From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Sat, 30 Aug 2025 10:01:01 +0000 (+0900)
Subject: cramfs: Verify inode mode when loading from disk
X-Git-Tag: v6.18-rc1~242^2~16
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7f9d34b0a7cb93d678ee7207f0634dbf79e47fe5;p=thirdparty%2Flinux.git

cramfs: 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@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=895c23f6917da440ed0d
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: https://lore.kernel.org/429b3ef1-13de-4310-9a8e-c2dc9a36234a@I-love.SAKURA.ne.jp
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
---

diff --git a/fs/cramfs/inode.c b/fs/cramfs/inode.c
index b002e9b734f99..12daa85ed941b 100644
--- a/fs/cramfs/inode.c
+++ b/fs/cramfs/inode.c
@@ -116,9 +116,18 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
 		inode_nohighmem(inode);
 		inode->i_data.a_ops = &cramfs_aops;
 		break;
-	default:
+	case S_IFCHR:
+	case S_IFBLK:
+	case S_IFIFO:
+	case S_IFSOCK:
 		init_special_inode(inode, cramfs_inode->mode,
 				old_decode_dev(cramfs_inode->size));
+		break;
+	default:
+		printk(KERN_DEBUG "CRAMFS: Invalid file type 0%04o for inode %lu.\n",
+		       inode->i_mode, inode->i_ino);
+		iget_failed(inode);
+		return ERR_PTR(-EIO);
 	}
 
 	inode->i_mode = cramfs_inode->mode;