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author	Ed Maste <emaste@FreeBSD.org>	2021-02-14 21:00:25 +0000
committer	Ed Maste <emaste@FreeBSD.org>	2021-02-14 21:00:25 +0000
commit	0194e6d04277a638afac6c4a664d3bc6a0d944eb (patch)
tree	e97a6dcafc6763aea7c804e4e113c2750cb1400d /kex.c
parent	f02e39982452024dafcf0ea6e536ebff586ffce4 (diff)

Vendor import of OpenSSH 8.1p1vendor/openssh/8.1p1

Diffstat (limited to 'kex.c')

-rw-r--r--

kex.c

105

1 files changed, 79 insertions, 26 deletions

diff --git a/kex.c b/kex.c
index 34808b5c39da..49d701568c28 100644
--- a/kex.c
+++ b/kex.c

@@ -1,4 +1,4 @@

-/* $OpenBSD: kex.c,v 1.150 2019/01/21 12:08:13 djm Exp $ */

+/* $OpenBSD: kex.c,v 1.155 2019/10/08 22:40:39 dtucker Exp $ */

@@ -111,7 +111,7 @@ static const struct kexalg kexalgs[] = {

{ KEX_SNTRUP4591761X25519_SHA512, KEX_KEM_SNTRUP4591761X25519_SHA512, 0,

SSH_DIGEST_SHA512 },

#endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */

- { NULL, -1, -1, -1},

+ { NULL, 0, -1, -1},

};

char *

@@ -213,8 +213,9 @@ kex_names_cat(const char *a, const char *b)

* Assemble a list of algorithms from a default list and a string from a

* configuration file. The user-provided string may begin with '+' to

- * indicate that it should be appended to the default or '-' that the

- * specified names should be removed.

+ * indicate that it should be appended to the default, '-' that the

+ * specified names should be removed, or '^' that they should be placed

+ * at the head.

int

kex_assemble_names(char **listp, const char *def, const char *all)

@@ -223,7 +224,10 @@ kex_assemble_names(char **listp, const char *def, const char *all)

char *list = NULL, *ret = NULL, *matching = NULL, *opatterns = NULL;

int r = SSH_ERR_INTERNAL_ERROR;

- if (listp == NULL || *listp == NULL || **listp == '\0') {

+ if (listp == NULL || def == NULL || all == NULL)

+ return SSH_ERR_INVALID_ARGUMENT;

+ if (*listp == NULL || **listp == '\0') {

if ((*listp = strdup(def)) == NULL)

return SSH_ERR_ALLOC_FAIL;

return 0;

@@ -248,6 +252,14 @@ kex_assemble_names(char **listp, const char *def, const char *all)

free(list);

/* filtering has already been done */

return 0;

+ } else if (*list == '^') {

+ /* Place names at head of default list */

+ if ((tmp = kex_names_cat(list + 1, def)) == NULL) {

+ r = SSH_ERR_ALLOC_FAIL;

+ goto fail;

+ }

+ free(list);

+ list = tmp;

} else {

/* Explicit list, overrides default - just use "list" as is */

}

@@ -345,18 +357,25 @@ kex_buf2prop(struct sshbuf *raw, int *first_kex_follows, char ***propp)

r = SSH_ERR_ALLOC_FAIL;

goto out;

}

- if ((r = sshbuf_consume(b, KEX_COOKIE_LEN)) != 0) /* skip cookie */

+ if ((r = sshbuf_consume(b, KEX_COOKIE_LEN)) != 0) { /* skip cookie */

+ error("%s: consume cookie: %s", __func__, ssh_err(r));

goto out;

+ }

/* extract kex init proposal strings */

for (i = 0; i < PROPOSAL_MAX; i++) {

- if ((r = sshbuf_get_cstring(b, &(proposal[i]), NULL)) != 0)

+ if ((r = sshbuf_get_cstring(b, &(proposal[i]), NULL)) != 0) {

+ error("%s: parse proposal %u: %s", __func__,

+ i, ssh_err(r));

goto out;

+ }

debug2("%s: %s", proposal_names[i], proposal[i]);

}

/* first kex follows / reserved */

if ((r = sshbuf_get_u8(b, &v)) != 0 || /* first_kex_follows */

- (r = sshbuf_get_u32(b, &i)) != 0) /* reserved */

+ (r = sshbuf_get_u32(b, &i)) != 0) { /* reserved */

+ error("%s: parse: %s", __func__, ssh_err(r));

goto out;

+ }

if (first_kex_follows != NULL)

*first_kex_follows = v;

debug2("first_kex_follows %d ", v);

@@ -409,6 +428,7 @@ kex_send_ext_info(struct ssh *ssh)

int r;

char *algs;

+ debug("Sending SSH2_MSG_EXT_INFO");

if ((algs = sshkey_alg_list(0, 1, 1, ',')) == NULL)

return SSH_ERR_ALLOC_FAIL;

/* XXX filter algs list by allowed pubkey/hostbased types */

@@ -416,8 +436,10 @@ kex_send_ext_info(struct ssh *ssh)

(r = sshpkt_put_u32(ssh, 1)) != 0 ||

(r = sshpkt_put_cstring(ssh, "server-sig-algs")) != 0 ||

(r = sshpkt_put_cstring(ssh, algs)) != 0 ||

- (r = sshpkt_send(ssh)) != 0)

+ (r = sshpkt_send(ssh)) != 0) {

+ error("%s: compose: %s", __func__, ssh_err(r));

goto out;

+ }

/* success */

r = 0;

out:

@@ -435,11 +457,11 @@ kex_send_newkeys(struct ssh *ssh)

(r = sshpkt_send(ssh)) != 0)

return r;

debug("SSH2_MSG_NEWKEYS sent");

- debug("expecting SSH2_MSG_NEWKEYS");

ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);

- if (ssh->kex->ext_info_c)

+ if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)

if ((r = kex_send_ext_info(ssh)) != 0)

return r;

+ debug("expecting SSH2_MSG_NEWKEYS");

return 0;

}

@@ -511,23 +533,32 @@ kex_send_kexinit(struct ssh *ssh)

struct kex *kex = ssh->kex;

int r;

- if (kex == NULL)

+ if (kex == NULL) {

+ error("%s: no hex", __func__);

return SSH_ERR_INTERNAL_ERROR;

+ }

if (kex->flags & KEX_INIT_SENT)

return 0;

kex->done = 0;

/* generate a random cookie */

- if (sshbuf_len(kex->my) < KEX_COOKIE_LEN)

+ if (sshbuf_len(kex->my) < KEX_COOKIE_LEN) {

+ error("%s: bad kex length: %zu < %d", __func__,

+ sshbuf_len(kex->my), KEX_COOKIE_LEN);

return SSH_ERR_INVALID_FORMAT;

- if ((cookie = sshbuf_mutable_ptr(kex->my)) == NULL)

+ }

+ if ((cookie = sshbuf_mutable_ptr(kex->my)) == NULL) {

+ error("%s: buffer error", __func__);

return SSH_ERR_INTERNAL_ERROR;

+ }

arc4random_buf(cookie, KEX_COOKIE_LEN);

if ((r = sshpkt_start(ssh, SSH2_MSG_KEXINIT)) != 0 ||

(r = sshpkt_putb(ssh, kex->my)) != 0 ||

- (r = sshpkt_send(ssh)) != 0)

+ (r = sshpkt_send(ssh)) != 0) {

+ error("%s: compose reply: %s", __func__, ssh_err(r));

return r;

+ }

debug("SSH2_MSG_KEXINIT sent");

kex->flags |= KEX_INIT_SENT;

return 0;

@@ -544,21 +575,28 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)

int r;

debug("SSH2_MSG_KEXINIT received");

- if (kex == NULL)

- return SSH_ERR_INVALID_ARGUMENT;

+ if (kex == NULL) {

+ error("%s: no hex", __func__);

+ return SSH_ERR_INTERNAL_ERROR;

+ }

ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);

ptr = sshpkt_ptr(ssh, &dlen);

if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)

return r;

/* discard packet */

- for (i = 0; i < KEX_COOKIE_LEN; i++)

- if ((r = sshpkt_get_u8(ssh, NULL)) != 0)

+ for (i = 0; i < KEX_COOKIE_LEN; i++) {

+ if ((r = sshpkt_get_u8(ssh, NULL)) != 0) {

+ error("%s: discard cookie: %s", __func__, ssh_err(r));

return r;

- for (i = 0; i < PROPOSAL_MAX; i++)

- if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)

+ }

+ for (i = 0; i < PROPOSAL_MAX; i++) {

+ if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {

+ error("%s: discard proposal: %s", __func__, ssh_err(r));

return r;

+ }

* XXX RFC4253 sec 7: "each side MAY guess" - currently no supported

* KEX method has the server move first, but a server might be using

@@ -583,6 +621,7 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)

if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)

return (kex->kex[kex->kex_type])(ssh);

+ error("%s: unknown kex type %u", __func__, kex->kex_type);

return SSH_ERR_INTERNAL_ERROR;

}

@@ -718,6 +757,7 @@ choose_enc(struct sshenc *enc, char *client, char *server)

if (name == NULL)

return SSH_ERR_NO_CIPHER_ALG_MATCH;

if ((enc->cipher = cipher_by_name(name)) == NULL) {

+ error("%s: unsupported cipher %s", __func__, name);

free(name);

return SSH_ERR_INTERNAL_ERROR;

}

@@ -739,6 +779,7 @@ choose_mac(struct ssh *ssh, struct sshmac *mac, char *client, char *server)

if (name == NULL)

return SSH_ERR_NO_MAC_ALG_MATCH;

if (mac_setup(mac, name) < 0) {

+ error("%s: unsupported MAC %s", __func__, name);

free(name);

return SSH_ERR_INTERNAL_ERROR;

}

@@ -762,6 +803,7 @@ choose_comp(struct sshcomp *comp, char *client, char *server)

} else if (strcmp(name, "none") == 0) {

comp->type = COMP_NONE;

} else {

+ error("%s: unsupported compression scheme %s", __func__, name);

free(name);

return SSH_ERR_INTERNAL_ERROR;

}

@@ -779,8 +821,10 @@ choose_kex(struct kex *k, char *client, char *server)

debug("kex: algorithm: %s", k->name ? k->name : "(no match)");

if (k->name == NULL)

return SSH_ERR_NO_KEX_ALG_MATCH;

- if ((kexalg = kex_alg_by_name(k->name)) == NULL)

+ if ((kexalg = kex_alg_by_name(k->name)) == NULL) {

+ error("%s: unsupported KEX method %s", __func__, k->name);

return SSH_ERR_INTERNAL_ERROR;

+ }

k->kex_type = kexalg->type;

k->hash_alg = kexalg->hash_alg;

k->ec_nid = kexalg->ec_nid;

@@ -797,8 +841,11 @@ choose_hostkeyalg(struct kex *k, char *client, char *server)

if (k->hostkey_alg == NULL)

return SSH_ERR_NO_HOSTKEY_ALG_MATCH;

k->hostkey_type = sshkey_type_from_name(k->hostkey_alg);

- if (k->hostkey_type == KEY_UNSPEC)

+ if (k->hostkey_type == KEY_UNSPEC) {

+ error("%s: unsupported hostkey algorithm %s", __func__,

+ k->hostkey_alg);

return SSH_ERR_INTERNAL_ERROR;

+ }

k->hostkey_nid = sshkey_ecdsa_nid_from_name(k->hostkey_alg);

return 0;

}

@@ -967,6 +1014,7 @@ derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,

kex->session_id_len) != 0 ||

ssh_digest_final(hashctx, digest, mdsz) != 0) {

r = SSH_ERR_LIBCRYPTO_ERROR;

+ error("%s: KEX hash failed", __func__);

goto out;

}

ssh_digest_free(hashctx);

@@ -983,6 +1031,7 @@ derive_key(struct ssh *ssh, int id, u_int need, u_char *hash, u_int hashlen,

ssh_digest_update(hashctx, hash, hashlen) != 0 ||

ssh_digest_update(hashctx, digest, have) != 0 ||

ssh_digest_final(hashctx, digest + have, mdsz) != 0) {

+ error("%s: KDF failed", __func__);

r = SSH_ERR_LIBCRYPTO_ERROR;

goto out;

}

@@ -1046,8 +1095,10 @@ kex_load_hostkey(struct ssh *ssh, struct sshkey **prvp, struct sshkey **pubp)

*pubp = NULL;

*prvp = NULL;

if (kex->load_host_public_key == NULL ||

- kex->load_host_private_key == NULL)

+ kex->load_host_private_key == NULL) {

+ error("%s: missing hostkey loader", __func__);

return SSH_ERR_INVALID_ARGUMENT;

+ }

*pubp = kex->load_host_public_key(kex->hostkey_type,

kex->hostkey_nid, ssh);

*prvp = kex->load_host_private_key(kex->hostkey_type,

@@ -1062,8 +1113,10 @@ kex_verify_host_key(struct ssh *ssh, struct sshkey *server_host_key)

{

struct kex *kex = ssh->kex;

- if (kex->verify_host_key == NULL)

+ if (kex->verify_host_key == NULL) {

+ error("%s: missing hostkey verifier", __func__);

return SSH_ERR_INVALID_ARGUMENT;

+ }

if (server_host_key->type != kex->hostkey_type ||

(kex->hostkey_type == KEY_ECDSA &&

server_host_key->ecdsa_nid != kex->hostkey_nid))