From a8e1eeba8a2ff7eb5b2c6165d63f003fd0dfe3eb Mon Sep 17 00:00:00 2001 From: Michael Haardt Date: Thu, 18 Feb 2010 12:09:15 +0000 Subject: [PATCH] Treat the transport option dkim_domain as a colon separated list, not as a single string, and sign the message with each element, omitting multiple occurences of the same signer. The transport option dkim_domain should be renamed to dkim_add_signers. The values of dkim_selector and dkim_private_key are expanded for each signer available in $dkim_domain. It is unclear if signatures for domains that already signed the mail should be omitted and if we need a new variable for signatures to omit or if it could be hardcoded, but this question is independent of this patch. --- src/src/dkim.c | 223 +++++++++++++++++++++++++++---------------------- 1 file changed, 122 insertions(+), 101 deletions(-) diff --git a/src/src/dkim.c b/src/src/dkim.c index e303776c2..d2abaff76 100644 --- a/src/src/dkim.c +++ b/src/src/dkim.c @@ -1,4 +1,4 @@ -/* $Cambridge: exim/src/src/dkim.c,v 1.11 2009/12/15 08:23:15 tom Exp $ */ +/* $Cambridge: exim/src/src/dkim.c,v 1.12 2010/02/18 12:09:15 michael Exp $ */ /************************************************* * Exim - an Internet mail transport agent * @@ -387,6 +387,14 @@ uschar *dkim_exim_sign(int dkim_fd, uschar *dkim_selector, uschar *dkim_canon, uschar *dkim_sign_headers) { + 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; pdkim_ctx *ctx = NULL; uschar *rc = NULL; pdkim_signature *signature; @@ -405,127 +413,140 @@ uschar *dkim_exim_sign(int dkim_fd, rc = NULL; goto CLEANUP; } - /* Set up $dkim_domain expansion variable. */ - dkim_signing_domain = dkim_domain; - /* Get selector to use. */ - dkim_selector = expand_string(dkim_selector); - if (dkim_selector == NULL) { - log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " - "dkim_selector: %s", expand_string_message); - rc = NULL; - goto CLEANUP; - } - /* Set up $dkim_selector expansion variable. */ - dkim_signing_selector = dkim_selector; + /* Set $dkim_domain expansion variable to each unique domain in list. */ + while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, + itembuf, + sizeof(itembuf))) != NULL) { + if (!dkim_signing_domain || (dkim_signing_domain[0] == '\0')) continue; + /* Only sign once for each domain, no matter how often it + appears in the expanded list. */ + if (seen_items != NULL) { + uschar *seen_items_list = seen_items; + if (match_isinlist(dkim_signing_domain, + &seen_items_list,0,NULL,NULL,MCL_STRING,TRUE,NULL) == OK) + continue; + seen_items = string_append(seen_items,&seen_items_size,&seen_items_offset,1,":"); + } + seen_items = string_append(seen_items,&seen_items_size,&seen_items_offset,1,dkim_signing_domain); + seen_items[seen_items_offset] = '\0'; - /* Get canonicalization to use */ - dkim_canon = expand_string(dkim_canon?dkim_canon:US"relaxed"); - if (dkim_canon == NULL) { - /* 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; - } - if (Ustrcmp(dkim_canon, "relaxed") == 0) - pdkim_canon = PDKIM_CANON_RELAXED; - else if (Ustrcmp(dkim_canon, "simple") == 0) - pdkim_canon = PDKIM_CANON_SIMPLE; - else { - log_write(0, LOG_MAIN, "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n",dkim_canon); - pdkim_canon = PDKIM_CANON_RELAXED; - } + /* Set up $dkim_selector expansion variable. */ + dkim_signing_selector = expand_string(dkim_selector); + if (dkim_signing_selector == NULL) { + log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " + "dkim_selector: %s", expand_string_message); + rc = NULL; + goto CLEANUP; + } - /* Expand signing headers once */ - if (dkim_sign_headers != NULL) { - dkim_sign_headers = expand_string(dkim_sign_headers); - if (dkim_sign_headers == NULL) { + /* Get canonicalization to use */ + dkim_canon_expanded = expand_string(dkim_canon?dkim_canon:US"relaxed"); + if (dkim_canon_expanded == NULL) { + /* expansion error, do not send message. */ log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " - "dkim_sign_headers: %s", expand_string_message); + "dkim_canon: %s", expand_string_message); rc = NULL; goto CLEANUP; } - } + if (Ustrcmp(dkim_canon_expanded, "relaxed") == 0) + pdkim_canon = PDKIM_CANON_RELAXED; + else if (Ustrcmp(dkim_canon_expanded, "simple") == 0) + pdkim_canon = PDKIM_CANON_SIMPLE; + else { + log_write(0, LOG_MAIN, "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n",dkim_canon_expanded); + pdkim_canon = PDKIM_CANON_RELAXED; + } - /* Get private key to use. */ - dkim_private_key = expand_string(dkim_private_key); - if (dkim_private_key == NULL) { - log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " - "dkim_private_key: %s", expand_string_message); - rc = NULL; - goto CLEANUP; - } - if ( (Ustrlen(dkim_private_key) == 0) || - (Ustrcmp(dkim_private_key,"0") == 0) || - (Ustrcmp(dkim_private_key,"false") == 0) ) { - /* don't sign, but no error */ - rc = US""; - goto CLEANUP; - } + dkim_sign_headers_expanded = expand_string(dkim_sign_headers); + if (dkim_sign_headers_expanded == NULL) { + log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " + "dkim_sign_headers: %s", expand_string_message); + rc = NULL; + goto CLEANUP; + } - if (dkim_private_key[0] == '/') { - int privkey_fd = 0; - /* Looks like a filename, load the private key. */ - memset(big_buffer,0,big_buffer_size); - privkey_fd = open(CS dkim_private_key,O_RDONLY); - if (privkey_fd < 0) { - log_write(0, LOG_MAIN|LOG_PANIC, "unable to open " - "private key file for reading: %s", dkim_private_key); + /* Get private key to use. */ + dkim_private_key_expanded = expand_string(dkim_private_key); + if (dkim_private_key_expanded == NULL) { + log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " + "dkim_private_key: %s", expand_string_message); rc = NULL; goto CLEANUP; } - (void)read(privkey_fd,big_buffer,(big_buffer_size-2)); - (void)close(privkey_fd); - dkim_private_key = big_buffer; - } + if ( (Ustrlen(dkim_private_key_expanded) == 0) || + (Ustrcmp(dkim_private_key_expanded,"0") == 0) || + (Ustrcmp(dkim_private_key_expanded,"false") == 0) ) { + /* don't sign, but no error */ + rc = US""; + goto CLEANUP; + } + + if (dkim_private_key_expanded[0] == '/') { + int privkey_fd = 0; + /* 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) { + log_write(0, LOG_MAIN|LOG_PANIC, "unable to open " + "private key file for reading: %s", dkim_private_key_expanded); + rc = NULL; + goto CLEANUP; + } + (void)read(privkey_fd,big_buffer,(big_buffer_size-2)); + (void)close(privkey_fd); + dkim_private_key_expanded = big_buffer; + } - ctx = pdkim_init_sign(PDKIM_INPUT_SMTP, - (char *)dkim_signing_domain, - (char *)dkim_signing_selector, - (char *)dkim_private_key - ); - - pdkim_set_debug_stream(ctx,debug_file); - - pdkim_set_optional(ctx, - (char *)dkim_sign_headers, - NULL, - pdkim_canon, - pdkim_canon, - -1, - PDKIM_ALGO_RSA_SHA256, - 0, - 0); - - while((sread = read(dkim_fd,&buf,4096)) > 0) { - if (pdkim_feed(ctx,buf,sread) != PDKIM_OK) { + ctx = pdkim_init_sign(PDKIM_INPUT_SMTP, + (char *)dkim_signing_domain, + (char *)dkim_signing_selector, + (char *)dkim_private_key_expanded + ); + + pdkim_set_debug_stream(ctx,debug_file); + + pdkim_set_optional(ctx, + (char *)dkim_sign_headers_expanded, + NULL, + pdkim_canon, + pdkim_canon, + -1, + PDKIM_ALGO_RSA_SHA256, + 0, + 0); + + while((sread = read(dkim_fd,&buf,4096)) > 0) { + if (pdkim_feed(ctx,buf,sread) != PDKIM_OK) { + rc = NULL; + goto CLEANUP; + } + } + /* Handle failed read above. */ + if (sread == -1) { + debug_printf("DKIM: Error reading -K file.\n"); + save_errno = errno; rc = NULL; goto CLEANUP; } - } - /* Handle failed read above. */ - if (sread == -1) { - debug_printf("DKIM: Error reading -K file.\n"); - save_errno = errno; - rc = NULL; - goto CLEANUP; - } - pdkim_rc = pdkim_feed_finish(ctx,&signature); - if (pdkim_rc != PDKIM_OK) { - log_write(0, LOG_MAIN|LOG_PANIC, "DKIM: signing failed (RC %d)", pdkim_rc); - goto CLEANUP; - } + pdkim_rc = pdkim_feed_finish(ctx,&signature); + if (pdkim_rc != PDKIM_OK) { + log_write(0, LOG_MAIN|LOG_PANIC, "DKIM: signing failed (RC %d)", pdkim_rc); + goto CLEANUP; + } - rc = store_get(strlen(signature->signature_header)+3); - Ustrcpy(rc,US signature->signature_header); - Ustrcat(rc,US"\r\n"); + rc = store_get(strlen(signature->signature_header)+3); + Ustrcpy(rc,US signature->signature_header); + Ustrcat(rc,US"\r\n"); - CLEANUP: - if (ctx != NULL) { pdkim_free_ctx(ctx); + ctx = NULL; } + + CLEANUP: + if (ctx != NULL) + pdkim_free_ctx(ctx); store_pool = old_pool; errno = save_errno; return rc; -- 2.25.1