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| author | Alessandro Astone <ales.astone@gmail.com> | 2022-04-15 14:00:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-22 17:22:51 +0200 |
| commit | ef38de9217a04c9077629a24652689d8fdb4c6c6 (patch) | |
| tree | 238222878c25d6e32441102babbc9f60922e7842 | |
| parent | 2d1746e3fda0c3612143d7c06f8e1d1830c13e23 (diff) | |
| download | linux-ef38de9217a04c9077629a24652689d8fdb4c6c6.tar.bz2 | |
binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0
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 <tkjos@google.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Alessandro Astone <ales.astone@gmail.com>
Link: https://lore.kernel.org/r/20220415120015.52684-1-ales.astone@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/android/binder.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 31176edb1069..f3b639e89dd8 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2491,6 +2491,9 @@ 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", |