* [PATCH stable,4.19 1/2] tcp: Clean up kernel listener's reqsk in inet_twsk_purge()
2024-04-29 12:32 [PATCH stable,4.19 0/2] introduce stop timer to solve the problem of CVE-2024-26865 Zhengchao Shao
@ 2024-04-29 12:32 ` Zhengchao Shao
2024-04-29 12:32 ` [PATCH stable,4.19 2/2] tcp: Fix NEW_SYN_RECV handling " Zhengchao Shao
1 sibling, 0 replies; 3+ messages in thread
From: Zhengchao Shao @ 2024-04-29 12:32 UTC (permalink / raw)
To: stable
Cc: netdev, gregkh, davem, kuznet, yoshfuji, kuba, edumazet, kuniyu,
weiyongjun1, yuehaibing, shaozhengchao
From: Kuniyuki Iwashima <kuniyu@amazon.com>
commit 740ea3c4a0b2e326b23d7cdf05472a0e92aa39bc upstream
Eric Dumazet reported a use-after-free related to the per-netns ehash
series. [0]
When we create a TCP socket from userspace, the socket always holds a
refcnt of the netns. This guarantees that a reqsk timer is always fired
before netns dismantle. Each reqsk has a refcnt of its listener, so the
listener is not freed before the reqsk, and the net is not freed before
the listener as well.
OTOH, when in-kernel users create a TCP socket, it might not hold a refcnt
of its netns. Thus, a reqsk timer can be fired after the netns dismantle
and access freed per-netns ehash.
To avoid the use-after-free, we need to clean up TCP_NEW_SYN_RECV sockets
in inet_twsk_purge() if the netns uses a per-netns ehash.
[0]: https://lore.kernel.org/netdev/CANn89iLXMup0dRD_Ov79Xt8N9FM0XdhCHEN05sf3eLwxKweM6w@mail.gmail.com/
BUG: KASAN: use-after-free in tcp_or_dccp_get_hashinfo
include/net/inet_hashtables.h:181 [inline]
BUG: KASAN: use-after-free in reqsk_queue_unlink+0x320/0x350
net/ipv4/inet_connection_sock.c:913
Read of size 8 at addr ffff88807545bd80 by task syz-executor.2/8301
CPU: 1 PID: 8301 Comm: syz-executor.2 Not tainted
6.0.0-syzkaller-02757-gaf7d23f9d96a #0
Hardware name: Google Google Compute Engine/Google Compute Engine,
BIOS Google 09/22/2022
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:317 [inline]
print_report.cold+0x2ba/0x719 mm/kasan/report.c:433
kasan_report+0xb1/0x1e0 mm/kasan/report.c:495
tcp_or_dccp_get_hashinfo include/net/inet_hashtables.h:181 [inline]
reqsk_queue_unlink+0x320/0x350 net/ipv4/inet_connection_sock.c:913
inet_csk_reqsk_queue_drop net/ipv4/inet_connection_sock.c:927 [inline]
inet_csk_reqsk_queue_drop_and_put net/ipv4/inet_connection_sock.c:939 [inline]
reqsk_timer_handler+0x724/0x1160 net/ipv4/inet_connection_sock.c:1053
call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474
expire_timers kernel/time/timer.c:1519 [inline]
__run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790
__run_timers kernel/time/timer.c:1768 [inline]
run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803
__do_softirq+0x1d0/0x9c8 kernel/softirq.c:571
invoke_softirq kernel/softirq.c:445 [inline]
__irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
irq_exit_rcu+0x5/0x20 kernel/softirq.c:662
sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1107
</IRQ>
Fixes: d1e5e6408b30 ("tcp: Introduce optional per-netns ehash.")
Reported-by: syzbot <syzkaller@googlegroups.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20221012145036.74960-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[shaozhengchao: resolved conflicts in 5.10]
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
---
net/ipv4/inet_timewait_sock.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 88c5069b5d20..0ab4e0e28baf 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -267,8 +267,21 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
rcu_read_lock();
restart:
sk_nulls_for_each_rcu(sk, node, &head->chain) {
- if (sk->sk_state != TCP_TIME_WAIT)
+ if (sk->sk_state != TCP_TIME_WAIT) {
+ /* A kernel listener socket might not hold refcnt for net,
+ * so reqsk_timer_handler() could be fired after net is
+ * freed. Userspace listener and reqsk never exist here.
+ */
+ if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV &&
+ hashinfo->pernet)) {
+ struct request_sock *req = inet_reqsk(sk);
+
+ inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req);
+ }
+
continue;
+ }
+
tw = inet_twsk(sk);
if ((tw->tw_family != family) ||
refcount_read(&twsk_net(tw)->count))
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH stable,4.19 2/2] tcp: Fix NEW_SYN_RECV handling in inet_twsk_purge()
2024-04-29 12:32 [PATCH stable,4.19 0/2] introduce stop timer to solve the problem of CVE-2024-26865 Zhengchao Shao
2024-04-29 12:32 ` [PATCH stable,4.19 1/2] tcp: Clean up kernel listener's reqsk in inet_twsk_purge() Zhengchao Shao
@ 2024-04-29 12:32 ` Zhengchao Shao
1 sibling, 0 replies; 3+ messages in thread
From: Zhengchao Shao @ 2024-04-29 12:32 UTC (permalink / raw)
To: stable
Cc: netdev, gregkh, davem, kuznet, yoshfuji, kuba, edumazet, kuniyu,
weiyongjun1, yuehaibing, shaozhengchao
From: Eric Dumazet <edumazet@google.com>
commit 1c4e97dd2d3c9a3e84f7e26346aa39bc426d3249 upstream
inet_twsk_purge() uses rcu to find TIME_WAIT and NEW_SYN_RECV
objects to purge.
These objects use SLAB_TYPESAFE_BY_RCU semantic and need special
care. We need to use refcount_inc_not_zero(&sk->sk_refcnt).
Reuse the existing correct logic I wrote for TIME_WAIT,
because both structures have common locations for
sk_state, sk_family, and netns pointer.
If after the refcount_inc_not_zero() the object fields longer match
the keys, use sock_gen_put(sk) to release the refcount.
Then we can call inet_twsk_deschedule_put() for TIME_WAIT,
inet_csk_reqsk_queue_drop_and_put() for NEW_SYN_RECV sockets,
with BH disabled.
Then we need to restart the loop because we had drop rcu_read_lock().
Fixes: 740ea3c4a0b2 ("tcp: Clean up kernel listener's reqsk in inet_twsk_purge()")
Link: https://lore.kernel.org/netdev/CANn89iLvFuuihCtt9PME2uS1WJATnf5fKjDToa1WzVnRzHnPfg@mail.gmail.com/T/#u
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240308200122.64357-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[shaozhengchao: resolved conflicts in 5.10]
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
---
net/ipv4/inet_timewait_sock.c | 41 ++++++++++++++++-------------------
1 file changed, 19 insertions(+), 22 deletions(-)
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 0ab4e0e28baf..fc01efef980a 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -253,12 +253,12 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
}
EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
+/* Remove all non full sockets (TIME_WAIT and NEW_SYN_RECV) for dead netns */
void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
{
- struct inet_timewait_sock *tw;
- struct sock *sk;
struct hlist_nulls_node *node;
unsigned int slot;
+ struct sock *sk;
for (slot = 0; slot <= hashinfo->ehash_mask; slot++) {
struct inet_ehash_bucket *head = &hashinfo->ehash[slot];
@@ -267,38 +267,35 @@ void inet_twsk_purge(struct inet_hashinfo *hashinfo, int family)
rcu_read_lock();
restart:
sk_nulls_for_each_rcu(sk, node, &head->chain) {
- if (sk->sk_state != TCP_TIME_WAIT) {
- /* A kernel listener socket might not hold refcnt for net,
- * so reqsk_timer_handler() could be fired after net is
- * freed. Userspace listener and reqsk never exist here.
- */
- if (unlikely(sk->sk_state == TCP_NEW_SYN_RECV &&
- hashinfo->pernet)) {
- struct request_sock *req = inet_reqsk(sk);
-
- inet_csk_reqsk_queue_drop_and_put(req->rsk_listener, req);
- }
+ int state = inet_sk_state_load(sk);
+ if ((1 << state) & ~(TCPF_TIME_WAIT |
+ TCPF_NEW_SYN_RECV))
continue;
- }
- tw = inet_twsk(sk);
- if ((tw->tw_family != family) ||
- refcount_read(&twsk_net(tw)->count))
+ if (sk->sk_family != family ||
+ refcount_read(&sock_net(sk)->count))
continue;
- if (unlikely(!refcount_inc_not_zero(&tw->tw_refcnt)))
+ if (unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
continue;
- if (unlikely((tw->tw_family != family) ||
- refcount_read(&twsk_net(tw)->count))) {
- inet_twsk_put(tw);
+ if (unlikely(sk->sk_family != family ||
+ refcount_read(&sock_net(sk)->count))) {
+ sock_gen_put(sk);
goto restart;
}
rcu_read_unlock();
local_bh_disable();
- inet_twsk_deschedule_put(tw);
+ if (state == TCP_TIME_WAIT) {
+ inet_twsk_deschedule_put(inet_twsk(sk));
+ } else {
+ struct request_sock *req = inet_reqsk(sk);
+
+ inet_csk_reqsk_queue_drop_and_put(req->rsk_listener,
+ req);
+ }
local_bh_enable();
goto restart_rcu;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread