From: John Fastabend <john.fastabend@gmail.com>
To: Pengcheng Yang <yangpc@wangsu.com>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Sitnicki <jakub@cloudflare.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org
Cc: Pengcheng Yang <yangpc@wangsu.com>
Subject: RE: [PATCH bpf 1/4] bpf, sockmap: Fix repeated calls to sock_put() when msg has more_data
Date: Mon, 21 Nov 2022 18:16:45 -0800 [thread overview]
Message-ID: <637c310d61447_18ed9208e5@john.notmuch> (raw)
In-Reply-To: <1668598161-15455-2-git-send-email-yangpc@wangsu.com>
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>
I'll wait for the resend with all the patches but for this one.
Acked-by: John Fastabend <john.fastabend@gmail.com>
prev parent reply other threads:[~2022-11-22 2:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-16 11:29 [PATCH bpf 0/4] bpf, sockmap: Fix some issues with using apply_bytes Pengcheng Yang
2022-11-16 11:29 ` [PATCH bpf 2/4] bpf, sockmap: Fix missing BPF_F_INGRESS flag when " Pengcheng Yang
2022-11-16 11:29 ` [PATCH bpf 4/4] selftests/bpf: Add ingress tests for txmsg with apply_bytes Pengcheng Yang
2022-11-21 9:35 ` [PATCH bpf 0/4] bpf, sockmap: Fix some issues with using apply_bytes Jakub Sitnicki
2022-11-21 16:38 ` Daniel Borkmann
[not found] ` <1668598161-15455-2-git-send-email-yangpc@wangsu.com>
2022-11-22 2:16 ` John Fastabend [this message]
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