On 2020/5/27 5:10, John Fastabend wrote:
dihu wrote:
From 865a45747de6b68fd02a0ff128a69a5c8feb73c3 Mon Sep 17 00:00:00 2001
From: dihu <anny.hu@xxxxxxxxxxxxxxxxx>
Date: Mon, 25 May 2020 17:23:16 +0800
Subject: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg
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@xxxxxxxxxxxxxxxxx>
---
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..c0d4624 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;
Thanks. Change looks good but spacing is a bit off . Can we
turn those spaces into tabs? Otherwise adding fixes tag and
my ack would be great.
Fixes: 02c558b2d5d67 ("bpf: sockmap, support for msg_peek in sk_msg with redirect ingress")
Acked-by: John Fastabend <john.fastabend@xxxxxxxxx>
From 127a334fa5e5d029353ceb1a0414886c527f4be5 Mon Sep 17 00:00:00 2001
From: dihu <anny.hu@xxxxxxxxxxxxxxxxx>
Date: Fri, 29 May 2020 16:38:50 +0800
Subject: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg
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@xxxxxxxxxxxxxxxxx>
---
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;
}
--
1.8.3.1
