linux-hardening - Re: [PATCH v5] checkpatch: Check for 0-length and 1-element arrays

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: <ce30e9e307da06dfec01e6449c21800d76460fc5.camel@perches.com>
Date:   Thu, 01 Jun 2023 13:08:20 -0700
From:   Joe Perches <joe@...ches.com>
To:     Kees Cook <keescook@...omium.org>,
        Andy Whitcroft <apw@...onical.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Dwaipayan Ray <dwaipayanray1@...il.com>,
        Lukas Bulwahn <lukas.bulwahn@...il.com>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH v5] checkpatch: Check for 0-length and 1-element arrays

On Thu, 2023-06-01 at 09:07 -0700, Kees Cook wrote:
> Fake flexible arrays have been deprecated since last millennium. Proper
> C99 flexible arrays must be used throughout the kernel so
> CONFIG_FORTIFY_SOURCE and CONFIG_UBSAN_BOUNDS can provide proper array
> bounds checking.
> 
> Cc: Andy Whitcroft <apw@...onical.com>
> Cc: Dwaipayan Ray <dwaipayanray1@...il.com>
> Cc: Lukas Bulwahn <lukas.bulwahn@...il.com>
> Fixed-by: Joe Perches <joe@...ches.com>
> Signed-off-by: Kees Cook <keescook@...omium.org>
> Acked-by: Gustavo A. R. Silva <gustavoars@...nel.org>
> Link: https://lore.kernel.org/r/20230517204530.never.151-kees@kernel.org

Acked-by: Joe Perches <joe@...ches.com>

> ---
> v5: - add __packed to outer struct regex too (joe)
> v4: https://lore.kernel.org/lkml/20230531004929.you.436-kees@kernel.org
> v3: https://lore.kernel.org/r/20230527020929.give.261-kees@kernel.org
> v2: https://lore.kernel.org/lkml/20230526173921.gonna.349-kees@kernel.org
> v1: https://lore.kernel.org/lkml/20230517204530.never.151-kees@kernel.org
> ---
>  scripts/checkpatch.pl | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 30b0b4fdb3bf..7bfa4d39d17f 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -7430,6 +7430,16 @@ sub process {
>  			}
>  		}
>  
> +# check for array definition/declarations that should use flexible arrays instead
> +		if ($sline =~ /^[\+ ]\s*\}(?:\s*__packed)?\s*;\s*$/ &&
> +		    $prevline =~ /^\+\s*(?:\}(?:\s*__packed\s*)?|$Type)\s*$Ident\s*\[\s*(0|1)\s*\]\s*;\s*$/) {
> +			if (ERROR("FLEXIBLE_ARRAY",
> +				  "Use C99 flexible arrays - see https://docs.kernel.org/process/deprecated.html#zero-length-and-one-element-arrays\n" . $hereprev) &&
> +			    $1 == '0' && $fix) {
> +				$fixed[$fixlinenr - 1] =~ s/\[\s*0\s*\]/[]/;
> +			}
> +		}
> +
>  # nested likely/unlikely calls
>  		if ($line =~ /\b(?:(?:un)?likely)\s*\(\s*!?\s*(IS_ERR(?:_OR_NULL|_VALUE)?|WARN)/) {
>  			WARN("LIKELY_MISUSE",