linux-kernel - [PATCH v2 3/2] lib/uuid.c: Silence an unchecked return value warning

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: <20160604131622.28377.qmail@ns.sciencehorizons.net>
Date:	4 Jun 2016 09:16:22 -0400
From:	"George Spelvin" <linux@...encehorizons.net>
To:	andriy.shevchenko@...ux.intel.com
Cc:	bjorn@...k.no, linux-kernel@...r.kernel.org,
	linux@...encehorizons.net, matt@...eblueprint.co.uk,
	rv@...musvillemoes.dk
Subject: [PATCH v2 3/2] lib/uuid.c: Silence an unchecked return value warning

Andy Shevchenko pointed out that __uuid_to_bin doesn't need to check
the return value from hex2bin(), because the preceding uuid_is_valid()
check already took care of that.

But hex2bin() is declared __must_check, so checking anyway is the
simplest way to silence the warning.

This cancels a small fraction of the the space savings, but not all:

	vs. previous patch		vs. before patch series
	Before  After   Delta   Percent	Orig.	Delta Percent
x86-32	90	 96	 +6	6.7%	122	-26	-21.3%
x86-64	90	 96	 +6	6.7%	127     -31	-24.4%
arm	92	104	+12	13.0%	116     -12	-10.3%
thumb	50	 62	+12	24.0%	100     -38	-38.0%
arm64	116	124	 +8	6.9%	148     -24	-16.2%

Signed-off-by: George Spelvin <linux@...encehorizons.net>
---
 lib/uuid.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/uuid.c b/lib/uuid.c
index 93945915..1a6dbbd2 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -104,7 +104,8 @@ static int __uuid_to_bin(const char uuid[36], __u8 b[16], const u8 pos[16])
 		return -EINVAL;
 
 	for (i = 0; i < 16; i++)
-		hex2bin(b + i, uuid + pos[i], 1);
+		if (hex2bin(b + i, uuid + pos[i], 1) < 0)
+			return -EINVAL;
 
 	return 0;
 }
-- 
2.8.1