From 665ac314c3f16afd1f1ed247b96e9136452ddd9e Mon Sep 17 00:00:00 2001
From: Milan Broz <gmazyland@gmail.com>
Date: Sun, 4 Jun 2023 19:15:55 +0200
Subject: [PATCH] libblkid: jfs - avoid undefined shift

Fix previous commit 04a0717b0b0faa1a8078dc6fad05183b8bada395
to avoid undefined shift if value is exactly 32.

  libblkid/src/superblocks/jfs.c:46:39: runtime error:
  shift exponent 32 is too large for 32-bit type 'unsigned int'

Reproducer found with OSS-Fuzz (issue 59284) running over
cryptsetup project (blkid is used in header init).

Signed-off-by: Milan Broz <gmazyland@gmail.com>
---
 libblkid/src/superblocks/jfs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libblkid/src/superblocks/jfs.c b/libblkid/src/superblocks/jfs.c
index 3de8c2e..bf03b21 100644
--- a/libblkid/src/superblocks/jfs.c
+++ b/libblkid/src/superblocks/jfs.c
@@ -41,6 +41,8 @@ static int probe_jfs(blkid_probe pr, const struct blkid_idmag *mag)
 	js = blkid_probe_get_sb(pr, mag, struct jfs_super_block);
 	if (!js)
 		return errno ? -errno : 1;
+	if (le16_to_cpu(js->js_l2bsize) > 31 || le16_to_cpu(js->js_l2pbsize) > 31)
+ 		return 1;
 	if (le32_to_cpu(js->js_bsize) != (1U << le16_to_cpu(js->js_l2bsize)))
 		return 1;
 	if (le32_to_cpu(js->js_pbsize) != (1U << le16_to_cpu(js->js_l2pbsize)))
-- 
2.33.0

