linux-kernel - Re: byteorder: cpu_to_le32_array vs cpu_to_be32

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: <AM0PR0502MB3668C7B77C05918FF96EF10DBA6E0@AM0PR0502MB3668.eurprd05.prod.outlook.com>
Date:   Sun, 20 Oct 2019 19:28:46 +0000
From:   Anatol Belski <weltling@...look.de>
To:     Joe Perches <joe@...ches.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
CC:     linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: byteorder: cpu_to_le32_array vs cpu_to_be32_array function API
 differences

Hi,

On Sun, 2019-10-20 at 12:02 -0700, Joe Perches wrote:
> There's an argument inconsistency between these 4 functions
> in include/linux/byteorder/generic.h
> 
> It'd be more a consistent API with one form and not two.
> 
>    static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
>    {
>    	while (words--) {
>    		__le32_to_cpus(buf);
>    		buf++;
>    	}
>    }
> 
>    static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
>    {
>    	while (words--) {
>    		__cpu_to_le32s(buf);
>    		buf++;
>    	}
>    }
> 
> vs
> 
>    static inline void cpu_to_be32_array(__be32 *dst, const u32 *src,
> size_t len)
>    {
>    	int i;
> 
>    	for (i = 0; i < len; i++)
>    		dst[i] = cpu_to_be32(src[i]);
>    }
> 
>    static inline void be32_to_cpu_array(u32 *dst, const __be32 *src,
> size_t len)
>    {
>    	int i;
> 
>    	for (i = 0; i < len; i++)
>    		dst[i] = be32_to_cpu(src[i]);
>    }
> 
> 

size_t is the right choice for this, as it'll generate more correct
binary depending on 32/64 bit. I've sent a patch in
'include/linux/byteorder/generic.h: fix signed/unsigned warnings'
before, but only touched the place where i've seen warnings. My very
bet is, that changing between size_t/unsigned, while it would be
consistent, wouldn't change the functionality. It'd probably make sense
to extend the aforementioned patch to move unsigned -> size_t.

Regards

Anatol