/*
* PDKIM - a RFC4871 (DKIM) implementation
*
+ * Copyright (c) The Exim Maintainers 2021 - 2022
* Copyright (C) 2009 - 2016 Tom Kistner <tom@duncanthrax.net>
- * Copyright (C) 2016 - 2018 Jeremy Harris <jgh@exim.org>
+ * Copyright (C) 2016 - 2020 Jeremy Harris <jgh@exim.org>
+ * SPDX-License-Identifier: GPL-2.0-or-later
*
* http://duncanthrax.net/pdkim/
*
};
-static blob lineending = {.data = US"\r\n", .len = 2};
+static const blob lineending = {.data = US"\r\n", .len = 2};
/* -------------------------------------------------------------------------- */
uschar *
case PDKIM_VERIFY_INVALID_BUFFER_SIZE: return "PDKIM_VERIFY_INVALID_BUFFER_SIZE";
case PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD: return "PDKIM_VERIFY_INVALID_PUBKEY_DNSRECORD";
case PDKIM_VERIFY_INVALID_PUBKEY_IMPORT: return "PDKIM_VERIFY_INVALID_PUBKEY_IMPORT";
+ case PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE: return "PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE";
case PDKIM_VERIFY_INVALID_SIGNATURE_ERROR: return "PDKIM_VERIFY_INVALID_SIGNATURE_ERROR";
case PDKIM_VERIFY_INVALID_DKIM_VERSION: return "PDKIM_VERIFY_INVALID_DKIM_VERSION";
default: return "PDKIM_VERIFY_UNKNOWN";
static pdkim_stringlist *
pdkim_prepend_stringlist(pdkim_stringlist * base, const uschar * str)
{
-pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), FALSE);
+pdkim_stringlist * new_entry = store_get(sizeof(pdkim_stringlist), GET_UNTAINTED);
memset(new_entry, 0, sizeof(pdkim_stringlist));
new_entry->value = string_copy(str);
{
BOOL past_field_name = FALSE;
BOOL seen_wsp = FALSE;
-uschar * relaxed = store_get(len+3, TRUE); /* tainted */
+uschar * relaxed = store_get(len+3, GET_TAINTED);
uschar * q = relaxed;
for (const uschar * p = header; p - header < len; p++)
int nchar = 0;
uschar * q;
const uschar * p = str;
-uschar * n = store_get(Ustrlen(str)+1, TRUE);
+uschar * n = store_get(Ustrlen(str)+1, GET_TAINTED);
*n = '\0';
q = n;
BOOL in_b_val = FALSE;
int where = PDKIM_HDR_LIMBO;
-sig = store_get(sizeof(pdkim_signature), FALSE);
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
memset(sig, 0, sizeof(pdkim_signature));
sig->bodylength = -1;
sig->keytype = -1;
sig->hashtype = -1;
-q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, TRUE); /* tainted */
+q = sig->rawsig_no_b_val = store_get(Ustrlen(raw_hdr)+1, GET_TAINTED);
for (uschar * p = raw_hdr; ; p++)
{
int sep = ';';
pdkim_pubkey * pub;
-pub = store_get(sizeof(pdkim_pubkey), TRUE); /* tainted */
+pub = store_get(sizeof(pdkim_pubkey), GET_TAINTED);
memset(pub, 0, sizeof(pdkim_pubkey));
while ((ele = string_nextinlist(&raw_record, &sep, NULL, 0)))
If we have to relax the data for this sig, return our copy of it. */
static blob *
-pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, blob * orig_data, blob * relaxed_data)
+pdkim_update_ctx_bodyhash(pdkim_bodyhash * b, const blob * orig_data, blob * relaxed_data)
{
-blob * canon_data = orig_data;
+const blob * canon_data = orig_data;
+size_t left;
+
/* Defaults to simple canon (no further treatment necessary) */
if (b->canon_method == PDKIM_CANON_RELAXED)
}
/* Make sure we don't exceed the to-be-signed body length */
+left = canon_data->len;
if ( b->bodylength >= 0
- && b->signed_body_bytes + (unsigned long)canon_data->len > b->bodylength
+ && left > (unsigned long)b->bodylength - b->signed_body_bytes
)
- canon_data->len = b->bodylength - b->signed_body_bytes;
+ left = (unsigned long)b->bodylength - b->signed_body_bytes;
-if (canon_data->len > 0)
+if (left > 0)
{
- 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);
+ exim_sha_update(&b->body_hash_ctx, CUS canon_data->data, left);
+ b->signed_body_bytes += left;
+ DEBUG(D_acl) pdkim_quoteprint(canon_data->data, left);
}
return relaxed_data;
{
for (pdkim_bodyhash * b = ctx->bodyhash; b; b = b->next) /* Finish hashes */
{
- DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %d/%d/%ld len %ld\n",
- b->hashtype, b->canon_method, b->bodylength, b->signed_body_bytes);
+ DEBUG(D_acl) debug_printf("DKIM: finish bodyhash %s/%s/%ld len %ld\n",
+ pdkim_hashes[b->hashtype].dkim_hashname, pdkim_canons[b->canon_method],
+ b->bodylength, b->signed_body_bytes);
exim_sha_finish(&b->body_hash_ctx, &b->bh);
}
DEBUG(D_acl)
{
- debug_printf("DKIM [%s] Body bytes (%s) hashed: %lu\n"
- "DKIM [%s] Body %s computed: ",
- sig->domain, pdkim_canons[b->canon_method], b->signed_body_bytes,
- sig->domain, pdkim_hashes[b->hashtype].dkim_hashname);
+ debug_printf("DKIM [%s]%s Body bytes (%s) hashed: %lu\n"
+ "DKIM [%s]%s Body %s computed: ",
+ sig->domain, sig->selector, pdkim_canons[b->canon_method], b->signed_body_bytes,
+ sig->domain, sig->selector, pdkim_hashes[b->hashtype].dkim_hashname);
pdkim_hexprint(CUS b->bh.data, b->bh.len);
}
/* VERIFICATION --------------------------------------------------------- */
/* Be careful that the header sig included a bodyash */
- if ( sig->bodyhash.data
+ if (sig->bodyhash.data && sig->bodyhash.len == b->bh.len
&& memcmp(b->bh.data, sig->bodyhash.data, b->bh.len) == 0)
{
DEBUG(D_acl) debug_printf("DKIM [%s] Body hash compared OK\n", sig->domain);
last_sig->next = sig;
}
- if (--dkim_collect_input == 0)
+ if (dkim_collect_input && --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';
/*
* RFC 5322 specifies that header line length SHOULD be no more than 78
- * lets make it so!
* pdkim_headcat
*
- * returns uschar * (not nul-terminated)
+ * Returns gstring (not nul-terminated) appending to one supplied
*
* col: this int holds and receives column number (octets since last '\n')
* str: partial string to append to
- * pad: padding, split line or space after before or after eg: ";"
+ * pad: padding, split line or space after before or after eg: ";".
+ * Only the initial charater is used.
* intro: - must join to payload eg "h=", usually the tag name
* payload: eg base64 data - long data can be split arbitrarily.
*
* pairs and inside long values. it also always spaces or breaks after the
* "pad"
*
- * no guarantees are made for output given out-of range input. like tag
+ * No guarantees are made for output given out-of range input. like tag
* names longer than 78, or bogus col. Input is assumed to be free of line breaks.
*/
pdkim_headcat(int * col, gstring * str,
const uschar * pad, const uschar * intro, const uschar * payload)
{
-size_t l;
-
-if (pad)
- {
- l = Ustrlen(pad);
- if (*col + l > 78)
- str = pdkim_hdr_cont(str, col);
- str = string_catn(str, pad, l);
- *col += l;
- }
-
-l = (pad?1:0) + (intro?Ustrlen(intro):0);
-
-if (*col + l > 78)
- { /*can't fit intro - start a new line to make room.*/
- str = pdkim_hdr_cont(str, col);
- l = intro?Ustrlen(intro):0;
- }
-
-l += payload ? Ustrlen(payload):0 ;
-
-while (l>77)
- { /* this fragment will not fit on a single line */
- if (pad)
- {
- str = string_catn(str, US" ", 1);
- *col += 1;
- pad = NULL; /* only want this once */
- l--;
- }
-
- if (intro)
- {
- size_t sl = Ustrlen(intro);
+int len, chomp, padded = 0;
- str = string_catn(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL; /* only want this once */
- }
+/* If we can fit at least the pad at the end of current line, do it now.
+Otherwise, wrap if there is a pad. */
- if (payload)
+if (pad)
+ if (*col + 1 <= 78)
{
- size_t sl = Ustrlen(payload);
- size_t chomp = *col+sl < 77 ? sl : 78-*col;
-
- str = string_catn(str, payload, chomp);
- *col += chomp;
- payload += chomp;
- l -= chomp-1;
+ str = string_catn(str, pad, 1);
+ (*col)++;
+ pad = NULL;
+ padded = 1;
}
+ else
+ str = pdkim_hdr_cont(str, col);
- /* the while precondition tells us it didn't fit. */
- str = pdkim_hdr_cont(str, col);
- }
+/* Special case: if the whole addition does not fit at the end of the current
+line, but could fit on a new line, wrap to give it its full, dedicated line. */
-if (*col + l > 78)
+len = (pad ? 2 : padded)
+ + (intro ? Ustrlen(intro) : 0)
+ + (payload ? Ustrlen(payload) : 0);
+if (len <= 77 && *col+len > 78)
{
str = pdkim_hdr_cont(str, col);
- pad = NULL;
+ padded = 0;
}
+/* Either we already dealt with the pad or we know there is room */
+
if (pad)
{
+ str = string_catn(str, pad, 1);
str = string_catn(str, US" ", 1);
- *col += 1;
- pad = NULL;
+ *col += 2;
}
-
-if (intro)
+else if (padded && *col < 78)
{
- size_t sl = Ustrlen(intro);
-
- str = string_catn(str, intro, sl);
- *col += sl;
- l -= sl;
- intro = NULL;
+ str = string_catn(str, US" ", 1);
+ (*col)++;
}
-if (payload)
- {
- size_t sl = Ustrlen(payload);
+/* Call recursively with intro as payload: it gets the same, special treatment
+(that is, not split if < 78). */
- str = string_catn(str, payload, sl);
- *col += sl;
- }
+if (intro)
+ str = pdkim_headcat(col, str, NULL, NULL, intro);
+
+if (payload)
+ for (len = Ustrlen(payload); len; len -= chomp)
+ {
+ if (*col >= 78)
+ str = pdkim_hdr_cont(str, col);
+ chomp = *col+len > 78 ? 78 - *col : len;
+ str = string_catn(str, payload, chomp);
+ *col += chomp;
+ payload += chomp;
+ }
return str;
}
if (sig->created > 0)
{
- uschar minibuf[20];
+ uschar minibuf[21];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->created);
hdr = pdkim_headcat(&col, hdr, US";", US"t=", minibuf);
if (sig->expires > 0)
{
- uschar minibuf[20];
+ uschar minibuf[21];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->expires);
hdr = pdkim_headcat(&col, hdr, US";", US"x=", minibuf);
if (sig->bodylength >= 0)
{
- uschar minibuf[20];
+ uschar minibuf[21];
snprintf(CS minibuf, sizeof(minibuf), "%lu", sig->bodylength);
hdr = pdkim_headcat(&col, hdr, US";", US"l=", minibuf);
int excess = p->key.len - 32;
if (excess > 0)
{
- DEBUG(D_acl) debug_printf("DKIM: unexpected pubkey len %lu\n", p->key.len);
+ DEBUG(D_acl)
+ debug_printf("DKIM: unexpected pubkey len %lu\n", (unsigned long) p->key.len);
p->key.data += excess; p->key.len = 32;
}
}
if ((*errstr = exim_dkim_verify_init(&p->key,
sig->keytype == KEYTYPE_ED25519 ? KEYFMT_ED25519_BARE : KEYFMT_DER,
- vctx)))
+ vctx, &sig->keybits)))
{
DEBUG(D_acl) debug_printf("verify_init: %s\n", *errstr);
sig->verify_status = PDKIM_VERIFY_INVALID;
rh = pdkim_relax_header(rh, TRUE); /* cook header for relaxed canon */
/* Feed header to the hash algorithm */
- exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh));
+ exim_sha_update_string(&hhash_ctx, CUS 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 */
: string_copy(CUS hdrs->value);
/* Feed header to the hash algorithm */
- exim_sha_update(&hhash_ctx, CUS rh, Ustrlen(rh));
+ exim_sha_update_string(&hhash_ctx, CUS rh);
DEBUG(D_acl) pdkim_quoteprint(rh, Ustrlen(rh));
hdrs->tag = 1;
}
/* Finalize header hash */
- exim_sha_update(&hhash_ctx, CUS sig_hdr, Ustrlen(sig_hdr));
+ exim_sha_update_string(&hhash_ctx, CUS sig_hdr);
exim_sha_finish(&hhash_ctx, &hhash);
DEBUG(D_acl)
sig->verify_ext_status = PDKIM_VERIFY_FAIL_MESSAGE;
goto NEXT_VERIFY;
}
+ if (*dkim_verify_min_keysizes)
+ {
+ unsigned minbits;
+ uschar * ss = expand_getkeyed(US pdkim_keytypes[sig->keytype],
+ dkim_verify_min_keysizes);
+ if (ss && (minbits = atoi(CS ss)) > sig->keybits)
+ {
+ DEBUG(D_acl) debug_printf("Key too short: Actual: %s %u Minima '%s'\n",
+ pdkim_keytypes[sig->keytype], sig->keybits, dkim_verify_min_keysizes);
+ sig->verify_status = PDKIM_VERIFY_FAIL;
+ sig->verify_ext_status = PDKIM_VERIFY_INVALID_PUBKEY_KEYSIZE;
+ }
+ }
/* We have a winner! (if bodyhash was correct earlier) */
{
pdkim_ctx * ctx;
-ctx = store_get(sizeof(pdkim_ctx), FALSE);
+ctx = store_get(sizeof(pdkim_ctx), GET_UNTAINTED);
memset(ctx, 0, sizeof(pdkim_ctx));
if (dot_stuffing) ctx->flags = PDKIM_DOT_TERM;
/* The line-buffer is for message data, hence tainted */
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE);
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
ctx->dns_txt_callback = dns_txt_callback;
+ctx->cur_header = string_get_tainted(36, GET_TAINTED);
return ctx;
}
/* Allocate & init one signature struct */
-sig = store_get(sizeof(pdkim_signature), FALSE);
+sig = store_get(sizeof(pdkim_signature), GET_UNTAINTED);
memset(sig, 0, sizeof(pdkim_signature));
sig->bodylength = -1;
&& canon_method == b->canon_method
&& bodylength == b->bodylength)
{
- DEBUG(D_receive) debug_printf("DKIM: using existing bodyhash %d/%d/%ld\n",
- hashtype, canon_method, bodylength);
+ DEBUG(D_receive) debug_printf("DKIM: using existing bodyhash %s/%s/%ld\n",
+ pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
return b;
}
-DEBUG(D_receive) debug_printf("DKIM: new bodyhash %d/%d/%ld\n",
- hashtype, canon_method, bodylength);
-b = store_get(sizeof(pdkim_bodyhash), FALSE);
+DEBUG(D_receive) debug_printf("DKIM: new bodyhash %s/%s/%ld\n",
+ pdkim_hashes[hashtype].dkim_hashname, pdkim_canons[canon_method], bodylength);
+b = store_get(sizeof(pdkim_bodyhash), GET_UNTAINTED);
b->next = ctx->bodyhash;
b->hashtype = hashtype;
b->canon_method = canon_method;
memset(ctx, 0, sizeof(pdkim_ctx));
ctx->flags = dot_stuffed ? PDKIM_MODE_SIGN | PDKIM_DOT_TERM : PDKIM_MODE_SIGN;
/* The line buffer is for message data, hence tainted */
-ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, TRUE);
+ctx->linebuf = store_get(PDKIM_MAX_BODY_LINE_LEN, GET_TAINTED);
DEBUG(D_acl) ctx->dns_txt_callback = dns_txt_callback;
}
git://git.exim.org / exim.git / blobdiff