In blamed commit, TCP started to attach timewait sockets to
some skbs.
syzbot reported that selinux_ip_output() was not expecting them yet.
Note that using sk_to_full_sk() is still allowing the
following sk_listener() check to work as before.
BUG: KASAN: slab-out-of-bounds in selinux_sock security/selinux/include/objsec.h:207 [inline]
BUG: KASAN: slab-out-of-bounds in selinux_ip_output+0x1e0/0x1f0 security/selinux/hooks.c:5761
Read of size 8 at addr ffff88804e86e758 by task syz-executor347/5894
CPU: 0 UID: 0 PID: 5894 Comm: syz-executor347 Not tainted 6.12.0-syzkaller-05480-gfcc79e1714e8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/30/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
selinux_sock security/selinux/include/objsec.h:207 [inline]
selinux_ip_output+0x1e0/0x1f0 security/selinux/hooks.c:5761
nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]
nf_hook_slow+0xbb/0x200 net/netfilter/core.c:626
nf_hook+0x386/0x6d0 include/linux/netfilter.h:269
__ip_local_out+0x339/0x640 net/ipv4/ip_output.c:119
ip_local_out net/ipv4/ip_output.c:128 [inline]
ip_send_skb net/ipv4/ip_output.c:1505 [inline]
ip_push_pending_frames+0xa0/0x5b0 net/ipv4/ip_output.c:1525
ip_send_unicast_reply+0xd0e/0x1650 net/ipv4/ip_output.c:1672
tcp_v4_send_ack+0x976/0x13f0 net/ipv4/tcp_ipv4.c:1024
tcp_v4_timewait_ack net/ipv4/tcp_ipv4.c:1077 [inline]
tcp_v4_rcv+0x2f96/0x4390 net/ipv4/tcp_ipv4.c:2428
ip_protocol_deliver_rcu+0xba/0x4c0 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x316/0x570 net/ipv4/ip_input.c:233
NF_HOOK include/linux/netfilter.h:314 [inline]
NF_HOOK include/linux/netfilter.h:308 [inline]
ip_local_deliver+0x18e/0x1f0 net/ipv4/ip_input.c:254
dst_input include/net/dst.h:460 [inline]
ip_rcv_finish net/ipv4/ip_input.c:447 [inline]
NF_HOOK include/linux/netfilter.h:314 [inline]
NF_HOOK include/linux/netfilter.h:308 [inline]
ip_rcv+0x2c3/0x5d0 net/ipv4/ip_input.c:567
__netif_receive_skb_one_core+0x199/0x1e0 net/core/dev.c:5672
__netif_receive_skb+0x1d/0x160 net/core/dev.c:5785
process_backlog+0x443/0x15f0 net/core/dev.c:6117
__napi_poll.constprop.0+0xb7/0x550 net/core/dev.c:6877
napi_poll net/core/dev.c:6946 [inline]
net_rx_action+0xa94/0x1010 net/core/dev.c:7068
handle_softirqs+0x213/0x8f0 kernel/softirq.c:554
do_softirq kernel/softirq.c:455 [inline]
do_softirq+0xb2/0xf0 kernel/softirq.c:442
</IRQ>
<TASK>
__local_bh_enable_ip+0x100/0x120 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
__dev_queue_xmit+0x8af/0x43e0 net/core/dev.c:4461
dev_queue_xmit include/linux/netdevice.h:3168 [inline]
neigh_hh_output include/net/neighbour.h:523 [inline]
neigh_output include/net/neighbour.h:537 [inline]
ip_finish_output2+0xc6c/0x2150 net/ipv4/ip_output.c:236
__ip_finish_output net/ipv4/ip_output.c:314 [inline]
__ip_finish_output+0x49e/0x950 net/ipv4/ip_output.c:296
ip_finish_output+0x35/0x380 net/ipv4/ip_output.c:324
NF_HOOK_COND include/linux/netfilter.h:303 [inline]
ip_output+0x13b/0x2a0 net/ipv4/ip_output.c:434
dst_output include/net/dst.h:450 [inline]
ip_local_out+0x33e/0x4a0 net/ipv4/ip_output.c:130
__ip_queue_xmit+0x777/0x1970 net/ipv4/ip_output.c:536
__tcp_transmit_skb+0x2b39/0x3df0 net/ipv4/tcp_output.c:1466
tcp_transmit_skb net/ipv4/tcp_output.c:1484 [inline]
tcp_write_xmit+0x12b1/0x8560 net/ipv4/tcp_output.c:2827
__tcp_push_pending_frames+0xaf/0x390 net/ipv4/tcp_output.c:3010
tcp_send_fin+0x154/0xc70 net/ipv4/tcp_output.c:3616
__tcp_close+0x96b/0xff0 net/ipv4/tcp.c:3130
tcp_close+0x28/0x120 net/ipv4/tcp.c:3221
inet_release+0x13c/0x280 net/ipv4/af_inet.c:435
__sock_release net/socket.c:640 [inline]
sock_release+0x8e/0x1d0 net/socket.c:668
smc_clcsock_release+0xb7/0xe0 net/smc/smc_close.c:34
__smc_release+0x5c2/0x880 net/smc/af_smc.c:301
smc_release+0x1fc/0x5f0 net/smc/af_smc.c:344
__sock_release+0xb0/0x270 net/socket.c:640
sock_close+0x1c/0x30 net/socket.c:1408
__fput+0x3f8/0xb60 fs/file_table.c:450
__fput_sync+0xa1/0xc0 fs/file_table.c:535
__do_sys_close fs/open.c:1550 [inline]
__se_sys_close fs/open.c:1535 [inline]
__x64_sys_close+0x86/0x100 fs/open.c:1535
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6814c9ae10
Code: ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 80 3d b1 e2 07 00 00 74 17 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c
RSP: 002b:00007fffb2389758 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f6814c9ae10
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 00000000000f4240 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000202 R12: 00007fffb23897b0
R13: 00000000000141c3 R14: 00007fffb238977c R15: 00007fffb2389790
</TASK>
Fixes: 79636038d37e ("ipv4: tcp: give socket pointer to control skbs")
Reported-by: syzbot+2d9f5f948c31dcb7745e@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lore.kernel.org/lkml/6745e1a2.050a0220.1286eb.001c.GAE@xxxxxxxxxx/T/#u
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
---
Cc: Paul Moore <paul@xxxxxxxxxxxxxx>
Cc: Stephen Smalley <stephen.smalley.work@xxxxxxxxx>
Cc: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
Cc: selinux@xxxxxxxxxxxxxxx
Cc: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Cc: Brian Vazquez <brianvv@xxxxxxxxxx>
---
security/selinux/hooks.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index f5a08f94e09402b6b0b1538fae1a7a3f5af19fe6..366c87a40bd15707f6da4f25e8de4ddce3d281fc 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -5738,7 +5738,7 @@ static unsigned int selinux_ip_output(void *priv, struct sk_buff *skb,
/* we do this in the LOCAL_OUT path and not the POST_ROUTING path
* because we want to make sure we apply the necessary labeling
* before IPsec is applied so we can leverage AH protection */
- sk = skb->sk;
+ sk = sk_to_full_sk(skb->sk);
if (sk) {
struct sk_security_struct *sksec;
--
2.47.0.338.g60cca15819-goog
