net/bpfilter: Initialize pos in __bpfilter_process_sockopt
__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 now verified the
position, which can lead to a failure depending on the exact stack
initialization pattern. Initialize the variable to zero to make
rw_verify_area happy.
Fixes: 6955a76fbc
("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>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Rodrigo Madera <rodrigo.madera@gmail.com>
Tested-by: Christian Brauner <christian.brauner@ubuntu.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/bpf/20200730160900.187157-1-hch@lst.de
This commit is contained in:
parent
0ba5834841
commit
4f010246b4
|
@ -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;
|
||||
|
||||
|
|
Loading…
Reference in New Issue