[PATCH 059/115] ext4: add check for inodes_count overflow in new resize ioctl

[Luis Henriques]

3.5.7.13 -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: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 fs/ext4/resize.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 097a7b0..d0ba1a9 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1680,6 +1680,10 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
 		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 = (n_group + EXT4_DESC_PER_BLOCK(sb)) /
-- 
1.8.1.2

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