This is a note to let you know that I've just added the patch titled
binder: Address corner cases in deferred copy and fixup
to the 5.4-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-address-corner-cases-in-deferred-copy-and-fixup.patch
and it can be found in the queue-5.4 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 05:32:15 PM CET 2022
From: Carlos Llamas <cmllamas@xxxxxxxxxx>
Date: Wed, 30 Nov 2022 03:58:04 +0000
Subject: binder: Address corner cases in deferred copy and fixup
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: <20221130035805.1823970-6-cmllamas@xxxxxxxxxx>
From: Alessandro Astone <ales.astone@xxxxxxxxx>
commit 2d1746e3fda0c3612143d7c06f8e1d1830c13e23 upstream.
When handling BINDER_TYPE_FDA object we are pushing a parent fixup
with a certain skip_size but no scatter-gather copy object, since
the copy is handled standalone.
If BINDER_TYPE_FDA is the last children the scatter-gather copy
loop will never stop to skip it, thus we are left with an item in
the parent fixup list. This will trigger the BUG_ON().
This is reproducible in android when playing a video.
We receive a transaction that looks like this:
obj[0] BINDER_TYPE_PTR, parent
obj[1] BINDER_TYPE_PTR, child
obj[2] BINDER_TYPE_PTR, child
obj[3] BINDER_TYPE_FDA, child
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/20220415120015.52684-2-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 | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2698,6 +2698,7 @@ static int binder_do_deferred_txn_copies
{
int ret = 0;
struct binder_sg_copy *sgc, *tmpsgc;
+ struct binder_ptr_fixup *tmppf;
struct binder_ptr_fixup *pf =
list_first_entry_or_null(pf_head, struct binder_ptr_fixup,
node);
@@ -2752,7 +2753,11 @@ static int binder_do_deferred_txn_copies
list_del(&sgc->node);
kfree(sgc);
}
- BUG_ON(!list_empty(pf_head));
+ list_for_each_entry_safe(pf, tmppf, pf_head, node) {
+ BUG_ON(pf->skip_size == 0);
+ list_del(&pf->node);
+ kfree(pf);
+ }
BUG_ON(!list_empty(sgc_head));
return ret > 0 ? -EINVAL : ret;
Patches currently in stable-queue which might be from cmllamas@xxxxxxxxxx are
queue-5.4/binder-address-corner-cases-in-deferred-copy-and-fixup.patch
queue-5.4/binder-gracefully-handle-binder_type_fda-objects-with-num_fds-0.patch
queue-5.4/binder-read-pre-translated-fds-from-sender-buffer.patch
queue-5.4/binder-avoid-potential-data-leakage-when-copying-txn.patch
queue-5.4/binder-fix-pointer-cast-warning.patch
queue-5.4/binder-defer-copies-of-pre-patched-txn-data.patch
