ext2: protect inode changes in the SETVERSION and SETFLAGS ioctls

Unlock mutex after i_flags and i_ctime updates in the EXT2_IOC_SETFLAGS
ioctl.

Use i_mutex in the EXT2_IOC_SETVERSION ioctl to protect i_ctime and
i_generation updates and make the ioctl consistent since i_mutex is
also used in other places to protect timestamps and inode changes.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 16 insertions, 6 deletions

diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index 1089f760c847..2de655f5d625 100644
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -77,10 +77,11 @@ long ext2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
                 flags = flags & EXT2_FL_USER_MODIFIABLE;
                 flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
                 ei->i_flags = flags;
-                mutex_unlock(&inode->i_mutex);
 
                 ext2_set_inode_flags(inode);
                 inode->i_ctime = CURRENT_TIME_SEC;
+                mutex_unlock(&inode->i_mutex);
+
                 mark_inode_dirty(inode);
 setflags_out:
                 mnt_drop_write_file(filp);
@@ -88,20 +89,29 @@ setflags_out:
         }
         case EXT2_IOC_GETVERSION:
                 return put_user(inode->i_generation, (int __user *) arg);
-        case EXT2_IOC_SETVERSION:
+        case EXT2_IOC_SETVERSION: {
+                __u32 generation;
+
                 if (!inode_owner_or_capable(inode))
                         return -EPERM;
                 ret = mnt_want_write_file(filp);
                 if (ret)
                         return ret;
-                if (get_user(inode->i_generation, (int __user *) arg)) {
+                if (get_user(generation, (int __user *) arg)) {
                         ret = -EFAULT;
-                } else {
-                        inode->i_ctime = CURRENT_TIME_SEC;
-                        mark_inode_dirty(inode);
+                        goto setversion_out;
                 }
+
+                mutex_lock(&inode->i_mutex);
+                inode->i_ctime = CURRENT_TIME_SEC;
+                inode->i_generation = generation;
+                mutex_unlock(&inode->i_mutex);
+
+                mark_inode_dirty(inode);
+setversion_out:
                 mnt_drop_write_file(filp);
                 return ret;
+        }
         case EXT2_IOC_GETRSVSZ:
                 if (test_opt(inode->i_sb, RESERVATION)
                         && S_ISREG(inode->i_mode)