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List:       linux-fsdevel
Subject:    [PATCH] jfs: fix uaf in jfs_evict_inode
From:       Edward Adam Davis <eadavis () qq ! com>
Date:       2023-10-31 5:39:04
Message-ID: tencent_69E996EDCACDBC79A66CB02F956C3494D80A () qq ! com
[Download RAW message or body]

When the execution of diMount(ipimap) fails, the object ipimap that has been
released may be accessed in diFreeSpecial(). Asynchronous ipimap release occurs
when rcu_core() calls jfs_free_node().

Therefore, when diMount(ipimap) fails, sbi->ipimap should not be initialized as
ipimap.

Reported-and-tested-by: syzbot+01cf2dbcbe2022454388@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/jfs/jfs_mount.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/jfs/jfs_mount.c b/fs/jfs/jfs_mount.c
index 415eb65a36ff..9b5c6a20b30c 100644
--- a/fs/jfs/jfs_mount.c
+++ b/fs/jfs/jfs_mount.c
@@ -172,15 +172,15 @@ int jfs_mount(struct super_block *sb)
 	}
 	jfs_info("jfs_mount: ipimap:0x%p", ipimap);
 
-	/* map further access of per fileset inodes by the fileset inode */
-	sbi->ipimap = ipimap;
-
 	/* initialize fileset inode allocation map */
 	if ((rc = diMount(ipimap))) {
 		jfs_err("jfs_mount: diMount failed w/rc = %d", rc);
 		goto err_ipimap;
 	}
 
+	/* map further access of per fileset inodes by the fileset inode */
+	sbi->ipimap = ipimap;
+
 	return rc;
 
 	/*
-- 
2.25.1


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