Add some warnings for using ethtool_sprintf() where a simple
ethtool_puts() would suffice.

The two cases are:

1) Use ethtool_sprintf() with just two arguments:
|       ethtool_sprintf(&data, driver[i].name);
or
2) Use ethtool_sprintf() with a standalone "%s" fmt string:
|       ethtool_sprintf(&data, "%s", driver[i].name);

The former may cause -Wformat-security warnings while the latter is just
not preferred. Both are safely in the category of warnings, not errors.

Signed-off-by: Justin Stitt <justinstitt@google.com>
---
 scripts/checkpatch.pl | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7d16f863edf1..1ba9ce778746 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -7020,6 +7020,19 @@ sub process {
 			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
 		}
 
+# ethtool_sprintf uses that should likely be ethtool_puts
+		if (   $line =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/   ) {
+			WARN("ETHTOOL_SPRINTF",
+			     "Prefer ethtool_puts over ethtool_sprintf with only two arguments" . $herecurr);
+		}
+
+		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
+		if (   $rawline =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*\"\%s\"\s*,\s*$FuncArg\s*\)/   ) {
+			WARN("ETHTOOL_SPRINTF2",
+			     "Prefer ethtool_puts over ethtool_sprintf with standalone \"%s\" specifier" . $herecurr);
+		}
+
+
 # typecasts on min/max could be min_t/max_t
 		if ($perl_version_ok &&
 		    defined $stat &&

-- 
2.42.0.758.gaed0368e0e-goog

On Wed, 2023-10-25 at 23:40 +0000, Justin Stitt wrote:
> Add some warnings for using ethtool_sprintf() where a simple
> ethtool_puts() would suffice.

Hi again Justin.

After I read patch 1/3 I don't object at all.

spatch/cocci will always be a better option than checkpatch
for conversions like this because it's a proper grammar parser
and checkpatch is a stupid little perl script.

If you resubmit this please:


> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -7020,6 +7020,19 @@ sub process {
>  			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
>  		}
>  
> +# ethtool_sprintf uses that should likely be ethtool_puts
> +		if (   $line =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/   ) {
> +			WARN("ETHTOOL_SPRINTF",
> +			     "Prefer ethtool_puts over ethtool_sprintf with only two arguments" . $herecurr);
> +		}
> +
> +		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
> +		if (   $rawline =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*\"\%s\"\s*,\s*$FuncArg\s*\)/   ) {
> +			WARN("ETHTOOL_SPRINTF2",
> +			     "Prefer ethtool_puts over ethtool_sprintf with standalone \"%s\" specifier" . $herecurr);
> +		}

o remove the whitespace before and after the parentheses
o use the same type "ETHTOOL_SPRINTF" or maybe "PREFER_ETHTOOL_PUTS"
  for both warnings.
o Add a newline on the message output
o Add a --fix option

Something like:
---
 scripts/checkpatch.pl | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 25fdb7fda1128..6924731110d87 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -7011,6 +7011,25 @@ sub process {
 			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
 		}
 
+# ethtool_sprintf uses that should likely be ethtool_puts
+		if ($line =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/) {
+			if (WARN("PREFER_ETHTOOL_PUTS",
+				 "Prefer ethtool_puts over ethtool_sprintf with only two arguments\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$fixlinenr] =~ s/\bethtool_sprintf\s*\(\s*($FuncArg)\s*,\s*($FuncArg)/ethtool_puts($1, $7)/;
+			}
+		}
+
+		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
+		if ($rawline =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*\"\%s\"\s*,\s*$FuncArg\s*\)/) {
+			if (WARN("PREFER_ETHTOOL_PUTS",
+				 "Prefer ethtool_puts over ethtool_sprintf with standalone \"%s\" specifier\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$fixlinenr] =~ s/\bethtool_sprintf\s*\(\s*($FuncArg)\s*,\s*"\%s"\s*,\s*($FuncArg)/ethtool_puts($1, $7)/;
+			}
+		}
+
+
 # typecasts on min/max could be min_t/max_t
 		if ($perl_version_ok &&
 		    defined $stat &&

On 10/26/23 01:40, Justin Stitt wrote:
> Add some warnings for using ethtool_sprintf() where a simple
> ethtool_puts() would suffice.
> 
> The two cases are:
> 
> 1) Use ethtool_sprintf() with just two arguments:
> |       ethtool_sprintf(&data, driver[i].name);
> or
> 2) Use ethtool_sprintf() with a standalone "%s" fmt string:
> |       ethtool_sprintf(&data, "%s", driver[i].name);
> 
> The former may cause -Wformat-security warnings while the latter is just
> not preferred. Both are safely in the category of warnings, not errors.
> 
> Signed-off-by: Justin Stitt <justinstitt@google.com>
> ---
>   scripts/checkpatch.pl | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 7d16f863edf1..1ba9ce778746 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -7020,6 +7020,19 @@ sub process {
>   			     "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
>   		}
>   
> +# ethtool_sprintf uses that should likely be ethtool_puts
> +		if (   $line =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\)/   ) {

no need for whitespace right after opening parenthesis, same at the end

Does it work for ethtool_sprintf(calls broken
				 into multiple lines)?

BTW, I really like this series!

> +			WARN("ETHTOOL_SPRINTF",
> +			     "Prefer ethtool_puts over ethtool_sprintf with only two arguments" . $herecurr);
> +		}
> +
> +		# use $rawline because $line loses %s via sanitization and thus we can't match against it.
> +		if (   $rawline =~ /\bethtool_sprintf\s*\(\s*$FuncArg\s*,\s*\"\%s\"\s*,\s*$FuncArg\s*\)/   ) {
> +			WARN("ETHTOOL_SPRINTF2",
> +			     "Prefer ethtool_puts over ethtool_sprintf with standalone \"%s\" specifier" . $herecurr);
> +		}
> +
> +
>   # typecasts on min/max could be min_t/max_t
>   		if ($perl_version_ok &&
>   		    defined $stat &&
>

On Wed, 2023-10-25 at 23:40 +0000, Justin Stitt wrote:
> Add some warnings for using ethtool_sprintf() where a simple
> ethtool_puts() would suffice.
> 
> The two cases are:
> 
> 1) Use ethtool_sprintf() with just two arguments:
> >       ethtool_sprintf(&data, driver[i].name);

OK.

> or
> 2) Use ethtool_sprintf() with a standalone "%s" fmt string:
> >       ethtool_sprintf(&data, "%s", driver[i].name);

I'm rather doubt this is really desired or appropriate.