PM / hibernate: Fix oops at snapshot_write()

syzbot is reporting NULL pointer dereference at snapshot_write() [1].
This is because data->handle is zero-cleared by ioctl(SNAPSHOT_FREE).
Fix this by checking data_of(data->handle) != NULL before using it.

[1] https://syzkaller.appspot.com/bug?id=828a3c71bd344a6de8b6a31233d51a72099f27fd

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: syzbot <syzbot+ae590932da6e45d6564d@syzkaller.appspotmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Tetsuo Handa 2018-05-26 09:59:36 +09:00 committed by Rafael J. Wysocki
parent 62fc00a661
commit fc14eebfc2

View File

@ -186,6 +186,11 @@ static ssize_t snapshot_write(struct file *filp, const char __user *buf,
res = PAGE_SIZE - pg_offp;
}
if (!data_of(data->handle)) {
res = -EINVAL;
goto unlock;
}
res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
buf, count);
if (res > 0)