Since ntfs_read_mft() not only accepts file modes which may_open() accepts but also accepts (fname && fname->home.low == cpu_to_le32(MFT_REC_EXTEND) && fname->home.seq == cpu_to_le16(MFT_REC_EXTEND) case when the file mode is none of S_IFDIR/S_IFLNK/S_IFREG/S_IFCHR/S_IFBLK/S_IFIFO/S_IFSOCK, may_open() cannot unconditionally expect IS_ANON_FILE(inode) when the file mode is none of S_IFDIR/S_IFLNK/S_IFREG/S_IFCHR/S_IFBLK/S_IFIFO/S_IFSOCK. Treat as if S_IFREG when the inode is for NTFS3 filesystem. Reported-by: syzbot <syzbot+895c23f6917da440ed0d@xxxxxxxxxxxxxxxxxxxxxxxxx> Closes: https://syzkaller.appspot.com/bug?extid=895c23f6917da440ed0d Fixes: af153bb63a33 ("vfs: catch invalid modes in may_open()") Signed-off-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> --- Is it possible to handle this problem on the NTFS3 side? --- a/fs/ntfs3/inode.c +++ b/fs/ntfs3/inode.c @@ -470,8 +470,9 @@ static struct inode *ntfs_read_mft(struct inode *inode, } else if (fname && fname->home.low == cpu_to_le32(MFT_REC_EXTEND) && fname->home.seq == cpu_to_le16(MFT_REC_EXTEND)) { /* Records in $Extend are not a files or general directories. */ inode->i_op = &ntfs_file_inode_operations; + mode = S_IFREG; } else { err = -EINVAL; goto out; } I don't know what breaks if we pretend as if S_IFREG... fs/namei.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/namei.c b/fs/namei.c index cd43ff89fbaa..a66599754394 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3471,6 +3471,12 @@ static int may_open(struct mnt_idmap *idmap, const struct path *path, return -EACCES; break; default: + /* Special handling for ntfs_read_mft() case. */ + if (inode->i_sb->s_magic == 0x7366746e) { + if ((acc_mode & MAY_EXEC) && path_noexec(path)) + return -EACCES; + break; + } VFS_BUG_ON_INODE(!IS_ANON_FILE(inode), inode); } -- 2.50.1
