X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/a79d883474c84fa2a286b7797a7664b599912fcd..cb45303cf2a8d9922702f13db42b3285c48f6aa7:/src/src/dkim.c diff --git a/src/src/dkim.c b/src/src/dkim.c index 9a13e2a80..0153024df 100644 --- a/src/src/dkim.c +++ b/src/src/dkim.c @@ -2,7 +2,8 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge, 1995 - 2017 */ +/* Copyright (c) University of Cambridge, 1995 - 2018 */ +/* Copyright (c) The Exim Maintainers 2020 - 2021*/ /* See the file NOTICE for conditions of use and distribution. */ /* Code for DKIM support. Other DKIM relevant code is in @@ -21,68 +22,81 @@ void params_dkim(void) { builtin_macro_create_var(US"_DKIM_SIGN_HEADERS", US PDKIM_DEFAULT_SIGN_HEADERS); +builtin_macro_create_var(US"_DKIM_OVERSIGN_HEADERS", US PDKIM_OVERSIGN_HEADERS); } # else /*!MACRO_PREDEF*/ +pdkim_ctx dkim_sign_ctx; int dkim_verify_oldpool; pdkim_ctx *dkim_verify_ctx = NULL; -pdkim_signature *dkim_signatures = NULL; pdkim_signature *dkim_cur_sig = NULL; static const uschar * dkim_collect_error = NULL; +#define DKIM_MAX_SIGNATURES 20 -/*XXX the caller only uses the first record if we return multiple. -Could we hand back an allocated string? + +/* Look up the DKIM record in DNS for the given hostname. +Will use the first found if there are multiple. +The return string is tainted, having come from off-site. */ -static int -dkim_exim_query_dns_txt(char *name, char *answer) +uschar * +dkim_exim_query_dns_txt(const uschar * name) { -dns_answer dnsa; +dns_answer * dnsa = store_get_dns_answer(); dns_scan dnss; -dns_record *rr; +rmark reset_point = store_mark(); +gstring * g = string_get_tainted(256, GET_TAINTED); lookup_dnssec_authenticated = NULL; -if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) - return PDKIM_FAIL; /*XXX better error detail? logging? */ +if (dns_lookup(dnsa, name, T_TXT, NULL) != DNS_SUCCEED) + goto bad; /* Search for TXT record */ -for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); +for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr; - rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) + rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_TXT) - { - int rr_offset = 0; - int answer_offset = 0; - - /* Copy record content to the answer buffer */ - - while (rr_offset < rr->size) + { /* Copy record content to the answer buffer */ + for (int rr_offset = 0; rr_offset < rr->size; ) { uschar len = rr->data[rr_offset++]; - snprintf(answer + answer_offset, - PDKIM_DNS_TXT_MAX_RECLEN - answer_offset, - "%.*s", (int)len, CS (rr->data + rr_offset)); + + g = string_catn(g, US(rr->data + rr_offset), len); + if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) + goto bad; + rr_offset += len; - answer_offset += len; - if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) - return PDKIM_FAIL; /*XXX better error detail? logging? */ } - return PDKIM_OK; + + /* Check if this looks like a DKIM record */ + if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0) + { + store_free_dns_answer(dnsa); + gstring_release_unused(g); + return string_from_gstring(g); + } + + g->ptr = 0; /* overwrite previous record */ } -return PDKIM_FAIL; /*XXX better error detail? logging? */ +bad: +store_reset(reset_point); +store_free_dns_answer(dnsa); +return NULL; /*XXX better error detail? logging? */ } void dkim_exim_init(void) { +if (f.dkim_init_done) return; +f.dkim_init_done = TRUE; pdkim_init(); } @@ -91,12 +105,17 @@ pdkim_init(); void dkim_exim_verify_init(BOOL dot_stuffing) { -/* There is a store-reset between header & body reception -so cannot use the main pool. Any allocs done by Exim -memory-handling must use the perm pool. */ +dkim_exim_init(); + +/* There is a store-reset between header & body reception for the main pool +(actually, after every header line) so cannot use that as we need the data we +store per-header, during header processing, at the end of body reception +for evaluating the signature. Any allocs done for dkim verify +memory-handling must use a different pool. We use a separate one that we +can reset per message. */ dkim_verify_oldpool = store_pool; -store_pool = POOL_PERM; +store_pool = POOL_MESSAGE; /* Free previous context if there is one */ @@ -106,29 +125,32 @@ if (dkim_verify_ctx) /* Create new context */ dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); -dkim_collect_input = !!dkim_verify_ctx; +dkim_collect_input = dkim_verify_ctx ? DKIM_MAX_SIGNATURES : 0; dkim_collect_error = NULL; -/* Start feed up with any cached data */ -receive_get_cache(); +/* Start feed up with any cached data, but limited to message data */ +receive_get_cache(chunking_state == CHUNKING_LAST + ? chunking_data_left : GETC_BUFFER_UNLIMITED); store_pool = dkim_verify_oldpool; } +/* Submit a chunk of data for verification input. +Only use the data when the feed is activated. */ void dkim_exim_verify_feed(uschar * data, int len) { int rc; -store_pool = POOL_PERM; +store_pool = POOL_MESSAGE; if ( dkim_collect_input && (rc = pdkim_feed(dkim_verify_ctx, data, len)) != PDKIM_OK) { dkim_collect_error = pdkim_errstr(rc); log_write(0, LOG_MAIN, "DKIM: validation error: %.100s", dkim_collect_error); - dkim_collect_input = FALSE; + dkim_collect_input = 0; } store_pool = dkim_verify_oldpool; } @@ -138,126 +160,156 @@ store_pool = dkim_verify_oldpool; static void dkim_exim_verify_log_sig(pdkim_signature * sig) { -gstring * logmsg = string_catn(NULL, "DKIM: ", 6); +gstring * logmsg; uschar * s; +if (!sig) return; + +/* Remember the domain for the first pass result */ + +if ( !dkim_verify_overall + && dkim_verify_status + ? Ustrcmp(dkim_verify_status, US"pass") == 0 + : sig->verify_status == PDKIM_VERIFY_PASS + ) + dkim_verify_overall = string_copy(sig->domain); + +/* Rewrite the sig result if the ACL overrode it. This is only +needed because the DMARC code (sigh) peeks at the dkim sigs. +Mark the sig for this having been done. */ + +if ( dkim_verify_status + && ( dkim_verify_status != dkim_exim_expand_query(DKIM_VERIFY_STATUS) + || dkim_verify_reason != dkim_exim_expand_query(DKIM_VERIFY_REASON) + ) ) + { /* overridden by ACL */ + sig->verify_ext_status = -1; + if (Ustrcmp(dkim_verify_status, US"fail") == 0) + sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_FAIL; + else if (Ustrcmp(dkim_verify_status, US"invalid") == 0) + sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_INVALID; + else if (Ustrcmp(dkim_verify_status, US"none") == 0) + sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_NONE; + else if (Ustrcmp(dkim_verify_status, US"pass") == 0) + sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_PASS; + else + sig->verify_status = -1; + } + +if (!LOGGING(dkim_verbose)) return; + + +logmsg = string_catn(NULL, US"DKIM: ", 6); if (!(s = sig->domain)) s = US""; logmsg = string_append(logmsg, 2, "d=", s); if (!(s = sig->selector)) s = US""; logmsg = string_append(logmsg, 2, " s=", s); -logmsg = string_append(logmsg, 7, -" c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", -"/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", -" a=", dkim_sig_to_a_tag(sig), -string_sprintf(" b=" SIZE_T_FMT, - (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); +logmsg = string_fmt_append(logmsg, " c=%s/%s a=%s b=" SIZE_T_FMT, + sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", + sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", + dkim_sig_to_a_tag(sig), + (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : (size_t)0); if ((s= sig->identity)) logmsg = string_append(logmsg, 2, " i=", s); -if (sig->created > 0) logmsg = string_cat(logmsg, - string_sprintf(" t=%lu", sig->created)); -if (sig->expires > 0) logmsg = string_cat(logmsg, - string_sprintf(" x=%lu", sig->expires)); -if (sig->bodylength > -1) logmsg = string_cat(logmsg, - string_sprintf(" l=%lu", sig->bodylength)); - -if ( !dkim_verify_status - || ( dkim_verify_status == dkim_exim_expand_query(DKIM_VERIFY_STATUS) - && dkim_verify_reason == dkim_exim_expand_query(DKIM_VERIFY_REASON) - ) ) +if (sig->created > 0) logmsg = string_fmt_append(logmsg, " t=%lu", + sig->created); +if (sig->expires > 0) logmsg = string_fmt_append(logmsg, " x=%lu", + sig->expires); +if (sig->bodylength > -1) logmsg = string_fmt_append(logmsg, " l=%lu", + sig->bodylength); + +if (sig->verify_status & PDKIM_VERIFY_POLICY) + logmsg = string_append(logmsg, 5, + US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); +else switch (sig->verify_status) { case PDKIM_VERIFY_NONE: - logmsg = string_cat(logmsg, " [not verified]"); + logmsg = string_cat(logmsg, US" [not verified]"); break; case PDKIM_VERIFY_INVALID: - logmsg = string_cat(logmsg, " [invalid - "); + logmsg = string_cat(logmsg, US" [invalid - "); switch (sig->verify_ext_status) { case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: logmsg = string_cat(logmsg, - "public key record (currently?) unavailable]"); + US"public key record (currently?) unavailable]"); break; case PDKIM_VERIFY_INVALID_BUFFER_SIZE: - logmsg = string_cat(logmsg, "overlong public key record]"); + logmsg = string_cat(logmsg, US"overlong public key record]"); break; case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: - logmsg = string_cat(logmsg, "syntax error in public key record]"); + logmsg = string_cat(logmsg, US"syntax error in public key record]"); break; case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: - logmsg = string_cat(logmsg, "signature tag missing or invalid]"); + logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); break; case PDKIM_VERIFY_INVALID_DKIM_VERSION: - logmsg = string_cat(logmsg, "unsupported DKIM version]"); + logmsg = string_cat(logmsg, US"unsupported DKIM version]"); break; default: - logmsg = string_cat(logmsg, "unspecified problem]"); + logmsg = string_cat(logmsg, US"unspecified problem]"); } break; case PDKIM_VERIFY_FAIL: - logmsg = string_cat(logmsg, " [verification failed - "); + logmsg = string_cat(logmsg, US" [verification failed - "); switch (sig->verify_ext_status) { case PDKIM_VERIFY_FAIL_BODY: logmsg = string_cat(logmsg, - "body hash mismatch (body probably modified in transit)]"); + US"body hash mismatch (body probably modified in transit)]"); break; case PDKIM_VERIFY_FAIL_MESSAGE: logmsg = string_cat(logmsg, - "signature did not verify (headers probably modified in transit)]"); - break; + US"signature did not verify " + "(headers probably modified in transit)]"); + break; + + case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: + logmsg = string_cat(logmsg, + US"signature invalid (key too short)]"); + break; default: - logmsg = string_cat(logmsg, "unspecified reason]"); + logmsg = string_cat(logmsg, US"unspecified reason]"); } break; case PDKIM_VERIFY_PASS: - logmsg = string_cat(logmsg, " [verification succeeded]"); + logmsg = string_cat(logmsg, US" [verification succeeded]"); break; } -else - logmsg = string_append(logmsg, 5, - US" [", dkim_verify_status, US" - ", dkim_verify_reason, US"]"); -log_write(0, LOG_MAIN, string_from_gstring(logmsg)); +log_write(0, LOG_MAIN, "%s", string_from_gstring(logmsg)); return; } -/* Log a line for "the current" signature */ -void -dkim_exim_verify_log_item(void) -{ -dkim_exim_verify_log_sig(dkim_cur_sig); -} - - /* Log a line for each signature */ void dkim_exim_verify_log_all(void) { -pdkim_signature * sig; -for (sig = dkim_signatures; sig; sig = sig->next) dkim_exim_verify_log_sig(sig); +for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) + dkim_exim_verify_log_sig(sig); } void dkim_exim_verify_finish(void) { -pdkim_signature * sig; int rc; gstring * g = NULL; -const uschar * errstr; +const uschar * errstr = NULL; -store_pool = POOL_PERM; +store_pool = POOL_MESSAGE; /* Delete eventual previous signature chain */ @@ -269,25 +321,22 @@ if (dkim_collect_error) log_write(0, LOG_MAIN, "DKIM: Error during validation, disabling signature verification: %.100s", dkim_collect_error); - dkim_disable_verify = TRUE; + f.dkim_disable_verify = TRUE; goto out; } -dkim_collect_input = FALSE; +dkim_collect_input = 0; /* Finish DKIM operation and fetch link to signatures chain */ -rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr); -if (rc != PDKIM_OK) - { - log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc), - errstr ? ": " : "", errstr ? errstr : US""); - goto out; - } +rc = pdkim_feed_finish(dkim_verify_ctx, (pdkim_signature **)&dkim_signatures, + &errstr); +if (rc != PDKIM_OK && errstr) + log_write(0, LOG_MAIN, "DKIM: validation error: %s", errstr); /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ -for (sig = dkim_signatures; sig; sig = sig->next) +for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) { if (sig->domain) g = string_append_listele(g, ':', sig->domain); if (sig->identity) g = string_append_listele(g, ':', sig->identity); @@ -300,46 +349,92 @@ store_pool = dkim_verify_oldpool; } -void -dkim_exim_acl_setup(uschar * id) + +/* Args as per dkim_exim_acl_run() below */ +static int +dkim_acl_call(uschar * id, gstring ** res_ptr, + uschar ** user_msgptr, uschar ** log_msgptr) +{ +int rc; +DEBUG(D_receive) + debug_printf("calling acl_smtp_dkim for dkim_cur_signer='%s'\n", id); + +rc = acl_check(ACL_WHERE_DKIM, NULL, acl_smtp_dkim, user_msgptr, log_msgptr); +dkim_exim_verify_log_sig(dkim_cur_sig); +*res_ptr = string_append_listele(*res_ptr, ':', dkim_verify_status); +return rc; +} + + + +/* For the given identity, run the DKIM ACL once for each matching signature. + +Arguments + id Identity to look for in dkim signatures + res_ptr ptr to growable string-list of status results, + appended to per ACL run + user_msgptr where to put a user error (for SMTP response) + log_msgptr where to put a logging message (not for SMTP response) + +Returns: OK access is granted by an ACCEPT verb + DISCARD access is granted by a DISCARD verb + FAIL access is denied + FAIL_DROP access is denied; drop the connection + DEFER can't tell at the moment + ERROR disaster +*/ + +int +dkim_exim_acl_run(uschar * id, gstring ** res_ptr, + uschar ** user_msgptr, uschar ** log_msgptr) { -pdkim_signature * sig; uschar * cmp_val; +int rc = -1; -dkim_cur_sig = NULL; +dkim_verify_status = US"none"; +dkim_verify_reason = US""; dkim_cur_signer = id; -if (dkim_disable_verify || !id || !dkim_verify_ctx) - return; +if (f.dkim_disable_verify || !id || !dkim_verify_ctx) + return OK; -/* Find signature to run ACL on */ +/* Find signatures to run ACL on */ -for (sig = dkim_signatures; sig; sig = sig->next) +for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) && strcmpic(cmp_val, id) == 0 ) { - dkim_cur_sig = sig; - /* The "dkim_domain" and "dkim_selector" expansion variables have - related globals, since they are used in the signing code too. - Instead of inventing separate names for verification, we set - them here. This is easy since a domain and selector is guaranteed - to be in a signature. The other dkim_* expansion items are - dynamically fetched from dkim_cur_sig at expansion time (see - function below). */ + related globals, since they are used in the signing code too. + Instead of inventing separate names for verification, we set + them here. This is easy since a domain and selector is guaranteed + to be in a signature. The other dkim_* expansion items are + dynamically fetched from dkim_cur_sig at expansion time (see + dkim_exim_expand_query() below). */ + dkim_cur_sig = sig; dkim_signing_domain = US sig->domain; dkim_signing_selector = US sig->selector; - dkim_key_length = sig->sighash.len * 8; + dkim_key_length = sig->keybits; /* These two return static strings, so we can compare the addr later to see if the ACL overwrote them. Check that when logging */ dkim_verify_status = dkim_exim_expand_query(DKIM_VERIFY_STATUS); dkim_verify_reason = dkim_exim_expand_query(DKIM_VERIFY_REASON); - return; + + if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) + return rc; } + +if (rc != -1) + return rc; + +/* No matching sig found. Call ACL once anyway. */ + +dkim_cur_sig = NULL; +return dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr); } @@ -372,7 +467,7 @@ switch (what) uschar * dkim_exim_expand_query(int what) { -if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) +if (!dkim_verify_ctx || f.dkim_disable_verify || !dkim_cur_sig) return dkim_exim_expand_defaults(what); switch (what) @@ -475,6 +570,7 @@ switch (what) return US"pubkey_unavailable"; case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:return US"pubkey_dns_syntax"; case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return US"pubkey_der_syntax"; + case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: return US"pubkey_too_short"; case PDKIM_VERIFY_FAIL_BODY: return US"bodyhash_mismatch"; case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; } @@ -485,18 +581,33 @@ switch (what) } -/* Generate signatures for the given file, returning a string. +void +dkim_exim_sign_init(void) +{ +int old_pool = store_pool; + +dkim_exim_init(); +store_pool = POOL_MAIN; +pdkim_init_context(&dkim_sign_ctx, FALSE, &dkim_exim_query_dns_txt); +store_pool = old_pool; +} + + +/* Generate signatures for the given file. If a prefix is given, prepend it to the file for the calculations. + +Return: + NULL: error; error string written + string: signature header(s), or a zero-length string (not an error) */ gstring * dkim_exim_sign(int fd, off_t off, uschar * prefix, struct ob_dkim * dkim, const uschar ** errstr) { -const uschar * dkim_domain; +const uschar * dkim_domain = NULL; int sep = 0; gstring * seen_doms = NULL; -pdkim_ctx ctx; pdkim_signature * sig; gstring * sigbuf; int pdkim_rc; @@ -505,18 +616,21 @@ uschar buf[4096]; int save_errno = 0; int old_pool = store_pool; uschar * errwhen; +const uschar * s; -store_pool = POOL_MAIN; +if (dkim->dot_stuffed) + dkim_sign_ctx.flags |= PDKIM_DOT_TERM; -pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); +store_pool = POOL_MAIN; -if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) +if ((s = dkim->dkim_domain) && !(dkim_domain = expand_cstring(s))) /* expansion error, do not send message. */ { errwhen = US"dkim_domain"; goto expand_bad; } /* Set $dkim_domain expansion variable to each unique domain in list. */ -while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) +if (dkim_domain) + while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) { const uschar * dkim_sel; int sel_sep = 0; @@ -527,6 +641,7 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) /* Only sign once for each domain, no matter how often it appears in the expanded list. */ + dkim_signing_domain = string_copylc(dkim_signing_domain); if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) continue; @@ -537,7 +652,6 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) for this domain. */ if (!(dkim_sel = expand_string(dkim->dkim_selector))) - if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) { errwhen = US"dkim_selector"; goto expand_bad; } while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep, @@ -549,6 +663,8 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) uschar * dkim_private_key_expanded; uschar * dkim_hash_expanded; uschar * dkim_identity_expanded = NULL; + uschar * dkim_timestamps_expanded = NULL; + unsigned long tval = 0, xval = 0; /* Get canonicalization to use */ @@ -585,39 +701,10 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) ) continue; /* don't sign, but no error */ - if (dkim_private_key_expanded[0] == '/') - { - int privkey_fd, off = 0, len; - - /* Looks like a filename, load the private key. */ - - memset(big_buffer, 0, big_buffer_size); - - if ((privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY)) < 0) - { - log_write(0, LOG_MAIN | LOG_PANIC, "unable to open " - "private key file for reading: %s", - dkim_private_key_expanded); - goto bad; - } - - do - { - if ((len = read(privkey_fd, big_buffer + off, big_buffer_size - 2 - off)) < 0) - { - (void) close(privkey_fd); - log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", - dkim_private_key_expanded); - goto bad; - } - off += len; - } - while (len > 0); - - (void) close(privkey_fd); - big_buffer[off] = '\0'; - dkim_private_key_expanded = big_buffer; - } + if ( dkim_private_key_expanded[0] == '/' + && !(dkim_private_key_expanded = + expand_file_big_buffer(dkim_private_key_expanded))) + goto bad; if (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) { errwhen = US"dkim_hash"; goto expand_bad; } @@ -628,10 +715,14 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) else if (!*dkim_identity_expanded) dkim_identity_expanded = NULL; - /*XXX so we currently nail signing to RSA + this hash. - Need to extract algo from privkey and check for disallowed combos. */ + if (dkim->dkim_timestamps) + if (!(dkim_timestamps_expanded = expand_string(dkim->dkim_timestamps))) + { errwhen = US"dkim_timestamps"; goto expand_bad; } + else + xval = (tval = (unsigned long) time(NULL)) + + strtoul(CCS dkim_timestamps_expanded, NULL, 10); - if (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, + if (!(sig = pdkim_init_sign(&dkim_sign_ctx, dkim_signing_domain, dkim_signing_selector, dkim_private_key_expanded, dkim_hash_expanded, @@ -642,66 +733,163 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) pdkim_set_optional(sig, CS dkim_sign_headers_expanded, - dkim_identity_expanded, + CS dkim_identity_expanded, pdkim_canon, - pdkim_canon, -1, 0, 0); + pdkim_canon, -1, tval, xval); - if (!ctx.sig) /* link sig to context chain */ - ctx.sig = sig; + if (!pdkim_set_sig_bodyhash(&dkim_sign_ctx, sig)) + goto bad; + + if (!dkim_sign_ctx.sig) /* link sig to context chain */ + dkim_sign_ctx.sig = sig; else { - pdkim_signature * n = ctx.sig; + pdkim_signature * n = dkim_sign_ctx.sig; while (n->next) n = n->next; n->next = sig; } } } -if (prefix) - pdkim_feed(&ctx, prefix, Ustrlen(prefix)); - -if (lseek(fd, off, SEEK_SET) < 0) - sread = -1; -else - while ((sread = read(fd, &buf, sizeof(buf))) > 0) - if ((pdkim_rc = pdkim_feed(&ctx, buf, sread)) != PDKIM_OK) - goto pk_bad; +/* We may need to carry on with the data-feed even if there are no DKIM sigs to +produce, if some other package (eg. ARC) is signing. */ -/* Handle failed read above. */ -if (sread == -1) +if (!dkim_sign_ctx.sig && !dkim->force_bodyhash) { - debug_printf("DKIM: Error reading -K file.\n"); - save_errno = errno; - goto bad; + DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); + sigbuf = string_get(1); /* return a zero-len string */ } +else + { + if (prefix && (pdkim_rc = pdkim_feed(&dkim_sign_ctx, prefix, Ustrlen(prefix))) != PDKIM_OK) + goto pk_bad; + + if (lseek(fd, off, SEEK_SET) < 0) + sread = -1; + else + while ((sread = read(fd, &buf, sizeof(buf))) > 0) + if ((pdkim_rc = pdkim_feed(&dkim_sign_ctx, buf, sread)) != PDKIM_OK) + goto pk_bad; + + /* Handle failed read above. */ + if (sread == -1) + { + debug_printf("DKIM: Error reading -K file.\n"); + save_errno = errno; + goto bad; + } -/* Build string of headers, one per signature */ - -if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) - goto pk_bad; + /* Build string of headers, one per signature */ -for (sigbuf = NULL; sig; sig = sig->next) - sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); + if ((pdkim_rc = pdkim_feed_finish(&dkim_sign_ctx, &sig, errstr)) != PDKIM_OK) + goto pk_bad; -(void) string_from_gstring(sigbuf); + if (!sig) + { + DEBUG(D_transport) debug_printf("DKIM: no signatures to use\n"); + sigbuf = string_get(1); /* return a zero-len string */ + } + else for (sigbuf = NULL; sig; sig = sig->next) + sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); + } CLEANUP: + (void) string_from_gstring(sigbuf); store_pool = old_pool; errno = save_errno; return sigbuf; pk_bad: log_write(0, LOG_MAIN|LOG_PANIC, - "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); + "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); bad: sigbuf = NULL; goto CLEANUP; expand_bad: - log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand %s: %s", - errwhen, expand_string_message); + *errstr = string_sprintf("failed to expand %s: %s", + errwhen, expand_string_message); + log_write(0, LOG_MAIN | LOG_PANIC, "%s", *errstr); goto bad; } + + + +gstring * +authres_dkim(gstring * g) +{ +int start = 0; /* compiler quietening */ + +DEBUG(D_acl) start = g->ptr; + +for (pdkim_signature * sig = dkim_signatures; sig; sig = sig->next) + { + g = string_catn(g, US";\n\tdkim=", 8); + + if (sig->verify_status & PDKIM_VERIFY_POLICY) + g = string_append(g, 5, + US"policy (", dkim_verify_status, US" - ", dkim_verify_reason, US")"); + else switch(sig->verify_status) + { + case PDKIM_VERIFY_NONE: g = string_cat(g, US"none"); break; + case PDKIM_VERIFY_INVALID: + switch (sig->verify_ext_status) + { + case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: + g = string_cat(g, US"tmperror (pubkey unavailable)\n\t\t"); break; + case PDKIM_VERIFY_INVALID_BUFFER_SIZE: + g = string_cat(g, US"permerror (overlong public key record)\n\t\t"); break; + case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: + case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: + g = string_cat(g, US"neutral (public key record import problem)\n\t\t"); + break; + case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: + g = string_cat(g, US"neutral (signature tag missing or invalid)\n\t\t"); + break; + case PDKIM_VERIFY_INVALID_DKIM_VERSION: + g = string_cat(g, US"neutral (unsupported DKIM version)\n\t\t"); + break; + default: + g = string_cat(g, US"permerror (unspecified problem)\n\t\t"); break; + } + break; + case PDKIM_VERIFY_FAIL: + switch (sig->verify_ext_status) + { + case PDKIM_VERIFY_FAIL_BODY: + g = string_cat(g, + US"fail (body hash mismatch; body probably modified in transit)\n\t\t"); + break; + case PDKIM_VERIFY_FAIL_MESSAGE: + g = string_cat(g, + US"fail (signature did not verify; headers probably modified in transit)\n\t\t"); + break; + case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: /* should this really be "polcy"? */ + g = string_fmt_append(g, "fail (public key too short: %u bits)\n\t\t", sig->keybits); + break; + default: + g = string_cat(g, US"fail (unspecified reason)\n\t\t"); + break; + } + break; + case PDKIM_VERIFY_PASS: g = string_cat(g, US"pass"); break; + default: g = string_cat(g, US"permerror"); break; + } + if (sig->domain) g = string_append(g, 2, US" header.d=", sig->domain); + if (sig->identity) g = string_append(g, 2, US" header.i=", sig->identity); + if (sig->selector) g = string_append(g, 2, US" header.s=", sig->selector); + g = string_append(g, 2, US" header.a=", dkim_sig_to_a_tag(sig)); + } + +DEBUG(D_acl) + if (g->ptr == start) + debug_printf("DKIM: no authres\n"); + else + debug_printf("DKIM: authres '%.*s'\n", g->ptr - start - 3, g->s + start + 3); +return g; +} + + # endif /*!MACRO_PREDEF*/ #endif /*!DISABLE_DKIM*/