[ 26/73] ext4: add check for inodes_count overflow in new resize ioctl

[Greg Kroah-Hartman]

3.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Theodore Ts'o <tytso@xxxxxxx>

commit 3f8a6411fbada1fa482276591e037f3b1adcf55b upstream.

Addresses-Red-Hat-Bugzilla: #913245

Reported-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
Signed-off-by: Lingzhu Xiang <lxiang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ext4/resize.c |    4 ++++
 1 file changed, 4 insertions(+)

--- 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);


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