ext4: Fix compat EXT4_IOC_ADD_GROUP

struct ext4_new_group_input needs to be converted because u64 has
only 32-bit alignment on some 32-bit architectures, notably i386.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 23 insertions, 2 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 66fa0b030e37..6ddec84846cd 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -373,8 +373,29 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         case EXT4_IOC32_SETRSVSZ:
                 cmd = EXT4_IOC_SETRSVSZ;
                 break;
-        case EXT4_IOC_GROUP_ADD:
-                break;
+        case EXT4_IOC32_GROUP_ADD: {
+                struct compat_ext4_new_group_input __user *uinput;
+                struct ext4_new_group_input input;
+                mm_segment_t old_fs;
+                int err;
+
+                uinput = compat_ptr(arg);
+                err = get_user(input.group, &uinput->group);
+                err |= get_user(input.block_bitmap, &uinput->block_bitmap);
+                err |= get_user(input.inode_bitmap, &uinput->inode_bitmap);
+                err |= get_user(input.inode_table, &uinput->inode_table);
+                err |= get_user(input.blocks_count, &uinput->blocks_count);
+                err |= get_user(input.reserved_blocks,
+                                &uinput->reserved_blocks);
+                if (err)
+                        return -EFAULT;
+                old_fs = get_fs();
+                set_fs(KERNEL_DS);
+                err = ext4_ioctl(file, EXT4_IOC_GROUP_ADD,
+                                 (unsigned long) &input);
+                set_fs(old_fs);
+                return err;
+        }
         case EXT4_IOC_MOVE_EXT:
                 break;
         default: