* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge, 1995 - 2017 */
+/* 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
/*XXX the caller only uses the first record if we return multiple.
-Could we hand back an allocated string?
*/
-static int
-dkim_exim_query_dns_txt(char *name, char *answer)
+static uschar *
+dkim_exim_query_dns_txt(char * name)
{
dns_answer dnsa;
dns_scan dnss;
dns_record *rr;
+gstring * g = NULL;
lookup_dnssec_authenticated = NULL;
if (dns_lookup(&dnsa, US name, T_TXT, NULL) != DNS_SUCCEED)
- return PDKIM_FAIL; /*XXX better error detail? logging? */
+ return NULL; /*XXX better error detail? logging? */
/* Search for TXT record */
if (rr->type == T_TXT)
{
int rr_offset = 0;
- int answer_offset = 0;
/* Copy record content to the answer buffer */
while (rr_offset < rr->size)
{
uschar len = rr->data[rr_offset++];
- snprintf(answer + answer_offset,
- PDKIM_DNS_TXT_MAX_RECLEN - answer_offset,
- "%.*s", (int)len, CS (rr->data + rr_offset));
+
+ g = string_catn(g, US(rr->data + rr_offset), len);
+ if (g->ptr >= PDKIM_DNS_TXT_MAX_RECLEN)
+ goto bad;
+
rr_offset += len;
- answer_offset += len;
- if (answer_offset >= PDKIM_DNS_TXT_MAX_RECLEN)
- return PDKIM_FAIL; /*XXX better error detail? logging? */
}
/* check if this looks like a DKIM record */
- if (strncasecmp(answer, "v=dkim", 6) != 0) continue;
- return PDKIM_OK;
+ 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 (g) g->ptr = 0; /* overwrite previous record */
}
-return PDKIM_FAIL; /*XXX better error detail? logging? */
+bad:
+if (g) store_reset(g);
+return NULL; /*XXX better error detail? logging? */
}
if (!sig) return;
+/* Remember the domain for the first pass result */
+
if ( !dkim_verify_overall
&& dkim_verify_status
? Ustrcmp(dkim_verify_status, US"pass") == 0
)
dkim_verify_overall = string_copy(sig->domain);
+/* Rewrite the sig result if the ACL overrode it. This is only
+needed because the DMARC code (sigh) peeks at the dkim sigs.
+Mark the sig for this having been done. */
+
+if ( dkim_verify_status
+ && ( dkim_verify_status != dkim_exim_expand_query(DKIM_VERIFY_STATUS)
+ || dkim_verify_reason != dkim_exim_expand_query(DKIM_VERIFY_REASON)
+ ) )
+ { /* overridden by ACL */
+ sig->verify_ext_status = -1;
+ if (Ustrcmp(dkim_verify_status, US"fail") == 0)
+ sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_FAIL;
+ else if (Ustrcmp(dkim_verify_status, US"invalid") == 0)
+ sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_INVALID;
+ else if (Ustrcmp(dkim_verify_status, US"none") == 0)
+ sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_NONE;
+ else if (Ustrcmp(dkim_verify_status, US"pass") == 0)
+ sig->verify_status = PDKIM_VERIFY_POLICY | PDKIM_VERIFY_PASS;
+ else
+ sig->verify_status = -1;
+ }
+
if (!LOGGING(dkim_verbose)) return;
+
logmsg = string_catn(NULL, US"DKIM: ", 6);
if (!(s = sig->domain)) s = US"<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),
+ " 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->bodylength > -1) logmsg = string_cat(logmsg,
string_sprintf(" l=%lu", sig->bodylength));
-if ( !dkim_verify_status
- || ( dkim_verify_status == dkim_exim_expand_query(DKIM_VERIFY_STATUS)
- && dkim_verify_reason == dkim_exim_expand_query(DKIM_VERIFY_REASON)
- ) )
+if (sig->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"signature did not verify "
"(headers probably modified in transit)]");
- break;
+ break;
default:
logmsg = string_cat(logmsg, US"unspecified reason]");
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;
pdkim_signature * sig;
int rc;
gstring * g = NULL;
-const uschar * errstr;
+const uschar * errstr = NULL;
store_pool = POOL_PERM;
/* Finish DKIM operation and fetch link to signatures chain */
rc = pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures, &errstr);
-if (rc != PDKIM_OK)
- {
- log_write(0, LOG_MAIN, "DKIM: validation error: %.100s%s%s", pdkim_errstr(rc),
- errstr ? ": " : "", errstr ? errstr : US"");
- goto out;
- }
+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 */
}
-/* Generate signatures for the given file, returning a string.
+/* 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 *
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,
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
}
}
}
+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 (prefix)
- pdkim_feed(&ctx, prefix, Ustrlen(prefix));
+if (prefix && (pdkim_rc = pdkim_feed(&ctx, prefix, Ustrlen(prefix))) != PDKIM_OK)
+ goto pk_bad;
if (lseek(fd, off, SEEK_SET) < 0)
sread = -1;
for (sigbuf = NULL; sig; sig = sig->next)
sigbuf = string_append(sigbuf, 2, US sig->signature_header, US"\r\n");
-(void) string_from_gstring(sigbuf);
-
CLEANUP:
+ (void) string_from_gstring(sigbuf);
store_pool = old_pool;
errno = save_errno;
return sigbuf;
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=", 8);
+
+ if (sig->verify_status & PDKIM_VERIFY_POLICY)
+ g = string_append(g, 5,
+ US"policy (", dkim_verify_status, US" - ", dkim_verify_reason, US")");
+ else switch(sig->verify_status)
+ {
+ case PDKIM_VERIFY_NONE: g = string_cat(g, US"none"); break;
+ case PDKIM_VERIFY_INVALID:
+ switch (sig->verify_ext_status)
+ {
+ case PDKIM_VERIFY_INVALID_PUBKEY_UNAVAILABLE:
+ g = string_cat(g, US"tmperror (pubkey unavailable)"); 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 /*!MACRO_PREDEF*/
#endif /*!DISABLE_DKIM*/
git://git.exim.org / exim.git / blobdiff