Commit 2e7842b8 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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[PATCH] fix umask when noACL kernel meets extN tuned for ACLs 



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: default avatarHugh Dickins <hugh@veritas.com>
Cc: Tigran Aivazian <tigran@aivazian.fsnet.co.uk>
Cc: <linux-ext4@vger.kernel.org>
Cc: Andreas Gruenbacher <agruen@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9bbf81e4

fs/ext2/super.c

+4 −0
Original line number Diff line number Diff line
@@ -708,10 +708,14 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) 
		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);

fs/ext3/super.c

+4 −0
Original line number Diff line number Diff line
@@ -1459,10 +1459,14 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) 
		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)

fs/ext4/super.c

+4 −0
Original line number Diff line number Diff line
@@ -1518,10 +1518,14 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent) 
		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)

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