Re: [PATCH net] net/bpfilter: initialize pos in __bpfilter_process_sockopt
From: Christian Brauner <hidden>
Date: 2020-07-30 16:13:12
Also in:
bpf
On Thu, Jul 30, 2020 at 06:09:00PM +0200, Christoph Hellwig wrote:
__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
s/no/now/
position, which can lead to a failure depending on the exact stack initialization patter. Initialize the variable to zero to make
s/patter/pattern/
rw_verify_area happy.
Fixes: 6955a76fbcd5 ("bpfilter: switch to kernel_write")
Reported-by: Christian Brauner <redacted>
Reported-by: Rodrigo Madera <redacted>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Rodrigo Madera <redacted>
---Thanks for tracking this down, Christoph! This fixes the logging issue for me. Tested-by: Christian Brauner <redacted> Reviewed-by: Christian Brauner <redacted>
quoted hunk ↗ jump to hunk
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