Re: [RFC PATCH] checkpatch: add shebang check to EXECUTE_PERMISSIONS

From: Ujjwal Kumar
Date: Mon Oct 12 2020 - 09:53:10 EST


On 12/10/20 11:47 am, Joe Perches wrote:
> On Mon, 2020-10-12 at 11:19 +0530, Ujjwal Kumar wrote:
>> checkpatch.pl checks for invalid EXECUTE_PERMISSIONS on source
>> files. The script leverages filename extensions and its path in
>> the repository to decide whether to allow execute permissions on
>> the file or not.
>>
>> Based on current check conditions, a perl script file having
>> execute permissions, without '.pl' extension in its filename
>> and not belonging to 'scripts/' directory is reported as ERROR
>> which is a false-positive.
>>
>> Adding a shebang check along with current conditions will make
>> the check more generalised and improve checkpatch reports.
>> To do so, without breaking the core design decision of checkpatch,
>> we can fetch the first line from the patch itself and match it for
>> a shebang pattern.
>>
>> There can be cases where the first line is not part of the patch.
>
> For instance: a patch that only changes permissions
> without changing any of the file content.
>
>>
>> In that case there may be a false-positive report but in the end we
>> will have less false-positives as we will be handling some of the
>> unhandled cases.
>
>> Signed-off-by: Ujjwal Kumar <ujjwalkumar0501@xxxxxxxxx>
>> ---
>> Apologies, I forgot to include linux-kernel@xxxxxxxxxxxxxxx so I'm
>> now resending.
>>
>> scripts/checkpatch.pl | 19 +++++++++++++++++++
>> 1 file changed, 19 insertions(+)
>>
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> []
>> @@ -1795,6 +1795,23 @@ sub get_stat_here {
>> return $herectx;
>> }
>
> First some style trivia:
>
>> +sub get_shebang {
>> + my ($linenr, $realfile) = @_;
>> + my $rawline = "";
>> + my $shebang = "";
>> +
>> + $rawline = raw_line($linenr, 3);
>> + if (defined $rawline &&
>> + $rawline =~ /^\@\@ -\d+(?:,\d+)? \+(\d+)(,(\d+))? \@\@/) {
>
> alignment to open parenthesis please
>
>> + if (defined $1 && $1 == 1) {
>> + $shebang = raw_line($linenr, 4);
>> + $shebang = substr $shebang, 1;
>
> parentheses around substr please.
>
>> + }
>> + }
>> +
>> + return $shebang;
>> +}
>
> And some real notes:
>
> $realfile isn't used in this function so there doesn't
> seem to be a reason to have it as an function argument.
>
>> +
>> sub cat_vet {
>> my ($vet) = @_;
>> my ($res, $coded);
>> @@ -2680,7 +2697,9 @@ sub process {
>> # Check for incorrect file permissions
>> if ($line =~ /^new (file )?mode.*[7531]\d{0,2}$/) {
>
> probably better here to use a capture group for the permissions
>
> if ($line =~ /^new (?:file )?mode (\d+)$/) {
> my $mode = substr($1, -3);

This

>
>> my $permhere = $here . "FILE: $realfile\n";
>> + my $shebang = get_shebang($linenr, $realfile);
>> if ($realfile !~ m@scripts/@ &&
>
> Maybe remove the $realfile directory test as
> there are many source files that are not scripts
> in this directory and its subdirectories.

this

>
>> + $shebang !~ /^#!\s*(\/\w)+.*/ &&
>
> unnecessary capture group
>
> and add
>
> $mode =~ /[1357]/ &&

this

>
>> $realfile !~ /\.(py|pl|awk|sh)$/) {
>
> No need for a a capture group here either. (existing defect)

and this.

>
>> ERROR("EXECUTE_PERMISSIONS",
>> "do not set execute permissions for source files\n" . $permhere);
>
>
>

Should these new changes go as a separate patch or can they be
included in the next iteration of this patch?



Thanks
Ujjwal Kumar