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From:   Matthias Kaehlcke <mka@chromium.org>
To:     Alasdair Kergon <agk@redhat.com>,
        Mike Snitzer <snitzer@kernel.org>,
        Kees Cook <keescook@chromium.org>
Cc:     dm-devel@redhat.com, linux-kernel@vger.kernel.org,
        Matthias Kaehlcke <mka@chromium.org>, stable@vger.kernel.org
Subject: [PATCH] dm: verity-loadpin: Add NULL pointer check for 'bdev' parameter
Date:   Tue, 27 Jun 2023 20:28:01 +0000
Message-ID: <20230627202800.1.Id63f7f59536d20f1ab83e1abdc1fda1471c7d031@changeid>
MIME-Version: 1.0
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Add a NULL check for the 'bdev' parameter of
dm_verity_loadpin_is_bdev_trusted(). The function is called
by loadpin_check(), which passes the block device that
corresponds to the super block of the file system from which
a file is being loaded. Generally a super_block structure has
an associated block device, however that is not always the
case (e.g. tmpfs).

Cc: stable@vger.kernel.org # v6.0+
Fixes: b6c1c5745ccc ("dm: Add verity helpers for LoadPin")
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/md/dm-verity-loadpin.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/md/dm-verity-loadpin.c b/drivers/md/dm-verity-loadpin.c
index 4f78cc55c251..0666699b6858 100644
--- a/drivers/md/dm-verity-loadpin.c
+++ b/drivers/md/dm-verity-loadpin.c
@@ -58,6 +58,9 @@ bool dm_verity_loadpin_is_bdev_trusted(struct block_device *bdev)
 	int srcu_idx;
 	bool trusted = false;
 
+	if (bdev == NULL)
+		return false;
+
 	if (list_empty(&dm_verity_loadpin_trusted_root_digests))
 		return false;
 
-- 
2.41.0.255.g8b1d071c50-goog