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authorEd Maste <emaste@FreeBSD.org>2024-02-26 15:38:45 +0000
committerGordon Tetlow <gordon@FreeBSD.org>2024-03-28 03:05:12 +0000
commitf3195cc08ccc99365ec00900a3c1abc59ceefc9c (patch)
tree43920abee4698555827c4ab2f129393a17358b15
parenta839681443b6662571d6b90732baae364c97e9d9 (diff)
kern: fix panic with disabled ttys
PR: 277240, 277329 Reviewed by: kib (earlier version) Fixes: f1d0a0cbecf2 ("jail: Fix information leak.") MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D44086 Approved by: so Security: FreeBSD-EN-24:05.tty (cherry picked from commit 975d7730828a8bde28c2a0092b6e95c4c4e22f34) (cherry picked from commit 8d22744f5be165a2a82a2a204789e44bbdc5a2ee) (cherry picked from commit a60220bbb5511469fe53fd4290713ba891f8f48a)
-rw-r--r--sys/kern/tty.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 22c4bb6dffce..92dee3ceefc9 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -1314,7 +1314,8 @@ sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
struct xtty *xtlist, *xt;
struct tty *tp;
struct proc *p;
- int cansee, error;
+ int error;
+ bool cansee;
sx_slock(&tty_list_sx);
lsize = tty_list_count * sizeof(struct xtty);
@@ -1327,8 +1328,8 @@ sysctl_kern_ttys(SYSCTL_HANDLER_ARGS)
TAILQ_FOREACH(tp, &tty_list, t_list) {
tty_lock(tp);
- if (tp->t_session != NULL) {
- p = tp->t_session->s_leader;
+ if (tp->t_session != NULL &&
+ (p = atomic_load_ptr(&tp->t_session->s_leader)) != NULL) {
PROC_LOCK(p);
cansee = (p_cansee(td, p) == 0);
PROC_UNLOCK(p);