FROMGIT: binder: fix BUG_ON found by selinux-testsuite

The selinux-testsuite found an issue resulting in a BUG_ON()
where a conditional relied on a size_t going negative when
checking the validity of a buffer offset.

(cherry picked from commit 5997da82145bb7c9a56d834894cb81f81f219344
 git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
 char-misc-linus)
Bug: 67668716
Bug: 129349786
Change-Id: Ib3b408717141deadddcb6b95ad98c0b97d9d98ea
Fixes: 7a67a39320df ("binder: add function to copy binder object from buffer")
Reported-by: Paul Moore <paul@paul-moore.com>
Tested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
This commit is contained in:
Todd Kjos 2019-03-19 09:53:01 -07:00
commit c8ddc8cc40

View file

@ -2240,7 +2240,8 @@ static size_t binder_get_object(struct binder_proc *proc,
size_t object_size = 0;
read_size = min_t(size_t, sizeof(*object), buffer->data_size - offset);
if (read_size < sizeof(*hdr) || !IS_ALIGNED(offset, sizeof(u32)))
if (offset > buffer->data_size || read_size < sizeof(*hdr) ||
!IS_ALIGNED(offset, sizeof(u32)))
return 0;
binder_alloc_copy_from_buffer(&proc->alloc, object, buffer,
offset, read_size);