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From: Todd Kjos <tkjos@google.com>
To: tkjos@google.com, gregkh@linuxfoundation.org,
	christian@brauner.io, arve@android.com,
	devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
	maco@google.com
Cc: joel@joelfernandes.org, kernel-team@android.com,
	avakj45@gmail.com, Dan Carpenter <dan.carpenter@oracle.com>
Subject: [PATCH v2 1/4] binder: fix handling of error during copy
Date: Tue, 30 Nov 2021 10:51:49 -0800	[thread overview]
Message-ID: <20211130185152.437403-2-tkjos@google.com> (raw)
In-Reply-To: <20211130185152.437403-1-tkjos@google.com>

If a memory copy function fails to copy the whole buffer,
a positive integar with the remaining bytes is returned.
In binder_translate_fd_array() this can result in an fd being
skipped due to the failed copy, but the loop continues
processing fds since the early return condition expects a
negative integer on error.

Fix by returning "ret > 0 ? -EINVAL : ret" to handle this case.

Fixes: bb4a2e48d510 ("binder: return errors from buffer copy functions")
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Todd Kjos <tkjos@google.com>
---
v2: Added this patch to fix bug noticed by Dan Carpenter

 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 49fb74196d02..984e6263dcc7 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2269,8 +2269,8 @@ static int binder_translate_fd_array(struct binder_fd_array_object *fda,
 		if (!ret)
 			ret = binder_translate_fd(fd, offset, t, thread,
 						  in_reply_to);
-		if (ret < 0)
-			return ret;
+		if (ret)
+			return ret > 0 ? -EINVAL : ret;
 	}
 	return 0;
 }
-- 
2.34.0.rc2.393.gf8c9666880-goog


  reply	other threads:[~2021-11-30 18:52 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-30 18:51 [PATCH v2 0/4] binder: Prevent untranslated sender data from being copied to target Todd Kjos
2021-11-30 18:51 ` Todd Kjos [this message]
2021-12-01 13:49   ` [PATCH v2 1/4] binder: fix handling of error during copy Christian Brauner
2021-11-30 18:51 ` [PATCH v2 2/4] binder: avoid potential data leakage when copying txn Todd Kjos
2021-12-01 13:54   ` Christian Brauner
2021-11-30 18:51 ` [PATCH v2 3/4] binder: read pre-translated fds from sender buffer Todd Kjos
2021-12-01 13:58   ` Christian Brauner
2021-11-30 18:51 ` [PATCH v2 4/4] binder: defer copies of pre-patched txn data Todd Kjos
2021-12-01  6:13 ` [PATCH v2 0/4] binder: Prevent untranslated sender data from being copied to target Dan Carpenter

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