Thread (13 messages) 13 messages, 8 authors, 2023-12-08

Re: [Intel-wired-lan] [PATCH net-next v5 2/3] checkpatch: add ethtool_sprintf rules

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From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Date: 2023-12-07 07:42:00
Also in: bpf, intel-wired-lan, linux-hyperv, linux-mediatek, lkml

On 12/7/23 00:16, justinstitt@google.com 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 | 19 +++++++++++++++++++
  1 file changed, 19 insertions(+)
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
quoted hunk ↗ jump to hunk
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 25fdb7fda112..6924731110d8 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)/;
(not related to the patch)
without deeper digging it was completely unclear why it is $7 for the
"second" capture group, turns out that FuncArg contains parens and other
vars with parens :~
quoted hunk ↗ jump to hunk
+			}
+		}
+
+
  # typecasts on min/max could be min_t/max_t
  		if ($perl_version_ok &&
  		    defined $stat &&
  
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