sync with OpenBSD -current
This commit is contained in:
parent
da785accdf
commit
659ea2942e
GPG key ID:
F42C07F07E2E35B7
39 changed files with 1318 additions and 384 deletions
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@ -1,4 +1,4 @@
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/* $OpenBSD: kex.c,v 1.182 2023/10/11 04:46:29 djm Exp $ */
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/* $OpenBSD: kex.c,v 1.184 2023/12/18 14:45:49 djm Exp $ */
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/*
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* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
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*
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@ -60,7 +60,7 @@
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#include "xmalloc.h"
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/* prototype */
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static int kex_choose_conf(struct ssh *);
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static int kex_choose_conf(struct ssh *, uint32_t seq);
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static int kex_input_newkeys(int, u_int32_t, struct ssh *);
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static const char * const proposal_names[PROPOSAL_MAX] = {
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@ -162,6 +162,18 @@ kex_names_valid(const char *names)
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return 1;
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}
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/* returns non-zero if proposal contains any algorithm from algs */
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static int
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has_any_alg(const char *proposal, const char *algs)
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{
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char *cp;
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if ((cp = match_list(proposal, algs, NULL)) == NULL)
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return 0;
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free(cp);
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return 1;
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}
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/*
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* Concatenate algorithm names, avoiding duplicates in the process.
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* Caller must free returned string.
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@ -169,7 +181,7 @@ kex_names_valid(const char *names)
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char *
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kex_names_cat(const char *a, const char *b)
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{
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char *ret = NULL, *tmp = NULL, *cp, *p, *m;
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char *ret = NULL, *tmp = NULL, *cp, *p;
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size_t len;
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if (a == NULL || *a == '\0')
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@ -186,10 +198,8 @@ kex_names_cat(const char *a, const char *b)
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}
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strlcpy(ret, a, len);
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for ((p = strsep(&cp, ",")); p && *p != '\0'; (p = strsep(&cp, ","))) {
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if ((m = match_list(ret, p, NULL)) != NULL) {
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free(m);
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if (has_any_alg(ret, p))
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continue; /* Algorithm already present */
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}
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if (strlcat(ret, ",", len) >= len ||
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strlcat(ret, p, len) >= len) {
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free(tmp);
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@ -319,15 +329,23 @@ kex_proposal_populate_entries(struct ssh *ssh, char *prop[PROPOSAL_MAX],
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const char *defpropclient[PROPOSAL_MAX] = { KEX_CLIENT };
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const char **defprop = ssh->kex->server ? defpropserver : defpropclient;
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u_int i;
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char *cp;
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if (prop == NULL)
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fatal_f("proposal missing");
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/* Append EXT_INFO signalling to KexAlgorithms */
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if (kexalgos == NULL)
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kexalgos = defprop[PROPOSAL_KEX_ALGS];
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if ((cp = kex_names_cat(kexalgos, ssh->kex->server ?
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"ext-info-s,kex-strict-s-v00@openssh.com" :
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"ext-info-c,kex-strict-c-v00@openssh.com")) == NULL)
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fatal_f("kex_names_cat");
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for (i = 0; i < PROPOSAL_MAX; i++) {
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switch(i) {
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case PROPOSAL_KEX_ALGS:
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prop[i] = compat_kex_proposal(ssh,
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kexalgos ? kexalgos : defprop[i]);
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prop[i] = compat_kex_proposal(ssh, cp);
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break;
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case PROPOSAL_ENC_ALGS_CTOS:
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case PROPOSAL_ENC_ALGS_STOC:
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@ -348,6 +366,7 @@ kex_proposal_populate_entries(struct ssh *ssh, char *prop[PROPOSAL_MAX],
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prop[i] = xstrdup(defprop[i]);
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}
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}
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free(cp);
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}
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void
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@ -451,7 +470,12 @@ kex_protocol_error(int type, u_int32_t seq, struct ssh *ssh)
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{
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int r;
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error("kex protocol error: type %d seq %u", type, seq);
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/* If in strict mode, any unexpected message is an error */
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if ((ssh->kex->flags & KEX_INITIAL) && ssh->kex->kex_strict) {
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ssh_packet_disconnect(ssh, "strict KEX violation: "
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"unexpected packet type %u (seqnr %u)", type, seq);
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}
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error_f("type %u seq %u", type, seq);
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if ((r = sshpkt_start(ssh, SSH2_MSG_UNIMPLEMENTED)) != 0 ||
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(r = sshpkt_put_u32(ssh, seq)) != 0 ||
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(r = sshpkt_send(ssh)) != 0)
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@ -466,36 +490,138 @@ kex_reset_dispatch(struct ssh *ssh)
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SSH2_MSG_TRANSPORT_MAX, &kex_protocol_error);
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}
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void
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kex_set_server_sig_algs(struct ssh *ssh, const char *allowed_algs)
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{
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char *alg, *oalgs, *algs, *sigalgs;
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const char *sigalg;
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/*
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* NB. allowed algorithms may contain certificate algorithms that
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* map to a specific plain signature type, e.g.
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* rsa-sha2-512-cert-v01@openssh.com => rsa-sha2-512
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* We need to be careful here to match these, retain the mapping
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* and only add each signature algorithm once.
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*/
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if ((sigalgs = sshkey_alg_list(0, 1, 1, ',')) == NULL)
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fatal_f("sshkey_alg_list failed");
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oalgs = algs = xstrdup(allowed_algs);
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free(ssh->kex->server_sig_algs);
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ssh->kex->server_sig_algs = NULL;
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for ((alg = strsep(&algs, ",")); alg != NULL && *alg != '\0';
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(alg = strsep(&algs, ","))) {
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if ((sigalg = sshkey_sigalg_by_name(alg)) == NULL)
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continue;
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if (!has_any_alg(sigalg, sigalgs))
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continue;
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/* Don't add an algorithm twice. */
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if (ssh->kex->server_sig_algs != NULL &&
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has_any_alg(sigalg, ssh->kex->server_sig_algs))
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continue;
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xextendf(&ssh->kex->server_sig_algs, ",", "%s", sigalg);
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}
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free(oalgs);
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free(sigalgs);
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if (ssh->kex->server_sig_algs == NULL)
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ssh->kex->server_sig_algs = xstrdup("");
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}
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static int
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kex_send_ext_info(struct ssh *ssh)
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kex_compose_ext_info_server(struct ssh *ssh, struct sshbuf *m)
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{
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int r;
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char *algs;
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debug("Sending SSH2_MSG_EXT_INFO");
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if ((algs = sshkey_alg_list(0, 1, 1, ',')) == NULL)
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if (ssh->kex->server_sig_algs == NULL &&
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(ssh->kex->server_sig_algs = sshkey_alg_list(0, 1, 1, ',')) == NULL)
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return SSH_ERR_ALLOC_FAIL;
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/* XXX filter algs list by allowed pubkey/hostbased types */
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if ((r = sshpkt_start(ssh, SSH2_MSG_EXT_INFO)) != 0 ||
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(r = sshpkt_put_u32(ssh, 3)) != 0 ||
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(r = sshpkt_put_cstring(ssh, "server-sig-algs")) != 0 ||
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(r = sshpkt_put_cstring(ssh, algs)) != 0 ||
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(r = sshpkt_put_cstring(ssh,
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if ((r = sshbuf_put_u32(m, 3)) != 0 ||
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(r = sshbuf_put_cstring(m, "server-sig-algs")) != 0 ||
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(r = sshbuf_put_cstring(m, ssh->kex->server_sig_algs)) != 0 ||
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(r = sshbuf_put_cstring(m,
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"publickey-hostbound@openssh.com")) != 0 ||
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(r = sshpkt_put_cstring(ssh, "0")) != 0 ||
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(r = sshpkt_put_cstring(ssh, "ping@openssh.com")) != 0 ||
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(r = sshpkt_put_cstring(ssh, "0")) != 0 ||
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(r = sshpkt_send(ssh)) != 0) {
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(r = sshbuf_put_cstring(m, "0")) != 0 ||
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(r = sshbuf_put_cstring(m, "ping@openssh.com")) != 0 ||
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(r = sshbuf_put_cstring(m, "0")) != 0) {
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error_fr(r, "compose");
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return r;
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}
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return 0;
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}
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static int
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kex_compose_ext_info_client(struct ssh *ssh, struct sshbuf *m)
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{
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int r;
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if ((r = sshbuf_put_u32(m, 1)) != 0 ||
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(r = sshbuf_put_cstring(m, "ext-info-in-auth@openssh.com")) != 0 ||
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(r = sshbuf_put_cstring(m, "0")) != 0) {
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error_fr(r, "compose");
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goto out;
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}
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/* success */
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r = 0;
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out:
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free(algs);
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return r;
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}
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static int
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kex_maybe_send_ext_info(struct ssh *ssh)
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{
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int r;
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struct sshbuf *m = NULL;
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if ((ssh->kex->flags & KEX_INITIAL) == 0)
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return 0;
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if (!ssh->kex->ext_info_c && !ssh->kex->ext_info_s)
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return 0;
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/* Compose EXT_INFO packet. */
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if ((m = sshbuf_new()) == NULL)
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fatal_f("sshbuf_new failed");
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if (ssh->kex->ext_info_c &&
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(r = kex_compose_ext_info_server(ssh, m)) != 0)
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goto fail;
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if (ssh->kex->ext_info_s &&
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(r = kex_compose_ext_info_client(ssh, m)) != 0)
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goto fail;
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/* Send the actual KEX_INFO packet */
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debug("Sending SSH2_MSG_EXT_INFO");
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if ((r = sshpkt_start(ssh, SSH2_MSG_EXT_INFO)) != 0 ||
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(r = sshpkt_putb(ssh, m)) != 0 ||
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(r = sshpkt_send(ssh)) != 0) {
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error_f("send EXT_INFO");
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goto fail;
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}
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r = 0;
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fail:
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sshbuf_free(m);
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return r;
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}
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int
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kex_server_update_ext_info(struct ssh *ssh)
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{
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int r;
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if ((ssh->kex->flags & KEX_HAS_EXT_INFO_IN_AUTH) == 0)
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return 0;
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debug_f("Sending SSH2_MSG_EXT_INFO");
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if ((r = sshpkt_start(ssh, SSH2_MSG_EXT_INFO)) != 0 ||
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(r = sshpkt_put_u32(ssh, 1)) != 0 ||
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(r = sshpkt_put_cstring(ssh, "server-sig-algs")) != 0 ||
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(r = sshpkt_put_cstring(ssh, ssh->kex->server_sig_algs)) != 0 ||
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(r = sshpkt_send(ssh)) != 0) {
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error_f("send EXT_INFO");
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return r;
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}
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return 0;
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}
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int
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kex_send_newkeys(struct ssh *ssh)
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{
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@ -507,9 +633,8 @@ kex_send_newkeys(struct ssh *ssh)
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return r;
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debug("SSH2_MSG_NEWKEYS sent");
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ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_input_newkeys);
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if (ssh->kex->ext_info_c && (ssh->kex->flags & KEX_INITIAL) != 0)
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if ((r = kex_send_ext_info(ssh)) != 0)
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return r;
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if ((r = kex_maybe_send_ext_info(ssh)) != 0)
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return r;
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debug("expecting SSH2_MSG_NEWKEYS");
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return 0;
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}
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@ -531,10 +656,61 @@ kex_ext_info_check_ver(struct kex *kex, const char *name,
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return 0;
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}
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static int
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kex_ext_info_client_parse(struct ssh *ssh, const char *name,
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const u_char *value, size_t vlen)
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{
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int r;
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/* NB. some messages are only accepted in the initial EXT_INFO */
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if (strcmp(name, "server-sig-algs") == 0) {
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/* Ensure no \0 lurking in value */
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if (memchr(value, '\0', vlen) != NULL) {
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error_f("nul byte in %s", name);
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return SSH_ERR_INVALID_FORMAT;
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}
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debug_f("%s=<%s>", name, value);
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free(ssh->kex->server_sig_algs);
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ssh->kex->server_sig_algs = xstrdup((const char *)value);
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} else if (ssh->kex->ext_info_received == 1 &&
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strcmp(name, "publickey-hostbound@openssh.com") == 0) {
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if ((r = kex_ext_info_check_ver(ssh->kex, name, value, vlen,
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"0", KEX_HAS_PUBKEY_HOSTBOUND)) != 0) {
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return r;
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}
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} else if (ssh->kex->ext_info_received == 1 &&
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strcmp(name, "ping@openssh.com") == 0) {
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if ((r = kex_ext_info_check_ver(ssh->kex, name, value, vlen,
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"0", KEX_HAS_PING)) != 0) {
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return r;
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}
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} else
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debug_f("%s (unrecognised)", name);
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return 0;
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}
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static int
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kex_ext_info_server_parse(struct ssh *ssh, const char *name,
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const u_char *value, size_t vlen)
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{
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int r;
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if (strcmp(name, "ext-info-in-auth@openssh.com") == 0) {
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if ((r = kex_ext_info_check_ver(ssh->kex, name, value, vlen,
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"0", KEX_HAS_EXT_INFO_IN_AUTH)) != 0) {
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return r;
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}
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} else
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debug_f("%s (unrecognised)", name);
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return 0;
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}
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int
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kex_input_ext_info(int type, u_int32_t seq, struct ssh *ssh)
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{
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struct kex *kex = ssh->kex;
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const int max_ext_info = kex->server ? 1 : 2;
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u_int32_t i, ninfo;
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char *name;
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u_char *val;
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@ -542,13 +718,17 @@ kex_input_ext_info(int type, u_int32_t seq, struct ssh *ssh)
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int r;
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debug("SSH2_MSG_EXT_INFO received");
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if (++kex->ext_info_received > max_ext_info) {
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error("too many SSH2_MSG_EXT_INFO messages sent by peer");
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return dispatch_protocol_error(type, seq, ssh);
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}
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ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_protocol_error);
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if ((r = sshpkt_get_u32(ssh, &ninfo)) != 0)
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return r;
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if (ninfo >= 1024) {
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error("SSH2_MSG_EXT_INFO with too many entries, expected "
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"<=1024, received %u", ninfo);
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return SSH_ERR_INVALID_FORMAT;
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return dispatch_protocol_error(type, seq, ssh);
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}
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for (i = 0; i < ninfo; i++) {
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if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0)
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@ -557,34 +737,16 @@ kex_input_ext_info(int type, u_int32_t seq, struct ssh *ssh)
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free(name);
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return r;
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}
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if (strcmp(name, "server-sig-algs") == 0) {
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/* Ensure no \0 lurking in value */
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if (memchr(val, '\0', vlen) != NULL) {
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error_f("nul byte in %s", name);
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free(name);
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free(val);
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return SSH_ERR_INVALID_FORMAT;
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}
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debug_f("%s=<%s>", name, val);
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kex->server_sig_algs = val;
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val = NULL;
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} else if (strcmp(name,
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"publickey-hostbound@openssh.com") == 0) {
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if ((r = kex_ext_info_check_ver(kex, name, val, vlen,
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"0", KEX_HAS_PUBKEY_HOSTBOUND)) != 0) {
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free(name);
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free(val);
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debug3_f("extension %s", name);
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if (kex->server) {
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if ((r = kex_ext_info_server_parse(ssh, name,
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val, vlen)) != 0)
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return r;
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}
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} else if (strcmp(name, "ping@openssh.com") == 0) {
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if ((r = kex_ext_info_check_ver(kex, name, val, vlen,
|
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"0", KEX_HAS_PING)) != 0) {
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free(name);
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free(val);
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} else {
|
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if ((r = kex_ext_info_client_parse(ssh, name,
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val, vlen)) != 0)
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return r;
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}
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} else
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debug_f("%s (unrecognised)", name);
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}
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free(name);
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free(val);
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}
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@ -598,6 +760,8 @@ kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh)
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int r;
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|
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debug("SSH2_MSG_NEWKEYS received");
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if (kex->ext_info_c && (kex->flags & KEX_INITIAL) != 0)
|
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ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_input_ext_info);
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ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_protocol_error);
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ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit);
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if ((r = sshpkt_get_end(ssh)) != 0)
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|
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@ -666,7 +830,7 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
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error_f("no kex");
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return SSH_ERR_INTERNAL_ERROR;
|
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}
|
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ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
|
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ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_protocol_error);
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||||
ptr = sshpkt_ptr(ssh, &dlen);
|
||||
if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
|
||||
return r;
|
||||
|
|
@ -702,7 +866,7 @@ kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
|
|||
if (!(kex->flags & KEX_INIT_SENT))
|
||||
if ((r = kex_send_kexinit(ssh)) != 0)
|
||||
return r;
|
||||
if ((r = kex_choose_conf(ssh)) != 0)
|
||||
if ((r = kex_choose_conf(ssh, seq)) != 0)
|
||||
return r;
|
||||
|
||||
if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
|
||||
|
|
@ -964,20 +1128,14 @@ proposals_match(char *my[PROPOSAL_MAX], char *peer[PROPOSAL_MAX])
|
|||
return (1);
|
||||
}
|
||||
|
||||
/* returns non-zero if proposal contains any algorithm from algs */
|
||||
static int
|
||||
has_any_alg(const char *proposal, const char *algs)
|
||||
kexalgs_contains(char **peer, const char *ext)
|
||||
{
|
||||
char *cp;
|
||||
|
||||
if ((cp = match_list(proposal, algs, NULL)) == NULL)
|
||||
return 0;
|
||||
free(cp);
|
||||
return 1;
|
||||
return has_any_alg(peer[PROPOSAL_KEX_ALGS], ext);
|
||||
}
|
||||
|
||||
static int
|
||||
kex_choose_conf(struct ssh *ssh)
|
||||
kex_choose_conf(struct ssh *ssh, uint32_t seq)
|
||||
{
|
||||
struct kex *kex = ssh->kex;
|
||||
struct newkeys *newkeys;
|
||||
|
|
@ -1002,13 +1160,24 @@ kex_choose_conf(struct ssh *ssh)
|
|||
sprop=peer;
|
||||
}
|
||||
|
||||
/* Check whether client supports ext_info_c */
|
||||
if (kex->server && (kex->flags & KEX_INITIAL)) {
|
||||
char *ext;
|
||||
|
||||
ext = match_list("ext-info-c", peer[PROPOSAL_KEX_ALGS], NULL);
|
||||
kex->ext_info_c = (ext != NULL);
|
||||
free(ext);
|
||||
/* Check whether peer supports ext_info/kex_strict */
|
||||
if ((kex->flags & KEX_INITIAL) != 0) {
|
||||
if (kex->server) {
|
||||
kex->ext_info_c = kexalgs_contains(peer, "ext-info-c");
|
||||
kex->kex_strict = kexalgs_contains(peer,
|
||||
"kex-strict-c-v00@openssh.com");
|
||||
} else {
|
||||
kex->ext_info_s = kexalgs_contains(peer, "ext-info-s");
|
||||
kex->kex_strict = kexalgs_contains(peer,
|
||||
"kex-strict-s-v00@openssh.com");
|
||||
}
|
||||
if (kex->kex_strict) {
|
||||
debug3_f("will use strict KEX ordering");
|
||||
if (seq != 0)
|
||||
ssh_packet_disconnect(ssh,
|
||||
"strict KEX violation: "
|
||||
"KEXINIT was not the first packet");
|
||||
}
|
||||
}
|
||||
|
||||
/* Check whether client supports rsa-sha2 algorithms */
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue