linux-hardening - Re: [PATCH][next] checkpatch: add new alloc functions to alloc with multiplies check

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Date:   Tue, 26 Apr 2022 09:55:54 -0500
From:   "Gustavo A. R. Silva" <gustavoars@...nel.org>
To:     Andy Whitcroft <apw@...onical.com>, Joe Perches <joe@...ches.com>,
        Dwaipayan Ray <dwaipayanray1@...il.com>,
        Lukas Bulwahn <lukas.bulwahn@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH][next] checkpatch: add new alloc functions to alloc with
 multiplies check

On Tue, Apr 26, 2022 at 01:20:43AM -0500, Gustavo A. R. Silva wrote:
> kvmalloc() and kvzalloc() functions have now 2-factor multiplication
> argument forms kvmalloc_array() and kvcalloc(), correspondingly.
> 
> Add alloc-with-multiplies checks for these new functions.
> 
> Link: https://github.com/KSPP/linux/issues/187
> Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>

I've taken this in my -next tree for 5.19:

https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/commit/?h=for-next/kspp-checkpatch

Thanks
--
Gustavo

> ---
>  scripts/checkpatch.pl | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 577e02998701..503e8abbb2c1 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -7033,14 +7033,16 @@ sub process {
>  			    "Prefer $3(sizeof(*$1)...) over $3($4...)\n" . $herecurr);
>  		}
>  
> -# check for k[mz]alloc with multiplies that could be kmalloc_array/kcalloc
> +# check for (kv|k)[mz]alloc with multiplies that could be kmalloc_array/kvmalloc_array/kvcalloc/kcalloc
>  		if ($perl_version_ok &&
>  		    defined $stat &&
> -		    $stat =~ /^\+\s*($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)\s*,/) {
> +		    $stat =~ /^\+\s*($Lval)\s*\=\s*(?:$balanced_parens)?\s*((?:kv|k)[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)\s*,/) {
>  			my $oldfunc = $3;
>  			my $a1 = $4;
>  			my $a2 = $10;
>  			my $newfunc = "kmalloc_array";
> +			$newfunc = "kvmalloc_array" if ($oldfunc eq "kvmalloc");
> +			$newfunc = "kvcalloc" if ($oldfunc eq "kvzalloc");
>  			$newfunc = "kcalloc" if ($oldfunc eq "kzalloc");
>  			my $r1 = $a1;
>  			my $r2 = $a2;
> @@ -7057,7 +7059,7 @@ sub process {
>  					 "Prefer $newfunc over $oldfunc with multiply\n" . $herectx) &&
>  				    $cnt == 1 &&
>  				    $fix) {
> -					$fixed[$fixlinenr] =~ s/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/$1 . ' = ' . "$newfunc(" . trim($r1) . ', ' . trim($r2)/e;
> +					$fixed[$fixlinenr] =~ s/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*((?:kv|k)[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/$1 . ' = ' . "$newfunc(" . trim($r1) . ', ' . trim($r2)/e;
>  				}
>  			}
>  		}
> -- 
> 2.27.0
>