linux-kernel - [ 61/82] ext4: fix potential integer overflow in alloc_flex

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: <20120607040345.242563062@linuxfoundation.org>
Date:	Thu, 07 Jun 2012 13:04:37 +0900
From:	Greg KH <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	alan@...rguk.ukuu.org.uk, Eric Sandeen <sandeen@...hat.com>,
	Haogang Chen <haogangchen@...il.com>,
	"Theodore Tso" <tytso@....edu>
Subject: [ 61/82] ext4: fix potential integer overflow in alloc_flex_gd()

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

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

From: Haogang Chen <haogangchen@...il.com>

commit 967ac8af4475ce45474800709b12137aa7634c77 upstream.

In alloc_flex_gd(), when flexbg_size is large, kmalloc size would
overflow and flex_gd->groups would point to a buffer smaller than
expected, causing OOB accesses when it is used.

Note that in ext4_resize_fs(), flexbg_size is calculated using
sbi->s_log_groups_per_flex, which is read from the disk and only bounded
to [1, 31]. The patch returns NULL for too large flexbg_size.

Reviewed-by: Eric Sandeen <sandeen@...hat.com>
Signed-off-by: Haogang Chen <haogangchen@...il.com>
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/ext4/resize.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -161,6 +161,8 @@ static struct ext4_new_flex_group_data *
 	if (flex_gd == NULL)
 		goto out3;
 
+	if (flexbg_size >= UINT_MAX / sizeof(struct ext4_new_flex_group_data))
+		goto out2;
 	flex_gd->count = flexbg_size;
 
 	flex_gd->groups = kmalloc(sizeof(struct ext4_new_group_data) *


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/