diff options
| author | Cen Zhang (Microsoft) <blbllhy@gmail.com> | 2026-07-19 17:03:57 -0400 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-07-23 09:15:20 -0700 |
| commit | 167e54c703ccd4fa028feb568b0d1002020cff86 (patch) | |
| tree | 9b0a07bc981d59df701e889ecb09572cbd219857 | |
| parent | 313a123e1fca8827bb463db1f4bb211309764563 (diff) | |
rds: tcp: unregister sysctl before tearing down listen socket
rds_tcp_exit_net() frees the per-netns RDS TCP listen socket via
rds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since
rds_tcp_skbuf_handler() derives the netns from
rtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with
netns teardown and dereference the freed socket/sk.
KASAN reports the race as:
BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0
rds_tcp_skbuf_handler net/rds/tcp.c:721
proc_sys_call_handler fs/proc/proc_sysctl.c
vfs_write fs/read_write.c
__x64_sys_pwrite64 fs/read_write.c
Fix this by unregistering the RDS TCP sysctl table before calling
rds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl
handlers from starting and waits for in-flight handlers to finish, so
the listen socket can then be released safely. The fix was tested
against the linked reproducer.
Fixes: 7f5611cbc487 ("rds: sysctl: rds_tcp_{rcv,snd}buf: avoid using current->nsproxy")
Reported-by: AutonomousCodeSecurity@microsoft.com
Link: https://lore.kernel.org/all/20260719203718.9680-1-blbllhy@gmail.com
Reviewed-by: Allison Henderson <achender@kernel.org>
Signed-off-by: Cen Zhang (Microsoft) <blbllhy@gmail.com>
Link: https://patch.msgid.link/20260719210357.10179-1-blbllhy@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/rds/tcp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/rds/tcp.c b/net/rds/tcp.c index 955d92277d5a..5de35d556f29 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -657,13 +657,13 @@ static void __net_exit rds_tcp_exit_net(struct net *net) { struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid); - rds_tcp_kill_sock(net); - if (rtn->rds_tcp_sysctl) unregister_net_sysctl_table(rtn->rds_tcp_sysctl); if (net != &init_net) kfree(rtn->ctl_table); + + rds_tcp_kill_sock(net); } static struct pernet_operations rds_tcp_net_ops = { |