From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 6 Jun 2013 15:16:43 +0000 (-0400)
Subject: ext4: add sanity check to ext4_get_group_info()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=2f2e09eb15849562aede80ed007658e4504ded26;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

ext4: add sanity check to ext4_get_group_info()

The group number passed to ext4_get_group_info() should be valid, but
let's add an assert to check this before we start creating a pointer
based on that group number and dereferencing it.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index bd9890f6d9ce..f85f1fb49df8 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2313,6 +2313,7 @@ struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
 {
 	 struct ext4_group_info ***grp_info;
 	 long indexv, indexh;
+	 BUG_ON(group >= EXT4_SB(sb)->s_groups_count);
 	 grp_info = EXT4_SB(sb)->s_group_info;
 	 indexv = group >> (EXT4_DESC_PER_BLOCK_BITS(sb));
 	 indexh = group & ((EXT4_DESC_PER_BLOCK(sb)) - 1);