X-Git-Url: https://vcs.fsf.org/?a=blobdiff_plain;f=src%2Fsrc%2Fdkim.c;h=c7bf641527822a7fecc97fe383ca7c548a5ea2f1;hb=260958d632506e2789fc632381f560f5a0c77ed7;hp=3109168a33c44005ae6d44e940ef4aacf4007314;hpb=cf7453055ad53ee3d2ee7b790ee83168ce58412d;p=exim.git diff --git a/src/src/dkim.c b/src/src/dkim.c index 3109168a3..c7bf64152 100644 --- a/src/src/dkim.c +++ b/src/src/dkim.c @@ -1,10 +1,8 @@ -/* $Cambridge: exim/src/src/dkim.c,v 1.4 2009/10/13 18:32:05 tom Exp $ */ - /************************************************* * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 2009 */ +/* 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 @@ -14,505 +12,764 @@ #ifndef DISABLE_DKIM -#include "pdkim/pdkim.h" +# include "pdkim/pdkim.h" + +# ifdef MACRO_PREDEF +# include "macro_predef.h" + +void +params_dkim(void) +{ +builtin_macro_create_var(US"_DKIM_SIGN_HEADERS", US PDKIM_DEFAULT_SIGN_HEADERS); +} +# else /*!MACRO_PREDEF*/ + + -pdkim_ctx *dkim_verify_ctx = NULL; + +int dkim_verify_oldpool; +pdkim_ctx *dkim_verify_ctx = NULL; pdkim_signature *dkim_signatures = NULL; -pdkim_signature *dkim_cur_sig = NULL; +pdkim_signature *dkim_cur_sig = NULL; +static const uschar * dkim_collect_error = NULL; + + -int dkim_exim_query_dns_txt(char *name, char *answer) { - dns_answer dnsa; - dns_scan dnss; - dns_record *rr; +/*XXX the caller only uses the first record if we return multiple. +*/ - if (dns_lookup(&dnsa, (uschar *)name, T_TXT, NULL) != DNS_SUCCEED) return PDKIM_FAIL; +static uschar * +dkim_exim_query_dns_txt(char * name) +{ +dns_answer dnsa; +dns_scan dnss; +dns_record *rr; +gstring * g = NULL; - /* Search for TXT record */ - for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); - rr != NULL; - rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) - if (rr->type == T_TXT) break; +lookup_dnssec_authenticated = NULL; +if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED) + return NULL; /*XXX better error detail? logging? */ - /* Copy record content to the answer buffer */ - if (rr != NULL) { +/* Search for TXT record */ + +for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); + rr; + rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) + if (rr->type == T_TXT) + { int rr_offset = 0; - int answer_offset = 0; - while (rr_offset < rr->size) { - uschar len = (rr->data)[rr_offset++]; - snprintf(answer+(answer_offset), - PDKIM_DNS_TXT_MAX_RECLEN-(answer_offset), - "%.*s", (int)len, (char *)((rr->data)+rr_offset)); - rr_offset+=len; - answer_offset+=len; - } - } - else return PDKIM_FAIL; - return PDKIM_OK; -} + /* Copy record content to the answer buffer */ + while (rr_offset < rr->size) + { + uschar len = rr->data[rr_offset++]; -void dkim_exim_verify_init(void) { + g = string_catn(g, US(rr->data + rr_offset), len); + if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN) + goto bad; - /* Free previous context if there is one */ - if (dkim_verify_ctx) pdkim_free_ctx(dkim_verify_ctx); + rr_offset += len; + } - /* Create new context */ - dkim_verify_ctx = pdkim_init_verify(PDKIM_INPUT_SMTP, - &dkim_exim_query_dns_txt - ); + /* check if this looks like a DKIM record */ + if (Ustrncmp(g->s, "v=", 2) != 0 || strncasecmp(CS g->s, "v=dkim", 6) == 0) + { + store_reset(g->s + g->ptr + 1); + return string_from_gstring(g); + } - if (dkim_verify_ctx != NULL) { - dkim_collect_input = TRUE; - pdkim_set_debug_stream(dkim_verify_ctx,debug_file); - } - else dkim_collect_input = FALSE; + if (g) g->ptr = 0; /* overwrite previous record */ + } +bad: +if (g) store_reset(g); +return NULL; /*XXX better error detail? logging? */ } -void dkim_exim_verify_feed(uschar *data, int len) { - if (dkim_collect_input && - pdkim_feed(dkim_verify_ctx, - (char *)data, - len) != PDKIM_OK) dkim_collect_input = FALSE; +void +dkim_exim_init(void) +{ +pdkim_init(); } -void dkim_exim_verify_finish(void) { - pdkim_signature *sig = NULL; - int dkim_signing_domains_size = 0; - int dkim_signing_domains_ptr = 0; - dkim_signing_domains = NULL; - /* Delete eventual previous signature chain */ - dkim_signatures = NULL; +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. */ - /* 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) { - log_write(0, LOG_MAIN|LOG_PANIC, "DKIM: Error while running this message through validation, disabling signature verification."); - dkim_disable_verify = TRUE; - return; - } +dkim_verify_oldpool = store_pool; +store_pool = POOL_PERM; + +/* Free previous context if there is one */ + +if (dkim_verify_ctx) + pdkim_free_ctx(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_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 + && (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; + } +store_pool = dkim_verify_oldpool; +} - /* Finish DKIM operation and fetch link to signatures chain */ - if (pdkim_feed_finish(dkim_verify_ctx,&dkim_signatures) != PDKIM_OK) return; - - sig = dkim_signatures; - while (sig != NULL) { - int size = 0; - int ptr = 0; - /* Log a line for each signature */ - uschar *logmsg = string_append(NULL, &size, &ptr, 5, - - string_sprintf( "DKIM: d=%s s=%s c=%s/%s a=%s ", - 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->identity != NULL)? - 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"" - ) - ); - - switch(sig->verify_status) { - case PDKIM_VERIFY_NONE: - logmsg = string_append(logmsg, &size, &ptr, 1, "[not verified]"); + +/* Log the result for the given signature */ +static void +dkim_exim_verify_log_sig(pdkim_signature * sig) +{ +gstring * logmsg; +uschar * s; + +if (!sig) return; + +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); + +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)); +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) + ) ) + switch (sig->verify_status) + { + case PDKIM_VERIFY_NONE: + logmsg = string_cat(logmsg, US" [not verified]"); break; - case PDKIM_VERIFY_INVALID: - logmsg = string_append(logmsg, &size, &ptr, 1, "[invalid - "); - switch (sig->verify_ext_status) { - case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: - logmsg = string_append(logmsg, &size, &ptr, 1, "public key record (currently?) unavailable]"); - break; - case PDKIM_VERIFY_INVALID_BUFFER_SIZE: - logmsg = string_append(logmsg, &size, &ptr, 1, "overlong public key record]"); - break; - case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: - logmsg = string_append(logmsg, &size, &ptr, 1, "syntax error in public key record]"); - break; - default: - logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified problem]"); - } + + case PDKIM_VERIFY_INVALID: + logmsg = string_cat(logmsg, US" [invalid - "); + switch (sig->verify_ext_status) + { + case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: + logmsg = string_cat(logmsg, + US"public key record (currently?) unavailable]"); + break; + + case PDKIM_VERIFY_INVALID_BUFFER_SIZE: + 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, US"syntax error in public key record]"); + break; + + case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: + logmsg = string_cat(logmsg, US"signature tag missing or invalid]"); + break; + + case PDKIM_VERIFY_INVALID_DKIM_VERSION: + logmsg = string_cat(logmsg, US"unsupported DKIM version]"); + break; + + default: + logmsg = string_cat(logmsg, US"unspecified problem]"); + } break; - case PDKIM_VERIFY_FAIL: - logmsg = string_append(logmsg, &size, &ptr, 1, "[verification failed - "); - switch (sig->verify_ext_status) { - case PDKIM_VERIFY_FAIL_BODY: - logmsg = string_append(logmsg, &size, &ptr, 1, "body hash mismatch (body probably modified in transit)]"); - break; - case PDKIM_VERIFY_FAIL_MESSAGE: - logmsg = string_append(logmsg, &size, &ptr, 1, "signature did not verify (headers probably modified in transit)]"); - break; - default: - logmsg = string_append(logmsg, &size, &ptr, 1, "unspecified reason]"); - } + + case PDKIM_VERIFY_FAIL: + logmsg = string_cat(logmsg, US" [verification failed - "); + switch (sig->verify_ext_status) + { + case PDKIM_VERIFY_FAIL_BODY: + logmsg = string_cat(logmsg, + US"body hash mismatch (body probably modified in transit)]"); + break; + + case PDKIM_VERIFY_FAIL_MESSAGE: + logmsg = string_cat(logmsg, + US"signature did not verify " + "(headers probably modified in transit)]"); + break; + + default: + logmsg = string_cat(logmsg, US"unspecified reason]"); + } break; - case PDKIM_VERIFY_PASS: - logmsg = string_append(logmsg, &size, &ptr, 1, "[verification succeeded]"); + + case PDKIM_VERIFY_PASS: + 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, "%s", string_from_gstring(logmsg)); +return; +} + + +/* 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); +} + + +void +dkim_exim_verify_finish(void) +{ +pdkim_signature * sig; +int rc; +gstring * g = NULL; +const uschar * errstr = NULL; + +store_pool = POOL_PERM; + +/* Delete eventual previous signature chain */ - logmsg[ptr] = '\0'; - log_write(0, LOG_MAIN, (char *)logmsg); +dkim_signers = NULL; +dkim_signatures = NULL; - /* Build a colon-separated list of signing domains in dkim_signing_domains */ - dkim_signing_domains = string_append(dkim_signing_domains, - &dkim_signing_domains_size, - &dkim_signing_domains_ptr, - 2, - sig->domain, - ":" - ); +if (dkim_collect_error) + { + log_write(0, LOG_MAIN, + "DKIM: Error during validation, disabling signature verification: %.100s", + dkim_collect_error); + dkim_disable_verify = TRUE; + goto out; + } + +dkim_collect_input = FALSE; + +/* Finish DKIM operation and fetch link to signatures chain */ - /* Process next signature */ - sig = sig->next; +rc = pdkim_feed_finish(dkim_verify_ctx, &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) + { + if (sig->domain) g = string_append_listele(g, ':', sig->domain); + if (sig->identity) g = string_append_listele(g, ':', sig->identity); } - /* Chop the last colon from the domain list */ - if ((dkim_signing_domains != NULL) && - (Ustrlen(dkim_signing_domains) > 0)) - dkim_signing_domains[Ustrlen(dkim_signing_domains)-1] = '\0'; +if (g) dkim_signers = g->s; + +out: +store_pool = dkim_verify_oldpool; +} + + + +/* 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; } -void dkim_exim_acl_setup(uschar *id) { - pdkim_signature *sig = dkim_signatures; - dkim_cur_sig = NULL; - if (dkim_disable_verify || - !id || !sig || - !dkim_verify_ctx) return; - /* Find signature to run ACL on */ - while (sig != NULL) { - uschar *cmp_val = NULL; - if (Ustrchr(id,'@') != NULL) cmp_val = (uschar *)sig->identity; - else cmp_val = (uschar *)sig->domain; - if (cmp_val && (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). */ - dkim_signing_domain = (uschar *)sig->domain; - dkim_signing_selector = (uschar *)sig->selector; - return; + +/* 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_verify_status = US"none"; +dkim_verify_reason = US""; +dkim_cur_signer = id; + +if (dkim_disable_verify || !id || !dkim_verify_ctx) + return OK; + +/* Find signatures to run ACL on */ + +for (sig = dkim_signatures; sig; sig = sig->next) + if ( (cmp_val = Ustrchr(id, '@') != NULL ? US sig->identity : US sig->domain) + && strcmpic(cmp_val, id) == 0 + ) + { + /* 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). */ + + dkim_cur_sig = sig; + dkim_signing_domain = US sig->domain; + dkim_signing_selector = US sig->selector; + dkim_key_length = sig->sighash.len * 8; + + /* 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); + + if ((rc = dkim_acl_call(id, res_ptr, user_msgptr, log_msgptr)) != OK) + return rc; } - sig = sig->next; - } + +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); } -uschar *dkim_exim_expand_query(int what) { +static uschar * +dkim_exim_expand_defaults(int what) +{ +switch (what) + { + case DKIM_ALGO: return US""; + case DKIM_BODYLENGTH: return US"9999999999999"; + case DKIM_CANON_BODY: return US""; + case DKIM_CANON_HEADERS: return US""; + case DKIM_COPIEDHEADERS: return US""; + case DKIM_CREATED: return US"0"; + case DKIM_EXPIRES: return US"9999999999999"; + case DKIM_HEADERNAMES: return US""; + case DKIM_IDENTITY: return US""; + case DKIM_KEY_GRANULARITY: return US"*"; + case DKIM_KEY_SRVTYPE: return US"*"; + case DKIM_KEY_NOTES: return US""; + case DKIM_KEY_TESTING: return US"0"; + case DKIM_NOSUBDOMAINS: return US"0"; + case DKIM_VERIFY_STATUS: return US"none"; + case DKIM_VERIFY_REASON: return US""; + default: return US""; + } +} - if (!dkim_verify_ctx || - dkim_disable_verify || - !dkim_cur_sig) return dkim_exim_expand_defaults(what); - switch(what) { - case DKIM_ALGO: - switch(dkim_cur_sig->algo) { - case PDKIM_ALGO_RSA_SHA1: - return US"rsa-sha1"; - case PDKIM_ALGO_RSA_SHA256: - default: - return US"rsa-sha256"; - } - case DKIM_BODYLENGTH: - return (dkim_cur_sig->bodylength >= 0)? - (uschar *)string_sprintf(OFF_T_FMT,(LONGLONG_T)dkim_cur_sig->bodylength) - :dkim_exim_expand_defaults(what); - case DKIM_CANON_BODY: - switch(dkim_cur_sig->canon_body) { - case PDKIM_CANON_RELAXED: - return US"relaxed"; - case PDKIM_CANON_SIMPLE: - default: - return US"simple"; +uschar * +dkim_exim_expand_query(int what) +{ +if (!dkim_verify_ctx || dkim_disable_verify || !dkim_cur_sig) + return dkim_exim_expand_defaults(what); + +switch (what) + { + case DKIM_ALGO: + return dkim_sig_to_a_tag(dkim_cur_sig); + + case DKIM_BODYLENGTH: + return dkim_cur_sig->bodylength >= 0 + ? string_sprintf("%ld", dkim_cur_sig->bodylength) + : dkim_exim_expand_defaults(what); + + case DKIM_CANON_BODY: + switch (dkim_cur_sig->canon_body) + { + case PDKIM_CANON_RELAXED: return US"relaxed"; + case PDKIM_CANON_SIMPLE: + default: return US"simple"; } - case DKIM_CANON_HEADERS: - switch(dkim_cur_sig->canon_headers) { - case PDKIM_CANON_RELAXED: - return US"relaxed"; - case PDKIM_CANON_SIMPLE: - default: - return US"simple"; - } - case DKIM_COPIEDHEADERS: - return dkim_cur_sig->copiedheaders? - (uschar *)(dkim_cur_sig->copiedheaders) - :dkim_exim_expand_defaults(what); - case DKIM_CREATED: - return (dkim_cur_sig->created > 0)? - (uschar *)string_sprintf("%llu",dkim_cur_sig->created) - :dkim_exim_expand_defaults(what); - case DKIM_EXPIRES: - return (dkim_cur_sig->expires > 0)? - (uschar *)string_sprintf("%llu",dkim_cur_sig->expires) - :dkim_exim_expand_defaults(what); - case DKIM_HEADERNAMES: - return dkim_cur_sig->headernames? - (uschar *)(dkim_cur_sig->headernames) - :dkim_exim_expand_defaults(what); - case DKIM_IDENTITY: - return dkim_cur_sig->identity? - (uschar *)(dkim_cur_sig->identity) - :dkim_exim_expand_defaults(what); - case DKIM_KEY_GRANULARITY: - return dkim_cur_sig->pubkey? - (dkim_cur_sig->pubkey->granularity? - (uschar *)(dkim_cur_sig->pubkey->granularity) - :dkim_exim_expand_defaults(what) - ) - :dkim_exim_expand_defaults(what); - case DKIM_KEY_SRVTYPE: - return dkim_cur_sig->pubkey? - (dkim_cur_sig->pubkey->srvtype? - (uschar *)(dkim_cur_sig->pubkey->srvtype) - :dkim_exim_expand_defaults(what) - ) - :dkim_exim_expand_defaults(what); - case DKIM_KEY_NOTES: - return dkim_cur_sig->pubkey? - (dkim_cur_sig->pubkey->notes? - (uschar *)(dkim_cur_sig->pubkey->notes) - :dkim_exim_expand_defaults(what) - ) - :dkim_exim_expand_defaults(what); - case DKIM_KEY_TESTING: - return dkim_cur_sig->pubkey? - (dkim_cur_sig->pubkey->testing? - US"1" - :dkim_exim_expand_defaults(what) - ) - :dkim_exim_expand_defaults(what); - case DKIM_NOSUBDOMAINS: - return dkim_cur_sig->pubkey? - (dkim_cur_sig->pubkey->no_subdomaining? - US"1" - :dkim_exim_expand_defaults(what) - ) - :dkim_exim_expand_defaults(what); - case DKIM_VERIFY_STATUS: - switch(dkim_cur_sig->verify_status) { - case PDKIM_VERIFY_INVALID: - return US"invalid"; - case PDKIM_VERIFY_FAIL: - return US"fail"; - case PDKIM_VERIFY_PASS: - return US"pass"; - case PDKIM_VERIFY_NONE: - default: - return US"none"; + + case DKIM_CANON_HEADERS: + switch (dkim_cur_sig->canon_headers) + { + case PDKIM_CANON_RELAXED: return US"relaxed"; + case PDKIM_CANON_SIMPLE: + default: return US"simple"; } - case DKIM_VERIFY_REASON: - switch (dkim_cur_sig->verify_ext_status) { - case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: - return US"pubkey_unavailable"; - case PDKIM_VERIFY_INVALID_PUBKEY_PARSING: - return US"pubkey_syntax"; - case PDKIM_VERIFY_FAIL_BODY: - return US"bodyhash_mismatch"; - case PDKIM_VERIFY_FAIL_MESSAGE: - return US"signature_incorrect"; + + case DKIM_COPIEDHEADERS: + return dkim_cur_sig->copiedheaders + ? US dkim_cur_sig->copiedheaders : dkim_exim_expand_defaults(what); + + case DKIM_CREATED: + return dkim_cur_sig->created > 0 + ? string_sprintf("%lu", dkim_cur_sig->created) + : dkim_exim_expand_defaults(what); + + case DKIM_EXPIRES: + return dkim_cur_sig->expires > 0 + ? string_sprintf("%lu", dkim_cur_sig->expires) + : dkim_exim_expand_defaults(what); + + case DKIM_HEADERNAMES: + return dkim_cur_sig->headernames + ? dkim_cur_sig->headernames : dkim_exim_expand_defaults(what); + + case DKIM_IDENTITY: + return dkim_cur_sig->identity + ? US dkim_cur_sig->identity : dkim_exim_expand_defaults(what); + + case DKIM_KEY_GRANULARITY: + return dkim_cur_sig->pubkey + ? dkim_cur_sig->pubkey->granularity + ? US dkim_cur_sig->pubkey->granularity + : dkim_exim_expand_defaults(what) + : dkim_exim_expand_defaults(what); + + case DKIM_KEY_SRVTYPE: + return dkim_cur_sig->pubkey + ? dkim_cur_sig->pubkey->srvtype + ? US dkim_cur_sig->pubkey->srvtype + : dkim_exim_expand_defaults(what) + : dkim_exim_expand_defaults(what); + + case DKIM_KEY_NOTES: + return dkim_cur_sig->pubkey + ? dkim_cur_sig->pubkey->notes + ? US dkim_cur_sig->pubkey->notes + : dkim_exim_expand_defaults(what) + : dkim_exim_expand_defaults(what); + + case DKIM_KEY_TESTING: + return dkim_cur_sig->pubkey + ? dkim_cur_sig->pubkey->testing + ? US"1" + : dkim_exim_expand_defaults(what) + : dkim_exim_expand_defaults(what); + + case DKIM_NOSUBDOMAINS: + return dkim_cur_sig->pubkey + ? dkim_cur_sig->pubkey->no_subdomaining + ? US"1" + : dkim_exim_expand_defaults(what) + : dkim_exim_expand_defaults(what); + + case DKIM_VERIFY_STATUS: + switch (dkim_cur_sig->verify_status) + { + case PDKIM_VERIFY_INVALID: return US"invalid"; + case PDKIM_VERIFY_FAIL: return US"fail"; + case PDKIM_VERIFY_PASS: return US"pass"; + case PDKIM_VERIFY_NONE: + default: return US"none"; } - default: - return US""; - } -} + case DKIM_VERIFY_REASON: + switch (dkim_cur_sig->verify_ext_status) + { + case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE: + 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_FAIL_BODY: return US"bodyhash_mismatch"; + case PDKIM_VERIFY_FAIL_MESSAGE: return US"signature_incorrect"; + } -uschar *dkim_exim_expand_defaults(int what) { - switch(what) { - case DKIM_ALGO: return US""; - case DKIM_BODYLENGTH: return US"9999999999999"; - case DKIM_CANON_BODY: return US""; - case DKIM_CANON_HEADERS: return US""; - case DKIM_COPIEDHEADERS: return US""; - case DKIM_CREATED: return US"0"; - case DKIM_EXPIRES: return US"9999999999999"; - case DKIM_HEADERNAMES: return US""; - case DKIM_IDENTITY: return US""; - case DKIM_KEY_GRANULARITY: return US"*"; - case DKIM_KEY_SRVTYPE: return US"*"; - case DKIM_KEY_NOTES: return US""; - case DKIM_KEY_TESTING: return US"0"; - case DKIM_NOSUBDOMAINS: return US"0"; - case DKIM_VERIFY_STATUS: return US"none"; - case DKIM_VERIFY_REASON: return US""; - default: return US""; + default: + return US""; } } -uschar *dkim_exim_sign(int dkim_fd, - uschar *dkim_private_key, - uschar *dkim_domain, - uschar *dkim_selector, - uschar *dkim_canon, - uschar *dkim_sign_headers) { - pdkim_ctx *ctx = NULL; - uschar *rc = NULL; - pdkim_signature *signature; - int pdkim_canon; - int sread; - char buf[4096]; - int save_errno = 0; - int old_pool = store_pool; - - dkim_domain = expand_string(dkim_domain); - if (dkim_domain == NULL) { - /* 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; - } - /* 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; - - /* 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_RELAXED; - else { - log_write(0, LOG_MAIN, "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n",dkim_canon); - pdkim_canon = PDKIM_CANON_RELAXED; - } +/* 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; +int sep = 0; +gstring * seen_doms = NULL; +pdkim_ctx ctx; +pdkim_signature * sig; +gstring * sigbuf; +int pdkim_rc; +int sread; +uschar buf[4096]; +int save_errno = 0; +int old_pool = store_pool; +uschar * errwhen; + +store_pool = POOL_MAIN; + +pdkim_init_context(&ctx, dkim->dot_stuffed, &dkim_exim_query_dns_txt); + +if (!(dkim_domain = expand_cstring(dkim->dkim_domain))) + /* 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))) + { + const uschar * dkim_sel; + int sel_sep = 0; + + if (dkim_signing_domain[0] == '\0') + continue; + + /* Only sign once for each domain, no matter how often it + appears in the expanded list. */ + + if (match_isinlist(dkim_signing_domain, CUSS &seen_doms, + 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK) + continue; + + seen_doms = string_append_listele(seen_doms, ':', dkim_signing_domain); + + /* Set $dkim_selector expansion variable to each selector in list, + 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, + NULL, 0))) + { + uschar * dkim_canon_expanded; + int pdkim_canon; + uschar * dkim_sign_headers_expanded = NULL; + uschar * dkim_private_key_expanded; + uschar * dkim_hash_expanded; + uschar * dkim_identity_expanded = NULL; + + /* Get canonicalization to use */ + + dkim_canon_expanded = dkim->dkim_canon + ? expand_string(dkim->dkim_canon) : US"relaxed"; + if (!dkim_canon_expanded) /* expansion error, do not send message. */ + { errwhen = US"dkim_canon"; goto expand_bad; } + + 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; + } - /* Expand signing headers once */ - if (dkim_sign_headers != NULL) { - dkim_sign_headers = expand_string(dkim_sign_headers); - if (dkim_sign_headers == NULL) { - log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " - "dkim_sign_headers: %s", expand_string_message); - rc = NULL; - goto CLEANUP; - } - } + if ( dkim->dkim_sign_headers + && !(dkim_sign_headers_expanded = expand_string(dkim->dkim_sign_headers))) + { errwhen = US"dkim_sign_header"; goto expand_bad; } + /* else pass NULL, which means default header list */ + + /* Get private key to use. */ + + if (!(dkim_private_key_expanded = expand_string(dkim->dkim_private_key))) + { errwhen = US"dkim_private_key"; goto expand_bad; } + + if ( Ustrlen(dkim_private_key_expanded) == 0 + || Ustrcmp(dkim_private_key_expanded, "0") == 0 + || Ustrcmp(dkim_private_key_expanded, "false") == 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; + } - /* 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 (!(dkim_hash_expanded = expand_string(dkim->dkim_hash))) + { errwhen = US"dkim_hash"; goto expand_bad; } + + if (dkim->dkim_identity) + if (!(dkim_identity_expanded = expand_string(dkim->dkim_identity))) + { errwhen = US"dkim_identity"; goto expand_bad; } + 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 (!(sig = pdkim_init_sign(&ctx, dkim_signing_domain, + dkim_signing_selector, + dkim_private_key_expanded, + dkim_hash_expanded, + errstr + ))) + goto bad; + dkim_private_key_expanded[0] = '\0'; + + pdkim_set_optional(sig, + CS dkim_sign_headers_expanded, + CS dkim_identity_expanded, + pdkim_canon, + pdkim_canon, -1, 0, 0); + + if (!pdkim_set_bodyhash(&ctx, sig)) + goto bad; + + if (!ctx.sig) /* link sig to context chain */ + ctx.sig = sig; + else + { + pdkim_signature * n = ctx.sig; + while (n->next) n = n->next; + n->next = sig; + } + } } - 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; +if (!ctx.sig) + { + DEBUG(D_transport) debug_printf("DKIM: no viable signatures to use\n"); + sigbuf = string_get(1); /* return a zero-len string */ + 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); - rc = NULL; - goto CLEANUP; - } - (void)read(privkey_fd,big_buffer,(big_buffer_size-2)); - (void)close(privkey_fd); - dkim_private_key = big_buffer; +if (prefix && (pdkim_rc = pdkim_feed(&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(&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; } - 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) { - 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; - } +/* Build string of headers, one per signature */ - if (pdkim_feed_finish(ctx,&signature) != PDKIM_OK) - goto CLEANUP; +if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK) + goto pk_bad; - rc = store_get(strlen(signature->signature_header)+3); - Ustrcpy(rc,US signature->signature_header); - Ustrcat(rc,US"\r\n"); +for (sigbuf = NULL; sig; sig = sig->next) + sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n"); - CLEANUP: - if (ctx != NULL) { - pdkim_free_ctx(ctx); - } +CLEANUP: + (void) string_from_gstring(sigbuf); store_pool = old_pool; errno = save_errno; - return rc; -}; + return sigbuf; + +pk_bad: + log_write(0, LOG_MAIN|LOG_PANIC, + "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); + goto bad; +} -#endif +# endif /*!MACRO_PREDEF*/ +#endif /*!DISABLE_DKIM*/