diff options
Diffstat (limited to 'usr.bin/ssh/kex.c')
| -rw-r--r-- | usr.bin/ssh/kex.c | 31 |
1 files changed, 27 insertions, 4 deletions
diff --git a/usr.bin/ssh/kex.c b/usr.bin/ssh/kex.c index 050d0df1001..1e9ad51d882 100644 --- a/usr.bin/ssh/kex.c +++ b/usr.bin/ssh/kex.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kex.c,v 1.184 2023/12/18 14:45:49 djm Exp $ */ +/* $OpenBSD: kex.c,v 1.185 2024/01/08 00:34:33 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * @@ -757,10 +757,11 @@ static int kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh) { struct kex *kex = ssh->kex; - int r; + int r, initial = (kex->flags & KEX_INITIAL) != 0; + char *cp, **prop; debug("SSH2_MSG_NEWKEYS received"); - if (kex->ext_info_c && (kex->flags & KEX_INITIAL) != 0) + if (kex->ext_info_c && initial) ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_input_ext_info); ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_protocol_error); ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); @@ -768,10 +769,32 @@ kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh) return r; if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0) return r; + if (initial) { + /* Remove initial KEX signalling from proposal for rekeying */ + if ((r = kex_buf2prop(kex->my, NULL, &prop)) != 0) + return r; + if ((cp = match_filter_denylist(prop[PROPOSAL_KEX_ALGS], + kex->server ? + "ext-info-s,kex-strict-s-v00@openssh.com" : + "ext-info-c,kex-strict-c-v00@openssh.com")) == NULL) { + error_f("match_filter_denylist failed"); + goto fail; + } + free(prop[PROPOSAL_KEX_ALGS]); + prop[PROPOSAL_KEX_ALGS] = cp; + if ((r = kex_prop2buf(ssh->kex->my, prop)) != 0) { + error_f("kex_prop2buf failed"); + fail: + kex_proposal_free_entries(prop); + free(prop); + return SSH_ERR_INTERNAL_ERROR; + } + kex_proposal_free_entries(prop); + free(prop); + } kex->done = 1; kex->flags &= ~KEX_INITIAL; sshbuf_reset(kex->peer); - /* sshbuf_reset(kex->my); */ kex->flags &= ~KEX_INIT_SENT; free(kex->name); kex->name = NULL; |