diff options
| author | djm@openbsd.org <djm@openbsd.org> | 2023-12-18 14:48:08 +0000 |
|---|---|---|
| committer | Damien Miller <djm@mindrot.org> | 2023-12-19 01:53:40 +1100 |
| commit | 6d51feab157cedf1e7ef5b3f8781ca8ff9c4ab1b (patch) | |
| tree | e7631190f19db44da47e19d092e74bf92e8b14ac | |
| parent | 7ef3787c84b6b524501211b11a26c742f829af1a (diff) | |
| download | openssh-6d51feab157cedf1e7ef5b3f8781ca8ff9c4ab1b.tar.gz | |
upstream: ssh-agent: record failed session-bind attempts
Record failed attempts to session-bind a connection and refuse signing
operations on that connection henceforth.
Prevents a future situation where we add a new hostkey type that is not
recognised by an older ssh-agent, that consequently causes session-bind
to fail (this situation is only likely to arise when people mix ssh(1)
and ssh-agent(1) of different versions on the same host). Previously,
after such a failure the agent socket would be considered unbound and
not subject to restriction.
Spotted by Jann Horn
OpenBSD-Commit-ID: b0fdd023e920aa4831413f640de4c5307b53552e
| -rw-r--r-- | ssh-agent.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/ssh-agent.c b/ssh-agent.c index 12ec66cf8..b6a3f4810 100644 --- a/ssh-agent.c +++ b/ssh-agent.c @@ -1,4 +1,4 @@ -/* $OpenBSD: ssh-agent.c,v 1.302 2023/12/18 14:46:56 djm Exp $ */ +/* $OpenBSD: ssh-agent.c,v 1.303 2023/12/18 14:48:08 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -130,6 +130,7 @@ typedef struct socket_entry { struct sshbuf *request; size_t nsession_ids; struct hostkey_sid *session_ids; + int session_bind_attempted; } SocketEntry; u_int sockets_alloc = 0; @@ -477,6 +478,10 @@ identity_permitted(Identity *id, SocketEntry *e, char *user, e->nsession_ids, id->ndest_constraints); if (id->ndest_constraints == 0) return 0; /* unconstrained */ + if (e->session_bind_attempted && e->nsession_ids == 0) { + error_f("previous session bind failed on socket"); + return -1; + } if (e->nsession_ids == 0) return 0; /* local use */ /* @@ -556,6 +561,12 @@ identity_permitted(Identity *id, SocketEntry *e, char *user, return 0; } +static int +socket_is_remote(SocketEntry *e) +{ + return e->session_bind_attempted || (e->nsession_ids != 0); +} + /* return matching private key for given public key */ static Identity * lookup_identity(struct sshkey *key) @@ -1367,7 +1378,7 @@ process_add_identity(SocketEntry *e) if (strcasecmp(sk_provider, "internal") == 0) { debug_f("internal provider"); } else { - if (e->nsession_ids != 0 && !remote_add_provider) { + if (socket_is_remote(e) && !remote_add_provider) { verbose("failed add of SK provider \"%.100s\": " "remote addition of providers is disabled", sk_provider); @@ -1565,7 +1576,7 @@ process_add_smartcard_key(SocketEntry *e) goto send; } dump_dest_constraints(__func__, dest_constraints, ndest_constraints); - if (e->nsession_ids != 0 && !remote_add_provider) { + if (socket_is_remote(e) && !remote_add_provider) { verbose("failed PKCS#11 add of \"%.100s\": remote addition of " "providers is disabled", provider); goto send; @@ -1680,6 +1691,7 @@ process_ext_session_bind(SocketEntry *e) u_char fwd = 0; debug2_f("entering"); + e->session_bind_attempted = 1; if ((r = sshkey_froms(e->request, &key)) != 0 || (r = sshbuf_froms(e->request, &sid)) != 0 || (r = sshbuf_froms(e->request, &sig)) != 0 || |