This is a note to let you know that I've just added the patch titled
binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
binder-gracefully-handle-binder_type_fda-objects-with-num_fds-0.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Wed Nov 30 01:41:25 PM CET 2022
From: Carlos Llamas <cmllamas@xxxxxxxxxx>
Date: Wed, 30 Nov 2022 03:58:05 +0000
Subject: binder: Gracefully handle BINDER_TYPE_FDA objects with num_fds=0
To: stable@xxxxxxxxxx, "Greg Kroah-Hartman" <gregkh@xxxxxxxxxxxxxxxxxxx>, "Arve Hjønnevåg" <arve@xxxxxxxxxxx>, "Todd Kjos" <tkjos@xxxxxxxxxxx>, "Martijn Coenen" <maco@xxxxxxxxxxx>, "Joel Fernandes" <joel@xxxxxxxxxxxxxxxxx>, "Christian Brauner" <christian@xxxxxxxxxx>, "Hridya Valsaraju" <hridya@xxxxxxxxxx>, "Suren Baghdasaryan" <surenb@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx, kernel-team@xxxxxxxxxxx, Alessandro Astone <ales.astone@xxxxxxxxx>, Todd Kjos <tkjos@xxxxxxxxxx>, Carlos Llamas <cmllamas@xxxxxxxxxx>
Message-ID: <20221130035805.1823970-7-cmllamas@xxxxxxxxxx>
From: Alessandro Astone <ales.astone@xxxxxxxxx>
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 <tkjos@xxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
Signed-off-by: Alessandro Astone <ales.astone@xxxxxxxxx>
Link: https://lore.kernel.org/r/20220415120015.52684-1-ales.astone@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Carlos Llamas <cmllamas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/android/binder.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2891,6 +2891,9 @@ static int binder_translate_fd_array(str
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",
Patches currently in stable-queue which might be from cmllamas@xxxxxxxxxx are
queue-5.10/binder-address-corner-cases-in-deferred-copy-and-fixup.patch
queue-5.10/binder-gracefully-handle-binder_type_fda-objects-with-num_fds-0.patch
queue-5.10/binder-read-pre-translated-fds-from-sender-buffer.patch
queue-5.10/binder-avoid-potential-data-leakage-when-copying-txn.patch
queue-5.10/binder-fix-pointer-cast-warning.patch
queue-5.10/binder-defer-copies-of-pre-patched-txn-data.patch
