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From: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
To: Matthew Sakai <msakai@redhat.com>, dm-devel@lists.linux.dev,
        Mike Snitzer <snitzer@kernel.org>, Ken Raeburn <raeburn@redhat.com>,
        Chung Chung <cchung@redhat.com>, Thomas Jaskiewicz <tom@jaskiewicz.us>,
        Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>,
        John Wiele <jwiele@redhat.com>,
        "J. corwin Coburn" <corwin@hurlbutnet.net>,
        linux-kernel@vger.kernel.org
Cc: kernel-janitors@vger.kernel.org, dan.carpenter@linaro.org
Subject: [PATCH] dm vdo: Fix a use-after-free in load_index_save()
Date: Mon, 26 Feb 2024 06:41:35 -0800
Message-ID: <20240226144155.2101066-1-harshit.m.mogalapalli@oracle.com>
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Smatch warns:
	drivers/md/dm-vdo/indexer/index-layout.c:1570
	load_index_save() warn: 'table' was already freed.

Store the error value in result and then free the table before
returning.

Fixes: b46d79bdb82a ("dm vdo: add deduplication index storage interface")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis and only compile tested.
---
 drivers/md/dm-vdo/indexer/index-layout.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-vdo/indexer/index-layout.c b/drivers/md/dm-vdo/indexer/index-layout.c
index 1453fddaa656..18fac999e3e4 100644
--- a/drivers/md/dm-vdo/indexer/index-layout.c
+++ b/drivers/md/dm-vdo/indexer/index-layout.c
@@ -1566,10 +1566,11 @@ static int __must_check load_index_save(struct index_save_layout *isl,
 
 
 	if (table->header.type != RH_TYPE_SAVE) {
+		result = vdo_log_error_strerror(UDS_CORRUPT_DATA,
+						"unexpected index save %u header type %u",
+						instance, table->header.type);
 		vdo_free(table);
-		return vdo_log_error_strerror(UDS_CORRUPT_DATA,
-					      "unexpected index save %u header type %u",
-					      instance, table->header.type);
+		return result;
 	}
 
 	result = read_index_save_data(reader, isl, table->header.payload);
-- 
2.39.3