This is a note to let you know that I've just added the patch titled

binder: fix incorrect calculation for num_valid

to my char-misc git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From 16981742717b04644a41052570fb502682a315d2 Mon Sep 17 00:00:00 2001

From: Todd Kjos tkjos@android.com Date: Fri, 13 Dec 2019 12:25:31 -0800 Subject: binder: fix incorrect calculation for num_valid

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(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c index e9bc9fcc7ea5..b2dad43dbf82 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3310,7 +3310,7 @@ static void binder_transaction(struct binder_proc *proc, 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, @@ -3384,7 +3384,7 @@ static void binder_transaction(struct binder_proc *proc, 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,