This is a note to let you know that I've just added the patch titled
binder: check offset alignment in binder_get_object()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
binder-check-offset-alignment-in-binder_get_object.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From aaef73821a3b0194a01bd23ca77774f704a04d40 Mon Sep 17 00:00:00 2001
From: Carlos Llamas <cmllamas@xxxxxxxxxx>
Date: Sat, 30 Mar 2024 19:01:14 +0000
Subject: binder: check offset alignment in binder_get_object()
From: Carlos Llamas <cmllamas@xxxxxxxxxx>
commit aaef73821a3b0194a01bd23ca77774f704a04d40 upstream.
Commit 6d98eb95b450 ("binder: avoid potential data leakage when copying
txn") introduced changes to how binder objects are copied. In doing so,
it unintentionally removed an offset alignment check done through calls
to binder_alloc_copy_from_buffer() -> check_buffer().
These calls were replaced in binder_get_object() with copy_from_user(),
so now an explicit offset alignment check is needed here. This avoids
later complications when unwinding the objects gets harder.
It is worth noting this check existed prior to commit 7a67a39320df
("binder: add function to copy binder object from buffer"), likely
removed due to redundancy at the time.
Fixes: 6d98eb95b450 ("binder: avoid potential data leakage when copying txn")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Acked-by: Todd Kjos <tkjos@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240330190115.1877819-1-cmllamas@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/android/binder.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2047,8 +2047,10 @@ static size_t binder_get_object(struct b
size_t object_size = 0;
read_size = min_t(size_t, sizeof(*object), buffer->data_size - offset);
- if (offset > buffer->data_size || read_size < sizeof(*hdr))
+ if (offset > buffer->data_size || read_size < sizeof(*hdr) ||
+ !IS_ALIGNED(offset, sizeof(u32)))
return 0;
+
if (u) {
if (copy_from_user(object, u + offset, read_size))
return 0;
Patches currently in stable-queue which might be from cmllamas@xxxxxxxxxx are
queue-5.4/binder-check-offset-alignment-in-binder_get_object.patch
