From: Christoph Hellwig <hch@lst.de>
To: davem@davemloft.net, kuba@kernel.org, ast@kernel.org,
daniel@iogearbox.net
Cc: netdev@vger.kernel.org, bpf@vger.kernel.org,
Christian Brauner <christian.brauner@ubuntu.com>,
Rodrigo Madera <rodrigo.madera@gmail.com>
Subject: [PATCH net] net/bpfilter: initialize pos in __bpfilter_process_sockopt
Date: Thu, 30 Jul 2020 18:09:00 +0200 [thread overview]
Message-ID: <20200730160900.187157-1-hch@lst.de> (raw)
__bpfilter_process_sockopt never initialized the pos variable passed to
the pipe write. This has been mostly harmless in the past as pipes
ignore the offset, but the switch to kernel_write no verified the
position, which can lead to a failure depending on the exact stack
initialization patter. Initialize the variable to zero to make
rw_verify_area happy.
Fixes: 6955a76fbcd5 ("bpfilter: switch to kernel_write")
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Reported-by: Rodrigo Madera <rodrigo.madera@gmail.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Rodrigo Madera <rodrigo.madera@gmail.com>
---
net/bpfilter/bpfilter_kern.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 1905e01c3aa9a7..4494ea6056cdb8 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -39,7 +39,7 @@ static int __bpfilter_process_sockopt(struct sock *sk, int optname,
{
struct mbox_request req;
struct mbox_reply reply;
- loff_t pos;
+ loff_t pos = 0;
ssize_t n;
int ret = -EFAULT;
--
2.27.0
next reply other threads:[~2020-07-30 16:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 16:09 Christoph Hellwig [this message]
2020-07-30 16:13 ` [PATCH net] net/bpfilter: initialize pos in __bpfilter_process_sockopt Christian Brauner
2020-07-31 0:07 ` Daniel Borkmann
2020-08-01 19:48 ` Alexei Starovoitov
2020-08-03 14:56 ` Daniel Borkmann
2020-08-03 15:36 ` Rodrigo Madera
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