ext4: tighten restrictions on inode flags

At the moment there are few restrictions on which flags may be set on
which inodes.  Specifically DIRSYNC may only be set on directories and
IMMUTABLE and APPEND may not be set on links.  Tighten that to disallow
TOPDIR being set on non-directories and only NODUMP and NOATIME to be set
on non-regular file, non-directories.

Introduces a flags masking function which masks flags based on mode and
use it during inode creation and when flags are set via the ioctl to
facilitate future consistency.

Signed-off-by: Duane Griffin <duaneg@dghda.com>
Acked-by: Andreas Dilger <adilger@sun.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index d4700d101ea7b9a5352542662f612413e572ca2c..2cbfc0b04d370192d9c950868059b7366d4e88ee 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -246,6 +246,23 @@ struct flex_groups {
                           EXT4_NOCOMPR_FL | EXT4_JOURNAL_DATA_FL |\
                           EXT4_NOTAIL_FL | EXT4_DIRSYNC_FL)
 
+/* Flags that are appropriate for regular files (all but dir-specific ones). */
+#define EXT4_REG_FLMASK (~(EXT4_DIRSYNC_FL | EXT4_TOPDIR_FL))
+
+/* Flags that are appropriate for non-directories/regular files. */
+#define EXT4_OTHER_FLMASK (EXT4_NODUMP_FL | EXT4_NOATIME_FL)
+
+/* Mask out flags that are inappropriate for the given type of inode. */
+static inline __u32 ext4_mask_flags(umode_t mode, __u32 flags)
+{
+       if (S_ISDIR(mode))
+               return flags;
+       else if (S_ISREG(mode))
+               return flags & EXT4_REG_FLMASK;
+       else
+               return flags & EXT4_OTHER_FLMASK;
+}
+
 /*
  * Inode dynamic state flags
  */

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 1ff3df086e58b2b9416c38e5dd37e2a55723ea9d..ae3eb57dccdd09a949972107ec3db40d0a852016 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -885,16 +885,12 @@ got:
        ei->i_disksize = 0;
 
        /*
-        * Don't inherit extent flag from directory. We set extent flag on
-        * newly created directory and file only if -o extent mount option is
-        * specified
+        * Don't inherit extent flag from directory, amongst others. We set
+        * extent flag on newly created directory and file only if -o extent
+        * mount option is specified
         */
-       ei->i_flags = EXT4_I(dir)->i_flags & EXT4_FL_INHERITED;
-       if (S_ISLNK(mode))
-               ei->i_flags &= ~(EXT4_IMMUTABLE_FL|EXT4_APPEND_FL);
-       /* dirsync only applies to directories */
-       if (!S_ISDIR(mode))
-               ei->i_flags &= ~EXT4_DIRSYNC_FL;
+       ei->i_flags =
+               ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
        ei->i_file_acl = 0;
        ei->i_dtime = 0;
        ei->i_block_group = group;

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 42dc83fb247a98f6dd4450314bf2f96d4e36c175..22dd29f3ebc947ed8e67c384fa16671a498248d9 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -48,8 +48,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                if (err)
                        return err;
 
-               if (!S_ISDIR(inode->i_mode))
-                       flags &= ~EXT4_DIRSYNC_FL;
+               flags = ext4_mask_flags(inode->i_mode, flags);
 
                err = -EPERM;
                mutex_lock(&inode->i_mutex);