From: Zhen Lei <thunder.leizhen@huawei.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Subject: [PATCH 1/2] pipe: fix potential use-after-free in pipe_read()
Date: Mon, 15 Nov 2021 11:57:20 +0800 [thread overview]
Message-ID: <20211115035721.1909-2-thunder.leizhen@huawei.com> (raw)
In-Reply-To: <20211115035721.1909-1-thunder.leizhen@huawei.com>
Accessing buf->flags after pipe_buf_release(pipe, buf) is unsafe, because
the 'buf' memory maybe freed.
Fixes: e7d553d69cf6 ("pipe: Add notification lossage handling")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
---
fs/pipe.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/pipe.c b/fs/pipe.c
index 6d4342bad9f15b2..302f1e50ce3be1d 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -319,10 +319,12 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
}
if (!buf->len) {
+ unsigned int __maybe_unused flags = buf->flags;
+
pipe_buf_release(pipe, buf);
spin_lock_irq(&pipe->rd_wait.lock);
#ifdef CONFIG_WATCH_QUEUE
- if (buf->flags & PIPE_BUF_FLAG_LOSS)
+ if (flags & PIPE_BUF_FLAG_LOSS)
pipe->note_loss = true;
#endif
tail++;
--
2.26.0.106.g9fadedd
next prev parent reply other threads:[~2021-11-15 3:58 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-15 3:57 [PATCH 0/2] pipe: Fix a potential UAF and delete a duplicate line of code Zhen Lei
2021-11-15 3:57 ` Zhen Lei [this message]
2021-11-15 4:25 ` [PATCH 1/2] pipe: fix potential use-after-free in pipe_read() Matthew Wilcox
2021-11-15 6:13 ` Leizhen (ThunderTown)
2021-11-15 13:05 ` Matthew Wilcox
2021-11-23 1:09 ` Leizhen (ThunderTown)
2021-11-15 3:57 ` [PATCH 2/2] pipe: delete a duplicate line of code in pipe_write() Zhen Lei
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