_val->s, 0, - &sig->canon_headers, &sig->canon_body); - break; - case 'q': /* Query method (for pubkey)*/ - for (i = 0; pdkim_querymethods[i]; i++) - if (Ustrcmp(cur_val->s, pdkim_querymethods[i]) == 0) - { - sig->querymethod = i; /* we never actually use this */ - break; - } - 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; - } - } - cur_tag = cur_val = NULL; - in_b_val = FALSE; - where = PDKIM_HDR_LIMBO; - } - else - cur_val = string_catn(cur_val, p, 1); - } - -NEXT_CHAR: - if (c == '\0') - break; - - if (!in_b_val) - *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')) - *q = '\0'; - -DEBUG(D_acl) - { - debug_printf( - "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->sighash.len*8); - debug_printf( - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - -if (!pdkim_set_sig_bodyhash(ctx, sig)) - return NULL; - -return sig; -} - - -/* -------------------------------------------------------------------------- */ - -pdkim_pubkey * -pdkim_parse_pubkey_record(const uschar *raw_record) -{ -const uschar * ele; -int sep = ';'; -pdkim_pubkey * pub; - -pub = store_get(sizeof(pdkim_pubkey)); -memset(pub, 0, sizeof(pdkim_pubkey)); - -while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0))) - { - const uschar * val; - - if ((val = Ustrchr(ele, '='))) - { - int taglen = val++ - ele; - - DEBUG(D_acl) debug_printf(" %.*s=%s\n", taglen, ele, val); - switch (ele[0]) - { - 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; - } - } - } - -/* Set fallback defaults */ -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; -} - - -/* -------------------------------------------------------------------------- */ - -/* 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) -{ -blob * canon_data = orig_data; -/* Defaults to simple canon (no further treatment necessary) */ - -if (b->canon_method == PDKIM_CANON_RELAXED) - { - /* Relax the line if not done already */ - if (!relaxed_data) - { - BOOL seen_wsp = FALSE; - const uschar * p, * r; - 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(). */ - - relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1); - relaxed_data->data = US (relaxed_data+1); - - for (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--; - } - 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; - } - 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 ( b->bodylength >= 0 - && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength - ) - canon_data->len = b->bodylength - b->signed_body_bytes; - -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); - } - -return relaxed_data; -} - - -/* -------------------------------------------------------------------------- */ - -static void -pdkim_finish_bodyhash(pdkim_ctx * ctx) -{ -pdkim_bodyhash * b; -pdkim_signature * sig; - -for (b = ctx->bodyhash; b; b = b->next) /* Finish hashes */ - { - DEBUG(D_acl) debug_printf("PDKIM: finish bodyhash %d/%d/%d 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) - { - b = sig->calc_body_hash; - - DEBUG(D_acl) - { - debug_printf("PDKIM [%s] Body bytes (%s) hashed: %lu\n" - "PDKIM [%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) - { - /* If bodylength limit is set, and we have received less bytes - than the requested amount, effectively remove the limit tag. */ - if (b->signed_body_bytes < sig->bodylength) - sig->bodylength = -1; - } - - else - /* 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 compared OK\n", sig->domain); - } - else - { - DEBUG(D_acl) - { - debug_printf("PDKIM [%s] Body hash signature from headers: ", sig->domain); - 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; - } - } -} - - - -static void -pdkim_body_complete(pdkim_ctx * ctx) -{ -pdkim_bodyhash * b; - -/* In simple body mode, if any empty lines were buffered, -replace with one. rfc 4871 3.4.3 */ -/*XXX checking the signed-body-bytes is a gross hack; I think -it indicates that all linebreaks should be buffered, including -the one terminating a text line */ - -for (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; -} - - - -/* -------------------------------------------------------------------------- */ -/* Call from pdkim_feed below for processing complete body lines */ -/* NOTE: the line is not NUL-terminated; but we have a count */ - -static void -pdkim_bodyline_complete(pdkim_ctx * ctx) -{ -blob line = {.data = ctx->linebuf, .len = ctx->linebuf_offset}; -pdkim_bodyhash * b; -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 all_skip; - -/* We've always got one extra byte to stuff a zero ... */ -ctx->linebuf[line.len] = '\0'; - -/* Terminate on EOD marker */ -if (ctx->flags & PDKIM_DOT_TERM) - { - if (memcmp(line.data, ".\r\n", 3) == 0) - { pdkim_body_complete(ctx); return; } - - /* Unstuff dots */ - if (memcmp(line.data, "..", 2) == 0) - { line.data++; line.len--; } - } - -/* Empty lines need to be buffered until we find a non-empty line */ -if (memcmp(line.data, "\r\n", 2) == 0) - { - for (b = ctx->bodyhash; b; b = b->next) b->num_buffered_blanklines++; - goto all_skip; - } - -/* Process line for each bodyhash separately */ -for (b = ctx->bodyhash; b; b = b->next) - { - if (b->canon_method == PDKIM_CANON_RELAXED) - { - /* Lines with just spaces need to be buffered too */ - uschar * cp = line.data; - char c; - - while ((c = *cp)) - { - if (c == '\r' && cp[1] == '\n') break; - if (c != ' ' && c != '\t') goto hash_process; - cp++; - } - - b->num_buffered_blanklines++; - goto hash_skip; - } - -hash_process: - /* At this point, we have a non-empty line, so release the buffered ones. */ - - 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: ; - } - -if (rnl) store_free(rnl); -if (rline) store_free(rline); - -all_skip: - -ctx->linebuf_offset = 0; -return; -} - - -/* -------------------------------------------------------------------------- */ -/* Callback from pdkim_feed below for processing complete headers */ -#define DKIM_SIGNATURE_HEADERNAME "DKIM-Signature:" - -static int -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->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 - -if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL; - -/* SIGNING -------------------------------------------------------------- */ -if (ctx->flags & PDKIM_MODE_SIGN) - 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->s); - -/* 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->s, ctx->cur_header->ptr); - } -#endif - if (strncasecmp(CCS ctx->cur_header->s, - DKIM_SIGNATURE_HEADERNAME, - Ustrlen(DKIM_SIGNATURE_HEADERNAME)) == 0) - { - /* 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. */ - - DEBUG(D_acl) debug_printf( - "PDKIM >> Found sig, trying to parse >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); - - sig = pdkim_parse_sig_header(ctx, ctx->cur_header->s); - - if (!(last_sig = ctx->sig)) - ctx->sig = sig; - else - { - while (last_sig->next) last_sig = last_sig->next; - last_sig->next = sig; - } - } - - /* all headers are stored for signature verification */ - ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s); - } - -BAIL: -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, uschar * data, int len) -{ -int p, rc; - -/* Alternate EOD signal, used in non-dotstuffing mode */ -if (!data) - pdkim_body_complete(ctx); - -else for (p = 0; pflags & 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 == '\r') - ctx->flags |= PDKIM_SEEN_CR; - else if (c == '\n') - { - ctx->flags &= ~PDKIM_SEEN_CR; - pdkim_bodyline_complete(ctx); - } - - if (ctx->linebuf_offset == PDKIM_MAX_BODY_LINE_LEN-1) - return PDKIM_ERR_LONG_LINE; - } - else - { - /* Processing header byte */ - if (c == '\r') - ctx->flags |= PDKIM_SEEN_CR; - else if (c == '\n') - { - if (!(ctx->flags & PDKIM_SEEN_CR)) /* emulate the CR */ - ctx->cur_header = string_catn(ctx->cur_header, CUS "\r", 1); - - 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( - "PDKIM >> 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 || ctx->cur_header->ptr < PDKIM_MAX_HEADER_LEN) - ctx->cur_header = string_catn(ctx->cur_header, CUS &data[p], 1); - } - } -return PDKIM_OK; -} - - - -/* Extend a growing header with a continuation-linebreak */ -static gstring * -pdkim_hdr_cont(gstring * str, int * col) -{ -*col = 1; -return string_catn(str, US"\r\n\t", 3); -} - - - -/* - * RFC 5322 specifies that header line length SHOULD be no more than 78 - * lets make it so! - * pdkim_headcat - * - * returns uschar * (not nul-terminated) - * - * col: this int holds and receives column number (octets since last '\n') - * str: partial string to append to - * pad: padding, split line or space after before or after eg: ";" - * intro: - must join to payload eg "h=", usually the tag name - * payload: eg base64 data - long data can be split arbitrarily. - * - * this code doesn't fold the header in some of the places that RFC4871 - * allows: As per RFC5322(2.2.3) it only folds before or after tag-value - * pairs and inside long values. it also always spaces or breaks after the - * "pad" - * - * no guarantees are made for output given out-of range input. like tag - * names longer than 78, or bogus col. Input is assumed to be free of line breaks. - */ - -static gstring * -pdkim_headcat(int * col, gstring * str, - const uschar * pad, const uschar * intro, const uschar * payload) -{ -size_t l; - -if (pad) - { - l = Ustrlen(pad); - if (*col + l > 78) - str = pdkim_hdr_cont(str, col); - str = string_catn(str, pad, l); - *col += l; - } - -l = (pad?1:0) + (intro?Ustrlen(intro):0); - -if (*col + l > 78) - { /*can't fit intro - start a new line to make room.*/ - str = pdkim_hdr_cont(str, col); - l = intro?Ustrlen(intro):0; - } - -l += payload ? Ustrlen(payload):0 ; - -while (l>77) - { /* this fragment will not fit on a single line */ - if (pad) - { - str = string_catn(str, US" ", 1); - *col += 1; - pad = NULL; /* only want this once */ - l--; - } - - if (intro) - { - size_t sl = Ustrlen(intro); - - str = string_catn(str, intro, sl); - *col += sl; - l -= sl; - intro = NULL; /* only want this once */ - } - - if (payload) - { - size_t sl = Ustrlen(payload); - size_t chomp = *col+sl < 77 ? sl : 78-*col; - - 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, col); - } - -if (*col + l > 78) - { - str = pdkim_hdr_cont(str, col); - pad = NULL; - } - -if (pad) - { - str = string_catn(str, US" ", 1); - *col += 1; - pad = NULL; - } - -if (intro) - { - size_t sl = Ustrlen(intro); - - str = string_catn(str, intro, sl); - *col += sl; - l -= sl; - intro = NULL; - } - -if (payload) - { - size_t sl = Ustrlen(payload); - - str = string_catn(str, payload, sl); - *col += sl; - } - -return str; -} - - -/* -------------------------------------------------------------------------- */ - -/* Signing: create signature header -*/ -static uschar * -pdkim_create_header(pdkim_signature * sig, BOOL final) -{ -uschar * base64_bh; -uschar * base64_b; -int col = 0; -gstring * hdr; -gstring * canon_all; - -canon_all = string_cat (NULL, pdkim_canons[sig->canon_headers]); -canon_all = string_catn(canon_all, US"/", 1); -canon_all = string_cat (canon_all, pdkim_canons[sig->canon_body]); -(void) string_from_gstring(canon_all); - -hdr = string_cat(NULL, US"DKIM-Signature: v="PDKIM_SIGNATURE_VERSION); -col = hdr->ptr; - -/* Required and static bits */ -hdr = pdkim_headcat(&col, hdr, US";", US"a=", dkim_sig_to_a_tag(sig)); -hdr = pdkim_headcat(&col, hdr, US";", US"q=", pdkim_querymethods[sig->querymethod]); -hdr = pdkim_headcat(&col, hdr, US";", US"c=", canon_all->s); -hdr = pdkim_headcat(&col, hdr, US";", US"d=", sig->domain); -hdr = pdkim_headcat(&col, hdr, US";", US"s=", sig->selector); - -/* list of header names can be split between items. */ - { - uschar * n = string_copy(sig->headernames); - uschar * i = US"h="; - uschar * s = US";"; - - while (*n) - { - uschar * c = Ustrchr(n, ':'); - - if (c) *c ='\0'; - - if (!i) - hdr = pdkim_headcat(&col, hdr, NULL, NULL, US":"); - - hdr = pdkim_headcat(&col, hdr, s, i, n); - - if (!c) - break; - - n = c+1; - s = NULL; - i = NULL; - } - } - -base64_bh = pdkim_encode_base64(&sig->calc_body_hash->bh); -hdr = pdkim_headcat(&col, hdr, US";", US"bh=", base64_bh); - -/* Optional bits */ -if (sig->identity) - hdr = pdkim_headcat(&col, hdr, US";", US"i=", sig->identity); - -if (sig->created > 0) - { - uschar minibuf[20]; - - snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created); - 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, US";", US"x=", minibuf); - } - -if (sig->bodylength >= 0) - { - uschar minibuf[20]; - - snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength); - hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf); - } - -/* Preliminary or final version? */ -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); -} - - -/* -------------------------------------------------------------------------- */ - -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( - "PDKIM >> 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( - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - return NULL; - } - -DEBUG(D_acl) debug_printf( - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - -/* Import public key */ - -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; -} - - -/* -------------------------------------------------------------------------- */ - -DLLEXPORT int -pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures, - const uschar ** err) -{ -pdkim_bodyhash * b; -pdkim_signature * 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 '' */ -if (ctx->cur_header && ctx->cur_header->ptr > 0) - { - blob * rnl = NULL; - int rc; - - if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK) - return rc; - - for (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"); - -/* Build (and/or evaluate) body hash. Do this even if no DKIM sigs, in case we -have a hash to do for ARC. */ - -pdkim_finish_bodyhash(ctx); - -if (!ctx->sig) - { - DEBUG(D_acl) debug_printf("PDKIM: no signatures\n"); - *return_signatures = NULL; - return PDKIM_OK; - } - -for (sig = ctx->sig; sig; sig = sig->next) - { - hctx hhash_ctx; - uschar * sig_hdr = US""; - blob hhash; - gstring * hdata = NULL; - es_ctx sctx; - - if ( !(ctx->flags & PDKIM_MODE_SIGN) - && sig->verify_status == PDKIM_VERIFY_FAIL) - { - DEBUG(D_acl) - debug_printf("PDKIM: [%s] abandoning this signature\n", sig->domain); - continue; - } - - /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA - suging 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, - "PDKIM: hash setup error, possibly nonhandled hashtype"); - 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 (%-7s), in sequence >>\n", - pdkim_canons[sig->canon_headers]); - - - /* SIGNING ---------------------------------------------------------------- */ - /* When signing, walk through our header list and add them to the hash. As we - go, construct a list of the header's names to use for the h= parameter. - Then append to that list any remaining header names for which there was no - header to sign. */ - - if (ctx->flags & PDKIM_MODE_SIGN) - { - gstring * g = NULL; - pdkim_stringlist *p; - const uschar * l; - uschar * s; - int sep = 0; - - /* Import private key, including the keytype which we need for building - the signature header */ - -/*XXX extend for non-RSA algos */ - 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; - - for (sig->headernames = NULL, /* Collected signed header names */ - p = sig->headers; p; p = p->next) - { - uschar * rh = p->value; - - if (header_name_match(rh, sig->sign_headers) == PDKIM_OK) - { - /* Collect header names (Note: colon presence is guaranteed here) */ - g = string_append_listele_n(g, ':', rh, Ustrchr(rh, ':') - rh); - - if (sig->canon_headers == PDKIM_CANON_RELAXED) - rh = pdkim_relax_header(rh, TRUE); /* cook header for relaxed canon */ - - /* Feed header to the hash algorithm */ - exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); - - /* Remember headers block for signing (when the library cannot do incremental) */ - /*XXX we could avoid doing this for all but the GnuTLS/RSA case */ - hdata = exim_dkim_data_append(hdata, rh); - - DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); - } - } - - /* Any headers we wanted to sign but were not present must also be listed. - Ignore elements that have been ticked-off or are marked as never-oversign. */ - - l = sig->sign_headers; - while((s = string_nextinlist(&l, &sep, NULL, 0))) - { - if (*s == '+') /* skip oversigning marker */ - s++; - if (*s != '_' && *s != '=') - g = string_append_listele(g, ':', s); - } - sig->headernames = string_from_gstring(g); - - /* Create signature header with b= omitted */ - sig_hdr = pdkim_create_header(sig, FALSE); - } - - /* VERIFICATION ----------------------------------------------------------- */ - /* When verifying, walk through the header name list in the h= parameter and - add the headers to the hash in that order. */ - else - { - uschar * p = sig->headernames; - uschar * q; - pdkim_stringlist * hdrs; - - if (p) - { - /* clear tags */ - for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) - hdrs->tag = 0; - - p = string_copy(p); - while(1) - { - if ((q = Ustrchr(p, ':'))) - *q = '\0'; - - /*XXX walk the list of headers in same order as received. */ - for (hdrs = ctx->headers; hdrs; hdrs = hdrs->next) - if ( hdrs->tag == 0 - && strncasecmp(CCS hdrs->value, CCS p, Ustrlen(p)) == 0 - && (hdrs->value)[Ustrlen(p)] == ':' - ) - { - /* cook header for relaxed canon, or just copy it for simple */ - - uschar * rh = sig->canon_headers == PDKIM_CANON_RELAXED - ? pdkim_relax_header(hdrs->value, TRUE) - : string_copy(CUS hdrs->value); - - /* Feed header to the hash algorithm */ - exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh)); - - DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh)); - hdrs->tag = 1; - break; - } - - if (!q) break; - p = q+1; - } - - sig_hdr = string_copy(sig->rawsig_no_b_val); - } - } - - 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, FALSE); - - DEBUG(D_acl) - { - debug_printf("PDKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n", - pdkim_canons[sig->canon_headers]); - pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr)); - debug_printf( - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } - - /* Finalize header hash */ - exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr)); - exim_sha_finish(&hhash_ctx, &hhash); - - DEBUG(D_acl) - { - 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 signing library cannot do - incremental) */ - if (ctx->flags & PDKIM_MODE_SIGN) - hdata = exim_dkim_data_append(hdata, US sig_hdr); - - /* SIGNING ---------------------------------------------------------------- */ - if (ctx->flags & PDKIM_MODE_SIGN) - { - hashmethod hm = sig->keytype == KEYTYPE_ED25519 - ? HASH_SHA2_512 : pdkim_hashes[sig->hashtype].exim_hashmethod; - -#ifdef SIGN_HAVE_ED25519 - /* For GCrypt, and for EC, we pass the hash-of-headers to the signing - routine. For anything else we just pass the headers. */ - - if (sig->keytype != KEYTYPE_ED25519) -#endif - { - hhash.data = hdata->s; - hhash.len = hdata->ptr; - } - -/*XXX extend for non-RSA algos */ -/*- done for GnuTLS */ - if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash))) - { - log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err); - return PDKIM_ERR_RSA_SIGNING; - } - - DEBUG(D_acl) - { - debug_printf( "PDKIM [%s] b computed: ", sig->domain); - pdkim_hexprint(sig->sighash.data, sig->sighash.len); - } - - sig->signature_header = pdkim_create_header(sig, TRUE); - } - - /* VERIFICATION ----------------------------------------------------------- */ - else - { - ev_ctx vctx; - - /* Make sure we have all required signature tags */ - if (!( sig->domain && *sig->domain - && sig->selector && *sig->selector - && sig->headernames && *sig->headernames - && sig->bodyhash.data - && sig->sighash.data - && sig->keytype >= 0 - && sig->hashtype >= 0 - && sig->version - ) ) - { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR; - - DEBUG(D_acl) debug_printf( - " Error in DKIM-Signature header: tags missing or invalid (%s)\n" - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\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; - } - - /* Make sure sig uses supported DKIM version (only v1) */ - if (sig->version != 1) - { - sig->verify_status = PDKIM_VERIFY_INVALID; - sig->verify_ext_status = PDKIM_VERIFY_INVALID_DKIM_VERSION; - - DEBUG(D_acl) debug_printf( - " Error in DKIM-Signature header: unsupported DKIM version\n" - "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - 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))) - { - log_write(0, LOG_MAIN, "PDKIM: %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; - } - - /* 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 */ -/*XXX extend for non-RSA algos */ -/*- done for GnuTLS */ - 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; - sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE; - goto NEXT_VERIFY; - } - - - /* 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; - } - -NEXT_VERIFY: - - DEBUG(D_acl) - { - debug_printf("PDKIM [%s] %s signature status: %s", - sig->domain, dkim_sig_to_a_tag(sig), - pdkim_verify_status_str(sig->verify_status)); - if (sig->verify_ext_status > 0) - debug_printf(" (%s)\n", - pdkim_verify_ext_status_str(sig->verify_ext_status)); - else - debug_printf("\n"); - } - } - } - -/* If requested, set return pointer to signature(s) */ -if (return_signatures) - *return_signatures = ctx->sig; - -return ctx->flags & PDKIM_MODE_SIGN || verify_pass - ? PDKIM_OK : PDKIM_FAIL; -} - - -/* -------------------------------------------------------------------------- */ - -DLLEXPORT pdkim_ctx * -pdkim_init_verify(uschar * (*dns_txt_callback)(uschar *), BOOL dot_stuffing) -{ -pdkim_ctx * ctx; - -ctx = store_get(sizeof(pdkim_ctx)); -memset(ctx, 0, sizeof(pdkim_ctx)); - -if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM; -ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN); -ctx->dns_txt_callback = dns_txt_callback; - -return ctx; -} - - -/* -------------------------------------------------------------------------- */ - -DLLEXPORT pdkim_signature * -pdkim_init_sign(pdkim_ctx * ctx, - uschar * domain, uschar * selector, uschar * privkey, - uschar * hashname, const uschar ** errstr) -{ -int hashtype; -pdkim_signature * sig; - -if (!domain || !selector || !privkey) - return NULL; - -/* Allocate & init one signature struct */ - -sig = store_get(sizeof(pdkim_signature)); -memset(sig, 0, sizeof(pdkim_signature)); - -sig->bodylength = -1; - -sig->domain = string_copy(US domain); -sig->selector = string_copy(US selector); -sig->privkey = string_copy(US privkey); -sig->keytype = -1; - -for (hashtype = 0; hashtype < nelem(pdkim_hashes); hashtype++) - if (Ustrcmp(hashname, pdkim_hashes[hashtype].dkim_hashname) == 0) - { sig->hashtype = hashtype; break; } -if (hashtype >= nelem(pdkim_hashes)) - { - log_write(0, LOG_MAIN|LOG_PANIC, - "PDKIM: unrecognised hashname '%s'", hashname); - 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, errstr)) - debug_printf("WARNING: bad dkim key in dns\n"); - debug_printf("PDKIM (finished checking verify key)<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n"); - } -return sig; -} - - -/* -------------------------------------------------------------------------- */ - -DLLEXPORT void -pdkim_set_optional(pdkim_signature * sig, - char * sign_headers, - char * identity, - int canon_headers, - int canon_body, - long bodylength, - unsigned long created, - unsigned long expires) -{ -if (identity) - sig->identity = string_copy(US identity); - -sig->sign_headers = string_copy(sign_headers - ? US sign_headers : US PDKIM_DEFAULT_SIGN_HEADERS); - -sig->canon_headers = canon_headers; -sig->canon_body = canon_body; -sig->bodylength = bodylength; -sig->created = created; -sig->expires = expires; - -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; - -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("PDKIM: using existing bodyhash %d/%d/%ld\n", - hashtype, canon_method, bodylength); - return b; - } - -DEBUG(D_receive) debug_printf("PDKIM: new bodyhash %d/%d/%ld\n", - hashtype, canon_method, bodylength); -b = store_get(sizeof(pdkim_bodyhash)); -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("PDKIM: 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)(uschar *)) -{ -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_dkim_init(); -} - - - -#endif /*DISABLE_DKIM*/