From 2ab3543e3b3330317769adcbe4bdb2f3c0b855e9 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Thu, 24 Jul 2014 22:19:27 -0400
Subject: [PATCH 14/16] e2fsck: fix off-by-one bounds check on group number
commit b4f724c8a90987d4785fd1accfe69c125567be39
Since fs->group_desc_count is the number of block groups, the number
of the last group is always one less than this count. Fix the bounds
check to reflect that.
This flaw shouldn't have any user-visible side effects, since the
block bitmap test based on last_grp later on can handle overbig block
numbers.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
e2fsck/pass1.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 71b3000a..b58a0ca7 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -2599,8 +2599,8 @@ static void new_table_block(e2fsck_t ctx, blk64_t first_block, dgrp_t group,
first_block = ext2fs_group_first_block2(fs,
flexbg_size * flexbg);
last_grp = group | (flexbg_size - 1);
- if (last_grp > fs->group_desc_count)
- last_grp = fs->group_desc_count;
+ if (last_grp >= fs->group_desc_count)
+ last_grp = fs->group_desc_count - 1;
last_block = ext2fs_group_last_block2(fs, last_grp);
} else
last_block = ext2fs_group_last_block2(fs, group);
--
2.20.1