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Subject: Re: [PATCH] net/tls: Fix sk_psock refcnt leak in
 bpf_exec_tx_verdict()
From:   David Miller <davem@davemloft.net>
In-Reply-To: <1587819277-38974-1-git-send-email-xiyuyang19@fudan.edu.cn>
References: <1587819277-38974-1-git-send-email-xiyuyang19@fudan.edu.cn>
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From: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Date: Sat, 25 Apr 2020 20:54:37 +0800

> bpf_exec_tx_verdict() invokes sk_psock_get(), which returns a reference
> of the specified sk_psock object to "psock" with increased refcnt.
> 
> When bpf_exec_tx_verdict() returns, local variable "psock" becomes
> invalid, so the refcount should be decreased to keep refcount balanced.
> 
> The reference counting issue happens in one exception handling path of
> bpf_exec_tx_verdict(). When "policy" equals to NULL but "psock" is not
> NULL, the function forgets to decrease the refcnt increased by
> sk_psock_get(), causing a refcnt leak.
> 
> Fix this issue by calling sk_psock_put() on this error path before
> bpf_exec_tx_verdict() returns.
> 
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>

Applied and queued up for -stable.