4.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ian Kent raven@themaw.net
commit 0633da48f0793aeba27f82d30605624416723a91 upstream.
autofs_sbi() does not check the superblock magic number to verify it has been given an autofs super block.
Link: http://lkml.kernel.org/r/153475422934.17131.7563724552005298277.stgit@pluto.... Reported-by: syzbot+87c3c541582e56943277@syzkaller.appspotmail.com Signed-off-by: Ian Kent raven@themaw.net Reviewed-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Cc: Guenter Roeck groeck@google.com Cc: Zubin Mithra zsm@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/autofs/autofs_i.h | 4 +++- fs/autofs/inode.c | 1 - 2 files changed, 3 insertions(+), 2 deletions(-)
--- a/fs/autofs/autofs_i.h +++ b/fs/autofs/autofs_i.h @@ -26,6 +26,7 @@ #include <linux/list.h> #include <linux/completion.h> #include <linux/file.h> +#include <linux/magic.h>
/* This is the range of ioctl() numbers we claim as ours */ #define AUTOFS_IOC_FIRST AUTOFS_IOC_READY @@ -124,7 +125,8 @@ struct autofs_sb_info {
static inline struct autofs_sb_info *autofs_sbi(struct super_block *sb) { - return (struct autofs_sb_info *)(sb->s_fs_info); + return sb->s_magic != AUTOFS_SUPER_MAGIC ? + NULL : (struct autofs_sb_info *)(sb->s_fs_info); }
static inline struct autofs_info *autofs_dentry_ino(struct dentry *dentry) --- a/fs/autofs/inode.c +++ b/fs/autofs/inode.c @@ -10,7 +10,6 @@ #include <linux/seq_file.h> #include <linux/pagemap.h> #include <linux/parser.h> -#include <linux/magic.h>
#include "autofs_i.h"