| Message ID | 1669082309-2546-2-git-send-email-yangpc@wangsu.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | bpf, sockmap: Fix some issues with using apply_bytes | expand |
Pengcheng Yang wrote: > In tcp_bpf_send_verdict() redirection, the eval variable is assigned to > __SK_REDIRECT after the apply_bytes data is sent, if msg has more_data, > sock_put() will be called multiple times. > We should reset the eval variable to __SK_NONE every time more_data > starts. > > This causes: > > IPv4: Attempt to release TCP socket in state 1 00000000b4c925d7 > ------------[ cut here ]------------ > refcount_t: addition on 0; use-after-free. > WARNING: CPU: 5 PID: 4482 at lib/refcount.c:25 refcount_warn_saturate+0x7d/0x110 > Modules linked in: > CPU: 5 PID: 4482 Comm: sockhash_bypass Kdump: loaded Not tainted 6.0.0 #1 > Hardware name: Red Hat KVM, BIOS 1.11.0-2.el7 04/01/2014 > Call Trace: > <TASK> > __tcp_transmit_skb+0xa1b/0xb90 > ? __alloc_skb+0x8c/0x1a0 > ? __kmalloc_node_track_caller+0x184/0x320 > tcp_write_xmit+0x22a/0x1110 > __tcp_push_pending_frames+0x32/0xf0 > do_tcp_sendpages+0x62d/0x640 > tcp_bpf_push+0xae/0x2c0 > tcp_bpf_sendmsg_redir+0x260/0x410 > ? preempt_count_add+0x70/0xa0 > tcp_bpf_send_verdict+0x386/0x4b0 > tcp_bpf_sendmsg+0x21b/0x3b0 > sock_sendmsg+0x58/0x70 > __sys_sendto+0xfa/0x170 > ? xfd_validate_state+0x1d/0x80 > ? switch_fpu_return+0x59/0xe0 > __x64_sys_sendto+0x24/0x30 > do_syscall_64+0x37/0x90 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > Fixes: cd9733f5d75c ("tcp_bpf: Fix one concurrency problem in the tcp_bpf_send_verdict function") > Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> Thanks. Acked-by: John Fastabend <john.fastabend@gmail.com>
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index f8b12b9..ef5de4f 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -279,7 +279,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, bool cork = false, enospc = sk_msg_full(msg); struct sock *sk_redir; u32 tosend, origsize, sent, delta = 0; - u32 eval = __SK_NONE; + u32 eval; int ret; more_data: @@ -310,6 +310,7 @@ static int tcp_bpf_send_verdict(struct sock *sk, struct sk_psock *psock, tosend = msg->sg.size; if (psock->apply_bytes && psock->apply_bytes < tosend) tosend = psock->apply_bytes; + eval = __SK_NONE; switch (psock->eval) { case __SK_PASS:
In tcp_bpf_send_verdict() redirection, the eval variable is assigned to __SK_REDIRECT after the apply_bytes data is sent, if msg has more_data, sock_put() will be called multiple times. We should reset the eval variable to __SK_NONE every time more_data starts. This causes: IPv4: Attempt to release TCP socket in state 1 00000000b4c925d7 ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 5 PID: 4482 at lib/refcount.c:25 refcount_warn_saturate+0x7d/0x110 Modules linked in: CPU: 5 PID: 4482 Comm: sockhash_bypass Kdump: loaded Not tainted 6.0.0 #1 Hardware name: Red Hat KVM, BIOS 1.11.0-2.el7 04/01/2014 Call Trace: <TASK> __tcp_transmit_skb+0xa1b/0xb90 ? __alloc_skb+0x8c/0x1a0 ? __kmalloc_node_track_caller+0x184/0x320 tcp_write_xmit+0x22a/0x1110 __tcp_push_pending_frames+0x32/0xf0 do_tcp_sendpages+0x62d/0x640 tcp_bpf_push+0xae/0x2c0 tcp_bpf_sendmsg_redir+0x260/0x410 ? preempt_count_add+0x70/0xa0 tcp_bpf_send_verdict+0x386/0x4b0 tcp_bpf_sendmsg+0x21b/0x3b0 sock_sendmsg+0x58/0x70 __sys_sendto+0xfa/0x170 ? xfd_validate_state+0x1d/0x80 ? switch_fpu_return+0x59/0xe0 __x64_sys_sendto+0x24/0x30 do_syscall_64+0x37/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Fixes: cd9733f5d75c ("tcp_bpf: Fix one concurrency problem in the tcp_bpf_send_verdict function") Signed-off-by: Pengcheng Yang <yangpc@wangsu.com> --- net/ipv4/tcp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)