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From d5be669c872a313a71d60babee64f3a80340dc51 Mon Sep 17 00:00:00 2001
From: "djm@openbsd.org" <djm@openbsd.org>
Date: Mon, 18 Dec 2023 14:46:12 +0000
Subject: upstream: apply destination constraints to all p11 keys
Previously applied only to the first key returned from each token.
ok markus@
OpenBSD-Commit-ID: 36df3afb8eb94eec6b2541f063d0d164ef8b488d
Origin: backport, https://anongit.mindrot.org/openssh.git/commit/?id=881d9c6af9da4257c69c327c4e2f1508b2fa754b
Last-Update: 2023-12-19
Patch-Name: CVE-2023-51384.patch
---
ssh-agent.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 99 insertions(+), 4 deletions(-)
diff --git a/ssh-agent.c b/ssh-agent.c
index dce2849d8..27bf9b5ad 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -248,6 +248,91 @@ free_dest_constraints(struct dest_constraint *dcs, size_t ndcs)
free(dcs);
}
+static void
+dup_dest_constraint_hop(const struct dest_constraint_hop *dch,
+ struct dest_constraint_hop *out)
+{
+ u_int i;
+ int r;
+
+ out->user = dch->user == NULL ? NULL : xstrdup(dch->user);
+ out->hostname = dch->hostname == NULL ? NULL : xstrdup(dch->hostname);
+ out->is_ca = dch->is_ca;
+ out->nkeys = dch->nkeys;
+ out->keys = out->nkeys == 0 ? NULL :
+ xcalloc(out->nkeys, sizeof(*out->keys));
+ out->key_is_ca = out->nkeys == 0 ? NULL :
+ xcalloc(out->nkeys, sizeof(*out->key_is_ca));
+ for (i = 0; i < dch->nkeys; i++) {
+ if (dch->keys[i] != NULL &&
+ (r = sshkey_from_private(dch->keys[i],
+ &(out->keys[i]))) != 0)
+ fatal_fr(r, "copy key");
+ out->key_is_ca[i] = dch->key_is_ca[i];
+ }
+}
+
+static struct dest_constraint *
+dup_dest_constraints(const struct dest_constraint *dcs, size_t ndcs)
+{
+ size_t i;
+ struct dest_constraint *ret;
+
+ if (ndcs == 0)
+ return NULL;
+ ret = xcalloc(ndcs, sizeof(*ret));
+ for (i = 0; i < ndcs; i++) {
+ dup_dest_constraint_hop(&dcs[i].from, &ret[i].from);
+ dup_dest_constraint_hop(&dcs[i].to, &ret[i].to);
+ }
+ return ret;
+}
+
+#ifdef DEBUG_CONSTRAINTS
+static void
+dump_dest_constraint_hop(const struct dest_constraint_hop *dch)
+{
+ u_int i;
+ char *fp;
+
+ debug_f("user %s hostname %s is_ca %d nkeys %u",
+ dch->user == NULL ? "(null)" : dch->user,
+ dch->hostname == NULL ? "(null)" : dch->hostname,
+ dch->is_ca, dch->nkeys);
+ for (i = 0; i < dch->nkeys; i++) {
+ fp = NULL;
+ if (dch->keys[i] != NULL &&
+ (fp = sshkey_fingerprint(dch->keys[i],
+ SSH_FP_HASH_DEFAULT, SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug_f("key %u/%u: %s%s%s key_is_ca %d", i, dch->nkeys,
+ dch->keys[i] == NULL ? "" : sshkey_ssh_name(dch->keys[i]),
+ dch->keys[i] == NULL ? "" : " ",
+ dch->keys[i] == NULL ? "none" : fp,
+ dch->key_is_ca[i]);
+ free(fp);
+ }
+}
+#endif /* DEBUG_CONSTRAINTS */
+
+static void
+dump_dest_constraints(const char *context,
+ const struct dest_constraint *dcs, size_t ndcs)
+{
+#ifdef DEBUG_CONSTRAINTS
+ size_t i;
+
+ debug_f("%s: %zu constraints", context, ndcs);
+ for (i = 0; i < ndcs; i++) {
+ debug_f("constraint %zu / %zu: from: ", i, ndcs);
+ dump_dest_constraint_hop(&dcs[i].from);
+ debug_f("constraint %zu / %zu: to: ", i, ndcs);
+ dump_dest_constraint_hop(&dcs[i].to);
+ }
+ debug_f("done for %s", context);
+#endif /* DEBUG_CONSTRAINTS */
+}
+
static void
free_identity(Identity *id)
{
@@ -519,13 +604,22 @@ process_request_identities(SocketEntry *e)
Identity *id;
struct sshbuf *msg, *keys;
int r;
- u_int nentries = 0;
+ u_int i = 0, nentries = 0;
+ char *fp;
debug2_f("entering");
if ((msg = sshbuf_new()) == NULL || (keys = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
TAILQ_FOREACH(id, &idtab->idlist, next) {
+ if ((fp = sshkey_fingerprint(id->key, SSH_FP_HASH_DEFAULT,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal_f("fingerprint failed");
+ debug_f("key %u / %u: %s %s", i++, idtab->nentries,
+ sshkey_ssh_name(id->key), fp);
+ dump_dest_constraints(__func__,
+ id->dest_constraints, id->ndest_constraints);
+ free(fp);
/* identity not visible, don't include in response */
if (identity_permitted(id, e, NULL, NULL, NULL) != 0)
continue;
@@ -1225,6 +1319,7 @@ process_add_identity(SocketEntry *e)
sshbuf_reset(e->request);
goto out;
}
+ dump_dest_constraints(__func__, dest_constraints, ndest_constraints);
if (sk_provider != NULL) {
if (!sshkey_is_sk(k)) {
@@ -1404,6 +1499,7 @@ process_add_smartcard_key(SocketEntry *e)
error_f("failed to parse constraints");
goto send;
}
+ dump_dest_constraints(__func__, dest_constraints, ndest_constraints);
if (e->nsession_ids != 0 && !remote_add_provider) {
verbose("failed PKCS#11 add of \"%.100s\": remote addition of "
"providers is disabled", provider);
@@ -1439,10 +1535,9 @@ process_add_smartcard_key(SocketEntry *e)
}
id->death = death;
id->confirm = confirm;
- id->dest_constraints = dest_constraints;
+ id->dest_constraints = dup_dest_constraints(
+ dest_constraints, ndest_constraints);
id->ndest_constraints = ndest_constraints;
- dest_constraints = NULL; /* transferred */
- ndest_constraints = 0;
TAILQ_INSERT_TAIL(&idtab->idlist, id, next);
idtab->nentries++;
success = 1;
|
