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Message-Id: <1519706711-18580-2-git-send-email-me@tobin.cc>
Date: Tue, 27 Feb 2018 15:45:09 +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 1/3] leaking_addresses: skip all /proc/PID except /proc/1
When the system is idle it is likely that most files under /proc/PID
will be identical for various processes. Scanning _all_ the PIDs under
/proc is unnecessary and implies that we are thoroughly scanning /proc.
This is _not_ the case because there may be ways userspace can trigger
creation of /proc files that leak addresses but were not present during
a scan. For these two reasons we should exclude all PID directories
under /proc except '1/'
Exclude all /proc/PID except /proc/1.
Signed-off-by: Tobin C. Harding <me@...in.cc>
---
scripts/leaking_addresses.pl | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/scripts/leaking_addresses.pl b/scripts/leaking_addresses.pl
index 6e5bc57caeaa..fb40e2828f43 100755
--- a/scripts/leaking_addresses.pl
+++ b/scripts/leaking_addresses.pl
@@ -10,6 +10,14 @@
# Use --debug to output path before parsing, this is useful to find files that
# cause the script to choke.
+#
+# When the system is idle it is likely that most files under /proc/PID will be
+# identical for various processes. Scanning _all_ the PIDs under /proc is
+# unnecessary and implies that we are thoroughly scanning /proc. This is _not_
+# the case because there may be ways userspace can trigger creation of /proc
+# files that leak addresses but were not present during a scan. For these two
+# reasons we exclude all PID directories under /proc except '1/'
+
use warnings;
use strict;
use POSIX;
@@ -472,6 +480,9 @@ sub walk
my $path = "$pwd/$file";
next if (-l $path);
+ # skip /proc/PID except /proc/1
+ next if ($path =~ /\/proc\/(?:[2-9][0-9]*|1[0-9]+)/);
+
next if (skip($path));
if (-d $path) {
--
2.7.4
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