From: Hugh Dickins <hugh@xxxxxxxxxxx> Fix insecure default behaviour reported by Tigran Aivazian: if an ext2 or ext3 or ext4 filesystem is tuned to mount with "acl", but mounted by a kernel built without ACL support, then umask was ignored when creating inodes - though root or user has umask 022, touch creates files as 0666, and mkdir creates directories as 0777. This appears to have worked right until 2.6.11, when a fix to the default mode on symlinks (always 0777) assumed VFS applies umask: which it does, unless the mount is marked for ACLs; but ext[234] set MS_POSIXACL in s_flags according to s_mount_opt set according to def_mount_opts. We could revert to the 2.6.10 ext[234]_init_acl (adding an S_ISLNK test); but other filesystems only set MS_POSIXACL when ACLs are configured. We could fix this at another level; but it seems most robust to avoid setting the s_mount_opt flag in the first place (at the expense of more ifdefs). Likewise don't set the XATTR_USER flag when built without XATTR support. Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> Cc: Tigran Aivazian <tigran@xxxxxxxxxxxxxxxxxxxx> Cc: <linux-ext4@xxxxxxxxxxxxxxx> Cc: Andreas Gruenbacher <agruen@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/ext2/super.c | 4 ++++ fs/ext3/super.c | 4 ++++ fs/ext4/super.c | 4 ++++ 3 files changed, 12 insertions(+) diff -puN fs/ext2/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls fs/ext2/super.c --- a/fs/ext2/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls +++ a/fs/ext2/super.c @@ -708,10 +708,14 @@ static int ext2_fill_super(struct super_ set_opt(sbi->s_mount_opt, GRPID); if (def_mount_opts & EXT2_DEFM_UID16) set_opt(sbi->s_mount_opt, NO_UID32); +#ifdef CONFIG_EXT2_FS_XATTR if (def_mount_opts & EXT2_DEFM_XATTR_USER) set_opt(sbi->s_mount_opt, XATTR_USER); +#endif +#ifdef CONFIG_EXT2_FS_POSIX_ACL if (def_mount_opts & EXT2_DEFM_ACL) set_opt(sbi->s_mount_opt, POSIX_ACL); +#endif if (le16_to_cpu(sbi->s_es->s_errors) == EXT2_ERRORS_PANIC) set_opt(sbi->s_mount_opt, ERRORS_PANIC); diff -puN fs/ext3/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls fs/ext3/super.c --- a/fs/ext3/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls +++ a/fs/ext3/super.c @@ -1459,10 +1459,14 @@ static int ext3_fill_super (struct super set_opt(sbi->s_mount_opt, GRPID); if (def_mount_opts & EXT3_DEFM_UID16) set_opt(sbi->s_mount_opt, NO_UID32); +#ifdef CONFIG_EXT3_FS_XATTR if (def_mount_opts & EXT3_DEFM_XATTR_USER) set_opt(sbi->s_mount_opt, XATTR_USER); +#endif +#ifdef CONFIG_EXT3_FS_POSIX_ACL if (def_mount_opts & EXT3_DEFM_ACL) set_opt(sbi->s_mount_opt, POSIX_ACL); +#endif if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_DATA) sbi->s_mount_opt |= EXT3_MOUNT_JOURNAL_DATA; else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_ORDERED) diff -puN fs/ext4/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls fs/ext4/super.c --- a/fs/ext4/super.c~fix-umask-when-noacl-kernel-meets-extn-tuned-for-acls +++ a/fs/ext4/super.c @@ -1518,10 +1518,14 @@ static int ext4_fill_super (struct super set_opt(sbi->s_mount_opt, GRPID); if (def_mount_opts & EXT4_DEFM_UID16) set_opt(sbi->s_mount_opt, NO_UID32); +#ifdef CONFIG_EXT4DEV_FS_XATTR if (def_mount_opts & EXT4_DEFM_XATTR_USER) set_opt(sbi->s_mount_opt, XATTR_USER); +#endif +#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL if (def_mount_opts & EXT4_DEFM_ACL) set_opt(sbi->s_mount_opt, POSIX_ACL); +#endif if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_DATA) sbi->s_mount_opt |= EXT4_MOUNT_JOURNAL_DATA; else if ((def_mount_opts & EXT4_DEFM_JMODE) == EXT4_DEFM_JMODE_ORDERED) _ - To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
