6.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Carlos Llamas cmllamas@google.com
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@vger.kernel.org Signed-off-by: Carlos Llamas cmllamas@google.com Acked-by: Todd Kjos tkjos@google.com Link: https://lore.kernel.org/r/20240330190115.1877819-1-cmllamas@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/android/binder.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -1708,8 +1708,10 @@ 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;