| Message ID | 20200605084625.9783-1-anny.hu@linux.alibaba.com |
|---|---|
| State | Accepted |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg | expand |
dihu wrote: > When user application calls read() with MSG_PEEK flag to read data > of bpf sockmap socket, kernel panic happens at > __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg > queue after read out under MSG_PEEK flag is set. Because it's not > judged whether sk_msg is the last msg of ingress_msg queue, the next > sk_msg may be the head of ingress_msg queue, whose memory address of > sg page is invalid. So it's necessary to add check codes to prevent > this problem. > > [20759.125457] BUG: kernel NULL pointer dereference, address: > 0000000000000008 > [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G E > 5.4.32 #1 > [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS > 4.1.12 06/18/2017 > [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 > [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 > [20759.276099] tcp_bpf_recvmsg+0x113/0x370 > [20759.281137] inet_recvmsg+0x55/0xc0 > [20759.285734] __sys_recvfrom+0xc8/0x130 > [20759.290566] ? __audit_syscall_entry+0x103/0x130 > [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 > [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 > [20759.307235] __x64_sys_recvfrom+0x24/0x30 > [20759.312226] do_syscall_64+0x55/0x1b0 > [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Signed-off-by: dihu <anny.hu@linux.alibaba.com> > --- > net/ipv4/tcp_bpf.c | 3 +++ > 1 file changed, 3 insertions(+) > Thanks, looks good to me. Acked-by: John Fastabend <john.fastabend@gmail.com>
On Fri, Jun 05, 2020 at 10:46 AM CEST, dihu wrote: > When user application calls read() with MSG_PEEK flag to read data > of bpf sockmap socket, kernel panic happens at > __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg > queue after read out under MSG_PEEK flag is set. Because it's not > judged whether sk_msg is the last msg of ingress_msg queue, the next > sk_msg may be the head of ingress_msg queue, whose memory address of > sg page is invalid. So it's necessary to add check codes to prevent > this problem. > > [20759.125457] BUG: kernel NULL pointer dereference, address: > 0000000000000008 > [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G E > 5.4.32 #1 > [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS > 4.1.12 06/18/2017 > [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 > [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 > [20759.276099] tcp_bpf_recvmsg+0x113/0x370 > [20759.281137] inet_recvmsg+0x55/0xc0 > [20759.285734] __sys_recvfrom+0xc8/0x130 > [20759.290566] ? __audit_syscall_entry+0x103/0x130 > [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 > [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 > [20759.307235] __x64_sys_recvfrom+0x24/0x30 > [20759.312226] do_syscall_64+0x55/0x1b0 > [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Signed-off-by: dihu <anny.hu@linux.alibaba.com> > --- > net/ipv4/tcp_bpf.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c > index 5a05327..b82e4c3 100644 > --- a/net/ipv4/tcp_bpf.c > +++ b/net/ipv4/tcp_bpf.c > @@ -64,6 +64,9 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, > } while (i != msg_rx->sg.end); > > if (unlikely(peek)) { > + if (msg_rx == list_last_entry(&psock->ingress_msg, > + struct sk_msg, list)) > + break; > msg_rx = list_next_entry(msg_rx, list); > continue; > } Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
On Tue, Jun 9, 2020 at 2:04 AM Jakub Sitnicki <jakub@cloudflare.com> wrote: > > On Fri, Jun 05, 2020 at 10:46 AM CEST, dihu wrote: > > When user application calls read() with MSG_PEEK flag to read data > > of bpf sockmap socket, kernel panic happens at > > __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg > > queue after read out under MSG_PEEK flag is set. Because it's not > > judged whether sk_msg is the last msg of ingress_msg queue, the next > > sk_msg may be the head of ingress_msg queue, whose memory address of > > sg page is invalid. So it's necessary to add check codes to prevent > > this problem. > > > > [20759.125457] BUG: kernel NULL pointer dereference, address: > > 0000000000000008 > > [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G E > > 5.4.32 #1 > > [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS > > 4.1.12 06/18/2017 > > [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 > > [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 > > [20759.276099] tcp_bpf_recvmsg+0x113/0x370 > > [20759.281137] inet_recvmsg+0x55/0xc0 > > [20759.285734] __sys_recvfrom+0xc8/0x130 > > [20759.290566] ? __audit_syscall_entry+0x103/0x130 > > [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 > > [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 > > [20759.307235] __x64_sys_recvfrom+0x24/0x30 > > [20759.312226] do_syscall_64+0x55/0x1b0 > > [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > > > Signed-off-by: dihu <anny.hu@linux.alibaba.com> > > --- > > net/ipv4/tcp_bpf.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c > > index 5a05327..b82e4c3 100644 > > --- a/net/ipv4/tcp_bpf.c > > +++ b/net/ipv4/tcp_bpf.c > > @@ -64,6 +64,9 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, > > } while (i != msg_rx->sg.end); > > > > if (unlikely(peek)) { > > + if (msg_rx == list_last_entry(&psock->ingress_msg, > > + struct sk_msg, list)) > > + break; > > msg_rx = list_next_entry(msg_rx, list); > > continue; > > } > > Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Applied. Thanks
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 5a05327..b82e4c3 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -64,6 +64,9 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, } while (i != msg_rx->sg.end); if (unlikely(peek)) { + if (msg_rx == list_last_entry(&psock->ingress_msg, + struct sk_msg, list)) + break; msg_rx = list_next_entry(msg_rx, list); continue; }
When user application calls read() with MSG_PEEK flag to read data of bpf sockmap socket, kernel panic happens at __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg queue after read out under MSG_PEEK flag is set. Because it's not judged whether sk_msg is the last msg of ingress_msg queue, the next sk_msg may be the head of ingress_msg queue, whose memory address of sg page is invalid. So it's necessary to add check codes to prevent this problem. [20759.125457] BUG: kernel NULL pointer dereference, address: 0000000000000008 [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G E 5.4.32 #1 [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS 4.1.12 06/18/2017 [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 [20759.276099] tcp_bpf_recvmsg+0x113/0x370 [20759.281137] inet_recvmsg+0x55/0xc0 [20759.285734] __sys_recvfrom+0xc8/0x130 [20759.290566] ? __audit_syscall_entry+0x103/0x130 [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 [20759.307235] __x64_sys_recvfrom+0x24/0x30 [20759.312226] do_syscall_64+0x55/0x1b0 [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: dihu <anny.hu@linux.alibaba.com> --- net/ipv4/tcp_bpf.c | 3 +++ 1 file changed, 3 insertions(+)