From: Alessandro Astone <[email protected]>
commit ef38de9217a04c9077629a24652689d8fdb4c6c6 upstream.
Some android userspace is sending BINDER_TYPE_FDA objects with
num_fds=0. Like the previous patch, this is reproducible when
playing a video.
Before commit 09184ae9b575 BINDER_TYPE_FDA objects with num_fds=0
were 'correctly handled', as in no fixup was performed.
After commit 09184ae9b575 we aggregate fixup and skip regions in
binder_ptr_fixup structs and distinguish between the two by using
the skip_size field: if it's 0, then it's a fixup, otherwise skip.
When processing BINDER_TYPE_FDA objects with num_fds=0 we add a
skip region of skip_size=0, and this causes issues because now
binder_do_deferred_txn_copies will think this was a fixup region.
To address that, return early from binder_translate_fd_array to
avoid adding an empty skip region.
Fixes: 09184ae9b575 ("binder: defer copies of pre-patched txn data")
Acked-by: Todd Kjos <[email protected]>
Cc: stable <[email protected]>
Signed-off-by: Alessandro Astone <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Carlos Llamas <[email protected]>
---
drivers/android/binder.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 1ba8a98094b4..4473adef2f5a 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2891,6 +2891,9 @@ static int binder_translate_fd_array(struct list_head *pf_head,
struct binder_proc *proc = thread->proc;
int ret;
+ if (fda->num_fds == 0)
+ return 0;
+
fd_buf_size = sizeof(u32) * fda->num_fds;
if (fda->num_fds >= SIZE_MAX / sizeof(u32)) {
binder_user_error("%d:%d got transaction with invalid number of fds (%lld)\n",
--
2.38.1.584.g0f3c55d4c2-goog