linux-kernel - [PATCH 3/4] leaking_addresses: cache architecture name

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1519008649-15782-4-git-send-email-me@tobin.cc>
Date:   Mon, 19 Feb 2018 13:50:48 +1100
From:   "Tobin C. Harding" <me@...in.cc>
To:     Kernel Hardening <kernel-hardening@...ts.openwall.com>
Cc:     "Tobin C. Harding" <me@...in.cc>, Tycho Andersen <tycho@...ho.ws>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/4] leaking_addresses: cache architecture name

Currently we are repeatedly calling `uname -m`.  This is causing the
script to take a long time to run (more than 10 seconds to parse
/proc/kallsyms).  We can use Perl state variables to cache the result of
the first call to `uname -m`.  With this change in place the script
scans the whole kernel in under a minute.

Cache machine architecture in state variable.

Signed-off-by: Tobin C. Harding <me@...in.cc>
---
 scripts/leaking_addresses.pl | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/scripts/leaking_addresses.pl b/scripts/leaking_addresses.pl
index e7bf15a45a69..f52e91ef7d5c 100755
--- a/scripts/leaking_addresses.pl
+++ b/scripts/leaking_addresses.pl
@@ -175,7 +175,7 @@ sub is_32bit
 
 sub is_ix86_32
 {
-       my $arch = `uname -m`;
+       state $arch = `uname -m`;
 
        chomp $arch;
        if ($arch =~ m/i[3456]86/) {
@@ -198,12 +198,14 @@ sub is_arch
 
 sub is_x86_64
 {
-	return is_arch('x86_64');
+	state $is = is_arch('x86_64');
+	return $is;
 }
 
 sub is_ppc64
 {
-	return is_arch('ppc64');
+	state $is = is_arch('ppc64');
+	return $is;
 }
 
 # Gets config option value from kernel config file.
-- 
2.7.4