* PDKIM - a RFC4871 (DKIM) implementation
*
* Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net>
- * Copyright (C) 2016 - 2017 Jeremy Harris <jgh@exim.org>
+ * Copyright (C) 2016 - 2018 Jeremy Harris <jgh@exim.org>
*
* http://duncanthrax.net/pdkim/
*
NULL
};
-typedef struct {
- const uschar * dkim_hashname;
- hashmethod exim_hashmethod;
-} pdkim_hashtype;
-static const pdkim_hashtype pdkim_hashes[] = {
+const pdkim_hashtype pdkim_hashes[] = {
{ US"sha1", HASH_SHA1 },
{ US"sha256", HASH_SHA2_256 },
{ US"sha512", HASH_SHA2_512 }
};
const uschar * pdkim_keytypes[] = {
- US"rsa"
+ [KEYTYPE_RSA] = US"rsa",
+#ifdef SIGN_HAVE_ED25519
+ [KEYTYPE_ED25519] = US"ed25519", /* Works for 3.6.0 GnuTLS, OpenSSL 1.1.1 */
+#endif
+
+#ifdef notyet_EC_dkim_extensions /* https://tools.ietf.org/html/draft-srose-dkim-ecc-00 */
+ US"eccp256",
+ US"eccp348",
+ US"ed448",
+#endif
};
typedef struct pdkim_combined_canon_entry {
- const uschar * str;
- int canon_headers;
- int canon_body;
+ const uschar * str;
+ int canon_headers;
+ int canon_body;
} pdkim_combined_canon_entry;
pdkim_combined_canon_entry pdkim_combined_canons[] = {
}
+int
+pdkim_hashname_to_hashtype(const uschar * s, unsigned len)
+{
+int i;
+if (!len) len = Ustrlen(s);
+for (i = 0; i < nelem(pdkim_hashes); i++)
+ if (Ustrncmp(s, pdkim_hashes[i].dkim_hashname, len) == 0)
+ return i;
+return -1;
+}
+
+void
+pdkim_cstring_to_canons(const uschar * s, unsigned len,
+ int * canon_head, int * canon_body)
+{
+int i;
+if (!len) len = Ustrlen(s);
+for (i = 0; pdkim_combined_canons[i].str; i++)
+ if ( Ustrncmp(s, pdkim_combined_canons[i].str, len) == 0
+ && len == Ustrlen(pdkim_combined_canons[i].str))
+ {
+ *canon_head = pdkim_combined_canons[i].canon_headers;
+ *canon_body = pdkim_combined_canons[i].canon_body;
+ break;
+ }
+}
+
+
const char *
pdkim_verify_status_str(int status)
{
case PDKIM_OK: return US"OK";
case PDKIM_FAIL: return US"FAIL";
- case PDKIM_ERR_RSA_PRIVKEY: return US"RSA_PRIVKEY";
- case PDKIM_ERR_RSA_SIGNING: return US"RSA SIGNING";
- case PDKIM_ERR_LONG_LINE: return US"RSA_LONG_LINE";
+ case PDKIM_ERR_RSA_PRIVKEY: return US"PRIVKEY";
+ case PDKIM_ERR_RSA_SIGNING: return US"SIGNING";
+ case PDKIM_ERR_LONG_LINE: return US"LONG_LINE";
case PDKIM_ERR_BUFFER_TOO_SMALL: return US"BUFFER_TOO_SMALL";
+ case PDKIM_ERR_EXCESS_SIGS: return US"EXCESS_SIGS";
case PDKIM_SIGN_PRIVKEY_WRAP: return US"PRIVKEY_WRAP";
case PDKIM_SIGN_PRIVKEY_B64D: return US"PRIVKEY_B64D";
default: return US"(unknown)";
/* -------------------------------------------------------------------------- */
/* Print debugging functions */
-static void
+void
pdkim_quoteprint(const uschar *data, int len)
{
int i;
debug_printf("\n");
}
-static void
+void
pdkim_hexprint(const uschar *data, int len)
{
int i;
/* -------------------------------------------------------------------------- */
/* Performs "relaxed" canonicalization of a header. */
-static uschar *
-pdkim_relax_header(const uschar * header, BOOL append_crlf)
+uschar *
+pdkim_relax_header_n(const uschar * header, int len, BOOL append_crlf)
{
BOOL past_field_name = FALSE;
BOOL seen_wsp = FALSE;
const uschar * p;
-uschar * relaxed = store_get(Ustrlen(header)+3);
+uschar * relaxed = store_get(len+3);
uschar * q = relaxed;
-for (p = header; *p; p++)
+for (p = header; p - header < len; p++)
{
uschar c = *p;
}
+uschar *
+pdkim_relax_header(const uschar * header, BOOL append_crlf)
+{
+return pdkim_relax_header_n(header, Ustrlen(header), append_crlf);
+}
+
+
/* -------------------------------------------------------------------------- */
#define PDKIM_QP_ERROR_DECODE -1
/* -------------------------------------------------------------------------- */
-static void
+void
pdkim_decode_base64(const uschar * str, blob * b)
{
-int dlen;
-dlen = b64decode(str, &b->data);
+int dlen = b64decode(str, &b->data);
if (dlen < 0) b->data = NULL;
b->len = dlen;
}
-static uschar *
+uschar *
pdkim_encode_base64(blob * b)
{
return b64encode(b->data, b->len);
switch (*cur_tag->s)
{
- case 'b':
+ case 'b': /* sig-data or body-hash */
switch (cur_tag->s[1])
{
case '\0': pdkim_decode_base64(cur_val->s, &sig->sighash); break;
default: break;
}
break;
- case 'v':
+ case 'v': /* version */
/* We only support version 1, and that is currently the
only version there is. */
sig->version =
Ustrcmp(cur_val->s, PDKIM_SIGNATURE_VERSION) == 0 ? 1 : -1;
break;
- case 'a':
+ case 'a': /* algorithm */
{
- uschar * s = Ustrchr(cur_val->s, '-');
-
- for(i = 0; i < nelem(pdkim_keytypes); i++)
- if (Ustrncmp(cur_val->s, pdkim_keytypes[i], s - cur_val->s) == 0)
- { sig->keytype = i; break; }
- for (++s, i = 0; i < nelem(pdkim_hashes); i++)
- if (Ustrcmp(s, pdkim_hashes[i].dkim_hashname) == 0)
- { sig->hashtype = i; break; }
- break;
+ const uschar * list = cur_val->s;
+ int sep = '-';
+ uschar * elem;
+
+ if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+ for(i = 0; i < nelem(pdkim_keytypes); i++)
+ if (Ustrcmp(elem, pdkim_keytypes[i]) == 0)
+ { sig->keytype = i; break; }
+ if ((elem = string_nextinlist(&list, &sep, NULL, 0)))
+ for (i = 0; i < nelem(pdkim_hashes); i++)
+ if (Ustrcmp(elem, pdkim_hashes[i].dkim_hashname) == 0)
+ { sig->hashtype = i; break; }
}
- case 'c':
- for (i = 0; pdkim_combined_canons[i].str; i++)
- if (Ustrcmp(cur_val->s, pdkim_combined_canons[i].str) == 0)
- {
- sig->canon_headers = pdkim_combined_canons[i].canon_headers;
- sig->canon_body = pdkim_combined_canons[i].canon_body;
- break;
- }
+ case 'c': /* canonicalization */
+ pdkim_cstring_to_canons(cur_val->s, 0,
+ &sig->canon_headers, &sig->canon_body);
break;
- case 'q':
+ case 'q': /* Query method (for pubkey)*/
for (i = 0; pdkim_querymethods[i]; i++)
if (Ustrcmp(cur_val->s, pdkim_querymethods[i]) == 0)
{
- sig->querymethod = i;
+ sig->querymethod = i; /* we never actually use this */
break;
}
break;
- case 's':
+ case 's': /* Selector */
sig->selector = string_copyn(cur_val->s, cur_val->ptr); break;
- case 'd':
+ case 'd': /* SDID */
sig->domain = string_copyn(cur_val->s, cur_val->ptr); break;
- case 'i':
+ case 'i': /* AUID */
sig->identity = pdkim_decode_qp(cur_val->s); break;
- case 't':
+ case 't': /* Timestamp */
sig->created = strtoul(CS cur_val->s, NULL, 10); break;
- case 'x':
+ case 'x': /* Expiration */
sig->expires = strtoul(CS cur_val->s, NULL, 10); break;
- case 'l':
+ case 'l': /* Body length count */
sig->bodylength = strtol(CS cur_val->s, NULL, 10); break;
- case 'h':
+ case 'h': /* signed header fields */
sig->headernames = string_copyn(cur_val->s, cur_val->ptr); break;
- case 'z':
+ case 'z': /* Copied headfields */
sig->copiedheaders = pdkim_decode_qp(cur_val->s); break;
+/*XXX draft-ietf-dcrup-dkim-crypto-05 would need 'p' tag support
+for rsafp signatures. But later discussion is dropping those. */
default:
DEBUG(D_acl) debug_printf(" Unknown tag encountered\n");
break;
*q++ = c;
}
+if (sig->keytype < 0 || sig->hashtype < 0) /* Cannot verify this signature */
+ return NULL;
+
*q = '\0';
/* Chomp raw header. The final newline must not be added to the signature. */
while (--q > sig->rawsig_no_b_val && (*q == '\r' || *q == '\n'))
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
}
-/*XXX hash method: extend for sha512 */
-if (!exim_sha_init(&sig->body_hash_ctx,
- pdkim_hashes[sig->hashtype].exim_hashmethod))
- {
- DEBUG(D_acl)
- debug_printf("PDKIM: hash init error, possibly nonhandled hashtype\n");
+if (!pdkim_set_sig_bodyhash(ctx, sig))
return NULL;
- }
+
return sig;
}
/* -------------------------------------------------------------------------- */
-static pdkim_pubkey *
-pdkim_parse_pubkey_record(pdkim_ctx *ctx, const uschar *raw_record)
+pdkim_pubkey *
+pdkim_parse_pubkey_record(const uschar *raw_record)
{
const uschar * ele;
int sep = ';';
{
case 'v': pub->version = val; break;
case 'h': pub->hashes = val; break;
- case 'k': break;
+ case 'k': pub->keytype = val; break;
case 'g': pub->granularity = val; break;
case 'n': pub->notes = pdkim_decode_qp(val); break;
case 'p': pdkim_decode_base64(val, &pub->key); break;
}
/* Set fallback defaults */
-if (!pub->version ) pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
+if (!pub->version)
+ pub->version = string_copy(PDKIM_PUB_RECORD_VERSION);
else if (Ustrcmp(pub->version, PDKIM_PUB_RECORD_VERSION) != 0)
{
DEBUG(D_acl) debug_printf(" Bad v= field\n");
}
if (!pub->granularity) pub->granularity = US"*";
-/*
if (!pub->keytype ) pub->keytype = US"rsa";
-*/
if (!pub->srvtype ) pub->srvtype = US"*";
/* p= is required */
/* -------------------------------------------------------------------------- */
-/* Update the bodyhash for one sig, with some additional data.
+/* Update one bodyhash with some additional data.
If we have to relax the data for this sig, return our copy of it. */
-/*XXX Currently we calculate a hash for each sig. But it is possible
-that multi-signing will be wanted using different signing algos
-(rsa, ec) using the same hash and canonicalization. Consider in future
-hanging the hash+cacnon from the ctx and only referencing from the sig,
-so that it can be calculated only once - being over the body this
-caould be meagbytes, hence expensive. */
-
static blob *
-pdkim_update_sig_bodyhash(pdkim_signature * sig, blob * orig_data, blob * relaxed_data)
+pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, blob * orig_data, blob * relaxed_data)
{
blob * canon_data = orig_data;
/* Defaults to simple canon (no further treatment necessary) */
-if (sig->canon_body == PDKIM_CANON_RELAXED)
+if (b->canon_method == PDKIM_CANON_RELAXED)
{
/* Relax the line if not done already */
if (!relaxed_data)
{
BOOL seen_wsp = FALSE;
- const uschar * p;
+ const uschar * p, * r;
int q = 0;
/* We want to be able to free this else we allocate
relaxed_data = store_malloc(sizeof(blob) + orig_data->len+1);
relaxed_data->data = US (relaxed_data+1);
- for (p = orig_data->data; *p; p++)
+ for (p = orig_data->data, r = p + orig_data->len; p < r; p++)
{
char c = *p;
if (c == '\r')
}
/* Make sure we don't exceed the to-be-signed body length */
-if ( sig->bodylength >= 0
- && sig->signed_body_bytes + (unsigned long)canon_data->len > sig->bodylength
+if ( b->bodylength >= 0
+ && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength
)
- canon_data->len = sig->bodylength - sig->signed_body_bytes;
+ canon_data->len = b->bodylength - b->signed_body_bytes;
if (canon_data->len > 0)
{
- exim_sha_update(&sig->body_hash_ctx, CUS canon_data->data, canon_data->len);
- sig->signed_body_bytes += canon_data->len;
+ exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, canon_data->len);
+ b->signed_body_bytes += canon_data->len;
DEBUG(D_acl) pdkim_quoteprint(canon_data->data, canon_data->len);
}
static void
pdkim_finish_bodyhash(pdkim_ctx * ctx)
{
+pdkim_bodyhash * b;
pdkim_signature * sig;
+for (b = ctx->bodyhash; b; b = b->next) /* Finish hashes */
+ {
+ DEBUG(D_acl) debug_printf("PDKIM: finish bodyhash %d/%d/%ld len %ld\n",
+ b->hashtype, b->canon_method, b->bodylength, b->signed_body_bytes);
+ exim_sha_finish(&b->body_hash_ctx, &b->bh);
+ }
+
/* Traverse all signatures */
for (sig = ctx->sig; sig; sig = sig->next)
- { /* Finish hashes */
- blob bh;
-
- exim_sha_finish(&sig->body_hash_ctx, &bh);
+ {
+ b = sig->calc_body_hash;
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] Body bytes hashed: %lu\n"
+ debug_printf("PDKIM [%s] Body bytes (%s) hashed: %lu\n"
"PDKIM [%s] Body %s computed: ",
- sig->domain, sig->signed_body_bytes,
- sig->domain, pdkim_hashes[sig->hashtype].dkim_hashname);
- pdkim_hexprint(CUS bh.data, bh.len);
+ sig->domain, pdkim_canons[b->canon_method], b->signed_body_bytes,
+ sig->domain, pdkim_hashes[b->hashtype].dkim_hashname);
+ pdkim_hexprint(CUS b->bh.data, b->bh.len);
}
/* SIGNING -------------------------------------------------------------- */
if (ctx->flags & PDKIM_MODE_SIGN)
{
- sig->bodyhash = bh;
-
/* If bodylength limit is set, and we have received less bytes
than the requested amount, effectively remove the limit tag. */
- if (sig->signed_body_bytes < sig->bodylength)
+ if (b->signed_body_bytes < sig->bodylength)
sig->bodylength = -1;
}
/* VERIFICATION --------------------------------------------------------- */
/* Be careful that the header sig included a bodyash */
- if (sig->bodyhash.data && memcmp(bh.data, sig->bodyhash.data, bh.len) == 0)
+ if ( sig->bodyhash.data
+ && memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0)
{
- DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash verified OK\n", sig->domain);
+ DEBUG(D_acl) debug_printf("PDKIM [%s] Body hash compared OK\n", sig->domain);
}
else
{
static void
pdkim_body_complete(pdkim_ctx * ctx)
{
-pdkim_signature * sig;
+pdkim_bodyhash * b;
/* In simple body mode, if any empty lines were buffered,
replace with one. rfc 4871 3.4.3 */
it indicates that all linebreaks should be buffered, including
the one terminating a text line */
-for (sig = ctx->sig; sig; sig = sig->next)
- if ( sig->canon_body == PDKIM_CANON_SIMPLE
- && sig->signed_body_bytes == 0
- && sig->num_buffered_blanklines > 0
+for (b = ctx->bodyhash; b; b = b->next)
+ if ( b->canon_method == PDKIM_CANON_SIMPLE
+ && b->signed_body_bytes == 0
+ && b->num_buffered_blanklines > 0
)
- (void) pdkim_update_sig_bodyhash(sig, &lineending, NULL);
+ (void) pdkim_update_ctx_bodyhash(b, &lineending, NULL);
ctx->flags |= PDKIM_SEEN_EOD;
ctx->linebuf_offset = 0;
/* -------------------------------------------------------------------------- */
/* Call from pdkim_feed below for processing complete body lines */
+/* NOTE: the line is not NUL-terminated; but we have a count */
static void
pdkim_bodyline_complete(pdkim_ctx * ctx)
{
blob line = {.data = ctx->linebuf, .len = ctx->linebuf_offset};
-pdkim_signature * sig;
+pdkim_bodyhash * b;
blob * rnl = NULL;
blob * rline = NULL;
/* Empty lines need to be buffered until we find a non-empty line */
if (memcmp(line.data, "\r\n", 2) == 0)
{
- for (sig = ctx->sig; sig; sig = sig->next) sig->num_buffered_blanklines++;
+ for (b = ctx->bodyhash; b; b = b->next) b->num_buffered_blanklines++;
goto all_skip;
}
-/* Process line for each sig separately */
-for (sig = ctx->sig; sig; sig = sig->next)
+/* Process line for each bodyhash separately */
+for (b = ctx->bodyhash; b; b = b->next)
{
- if (sig->canon_body == PDKIM_CANON_RELAXED)
+ if (b->canon_method == PDKIM_CANON_RELAXED)
{
/* Lines with just spaces need to be buffered too */
uschar * cp = line.data;
while ((c = *cp))
{
if (c == '\r' && cp[1] == '\n') break;
- if (c != ' ' && c != '\t') goto sig_process;
+ if (c != ' ' && c != '\t') goto hash_process;
cp++;
}
- sig->num_buffered_blanklines++;
- goto sig_skip;
+ b->num_buffered_blanklines++;
+ goto hash_skip;
}
-sig_process:
+hash_process:
/* At this point, we have a non-empty line, so release the buffered ones. */
- while (sig->num_buffered_blanklines)
+ while (b->num_buffered_blanklines)
{
- rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl);
- sig->num_buffered_blanklines--;
+ rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
+ b->num_buffered_blanklines--;
}
- rline = pdkim_update_sig_bodyhash(sig, &line, rline);
-sig_skip: ;
+ rline = pdkim_update_ctx_bodyhash(b, &line, rline);
+hash_skip: ;
}
if (rnl) store_free(rnl);
--ctx->cur_header->ptr;
(void) string_from_gstring(ctx->cur_header);
+#ifdef EXPERIMENTAL_ARC
+/* Feed the header line to ARC processing */
+(void) arc_header_feed(ctx->cur_header, !(ctx->flags & PDKIM_MODE_SIGN));
+#endif
+
if (++ctx->num_headers > PDKIM_MAX_HEADERS) goto BAIL;
/* SIGNING -------------------------------------------------------------- */
while (last_sig->next) last_sig = last_sig->next;
last_sig->next = sig;
}
+
+ if (--dkim_collect_input == 0)
+ {
+ ctx->headers = pdkim_prepend_stringlist(ctx->headers, ctx->cur_header->s);
+ ctx->cur_header->s[ctx->cur_header->ptr = 0] = '\0';
+ return PDKIM_ERR_EXCESS_SIGS;
+ }
}
/* all headers are stored for signature verification */
if (!data)
pdkim_body_complete(ctx);
-else for (p = 0; p<len; p++)
+else for (p = 0; p < len; p++)
{
uschar c = data[p];
/* -------------------------------------------------------------------------- */
+/* Signing: create signature header
+*/
static uschar *
pdkim_create_header(pdkim_signature * sig, BOOL final)
{
}
}
-base64_bh = pdkim_encode_base64(&sig->bodyhash);
+base64_bh = pdkim_encode_base64(&sig->calc_body_hash->bh);
hdr = pdkim_headcat(&col, hdr, US";", US"bh=", base64_bh);
/* Optional bits */
/* -------------------------------------------------------------------------- */
+/* According to draft-ietf-dcrup-dkim-crypto-07 "keys are 256 bits" (referring
+to DNS, hence the pubkey). Check for more than 32 bytes; if so assume the
+alternate possible representation (still) being discussed: a
+SubjectPublickeyInfo wrapped key - and drop all but the trailing 32-bytes (it
+should be a DER, with exactly 12 leading bytes - but we could accept a BER also,
+which could be any size). We still rely on the crypto library for checking for
+undersize.
+
+When the RFC is published this should be re-addressed. */
+
+static void
+check_bare_ed25519_pubkey(pdkim_pubkey * p)
+{
+int excess = p->key.len - 32;
+if (excess > 0)
+ {
+ DEBUG(D_acl) debug_printf("PDKIM: unexpected pubkey len %lu\n", p->key.len);
+ p->key.data += excess; p->key.len = 32;
+ }
+}
+
+
static pdkim_pubkey *
pdkim_key_from_dns(pdkim_ctx * ctx, pdkim_signature * sig, ev_ctx * vctx,
const uschar ** errstr)
dns_txt_name = string_sprintf("%s._domainkey.%s.", sig->selector, sig->domain);
-dns_txt_reply = store_get(PDKIM_DNS_TXT_MAX_RECLEN);
-memset(dns_txt_reply, 0, PDKIM_DNS_TXT_MAX_RECLEN);
-
-if ( ctx->dns_txt_callback(CS dns_txt_name, CS dns_txt_reply) != PDKIM_OK
+if ( !(dns_txt_reply = ctx->dns_txt_callback(dns_txt_name))
|| dns_txt_reply[0] == '\0'
)
{
pdkim_quoteprint(CUS dns_txt_reply, Ustrlen(dns_txt_reply));
}
-if ( !(p = pdkim_parse_pubkey_record(ctx, CUS dns_txt_reply))
+if ( !(p = pdkim_parse_pubkey_record(CUS dns_txt_reply))
|| (Ustrcmp(p->srvtype, "*") != 0 && Ustrcmp(p->srvtype, "email") != 0)
)
{
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
/* Import public key */
-if ((*errstr = exim_dkim_verify_init(&p->key, vctx)))
+
+/* Normally we use the signature a= tag to tell us the pubkey format.
+When signing under debug we do a test-import of the pubkey, and at that
+time we do not have a signature so we must interpret the pubkey k= tag
+instead. Assume writing on the sig is ok in that case. */
+
+if (sig->keytype < 0)
+ {
+ int i;
+ for(i = 0; i < nelem(pdkim_keytypes); i++)
+ if (Ustrcmp(p->keytype, pdkim_keytypes[i]) == 0)
+ { sig->keytype = i; goto k_ok; }
+ DEBUG(D_acl) debug_printf("verify_init: unhandled keytype %s\n", p->keytype);
+ sig->verify_status = PDKIM_VERIFY_INVALID;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_IMPORT;
+ return NULL;
+ }
+k_ok:
+
+if (sig->keytype == KEYTYPE_ED25519)
+ check_bare_ed25519_pubkey(p);
+
+if ((*errstr = exim_dkim_verify_init(&p->key,
+ sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER,
+ vctx)))
{
DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr);
sig->verify_status = PDKIM_VERIFY_INVALID;
return NULL;
}
+vctx->keytype = sig->keytype;
return p;
}
pdkim_feed_finish(pdkim_ctx * ctx, pdkim_signature ** return_signatures,
const uschar ** err)
{
+pdkim_bodyhash * b;
pdkim_signature * sig;
+BOOL verify_pass = FALSE;
/* Check if we must still flush a (partial) header. If that is the
case, the message has no body, and we must compute a body hash
if ((rc = pdkim_header_complete(ctx)) != PDKIM_OK)
return rc;
- for (sig = ctx->sig; sig; sig = sig->next)
- rnl = pdkim_update_sig_bodyhash(sig, &lineending, rnl);
+ for (b = ctx->bodyhash; b; b = b->next)
+ rnl = pdkim_update_ctx_bodyhash(b, &lineending, rnl);
if (rnl) store_free(rnl);
}
else
DEBUG(D_acl) debug_printf(
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
-/* Build (and/or evaluate) body hash */
+/* Build (and/or evaluate) body hash. Do this even if no DKIM sigs, in case we
+have a hash to do for ARC. */
+
pdkim_finish_bodyhash(ctx);
+if (!ctx->sig)
+ {
+ DEBUG(D_acl) debug_printf("PDKIM: no signatures\n");
+ *return_signatures = NULL;
+ return PDKIM_OK;
+ }
+
for (sig = ctx->sig; sig; sig = sig->next)
{
hctx hhash_ctx;
uschar * sig_hdr = US"";
blob hhash;
gstring * hdata = NULL;
+ es_ctx sctx;
- if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+ if ( !(ctx->flags & PDKIM_MODE_SIGN)
+ && sig->verify_status == PDKIM_VERIFY_FAIL)
{
DEBUG(D_acl)
- debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+ debug_printf("PDKIM: [%s] abandoning this signature\n", sig->domain);
+ continue;
+ }
+
+ /*XXX The hash of the headers is needed for GCrypt (for which we can do RSA
+ suging only, as it happens) and for either GnuTLS and OpenSSL when we are
+ signing with EC (specifically, Ed25519). The former is because the GCrypt
+ signing operation is pure (does not do its own hash) so we must hash. The
+ latter is because we (stupidly, but this is what the IETF draft is saying)
+ must hash with the declared hash method, then pass the result to the library
+ hash-and-sign routine (because that's all the libraries are providing. And
+ we're stuck with whatever that hidden hash method is, too). We may as well
+ do this hash incrementally.
+ We don't need the hash we're calculating here for the GnuTLS and OpenSSL
+ cases of RSA signing, since those library routines can do hash-and-sign.
+
+ Some time in the future we could easily avoid doing the hash here for those
+ cases (which will be common for a long while. We could also change from
+ the current copy-all-the-headers-into-one-block, then call the hash-and-sign
+ implementation - to a proper incremental one. Unfortunately, GnuTLS just
+ cannot do incremental - either signing or verification. Unsure about GCrypt.
+ */
+
+ /*XXX The header hash is also used (so far) by the verify operation */
+
+ if (!exim_sha_init(&hhash_ctx, pdkim_hashes[sig->hashtype].exim_hashmethod))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "PDKIM: hash setup error, possibly nonhandled hashtype");
break;
}
sig->sign_headers);
DEBUG(D_acl) debug_printf(
- "PDKIM >> Header data for hash, canonicalized, in sequence >>>>>>>>>>>>\n");
+ "PDKIM >> Header data for hash, canonicalized (%-7s), in sequence >>\n",
+ pdkim_canons[sig->canon_headers]);
/* SIGNING ---------------------------------------------------------------- */
uschar * s;
int sep = 0;
- sig->headernames = NULL; /* Collected signed header names */
+ /* Import private key, including the keytype which we need for building
+ the signature header */
+
+/*XXX extend for non-RSA algos */
+ if ((*err = exim_dkim_signing_init(CUS sig->privkey, &sctx)))
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing_init: %s", *err);
+ return PDKIM_ERR_RSA_PRIVKEY;
+ }
+ sig->keytype = sctx.keytype;
- for (p = sig->headers; p; p = p->next)
+ for (sig->headernames = NULL, /* Collected signed header names */
+ p = sig->headers; p; p = p->next)
{
uschar * rh = p->value;
exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh));
/* Remember headers block for signing (when the library cannot do incremental) */
+ /*XXX we could avoid doing this for all but the GnuTLS/RSA case */
hdata = exim_dkim_data_append(hdata, rh);
DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
DEBUG(D_acl)
{
- debug_printf(
- "PDKIM >> Signed DKIM-Signature header, canonicalized >>>>>>>>>>>>>>>>>\n");
+ debug_printf("PDKIM >> Signed DKIM-Signature header, canonicalized (%-7s) >>>>>>>\n",
+ pdkim_canons[sig->canon_headers]);
pdkim_quoteprint(CUS sig_hdr, Ustrlen(sig_hdr));
debug_printf(
"PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
/* SIGNING ---------------------------------------------------------------- */
if (ctx->flags & PDKIM_MODE_SIGN)
{
- es_ctx sctx;
-
- /* Import private key, including the keytype */
-/*XXX extend for non-RSA algos */
- if ((*err = exim_dkim_signing_init(US sig->privkey, &sctx)))
- {
- DEBUG(D_acl) debug_printf("signing_init: %s\n", *err);
- return PDKIM_ERR_RSA_PRIVKEY;
- }
+ hashmethod hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+ ? HASH_NULL
+#else
+ ? HASH_SHA2_512
+#endif
+ : pdkim_hashes[sig->hashtype].exim_hashmethod;
- /* Do signing. With OpenSSL we are signing the hash of headers just
- calculated, with GnuTLS we have to sign an entire block of headers
- (due to available interfaces) and it recalculates the hash internally. */
+#ifdef SIGN_HAVE_ED25519
+ /* For GCrypt, and for EC, we pass the hash-of-headers to the signing
+ routine. For anything else we just pass the headers. */
-#if defined(SIGN_GNUTLS)
- hhash.data = hdata->s;
- hhash.len = hdata->ptr;
+ if (sig->keytype != KEYTYPE_ED25519)
#endif
+ {
+ hhash.data = hdata->s;
+ hhash.len = hdata->ptr;
+ }
-/*XXX extend for non-RSA algos */
- if ((*err = exim_dkim_sign(&sctx,
- pdkim_hashes[sig->hashtype].exim_hashmethod,
- &hhash, &sig->sighash)))
+ if ((*err = exim_dkim_sign(&sctx, hm, &hhash, &sig->sighash)))
{
- DEBUG(D_acl) debug_printf("signing: %s\n", *err);
+ log_write(0, LOG_MAIN|LOG_PANIC, "signing: %s", *err);
return PDKIM_ERR_RSA_SIGNING;
}
else
{
ev_ctx vctx;
+ hashmethod hm;
/* Make sure we have all required signature tags */
if (!( sig->domain && *sig->domain
sig->verify_ext_status = PDKIM_VERIFY_INVALID_SIGNATURE_ERROR;
DEBUG(D_acl) debug_printf(
- " Error in DKIM-Signature header: tags missing or invalid\n"
- "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
+ " Error in DKIM-Signature header: tags missing or invalid (%s)\n"
+ "PDKIM <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n",
+ !(sig->domain && *sig->domain) ? "d="
+ : !(sig->selector && *sig->selector) ? "s="
+ : !(sig->headernames && *sig->headernames) ? "h="
+ : !sig->bodyhash.data ? "bh="
+ : !sig->sighash.data ? "b="
+ : sig->keytype < 0 || sig->hashtype < 0 ? "a="
+ : "v="
+ );
goto NEXT_VERIFY;
}
-
+
/* Make sure sig uses supported DKIM version (only v1) */
if (sig->version != 1)
{
}
if (!(sig->pubkey = pdkim_key_from_dns(ctx, sig, &vctx, err)))
+ {
+ log_write(0, LOG_MAIN, "PDKIM: %s%s %s%s [failed key import]",
+ sig->domain ? "d=" : "", sig->domain ? sig->domain : US"",
+ sig->selector ? "s=" : "", sig->selector ? sig->selector : US"");
goto NEXT_VERIFY;
+ }
/* If the pubkey limits to a list of specific hashes, ignore sigs that
do not have the hash part of the sig algorithm matching */
}
}
+ hm = sig->keytype == KEYTYPE_ED25519
+#if defined(SIGN_OPENSSL)
+ ? HASH_NULL
+#else
+ ? HASH_SHA2_512
+#endif
+ : pdkim_hashes[sig->hashtype].exim_hashmethod;
+
/* Check the signature */
-/*XXX needs extension for non-RSA */
- if ((*err = exim_dkim_verify(&vctx,
- pdkim_hashes[sig->hashtype].exim_hashmethod,
- &hhash, &sig->sighash)))
+
+ if ((*err = exim_dkim_verify(&vctx, hm, &hhash, &sig->sighash)))
{
DEBUG(D_acl) debug_printf("headers verify: %s\n", *err);
sig->verify_status = PDKIM_VERIFY_FAIL;
/* We have a winner! (if bodyhash was correct earlier) */
if (sig->verify_status == PDKIM_VERIFY_NONE)
+ {
sig->verify_status = PDKIM_VERIFY_PASS;
+ verify_pass = TRUE;
+ }
NEXT_VERIFY:
DEBUG(D_acl)
{
- debug_printf("PDKIM [%s] signature status: %s",
- sig->domain, pdkim_verify_status_str(sig->verify_status));
+ debug_printf("PDKIM [%s] %s signature status: %s",
+ sig->domain, dkim_sig_to_a_tag(sig),
+ pdkim_verify_status_str(sig->verify_status));
if (sig->verify_ext_status > 0)
debug_printf(" (%s)\n",
pdkim_verify_ext_status_str(sig->verify_ext_status));
if (return_signatures)
*return_signatures = ctx->sig;
-return PDKIM_OK;
+return ctx->flags & PDKIM_MODE_SIGN || verify_pass
+ ? PDKIM_OK : PDKIM_FAIL;
}
/* -------------------------------------------------------------------------- */
DLLEXPORT pdkim_ctx *
-pdkim_init_verify(int(*dns_txt_callback)(char *, char *), BOOL dot_stuffing)
+pdkim_init_verify(uschar * (*dns_txt_callback)(uschar *), BOOL dot_stuffing)
{
pdkim_ctx * ctx;
/* -------------------------------------------------------------------------- */
-/*XXX ? needs extension to cover non-RSA algo? */
-
DLLEXPORT pdkim_signature *
pdkim_init_sign(pdkim_ctx * ctx,
uschar * domain, uschar * selector, uschar * privkey,
sig->domain = string_copy(US domain);
sig->selector = string_copy(US selector);
sig->privkey = string_copy(US privkey);
-/*XXX no keytype yet; comes from privkey */
+sig->keytype = -1;
for (hashtype = 0; hashtype < nelem(pdkim_hashes); hashtype++)
if (Ustrcmp(hashname, pdkim_hashes[hashtype].dkim_hashname) == 0)
{ sig->hashtype = hashtype; break; }
if (hashtype >= nelem(pdkim_hashes))
{
- DEBUG(D_acl)
- debug_printf("PDKIM: unrecognised hashname '%s'\n", hashname);
- return NULL;
- }
-
-if (!exim_sha_init(&sig->body_hash_ctx, pdkim_hashes[hashtype].exim_hashmethod))
- {
- DEBUG(D_acl)
- debug_printf("PDKIM: hash setup error, possibly nonhandled hashtype\n");
+ log_write(0, LOG_MAIN|LOG_PANIC,
+ "PDKIM: unrecognised hashname '%s'", hashname);
return NULL;
}
+/* Set up a blob for calculating the bodyhash according to the
+given needs. Use an existing one if possible, or create a new one.
+
+Return: hashblob pointer, or NULL on error
+*/
+pdkim_bodyhash *
+pdkim_set_bodyhash(pdkim_ctx * ctx, int hashtype, int canon_method,
+ long bodylength)
+{
+pdkim_bodyhash * b;
+
+for (b = ctx->bodyhash; b; b = b->next)
+ if ( hashtype == b->hashtype
+ && canon_method == b->canon_method
+ && bodylength == b->bodylength)
+ {
+ DEBUG(D_receive) debug_printf("PDKIM: using existing bodyhash %d/%d/%ld\n",
+ hashtype, canon_method, bodylength);
+ return b;
+ }
+
+DEBUG(D_receive) debug_printf("PDKIM: new bodyhash %d/%d/%ld\n",
+ hashtype, canon_method, bodylength);
+b = store_get(sizeof(pdkim_bodyhash));
+b->next = ctx->bodyhash;
+b->hashtype = hashtype;
+b->canon_method = canon_method;
+b->bodylength = bodylength;
+if (!exim_sha_init(&b->body_hash_ctx, /*XXX hash method: extend for sha512 */
+ pdkim_hashes[hashtype].exim_hashmethod))
+ {
+ DEBUG(D_acl)
+ debug_printf("PDKIM: hash init error, possibly nonhandled hashtype\n");
+ return NULL;
+ }
+b->signed_body_bytes = 0;
+b->num_buffered_blanklines = 0;
+ctx->bodyhash = b;
+return b;
+}
+
+
+/* Set up a blob for calculating the bodyhash according to the
+needs of this signature. Use an existing one if possible, or
+create a new one.
+
+Return: hashblob pointer, or NULL on error (only used as a boolean).
+*/
+pdkim_bodyhash *
+pdkim_set_sig_bodyhash(pdkim_ctx * ctx, pdkim_signature * sig)
+{
+pdkim_bodyhash * b = pdkim_set_bodyhash(ctx,
+ sig->hashtype, sig->canon_body, sig->bodylength);
+sig->calc_body_hash = b;
+return b;
+}
+
+
+/* -------------------------------------------------------------------------- */
+
+
void
pdkim_init_context(pdkim_ctx * ctx, BOOL dot_stuffed,
- int(*dns_txt_callback)(char *, char *))
+ uschar * (*dns_txt_callback)(uschar *))
{
memset(ctx, 0, sizeof(pdkim_ctx));
ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;
git://git.exim.org / exim.git / blobdiff