-/* $Cambridge: exim/src/src/dkim.c,v 1.3 2009/08/31 21:14:50 tom Exp $ */
-
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 2009 */
+/* Copyright (c) University of Cambridge, 1995 - 2018 */
/* See the file NOTICE for conditions of use and distribution. */
/* Code for DKIM support. Other DKIM relevant code is in
#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;
- if (dns_lookup(&dnsa, (uschar *)name, T_TXT, NULL) != DNS_SUCCEED) return PDKIM_FAIL;
+/*XXX the caller only uses the first record if we return multiple.
+*/
- /* 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;
+static uschar *
+dkim_exim_query_dns_txt(char * name)
+{
+dns_answer dnsa;
+dns_scan dnss;
+dns_record *rr;
+gstring * g = NULL;
- /* Copy record content to the answer buffer */
- if (rr != NULL) {
+lookup_dnssec_authenticated = NULL;
+if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED)
+ return NULL; /*XXX better error detail? logging? */
+
+/* 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_status
+ && ( dkim_verify_status != dkim_exim_expand_query(DKIM_VERIFY_STATUS)
+ || dkim_verify_reason != dkim_exim_expand_query(DKIM_VERIFY_REASON)
+ ) )
+ sig->verify_status |= PDKIM_VERIFY_POLICY;
+
+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"<UNSET>";
+logmsg = string_append(logmsg, 2, "d=", s);
+if (!(s = sig->selector)) s = US"<UNSET>";
+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 (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, 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;
}
- logmsg[ptr] = '\0';
- log_write(0, LOG_MAIN, (char *)logmsg);
+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 */
+
+dkim_signers = NULL;
+dkim_signatures = NULL;
+
+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 */
+
+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 in dkim_signing_domains */
- dkim_signing_domains = string_append(dkim_signing_domains,
- &dkim_signing_domains_size,
- &dkim_signing_domains_ptr,
- 2,
- sig->domain,
- ":"
- );
+/* Build a colon-separated list of signing domains (and identities, if present) in dkim_signers */
- /* Process next signature */
- sig = sig->next;
+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;
}
-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;
+
+/* 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_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);
- (void)read(privkey_fd,big_buffer,16383);
- (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;
+}
+
+
+
+
+gstring *
+authres_dkim(gstring * g)
+{
+pdkim_signature * sig;
+
+for (sig = dkim_signatures; sig; sig = sig->next)
+ {
+ g = string_catn(g, US";\\n\\tdkim=", 10);
+
+ 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)"); break;
+ case PDKIM_VERIFY_INVALID_BUFFER_SIZE:
+ g = string_cat(g, US"permerror (overlong public key record)"); break;
+ case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD:
+ case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT:
+ g = string_cat(g, US"neutral (syntax error in public key record)");
+ break;
+ case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR:
+ g = string_cat(g, US"neutral (signature tag missing or invalid)");
+ break;
+ case PDKIM_VERIFY_INVALID_DKIM_VERSION:
+ g = string_cat(g, US"neutral (unsupported DKIM version)");
+ break;
+ default:
+ g = string_cat(g, US"permerror (unspecified problem)"); 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)");
+ break;
+ case PDKIM_VERIFY_FAIL_MESSAGE:
+ g = string_cat(g,
+ US"fail (signature did not verify; headers probably modified in transit)");
+ break;
+ default:
+ g = string_cat(g, US"fail (unspecified reason)");
+ 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));
+ }
+return g;
+}
+
-#endif
+# endif /*!MACRO_PREDEF*/
+#endif /*!DISABLE_DKIM*/
projects / exim.git / blobdiff