2019-02-15 02:23:20

by Todd Kjos

Subject: [PATCH] binder: fix handling of misaligned binder object

Fixes crash found by syzbot:
kernel BUG at drivers/android/binder_alloc.c:LINE! (2)

Reported-by: [email protected]
Signed-off-by: Todd Kjos <[email protected]>
---
Applies to linux-next

drivers/android/binder.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 2dba539eb792c..8685882da64cd 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2057,7 +2057,7 @@ 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))
+ if (read_size < sizeof(*hdr) || !IS_ALIGNED(offset, sizeof(u32)))
return 0;
binder_alloc_copy_from_buffer(&proc->alloc, object, buffer,
offset, read_size);
--
2.21.0.rc0.258.g878e2cd30e-goog

2019-02-15 15:33:23

by Greg Kroah-Hartman

Subject: Re: [PATCH] binder: fix handling of misaligned binder object

On Thu, Feb 14, 2019 at 03:22:57PM -0800, Todd Kjos wrote:
> Fixes crash found by syzbot:
> kernel BUG at drivers/android/binder_alloc.c:LINE! (2)
>
> Reported-by: [email protected]

As the bot asked, this should be:
Reported-and-tested-by: [email protected]

I'll go fix that up...

thanks,

greg k-h