linux-kernel - [PATCH] md: dm-ioctl: drop always-false condition

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-next>] [day] [month] [year] [list]

Message-ID: <c8c9df45-1d59-3195-7631-51b3a58148ee@omp.ru>
Date:   Tue, 17 Jan 2023 23:59:55 +0300
From:   Sergey Shtylyov <s.shtylyov@....ru>
To:     Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...nel.org>, <dm-devel@...hat.com>
CC:     <linux-kernel@...r.kernel.org>, <lvc-patches@...uxtesting.org>,
        <lvc-patches@...uxtesting.org>
Subject: [PATCH] md: dm-ioctl: drop always-false condition

The expression 'indata[3] > ULONG_MAX' always evaluates to false since
indata[] is declared as an array of *unsigned long* elements and #define
ULONG_MAX represents the max value of that exact type...

Note that gcc seems to be able to detect the dead code here and eliminate
this check anyway...

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@....ru>

---
This patch is atop of the 'for-next' branch of the device-mapper repo...

 drivers/md/dm-ioctl.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: linux-dm/drivers/md/dm-ioctl.c
===================================================================
--- linux-dm.orig/drivers/md/dm-ioctl.c
+++ linux-dm/drivers/md/dm-ioctl.c
@@ -1073,8 +1073,7 @@ static int dev_set_geometry(struct file
 		goto out;
 	}
 
-	if (indata[0] > 65535 || indata[1] > 255 ||
-	    indata[2] > 255 || indata[3] > ULONG_MAX) {
+	if (indata[0] > 65535 || indata[1] > 255 || indata[2] > 255) {
 		DMERR("Geometry exceeds range limits.");
 		goto out;
 	}