X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/df3def249f555f5e6cbfa1bf3fb1a20db4f48fcd..31323b30449a59713ed7a99f86e356cb1b9d0fb7:/src/src/dkim.c diff --git a/src/src/dkim.c b/src/src/dkim.c index 36b103e8f..03efb18d4 100644 --- a/src/src/dkim.c +++ b/src/src/dkim.c @@ -2,7 +2,7 @@ * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge, 1995 - 2015 */ +/* Copyright (c) University of Cambridge, 1995 - 2017 */ /* See the file NOTICE for conditions of use and distribution. */ /* Code for DKIM support. Other DKIM relevant code is in @@ -14,9 +14,11 @@ #include "pdkim/pdkim.h" +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; static int dkim_exim_query_dns_txt(char *name, char *answer) @@ -27,7 +29,7 @@ dns_record *rr; lookup_dnssec_authenticated = NULL; if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) - return PDKIM_FAIL; + return PDKIM_FAIL; /*XXX better error detail? logging? */ /* Search for TXT record */ @@ -50,18 +52,33 @@ for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); rr_offset += len; answer_offset += len; if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN) - return PDKIM_FAIL; + return PDKIM_FAIL; /*XXX better error detail? logging? */ } return PDKIM_OK; } -return PDKIM_FAIL; +return PDKIM_FAIL; /*XXX better error detail? logging? */ } void -dkim_exim_verify_init(void) +dkim_exim_init(void) { +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_verify_oldpool = store_pool; +store_pool = POOL_PERM; + /* Free previous context if there is one */ if (dkim_verify_ctx) @@ -69,83 +86,105 @@ if (dkim_verify_ctx) /* Create new context */ -dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt); +dkim_verify_ctx = pdkim_init_verify(&dkim_exim_query_dns_txt, dot_stuffing); dkim_collect_input = !!dkim_verify_ctx; +dkim_collect_error = NULL; + +/* Start feed up with any cached data */ +receive_get_cache(); + +store_pool = dkim_verify_oldpool; } void dkim_exim_verify_feed(uschar * data, int len) { +int rc; + +store_pool = POOL_PERM; if ( dkim_collect_input - && pdkim_feed(dkim_verify_ctx, (char *)data, len) != PDKIM_OK) + && (rc = pdkim_feed(dkim_verify_ctx, CS 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; + } +store_pool = dkim_verify_oldpool; } void dkim_exim_verify_finish(void) { -pdkim_signature *sig = NULL; -int dkim_signers_size = 0; -int dkim_signers_ptr = 0; -dkim_signers = NULL; +pdkim_signature * sig = NULL; +int dkim_signers_size = 0, dkim_signers_ptr = 0, rc; +const uschar * errstr; + +store_pool = POOL_PERM; /* Delete eventual previous signature chain */ +dkim_signers = NULL; dkim_signatures = NULL; -/* If we have arrived here with dkim_collect_input == FALSE, it -means there was a processing error somewhere along the way. -Log the incident and disable futher verification. */ - -if (!dkim_collect_input) +if (dkim_collect_error) { log_write(0, LOG_MAIN, - "DKIM: Error while running this message through validation," - " disabling signature verification."); + "DKIM: Error during validation, disabling signature verification: %.100s", + dkim_collect_error); dkim_disable_verify = TRUE; - return; + goto out; } dkim_collect_input = FALSE; /* Finish DKIM operation and fetch link to signatures chain */ -if (pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures) != PDKIM_OK) - return; +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; + } for (sig = dkim_signatures; sig; sig = sig->next) { - int size = 0; - int ptr = 0; + int size = 0, ptr = 0; + uschar * logmsg = NULL, * s; /* Log a line for each signature */ - uschar *logmsg = string_append(NULL, &size, &ptr, 5, - string_sprintf("d=%s s=%s c=%s/%s a=%s b=%d ", - sig->domain, - sig->selector, - sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", - sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", - sig->algo == PDKIM_ALGO_RSA_SHA256 ? "rsa-sha256" : "rsa-sha1", - sig->sigdata_len * 8 - ), - - sig->identity ? string_sprintf("i=%s ", sig->identity) : US"", - sig->created > 0 ? string_sprintf("t=%lu ", sig->created) : US"", - sig->expires > 0 ? string_sprintf("x=%lu ", sig->expires) : US"", - sig->bodylength > -1 ? string_sprintf("l=%lu ", sig->bodylength) : US"" - ); + if (!(s = sig->domain)) s = US""; + logmsg = string_append(logmsg, &size, &ptr, 2, "d=", s); + if (!(s = sig->selector)) s = US""; + logmsg = string_append(logmsg, &size, &ptr, 2, " s=", s); + logmsg = string_append(logmsg, &size, &ptr, 7, + " c=", sig->canon_headers == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", + "/", sig->canon_body == PDKIM_CANON_SIMPLE ? "simple" : "relaxed", + " a=", sig->algo == PDKIM_ALGO_RSA_SHA256 + ? "rsa-sha256" + : sig->algo == PDKIM_ALGO_RSA_SHA1 ? "rsa-sha1" : "err", + string_sprintf(" b=%d", + (int)sig->sighash.len > -1 ? sig->sighash.len * 8 : 0)); + if ((s= sig->identity)) logmsg = string_append(logmsg, &size, &ptr, 2, " i=", s); + if (sig->created > 0) logmsg = string_append(logmsg, &size, &ptr, 1, + string_sprintf(" t=%lu", sig->created)); + if (sig->expires > 0) logmsg = string_append(logmsg, &size, &ptr, 1, + string_sprintf(" x=%lu", sig->expires)); + if (sig->bodylength > -1) logmsg = string_append(logmsg, &size, &ptr, 1, + string_sprintf(" l=%lu", sig->bodylength)); switch (sig->verify_status) { case PDKIM_VERIFY_NONE: - logmsg = string_append(logmsg, &size, &ptr, 1, "[not verified]"); + logmsg = string_append(logmsg, &size, &ptr, 1, " [not verified]"); break; case PDKIM_VERIFY_INVALID: - logmsg = string_append(logmsg, &size, &ptr, 1, "[invalid - "); + logmsg = string_append(logmsg, &size, &ptr, 1, " [invalid - "); switch (sig->verify_ext_status) { case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: @@ -164,6 +203,16 @@ for (sig = dkim_signatures; sig; sig = sig->next) "syntax error in public key record]"); break; + case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: + logmsg = string_append(logmsg, &size, &ptr, 1, + "signature tag missing or invalid]"); + break; + + case PDKIM_VERIFY_INVALID_DKIM_VERSION: + logmsg = string_append(logmsg, &size, &ptr, 1, + "unsupported DKIM version]"); + break; + default: logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified problem]"); @@ -172,7 +221,7 @@ for (sig = dkim_signatures; sig; sig = sig->next) case PDKIM_VERIFY_FAIL: logmsg = - string_append(logmsg, &size, &ptr, 1, "[verification failed - "); + string_append(logmsg, &size, &ptr, 1, " [verification failed - "); switch (sig->verify_ext_status) { case PDKIM_VERIFY_FAIL_BODY: @@ -192,7 +241,7 @@ for (sig = dkim_signatures; sig; sig = sig->next) case PDKIM_VERIFY_PASS: logmsg = - string_append(logmsg, &size, &ptr, 1, "[verification succeeded]"); + string_append(logmsg, &size, &ptr, 1, " [verification succeeded]"); break; } @@ -201,26 +250,17 @@ for (sig = dkim_signatures; sig; sig = sig->next) /* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */ - dkim_signers = string_append(dkim_signers, - &dkim_signers_size, - &dkim_signers_ptr, 2, sig->domain, ":"); + if (sig->domain) + dkim_signers = string_append_listele(dkim_signers, ':', sig->domain); if (sig->identity) - dkim_signers = string_append(dkim_signers, - &dkim_signers_size, - &dkim_signers_ptr, 2, sig->identity, ":"); + dkim_signers = string_append_listele(dkim_signers, ':', sig->identity); /* Process next signature */ } -/* NULL-terminate and chop the last colon from the domain list */ - -if (dkim_signers) - { - dkim_signers[dkim_signers_ptr] = '\0'; - if (Ustrlen(dkim_signers) > 0) - dkim_signers[Ustrlen(dkim_signers) - 1] = '\0'; - } +out: +store_pool = dkim_verify_oldpool; } @@ -255,7 +295,7 @@ for (sig = dkim_signatures; sig; sig = sig->next) dkim_signing_domain = US sig->domain; dkim_signing_selector = US sig->selector; - dkim_key_length = sig->sigdata_len * 8; + dkim_key_length = sig->sighash.len * 8; return; } } @@ -340,7 +380,7 @@ switch (what) case DKIM_HEADERNAMES: return dkim_cur_sig->headernames - ? US dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); + ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); case DKIM_IDENTITY: return dkim_cur_sig->identity @@ -408,16 +448,19 @@ switch (what) } +/* Generate signatures for the given file, returning a string. +If a prefix is given, prepend it to the file for the calculations. +*/ + uschar * -dkim_exim_sign(int dkim_fd, uschar * dkim_private_key, - const uschar * dkim_domain, uschar * dkim_selector, - uschar * dkim_canon, uschar * dkim_sign_headers) +dkim_exim_sign(int fd, off_t off, uschar * prefix, + struct ob_dkim * dkim, const uschar ** errstr) { +const uschar * dkim_domain; int sep = 0; uschar *seen_items = NULL; int seen_items_size = 0; int seen_items_offset = 0; -uschar itembuf[256]; uschar *dkim_canon_expanded; uschar *dkim_sign_headers_expanded; uschar *dkim_private_key_expanded; @@ -436,21 +479,19 @@ int old_pool = store_pool; store_pool = POOL_MAIN; -if (!(dkim_domain = expand_cstring(dkim_domain))) +if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) { /* expansion error, do not send message. */ log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " "dkim_domain: %s", expand_string_message); - rc = NULL; - goto CLEANUP; + goto bad; } /* Set $dkim_domain expansion variable to each unique domain in list. */ -while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, - itembuf, sizeof(itembuf)))) +while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0))) { - if (!dkim_signing_domain || dkim_signing_domain[0] == '\0') + if (dkim_signing_domain[0] == '\0') continue; /* Only sign once for each domain, no matter how often it @@ -475,24 +516,23 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, /* Set up $dkim_selector expansion variable. */ - if (!(dkim_signing_selector = expand_string(dkim_selector))) + if (!(dkim_signing_selector = expand_string(dkim->dkim_selector))) { log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " "dkim_selector: %s", expand_string_message); - rc = NULL; - goto CLEANUP; + goto bad; } /* Get canonicalization to use */ - dkim_canon_expanded = dkim_canon ? expand_string(dkim_canon) : US"relaxed"; + dkim_canon_expanded = dkim->dkim_canon + ? expand_string(dkim->dkim_canon) : US"relaxed"; if (!dkim_canon_expanded) { /* expansion error, do not send message. */ log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " "dkim_canon: %s", expand_string_message); - rc = NULL; - goto CLEANUP; + goto bad; } if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) @@ -508,24 +548,22 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, } dkim_sign_headers_expanded = NULL; - if (dkim_sign_headers) - if (!(dkim_sign_headers_expanded = expand_string(dkim_sign_headers))) + if (dkim->dkim_sign_headers) + if (!(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) { log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " "dkim_sign_headers: %s", expand_string_message); - rc = NULL; - goto CLEANUP; + goto bad; } /* else pass NULL, which means default header list */ /* Get private key to use. */ - if (!(dkim_private_key_expanded = expand_string(dkim_private_key))) + if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) { log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand " "dkim_private_key: %s", expand_string_message); - rc = NULL; - goto CLEANUP; + goto bad; } if ( Ustrlen(dkim_private_key_expanded) == 0 @@ -536,67 +574,74 @@ while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, if (dkim_private_key_expanded[0] == '/') { - int privkey_fd = 0; + int privkey_fd, off = 0, len; /* Looks like a filename, load the private key. */ memset(big_buffer, 0, big_buffer_size); - privkey_fd = open(CS dkim_private_key_expanded, O_RDONLY); - if (privkey_fd < 0) + + 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); - rc = NULL; - goto CLEANUP; + goto bad; } - if (read(privkey_fd, big_buffer, big_buffer_size - 2) < 0) + do { - log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s", - dkim_private_key_expanded); - rc = NULL; - goto CLEANUP; + 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; } - ctx = pdkim_init_sign( (char *) dkim_signing_domain, - (char *) dkim_signing_selector, - (char *) dkim_private_key_expanded, - PDKIM_ALGO_RSA_SHA256); + if (!(ctx = pdkim_init_sign(CS dkim_signing_domain, + CS dkim_signing_selector, + CS dkim_private_key_expanded, + PDKIM_ALGO_RSA_SHA256, + dkim->dot_stuffed, + &dkim_exim_query_dns_txt, + errstr + ))) + goto bad; + dkim_private_key_expanded[0] = '\0'; pdkim_set_optional(ctx, - (char *) dkim_sign_headers_expanded, + CS dkim_sign_headers_expanded, NULL, pdkim_canon, pdkim_canon, -1, 0, 0); - lseek(dkim_fd, 0, SEEK_SET); + if (prefix) + pdkim_feed(ctx, prefix, Ustrlen(prefix)); - while ((sread = read(dkim_fd, &buf, 4096)) > 0) - if (pdkim_feed(ctx, buf, sread) != PDKIM_OK) - { - rc = NULL; - goto CLEANUP; - } + 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; /* Handle failed read above. */ if (sread == -1) { debug_printf("DKIM: Error reading -K file.\n"); save_errno = errno; - rc = NULL; - goto CLEANUP; + goto bad; } - if ((pdkim_rc = pdkim_feed_finish(ctx, &signature)) != PDKIM_OK) - { - log_write(0, LOG_MAIN|LOG_PANIC, "DKIM: signing failed (RC %d)", pdkim_rc); - rc = NULL; - goto CLEANUP; - } + if ((pdkim_rc = pdkim_feed_finish(ctx, &signature, errstr)) != PDKIM_OK) + goto pk_bad; sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2, US signature->signature_header, US"\r\n"); @@ -614,11 +659,18 @@ else rc = US""; CLEANUP: -if (ctx) - pdkim_free_ctx(ctx); -store_pool = old_pool; -errno = save_errno; -return rc; + if (ctx) + pdkim_free_ctx(ctx); + store_pool = old_pool; + errno = save_errno; + return rc; + +pk_bad: + log_write(0, LOG_MAIN|LOG_PANIC, + "DKIM: signing failed: %.100s", pdkim_errstr(pdkim_rc)); +bad: + rc = NULL; + goto CLEANUP; } #endif