From: Todd Kjos tkjos@android.com
commit 16981742717b04644a41052570fb502682a315d2 upstream.
For BINDER_TYPE_PTR and BINDER_TYPE_FDA transactions, the num_valid local was calculated incorrectly causing the range check in binder_validate_ptr() to miss out-of-bounds offsets.
Fixes: bde4a19fc04f ("binder: use userspace pointer as base of buffer space") Signed-off-by: Todd Kjos tkjos@google.com Cc: stable stable@vger.kernel.org Link: https://lore.kernel.org/r/20191213202531.55010-1-tkjos@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/android/binder.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3314,7 +3314,7 @@ static void binder_transaction(struct bi binder_size_t parent_offset; struct binder_fd_array_object *fda = to_binder_fd_array_object(hdr); - size_t num_valid = (buffer_offset - off_start_offset) * + size_t num_valid = (buffer_offset - off_start_offset) / sizeof(binder_size_t); struct binder_buffer_object *parent = binder_validate_ptr(target_proc, t->buffer, @@ -3388,7 +3388,7 @@ static void binder_transaction(struct bi t->buffer->user_data + sg_buf_offset; sg_buf_offset += ALIGN(bp->length, sizeof(u64));
- num_valid = (buffer_offset - off_start_offset) * + num_valid = (buffer_offset - off_start_offset) / sizeof(binder_size_t); ret = binder_fixup_parent(t, thread, bp, off_start_offset,