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Diffstat (limited to 'ssh-dss.c')
-rw-r--r--ssh-dss.c135
1 files changed, 60 insertions, 75 deletions
diff --git a/ssh-dss.c b/ssh-dss.c
index 8ed19d84..fddc29cc 100644
--- a/ssh-dss.c
+++ b/ssh-dss.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssh-dss.c,v 1.32 2014/06/24 01:13:21 djm Exp $ */
+/* $OpenBSD: ssh-dss.c,v 1.39 2020/02/26 13:40:09 jsg Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
*
@@ -43,6 +43,8 @@
#define SSHKEY_INTERNAL
#include "sshkey.h"
+#include "openbsd-compat/openssl-compat.h"
+
#define INTBLOB_LEN 20
#define SIGBLOB_LEN (2*INTBLOB_LEN)
@@ -51,6 +53,7 @@ ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
const u_char *data, size_t datalen, u_int compat)
{
DSA_SIG *sig = NULL;
+ const BIGNUM *sig_r, *sig_s;
u_char digest[SSH_DIGEST_MAX_LENGTH], sigblob[SIGBLOB_LEN];
size_t rlen, slen, len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
struct sshbuf *b = NULL;
@@ -76,54 +79,40 @@ ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
goto out;
}
- rlen = BN_num_bytes(sig->r);
- slen = BN_num_bytes(sig->s);
+ DSA_SIG_get0(sig, &sig_r, &sig_s);
+ rlen = BN_num_bytes(sig_r);
+ slen = BN_num_bytes(sig_s);
if (rlen > INTBLOB_LEN || slen > INTBLOB_LEN) {
ret = SSH_ERR_INTERNAL_ERROR;
goto out;
}
explicit_bzero(sigblob, SIGBLOB_LEN);
- BN_bn2bin(sig->r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
- BN_bn2bin(sig->s, sigblob + SIGBLOB_LEN - slen);
-
- if (compat & SSH_BUG_SIGBLOB) {
- if (sigp != NULL) {
- if ((*sigp = malloc(SIGBLOB_LEN)) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- memcpy(*sigp, sigblob, SIGBLOB_LEN);
- }
- if (lenp != NULL)
- *lenp = SIGBLOB_LEN;
- ret = 0;
- } else {
- /* ietf-drafts */
- if ((b = sshbuf_new()) == NULL) {
+ BN_bn2bin(sig_r, sigblob + SIGBLOB_LEN - INTBLOB_LEN - rlen);
+ BN_bn2bin(sig_s, sigblob + SIGBLOB_LEN - slen);
+
+ if ((b = sshbuf_new()) == NULL) {
+ ret = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
+ (ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
+ goto out;
+
+ len = sshbuf_len(b);
+ if (sigp != NULL) {
+ if ((*sigp = malloc(len)) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
- if ((ret = sshbuf_put_cstring(b, "ssh-dss")) != 0 ||
- (ret = sshbuf_put_string(b, sigblob, SIGBLOB_LEN)) != 0)
- goto out;
- len = sshbuf_len(b);
- if (sigp != NULL) {
- if ((*sigp = malloc(len)) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- memcpy(*sigp, sshbuf_ptr(b), len);
- }
- if (lenp != NULL)
- *lenp = len;
- ret = 0;
+ memcpy(*sigp, sshbuf_ptr(b), len);
}
+ if (lenp != NULL)
+ *lenp = len;
+ ret = 0;
out:
explicit_bzero(digest, sizeof(digest));
- if (sig != NULL)
- DSA_SIG_free(sig);
- if (b != NULL)
- sshbuf_free(b);
+ DSA_SIG_free(sig);
+ sshbuf_free(b);
return ret;
}
@@ -133,6 +122,7 @@ ssh_dss_verify(const struct sshkey *key,
const u_char *data, size_t datalen, u_int compat)
{
DSA_SIG *sig = NULL;
+ BIGNUM *sig_r = NULL, *sig_s = NULL;
u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
size_t len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
int ret = SSH_ERR_INTERNAL_ERROR;
@@ -140,34 +130,27 @@ ssh_dss_verify(const struct sshkey *key,
char *ktype = NULL;
if (key == NULL || key->dsa == NULL ||
- sshkey_type_plain(key->type) != KEY_DSA)
+ sshkey_type_plain(key->type) != KEY_DSA ||
+ signature == NULL || signaturelen == 0)
return SSH_ERR_INVALID_ARGUMENT;
if (dlen == 0)
return SSH_ERR_INTERNAL_ERROR;
/* fetch signature */
- if (compat & SSH_BUG_SIGBLOB) {
- if ((sigblob = malloc(signaturelen)) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- memcpy(sigblob, signature, signaturelen);
- len = signaturelen;
- } else {
- /* ietf-drafts */
- if ((b = sshbuf_from(signature, signaturelen)) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
- sshbuf_get_string(b, &sigblob, &len) != 0) {
- ret = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if (strcmp("ssh-dss", ktype) != 0) {
- ret = SSH_ERR_KEY_TYPE_MISMATCH;
- goto out;
- }
- if (sshbuf_len(b) != 0) {
- ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
- goto out;
- }
+ if ((b = sshbuf_from(signature, signaturelen)) == NULL)
+ return SSH_ERR_ALLOC_FAIL;
+ if (sshbuf_get_cstring(b, &ktype, NULL) != 0 ||
+ sshbuf_get_string(b, &sigblob, &len) != 0) {
+ ret = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if (strcmp("ssh-dss", ktype) != 0) {
+ ret = SSH_ERR_KEY_TYPE_MISMATCH;
+ goto out;
+ }
+ if (sshbuf_len(b) != 0) {
+ ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
+ goto out;
}
if (len != SIGBLOB_LEN) {
@@ -177,16 +160,21 @@ ssh_dss_verify(const struct sshkey *key,
/* parse signature */
if ((sig = DSA_SIG_new()) == NULL ||
- (sig->r = BN_new()) == NULL ||
- (sig->s = BN_new()) == NULL) {
+ (sig_r = BN_new()) == NULL ||
+ (sig_s = BN_new()) == NULL) {
ret = SSH_ERR_ALLOC_FAIL;
goto out;
}
- if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig->r) == NULL) ||
- (BN_bin2bn(sigblob+ INTBLOB_LEN, INTBLOB_LEN, sig->s) == NULL)) {
+ if ((BN_bin2bn(sigblob, INTBLOB_LEN, sig_r) == NULL) ||
+ (BN_bin2bn(sigblob + INTBLOB_LEN, INTBLOB_LEN, sig_s) == NULL)) {
ret = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
+ if (!DSA_SIG_set0(sig, sig_r, sig_s)) {
+ ret = SSH_ERR_LIBCRYPTO_ERROR;
+ goto out;
+ }
+ sig_r = sig_s = NULL; /* transferred */
/* sha1 the data */
if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
@@ -207,16 +195,13 @@ ssh_dss_verify(const struct sshkey *key,
out:
explicit_bzero(digest, sizeof(digest));
- if (sig != NULL)
- DSA_SIG_free(sig);
- if (b != NULL)
- sshbuf_free(b);
- if (ktype != NULL)
- free(ktype);
- if (sigblob != NULL) {
- explicit_bzero(sigblob, len);
- free(sigblob);
- }
+ DSA_SIG_free(sig);
+ BN_clear_free(sig_r);
+ BN_clear_free(sig_s);
+ sshbuf_free(b);
+ free(ktype);
+ if (sigblob != NULL)
+ freezero(sigblob, len);
return ret;
}
#endif /* WITH_OPENSSL */
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-03 04:40:25 +0000