ext2: 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: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index b5598e1393d9a6b2bda89ce85c7a8da9b3d35226..66321a877e7458795616e0568c58fac83e0437fd 100644 (file)
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -565,12 +565,8 @@ got:
        inode->i_blocks = 0;
        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
        memset(ei->i_data, 0, sizeof(ei->i_data));
-       ei->i_flags = EXT2_I(dir)->i_flags & EXT2_FL_INHERITED;
-       if (S_ISLNK(mode))
-               ei->i_flags &= ~(EXT2_IMMUTABLE_FL|EXT2_APPEND_FL);
-       /* dirsync is only applied to directories */
-       if (!S_ISDIR(mode))
-               ei->i_flags &= ~EXT2_DIRSYNC_FL;
+       ei->i_flags =
+               ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
        ei->i_faddr = 0;
        ei->i_frag_no = 0;
        ei->i_frag_size = 0;

diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index de876fa793e1d140386f8bd9693785943f706c09..7cb4badef927433ec90618b67c69cc08bec936f1 100644 (file)
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -50,8 +50,7 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                        goto setflags_out;
                }
 
-               if (!S_ISDIR(inode->i_mode))
-                       flags &= ~EXT2_DIRSYNC_FL;
+               flags = ext2_mask_flags(inode->i_mode, flags);
 
                mutex_lock(&inode->i_mutex);
                /* Is it quota file? Do not allow user to mess with it */

diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h
index c3a051819363e47aa468d95a00e717590b191e01..121720d74e15babe70c9dab51eb4394cb0ca53b2 100644 (file)
--- a/include/linux/ext2_fs.h
+++ b/include/linux/ext2_fs.h
@@ -201,6 +201,23 @@ struct ext2_group_desc
                           EXT2_NOCOMP_FL | EXT2_JOURNAL_DATA_FL |\
                           EXT2_NOTAIL_FL | EXT2_DIRSYNC_FL)
 
+/* Flags that are appropriate for regular files (all but dir-specific ones). */
+#define EXT2_REG_FLMASK (~(EXT2_DIRSYNC_FL | EXT2_TOPDIR_FL))
+
+/* Flags that are appropriate for non-directories/regular files. */
+#define EXT2_OTHER_FLMASK (EXT2_NODUMP_FL | EXT2_NOATIME_FL)
+
+/* Mask out flags that are inappropriate for the given type of inode. */
+static inline __u32 ext2_mask_flags(umode_t mode, __u32 flags)
+{
+       if (S_ISDIR(mode))
+               return flags;
+       else if (S_ISREG(mode))
+               return flags & EXT2_REG_FLMASK;
+       else
+               return flags & EXT2_OTHER_FLMASK;
+}
+
 /*
  * ioctl commands
  */