autofs4: check dev ioctl size before allocating

commit e53d77eb8b upstream.

There wasn't any check of the size passed from userspace before trying
to allocate the memory required.

This meant that userspace might request more space than allowed,
triggering an OOM.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
This commit is contained in:
Sasha Levin 2014-04-08 16:04:11 -07:00 committed by Zefan Li
parent 4dd86a6aea
commit a5822a0847

View file

@ -103,6 +103,9 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
if (tmp.size < sizeof(tmp))
return ERR_PTR(-EINVAL);
if (tmp.size > (PATH_MAX + sizeof(tmp)))
return ERR_PTR(-ENAMETOOLONG);
res = memdup_user(in, tmp.size);
if (!IS_ERR(res))
res->size = tmp.size;