bbb13adb07
commit 8999dc89497ab1c80d0718828e838c7cd5f6bffe upstream.
We should check null before do x25_neigh_put in x25_disconnect,
otherwise may cause null-ptr-deref like this:
#include <sys/socket.h>
#include <linux/x25.h>
int main() {
int sck_x25;
sck_x25 = socket(AF_X25, SOCK_SEQPACKET, 0);
close(sck_x25);
return 0;
}
BUG: kernel NULL pointer dereference, address: 00000000000000d8
CPU: 0 PID: 4817 Comm: t2 Not tainted 5.7.0-rc3+ #159
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-
RIP: 0010:x25_disconnect+0x91/0xe0
Call Trace:
x25_release+0x18a/0x1b0
__sock_release+0x3d/0xc0
sock_close+0x13/0x20
__fput+0x107/0x270
____fput+0x9/0x10
task_work_run+0x6d/0xb0
exit_to_usermode_loop+0x102/0x110
do_syscall_64+0x23c/0x260
entry_SYSCALL_64_after_hwframe+0x49/0xb3
Reported-by: syzbot+6db548b615e5aeefdce2@syzkaller.appspotmail.com
Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.