linux-kernel - [PATCH 5.10 79/86] ext4: fix overhead calculation to account for the reserved gdt blocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220426081743.496343497@linuxfoundation.org>
Date:   Tue, 26 Apr 2022 10:21:47 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Theodore Tso <tytso@....edu>,
        stable@...nel.org
Subject: [PATCH 5.10 79/86] ext4: fix overhead calculation to account for the reserved gdt blocks

From: Theodore Ts'o <tytso@....edu>

commit 10b01ee92df52c8d7200afead4d5e5f55a5c58b1 upstream.

The kernel calculation was underestimating the overhead by not taking
into account the reserved gdt blocks.  With this change, the overhead
calculated by the kernel matches the overhead calculation in mke2fs.

Signed-off-by: Theodore Ts'o <tytso@....edu>
Cc: stable@...nel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/ext4/super.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3870,9 +3870,11 @@ static int count_overhead(struct super_b
 	ext4_fsblk_t		first_block, last_block, b;
 	ext4_group_t		i, ngroups = ext4_get_groups_count(sb);
 	int			s, j, count = 0;
+	int			has_super = ext4_bg_has_super(sb, grp);
 
 	if (!ext4_has_feature_bigalloc(sb))
-		return (ext4_bg_has_super(sb, grp) + ext4_bg_num_gdb(sb, grp) +
+		return (has_super + ext4_bg_num_gdb(sb, grp) +
+			(has_super ? le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0) +
 			sbi->s_itb_per_group + 2);
 
 	first_block = le32_to_cpu(sbi->s_es->s_first_data_block) +