* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge, 1995 - 2016 */
+/* 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
pdkim_ctx *dkim_verify_ctx = NULL;
pdkim_signature *dkim_signatures = NULL;
pdkim_signature *dkim_cur_sig = NULL;
+static const uschar * dkim_collect_error = NULL;
+
+
+
+/*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)
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 */
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));
+ "%.*s", (int)len, CS (rr->data + rr_offset));
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_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
/* 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, 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;
goto out;
}
/* Finish DKIM operation and fetch link to signatures chain */
-if (pdkim_feed_finish(dkim_verify_ctx, &dkim_signatures) != PDKIM_OK)
+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"
- : sig->algo == PDKIM_ALGO_RSA_SHA1 ? "rsa-sha1" : "err",
- (int)sig->sigdata.len > -1 ? sig->sigdata.len * 8 : 0
- ),
-
- 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"<UNSET>";
+ logmsg = string_append(logmsg, &size, &ptr, 2, "d=", s);
+ if (!(s = sig->selector)) s = US"<UNSET>";
+ 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=", dkim_sig_to_a_tag(sig),
+ 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:
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:
case PDKIM_VERIFY_PASS:
logmsg =
- string_append(logmsg, &size, &ptr, 1, "[verification succeeded]");
+ string_append(logmsg, &size, &ptr, 1, " [verification succeeded]");
break;
}
/* 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, &dkim_signers_size,
+ &dkim_signers_ptr, ':', 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, &dkim_signers_size,
+ &dkim_signers_ptr, ':', 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;
}
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;
}
}
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";
- }
+ return dkim_sig_to_a_tag(dkim_cur_sig);
case DKIM_BODYLENGTH:
return dkim_cur_sig->bodylength >= 0
}
-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)
+/* Generate signatures for the given file, returning a string.
+If a prefix is given, prepend it to the file for the calculations.
+*/
+
+blob *
+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;
-pdkim_ctx *ctx = NULL;
-uschar *rc = NULL;
-uschar *sigbuf = NULL;
+uschar * seen_doms = NULL;
+int seen_doms_size = 0;
+int seen_doms_offset = 0;
+pdkim_ctx ctx;
+pdkim_signature * sig;
+blob * sigbuf = NULL;
int sigsize = 0;
-int sigptr = 0;
-pdkim_signature *signature;
-int pdkim_canon;
int pdkim_rc;
int sread;
-char buf[4096];
+uschar buf[4096];
int save_errno = 0;
int old_pool = store_pool;
+uschar * errwhen;
store_pool = POOL_MAIN;
-if (!(dkim_domain = expand_cstring(dkim_domain)))
- {
+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. */
- log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand "
- "dkim_domain: %s", expand_string_message);
- rc = NULL;
- goto CLEANUP;
- }
+ { 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,
- itembuf, sizeof(itembuf))))
+while ((dkim_signing_domain = string_nextinlist(&dkim_domain, &sep, NULL, 0)))
{
- if (!dkim_signing_domain || dkim_signing_domain[0] == '\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 (seen_items)
- {
- const 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';
-
- /* Set up $dkim_selector expansion variable. */
+ if (match_isinlist(dkim_signing_domain, CUSS &seen_doms,
+ 0, NULL, NULL, MCL_STRING, TRUE, NULL) == OK)
+ continue;
- if (!(dkim_signing_selector = expand_string(dkim_selector)))
- {
- log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand "
- "dkim_selector: %s", expand_string_message);
- rc = NULL;
- goto CLEANUP;
- }
+ seen_doms = string_append_listele(seen_doms, &seen_doms_size,
+ &seen_doms_offset, ':', dkim_signing_domain);
- /* Get canonicalization to use */
+ /* Set $dkim_selector expansion variable to each selector in list,
+ for this domain. */
- dkim_canon_expanded = dkim_canon ? expand_string(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;
- }
+ if (!(dkim_sel = expand_string(dkim->dkim_selector)))
+ if (!(dkim_signing_selector = expand_string(dkim->dkim_selector)))
+ { errwhen = US"dkim_selector"; 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
+ while ((dkim_signing_selector = string_nextinlist(&dkim_sel, &sel_sep,
+ NULL, 0)))
{
- log_write(0, LOG_MAIN,
- "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n",
- dkim_canon_expanded);
- pdkim_canon = PDKIM_CANON_RELAXED;
- }
-
- dkim_sign_headers_expanded = NULL;
- if (dkim_sign_headers)
- if (!(dkim_sign_headers_expanded = expand_string(dkim_sign_headers)))
+ 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 | LOG_PANIC, "failed to expand "
- "dkim_sign_headers: %s", expand_string_message);
- rc = NULL;
- goto CLEANUP;
+ log_write(0, LOG_MAIN,
+ "DKIM: unknown canonicalization method '%s', defaulting to 'relaxed'.\n",
+ dkim_canon_expanded);
+ pdkim_canon = PDKIM_CANON_RELAXED;
}
- /* else pass NULL, which means default header list */
- /* Get private key to use. */
+ 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 */
- if (!(dkim_private_key_expanded = expand_string(dkim_private_key)))
- {
- log_write(0, LOG_MAIN | LOG_PANIC, "failed to expand "
- "dkim_private_key: %s", expand_string_message);
- rc = NULL;
- goto CLEANUP;
- }
+ /* Get private key to use. */
- 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 = expand_string(dkim->dkim_private_key)))
+ { errwhen = US"dkim_private_key"; goto expand_bad; }
- if (dkim_private_key_expanded[0] == '/')
- {
- int privkey_fd = 0;
+ 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 */
- /* 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 (dkim_private_key_expanded[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;
- }
+ int privkey_fd, off = 0, len;
- if (read(privkey_fd, big_buffer, big_buffer_size - 2) < 0)
- {
- log_write(0, LOG_MAIN|LOG_PANIC, "unable to read private key file: %s",
- dkim_private_key_expanded);
- rc = NULL;
- goto CLEANUP;
- }
+ /* Looks like a filename, load the private key. */
- (void) close(privkey_fd);
- dkim_private_key_expanded = big_buffer;
- }
+ memset(big_buffer, 0, big_buffer_size);
- ctx = pdkim_init_sign( (char *) dkim_signing_domain,
- (char *) dkim_signing_selector,
- (char *) dkim_private_key_expanded,
- PDKIM_ALGO_RSA_SHA256);
- pdkim_set_optional(ctx,
- (char *) dkim_sign_headers_expanded,
- NULL,
- pdkim_canon,
- pdkim_canon, -1, 0, 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);
+ goto bad;
+ }
- lseek(dkim_fd, 0, SEEK_SET);
+ 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);
- while ((sread = read(dkim_fd, &buf, 4096)) > 0)
- if (pdkim_feed(ctx, buf, sread) != PDKIM_OK)
- {
- rc = NULL;
- goto CLEANUP;
+ (void) close(privkey_fd);
+ big_buffer[off] = '\0';
+ dkim_private_key_expanded = big_buffer;
}
- /* Handle failed read above. */
- if (sread == -1)
- {
- debug_printf("DKIM: Error reading -K file.\n");
- save_errno = errno;
- 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,
+ dkim_identity_expanded,
+ pdkim_canon,
+ pdkim_canon, -1, 0, 0);
+
+ 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 ((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 (prefix)
+ pdkim_feed(&ctx, prefix, Ustrlen(prefix));
- sigbuf = string_append(sigbuf, &sigsize, &sigptr, 2,
- US signature->signature_header, US"\r\n");
+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;
- pdkim_free_ctx(ctx);
- ctx = NULL;
+/* Handle failed read above. */
+if (sread == -1)
+ {
+ debug_printf("DKIM: Error reading -K file.\n");
+ save_errno = errno;
+ goto bad;
}
-if (sigbuf)
+/* Build string of headers, one per signature */
+
+if ((pdkim_rc = pdkim_feed_finish(&ctx, &sig, errstr)) != PDKIM_OK)
+ goto pk_bad;
+
+sigbuf = store_get(sizeof(blob));
+sigbuf->data = NULL;
+sigbuf->len = 0;
+
+while (sig)
{
- sigbuf[sigptr] = '\0';
- rc = sigbuf;
+ int len = sigbuf->len;
+ sigbuf->data = string_append(sigbuf->data, &sigsize, &len, 2,
+ US sig->signature_header, US"\r\n");
+ sigbuf->len = len;
+ sig = sig->next;
}
+
+if (sigbuf->data)
+ sigbuf->data[sigbuf->len] = '\0';
else
- rc = US"";
+ sigbuf->data = US"";
CLEANUP:
-if (ctx)
- pdkim_free_ctx(ctx);
-store_pool = old_pool;
-errno = save_errno;
-return rc;
+ store_pool = old_pool;
+ errno = save_errno;
+ 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