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Date: Mon, 27 Feb 2017 12:54:55 -0800
From: Joe Perches <joe@...ches.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Andy Whitcroft <apw@...onical.com>
Cc: "Roberts, William C" <william.c.roberts@...el.com>,
kernel-hardening@...ts.openwall.com,
linux-kernel@...r.kernel.org
Subject: [PATCH] checkpatch: Add ability to find bad uses of vsprintf %p<foo> extensions
%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@...ches.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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