ext4: add check for inodes_count overflow in new resize ioctl

commit 3f8a6411fbada1fa482276591e037f3b1adcf55b upstream.

Addresses-Red-Hat-Bugzilla: #913245

Reported-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index a2fe9f53e59b..0cfa2f45abc1 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1880,6 +1880,10 @@ retry:
                 return 0;
 
         ext4_get_group_no_and_offset(sb, n_blocks_count - 1, &n_group, &offset);
+        if (n_group > (0xFFFFFFFFUL / EXT4_INODES_PER_GROUP(sb))) {
+                ext4_warning(sb, "resize would cause inodes_count overflow");
+                return -EINVAL;
+        }
         ext4_get_group_no_and_offset(sb, o_blocks_count - 1, &o_group, &offset);
 
         n_desc_blocks = num_desc_blocks(sb, n_group + 1);