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Groups > linux.kernel > #1588943

[PATCH] checkpatch: Add ability to find bad uses of vsprintf %p<foo> extensions

From Joe Perches <joe@perches.com>
Newsgroups linux.kernel
Subject [PATCH] checkpatch: Add ability to find bad uses of vsprintf %p<foo> extensions
Date 2017-02-27 22:00 +0100
Message-ID <tfAyL-2v1-33@gated-at.bofh.it> (permalink)
References <tfwls-86h-13@gated-at.bofh.it>
Organization linux.* mail to news gateway

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%pK was at least once misused at %pk in an out-of-tree module.
This lead to some security concerns.  Add the ability to track
single and multiple line statements for misuses of %p<foo>.

Signed-off-by: Joe Perches <joe@perches.com>
---

Andrew, this has gone back and forth a few times.

It's imperfect as a patch context with just a single
function addition can be missed, but that's not new
with $stat tests and just this patch.  Perhaps one day
the $stat identification mechanism can be improved.

Until then, can you please apply this?  Thanks.

 scripts/checkpatch.pl | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ad5ea5c545b2..9293b8a1c121 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5676,6 +5676,32 @@ sub process {
 			}
 		}
 
+		# check for vsprintf extension %p<foo> misuses
+		if ($^V && $^V ge 5.10.0 &&
+		    defined $stat &&
+		    $stat =~ /^\+(?![^\{]*\{\s*).*\b(\w+)\s*\(.*$String\s*,/s &&
+		    $1 !~ /^_*volatile_*$/) {
+			my $bad_extension = "";
+			my $lc = $stat =~ tr@\n@@;
+			$lc = $lc + $linenr;
+		        for (my $count = $linenr; $count <= $lc; $count++) {
+				my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0));
+				$fmt =~ s/%%//g;
+				if ($fmt =~ /(\%[\*\d\.]*p(?![\WFfSsBKRraEhMmIiUDdgVCbGN]).)/) {
+					$bad_extension = $1;
+					last;
+				}
+			}
+			if ($bad_extension ne "") {
+				my $stat_real = raw_line($linenr, 0);
+				for (my $count = $linenr + 1; $count <= $lc; $count++) {
+					$stat_real = $stat_real . "\n" . raw_line($count, 0);
+				}
+				WARN("VSPRINTF_POINTER_EXTENSION",
+				     "Invalid vsprintf pointer extension '$bad_extension'\n" . "$here\n$stat_real\n");
+			}
+		}
+
 # Check for misused memsets
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&
-- 
2.10.0.rc2.1.g053435c

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Thread

RE: [PATCH] checkpatch: add warning on %pk instead of %pK usage "Roberts, William C" <william.c.roberts@intel.com> - 2017-02-13 20:50 +0100
  Re: [PATCH] checkpatch: add warning on %pk instead of %pK usage Joe Perches <joe@perches.com> - 2017-02-13 21:20 +0100
  Re: [PATCH] checkpatch: add warning on %pk instead of %pK usage Joe Perches <joe@perches.com> - 2017-02-13 23:30 +0100
    RE: [PATCH] checkpatch: add warning on %pk instead of %pK usage "Roberts, William C" <william.c.roberts@intel.com> - 2017-02-16 00:50 +0100
      Re: [PATCH] checkpatch: add warning on %pk instead of %pK usage Joe Perches <joe@perches.com> - 2017-02-16 01:30 +0100
      RE: [PATCH] checkpatch: add warning on %pk instead of %pK usage "Roberts, William C" <william.c.roberts@intel.com> - 2017-02-27 17:30 +0100
        [PATCH] checkpatch: Add ability to find bad uses of vsprintf %p<foo> extensions Joe Perches <joe@perches.com> - 2017-02-27 22:00 +0100
          Re: [kernel-hardening] [PATCH] checkpatch: Add ability to find bad  uses of vsprintf %p<foo> extensions Kees Cook <keescook@chromium.org> - 2017-02-27 22:40 +0100
          RE: [PATCH] checkpatch: Add ability to find bad uses of vsprintf  %p<foo> extensions "Roberts, William C" <william.c.roberts@intel.com> - 2017-02-28 16:40 +0100
          Re: [PATCH] checkpatch: Add ability to find bad uses of vsprintf  %p<foo> extensions Joe Perches <joe@perches.com> - 2017-03-01 01:20 +0100
          Re: [kernel-hardening] Re: [PATCH] checkpatch: Add ability to find  bad uses of vsprintf %p<foo> extensions Kees Cook <keescook@chromium.org> - 2017-03-01 01:20 +0100
            Re: [kernel-hardening] Re: [PATCH] checkpatch: Add ability to find  bad uses of vsprintf %p<foo> extensions Joe Perches <joe@perches.com> - 2017-03-01 02:30 +0100
          Re: [PATCH] checkpatch: Add ability to find bad uses of vsprintf  %p<foo> extensions Andrew Morton <akpm@linux-foundation.org> - 2017-03-01 03:10 +0100

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