From: Yongpeng Yang <yangyongpeng1@oppo.com>
Date: Fri, 22 Dec 2023 03:29:00 +0000 (+0800)
Subject: f2fs: Constrain the modification range of dir_level in the sysfs
X-Git-Tag: v6.8-rc1~112^2~2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0145eed6ed3210f98b366e88363553251c41807d;p=thirdparty%2Flinux.git

f2fs: Constrain the modification range of dir_level in the sysfs

The {struct f2fs_sb_info}->dir_level can be modified through the sysfs
interface, but its value range is not limited. If the value exceeds
MAX_DIR_HASH_DEPTH and the mount options include "noinline_dentry",
the following error will occur:
[root@fedora ~]# mount -o noinline_dentry /dev/sdb  /mnt/sdb/
[root@fedora ~]# echo 128 > /sys/fs/f2fs/sdb/dir_level
[root@fedora ~]# cd /mnt/sdb/
[root@fedora sdb]# mkdir test
[root@fedora sdb]# cd test/
[root@fedora test]# mkdir test
mkdir: cannot create directory 'test': Argument list too long

Signed-off-by: Yongpeng Yang <yangyongpeng1@oppo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 7099ffa572993..8c8424b05fc7e 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -741,6 +741,13 @@ out:
 		return count;
 	}
 
+	if (!strcmp(a->attr.name, "dir_level")) {
+		if (t > MAX_DIR_HASH_DEPTH)
+			return -EINVAL;
+		sbi->dir_level = t;
+		return count;
+	}
+
 	*ui = (unsigned int)t;
 
 	return count;