linux-kernel - [PATCH] bcachefs: fix uninitialised-access bug in bch2_alloc_sectors_start

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250528190610.50604-1-qasdev00@gmail.com>
Date: Wed, 28 May 2025 20:06:10 +0100
From: Qasim Ijaz <qasdev00@...il.com>
To: kent.overstreet@...ux.dev
Cc: linux-bcachefs@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] bcachefs: fix uninitialised-access bug in bch2_alloc_sectors_start_trans

During bch2_alloc_sectors_start_trans() if bch2_trans_relock() fails
the code jumps to label "err", skipping "cl" initialisation. Once at
the "err" label "cl" could potentially be accessed leading to a uinit
access.

Fix this by moving "cl" initialisation before bch2_trans_relock().

Fixes: c2e7fa88544d ("bcachefs: Use a loop for open_bucket_add_buckets() retries")
Signed-off-by: Qasim Ijaz <qasdev00@...il.com>
---
 fs/bcachefs/alloc_foreground.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index 1410a4afb36a..ccd51bcbcec5 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -1277,6 +1277,11 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 
 	req->data_type		= req->wp->data_type;
 
+	/* If we're going to fall back to the whole fs, try nonblocking first */
+	struct closure *cl = req->target && !(flags & BCH_WRITE_only_specified_devs)
+		? _cl
+		: NULL;
+
 	ret = bch2_trans_relock(trans);
 	if (ret)
 		goto err;
@@ -1285,10 +1290,6 @@ int bch2_alloc_sectors_start_trans(struct btree_trans *trans,
 	if (req->data_type != BCH_DATA_user)
 		req->have_cache = true;
 
-	/* If we're going to fall back to the whole fs, try nonblocking first */
-	struct closure *cl = req->target && !(flags & BCH_WRITE_only_specified_devs)
-		? _cl
-		: NULL;
 	while (1) {
 		ret = open_bucket_add_buckets(trans, req, cl);
 		if (!ret ||
-- 
2.39.5