linux-kernel - [PATCH] minixfs: Verify inode mode when loading from disk

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Message-ID: <ec982681-84b8-4624-94fa-8af15b77cbd2@I-love.SAKURA.ne.jp>
Date: Wed, 13 Aug 2025 00:17:44 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: Christian Brauner <brauner@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] minixfs: Verify inode mode when loading from disk

The inode mode loaded from corrupted disk can be invalid. Do like what
commit 0a9e74051313 ("isofs: Verify inode mode when loading from disk")
does.

Reported-by: syzbot <syzbot+895c23f6917da440ed0d@...kaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=895c23f6917da440ed0d
Signed-off-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
---
 fs/minix/inode.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/minix/inode.c b/fs/minix/inode.c
index df9d11479caf..32db676127a9 100644
--- a/fs/minix/inode.c
+++ b/fs/minix/inode.c
@@ -492,8 +492,14 @@ void minix_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_op = &minix_symlink_inode_operations;
 		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &minix_aops;
-	} else
+	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+		   S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		init_special_inode(inode, inode->i_mode, rdev);
+	} else {
+		printk(KERN_DEBUG "MINIX-fs: Invalid file type 0%04o for inode %lu.\n",
+		       inode->i_mode, inode->i_ino);
+		make_bad_inode(inode);
+	}
 }
 
 /*
-- 
2.50.1