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authordjm@openbsd.org <djm@openbsd.org>2020-04-11 10:16:11 +0000
committerDamien Miller <djm@mindrot.org>2020-04-11 20:20:58 +1000
commit3779b50ee952078018a5d9e1df20977f4355df17 (patch)
tree4f21fc8fb3bdba5432e34064560f543479eee4ea /sshkey.c
parentb6a4013647db67ec622c144a9e05dd768f1966b3 (diff)
upstream: Refactor private key parsing. Eliminates a fair bit of
duplicated code and fixes oss-fuzz#20074 (NULL deref) caused by a missing key type check in the ECDSA_CERT parsing path. feedback and ok markus@ OpenBSD-Commit-ID: 4711981d88afb7196d228f7baad9be1d3b20f9c9
Diffstat (limited to 'sshkey.c')
-rw-r--r--sshkey.c187
1 files changed, 40 insertions, 147 deletions
diff --git a/sshkey.c b/sshkey.c
index d6cc6365..1571e3d9 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.107 2020/04/08 00:08:46 djm Exp $ */
+/* $OpenBSD: sshkey.c,v 1.108 2020/04/11 10:16:11 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
* Copyright (c) 2008 Alexander von Gernler. All rights reserved.
@@ -3394,38 +3394,52 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
if ((r = sshbuf_get_cstring(buf, &tname, NULL)) != 0)
goto out;
type = sshkey_type_from_name(tname);
- switch (type) {
-#ifdef WITH_OPENSSL
- case KEY_DSA:
+ if (sshkey_type_is_cert(type)) {
+ /*
+ * Certificate key private keys begin with the certificate
+ * itself. Make sure this matches the type of the enclosing
+ * private key.
+ */
+ if ((r = sshkey_froms(buf, &k)) != 0)
+ goto out;
+ if (k->type != type) {
+ r = SSH_ERR_KEY_CERT_MISMATCH;
+ goto out;
+ }
+ /* For ECDSA keys, the group must match too */
+ if (k->type == KEY_ECDSA &&
+ k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) {
+ r = SSH_ERR_KEY_CERT_MISMATCH;
+ goto out;
+ }
+ } else {
if ((k = sshkey_new(type)) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
+ }
+ switch (type) {
+#ifdef WITH_OPENSSL
+ case KEY_DSA:
if ((r = sshbuf_get_bignum2(buf, &dsa_p)) != 0 ||
(r = sshbuf_get_bignum2(buf, &dsa_q)) != 0 ||
(r = sshbuf_get_bignum2(buf, &dsa_g)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &dsa_pub_key)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &dsa_priv_key)) != 0)
+ (r = sshbuf_get_bignum2(buf, &dsa_pub_key)) != 0)
goto out;
if (!DSA_set0_pqg(k->dsa, dsa_p, dsa_q, dsa_g)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
dsa_p = dsa_q = dsa_g = NULL; /* transferred */
- if (!DSA_set0_key(k->dsa, dsa_pub_key, dsa_priv_key)) {
+ if (!DSA_set0_key(k->dsa, dsa_pub_key, NULL)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
- dsa_pub_key = dsa_priv_key = NULL; /* transferred */
- break;
+ dsa_pub_key = NULL; /* transferred */
+ /* FALLTHROUGH */
case KEY_DSA_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &dsa_priv_key)) != 0)
+ if ((r = sshbuf_get_bignum2(buf, &dsa_priv_key)) != 0)
goto out;
- if (k->type != type) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
if (!DSA_set0_key(k->dsa, NULL, dsa_priv_key)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
@@ -3434,10 +3448,6 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
break;
# ifdef OPENSSL_HAS_ECC
case KEY_ECDSA:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
@@ -3453,27 +3463,12 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
- if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &exponent)))
- goto out;
- if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- if ((r = sshkey_ec_validate_public(EC_KEY_get0_group(k->ecdsa),
- EC_KEY_get0_public_key(k->ecdsa))) != 0 ||
- (r = sshkey_ec_validate_private(k->ecdsa)) != 0)
+ if ((r = sshbuf_get_eckey(buf, k->ecdsa)) != 0)
goto out;
- break;
+ /* FALLTHROUGH */
case KEY_ECDSA_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &exponent)) != 0)
- goto out;
- if (k->type != type ||
- k->ecdsa_nid != sshkey_ecdsa_nid_from_name(tname)) {
- r = SSH_ERR_INVALID_FORMAT;
+ if ((r = sshbuf_get_bignum2(buf, &exponent)) != 0)
goto out;
- }
if (EC_KEY_set_private_key(k->ecdsa, exponent) != 1) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
@@ -3484,10 +3479,6 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
goto out;
break;
case KEY_ECDSA_SK:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
if ((k->ecdsa_nid = sshkey_ecdsa_nid_from_name(tname)) == -1) {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
@@ -3520,8 +3511,6 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
goto out;
break;
case KEY_ECDSA_SK_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0)
- goto out;
if ((k->sk_key_handle = sshbuf_new()) == NULL ||
(k->sk_reserved = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
@@ -3539,43 +3528,21 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
break;
# endif /* OPENSSL_HAS_ECC */
case KEY_RSA:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
if ((r = sshbuf_get_bignum2(buf, &rsa_n)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_e)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_d)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_iqmp)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_p)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_q)) != 0)
- goto out;
- if (!RSA_set0_key(k->rsa, rsa_n, rsa_e, rsa_d)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
+ (r = sshbuf_get_bignum2(buf, &rsa_e)) != 0)
goto out;
- }
- rsa_n = rsa_e = rsa_d = NULL; /* transferred */
- if (!RSA_set0_factors(k->rsa, rsa_p, rsa_q)) {
+ if (!RSA_set0_key(k->rsa, rsa_n, rsa_e, NULL)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
}
- rsa_p = rsa_q = NULL; /* transferred */
- if ((r = check_rsa_length(k->rsa)) != 0)
- goto out;
- if ((r = ssh_rsa_complete_crt_parameters(k, rsa_iqmp)) != 0)
- goto out;
- break;
+ rsa_n = rsa_e = NULL; /* transferred */
+ /* FALLTHROUGH */
case KEY_RSA_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_bignum2(buf, &rsa_d)) != 0 ||
+ if ((r = sshbuf_get_bignum2(buf, &rsa_d)) != 0 ||
(r = sshbuf_get_bignum2(buf, &rsa_iqmp)) != 0 ||
(r = sshbuf_get_bignum2(buf, &rsa_p)) != 0 ||
(r = sshbuf_get_bignum2(buf, &rsa_q)) != 0)
goto out;
- if (k->type != type) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
if (!RSA_set0_key(k->rsa, NULL, NULL, rsa_d)) {
r = SSH_ERR_LIBCRYPTO_ERROR;
goto out;
@@ -3593,30 +3560,10 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
break;
#endif /* WITH_OPENSSL */
case KEY_ED25519:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0 ||
- (r = sshbuf_get_string(buf, &ed25519_sk, &sklen)) != 0)
- goto out;
- if (pklen != ED25519_PK_SZ || sklen != ED25519_SK_SZ) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- k->ed25519_pk = ed25519_pk;
- k->ed25519_sk = ed25519_sk;
- ed25519_pk = ed25519_sk = NULL;
- break;
case KEY_ED25519_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0 ||
+ if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0 ||
(r = sshbuf_get_string(buf, &ed25519_sk, &sklen)) != 0)
goto out;
- if (k->type != type) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
if (pklen != ED25519_PK_SZ || sklen != ED25519_SK_SZ) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
@@ -3626,38 +3573,9 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
ed25519_pk = ed25519_sk = NULL; /* transferred */
break;
case KEY_ED25519_SK:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0)
- goto out;
- if (pklen != ED25519_PK_SZ) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if ((k->sk_key_handle = sshbuf_new()) == NULL ||
- (k->sk_reserved = sshbuf_new()) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if ((r = sshbuf_get_cstring(buf, &k->sk_application,
- NULL)) != 0 ||
- (r = sshbuf_get_u8(buf, &k->sk_flags)) != 0 ||
- (r = sshbuf_get_stringb(buf, k->sk_key_handle)) != 0 ||
- (r = sshbuf_get_stringb(buf, k->sk_reserved)) != 0)
- goto out;
- k->ed25519_pk = ed25519_pk;
- ed25519_pk = NULL;
- break;
case KEY_ED25519_SK_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0)
- goto out;
- if (k->type != type) {
- r = SSH_ERR_INVALID_FORMAT;
+ if ((r = sshbuf_get_string(buf, &ed25519_pk, &pklen)) != 0)
goto out;
- }
if (pklen != ED25519_PK_SZ) {
r = SSH_ERR_INVALID_FORMAT;
goto out;
@@ -3678,10 +3596,7 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
break;
#ifdef WITH_XMSS
case KEY_XMSS:
- if ((k = sshkey_new(type)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
+ case KEY_XMSS_CERT:
if ((r = sshbuf_get_cstring(buf, &xmss_name, NULL)) != 0 ||
(r = sshkey_xmss_init(k, xmss_name)) != 0 ||
(r = sshbuf_get_string(buf, &xmss_pk, &pklen)) != 0 ||
@@ -3699,28 +3614,6 @@ sshkey_private_deserialize(struct sshbuf *buf, struct sshkey **kp)
if ((r = sshkey_xmss_deserialize_state_opt(k, buf)) != 0)
goto out;
break;
- case KEY_XMSS_CERT:
- if ((r = sshkey_froms(buf, &k)) != 0 ||
- (r = sshbuf_get_cstring(buf, &xmss_name, NULL)) != 0 ||
- (r = sshbuf_get_string(buf, &xmss_pk, &pklen)) != 0 ||
- (r = sshbuf_get_string(buf, &xmss_sk, &sklen)) != 0)
- goto out;
- if (k->type != type || strcmp(xmss_name, k->xmss_name) != 0) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if (pklen != sshkey_xmss_pklen(k) ||
- sklen != sshkey_xmss_sklen(k)) {
- r = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- k->xmss_pk = xmss_pk;
- k->xmss_sk = xmss_sk;
- xmss_pk = xmss_sk = NULL;
- /* optional internal state */
- if ((r = sshkey_xmss_deserialize_state_opt(k, buf)) != 0)
- goto out;
- break;
#endif /* WITH_XMSS */
default:
r = SSH_ERR_KEY_TYPE_UNKNOWN;