Diff: scripts/malloc-init.pl

Revision:

1:9ebc941037d5

diff -r cdf462088d13 -r 9ebc941037d5 scripts/malloc-init.pl
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/malloc-init.pl	Fri Sep 29 18:41:59 2017 +0100
@@ -0,0 +1,70 @@
+#!/usr/bin/perl
+
+# Check for malloc calls not shortly followed by initialisation.
+#
+# Known limitations:
+# - false negative: can't see allocations spanning more than one line
+# - possible false negatives, see patterns
+# - false positive: malloc-malloc-init-init is not accepted
+# - false positives: "non-standard" init functions (eg, the things being
+# initialised is not the first arg, or initialise struct members)
+#
+# Since false positives are expected, the results must be manually reviewed.
+#
+# Typical usage: scripts/malloc-init.pl library/*.c
+
+use warnings;
+use strict;
+
+use utf8;
+use open qw(:std utf8);
+
+my $limit = 7;
+my $inits = qr/memset|memcpy|_init|fread|base64_..code/;
+
+# cases to bear in mind:
+#
+# 0. foo = malloc(...); memset( foo, ... );
+# 1. *foo = malloc(...); memset( *foo, ... );
+# 2. type *foo = malloc(...); memset( foo, ...);
+# 3. foo = malloc(...); foo_init( (type *) foo );
+# 4. foo = malloc(...); for(i=0..n) { init( &foo[i] ); }
+#
+# The chosen patterns are a bit relaxed, but unlikely to cause false positives
+# in real code (initialising *foo or &foo instead of foo will likely be caught
+# by functional tests).
+#
+my $id = qr/([a-zA-Z-0-9_\->\.]*)/;
+my $prefix = qr/\s(?:\*?|\&?|\([a-z_]* \*\))\s*/;
+
+my $name;
+my $line;
+my @bad;
+
+die "Usage: $0 file.c [...]\n" unless @ARGV;
+
+while (my $file = shift @ARGV)
+{
+    open my $fh, "<", $file or die "read $file failed: $!\n";
+    while (<$fh>)
+    {
+        if( /mbedtls_malloc\(/ ) {
+            if( /$id\s*=.*mbedtls_malloc\(/ ) {
+                push @bad, "$file:$line:$name" if $name;
+                $name = $1;
+                $line = $.;
+            } else {
+                push @bad, "$file:$.:???" unless /return mbedtls_malloc/;
+            }
+        } elsif( $name && /(?:$inits)\($prefix\Q$name\E\b/ ) {
+            undef $name;
+        } elsif( $name && $. - $line > $limit ) {
+            push @bad, "$file:$line:$name";
+            undef $name;
+            undef $line;
+        }
+    }
+    close $fh or die;
+}
+
+print "$_\n" for @bad;