linux-kernel - [PATCH 4/4] ktest.pl: Prevent recursion of default variable options

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20250617154352.029415598@goodmis.org>
Date: Tue, 17 Jun 2025 11:43:07 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: "John Warthog9 Hawley" <warthog9@...nel.org>,
 dhaval@...nis.ca
Subject: [PATCH 4/4] ktest.pl: Prevent recursion of default variable options

From: Steven Rostedt <rostedt@...dmis.org>

If a default variable contains itself, do not recurse on it.

For example:

  ADD_CONFIG := ${CONFIG_DIR}/temp_config
  DEFAULTS
  ADD_CONFIG = ${CONFIG_DIR}/default_config ${ADD_CONFIG}

The above works because the temp variable ADD_CONFIG (is a temp because it
is created with ":=") is already defined, it will be substituted in the
variable option. But if it gets commented out:

  # ADD_CONFIG := ${CONFIG_DIR}/temp_config
  DEFAULTS
  ADD_CONFIG = ${CONFIG_DIR}/default_config ${ADD_CONFIG}

Then the above will go into a recursive loop where ${ADD_CONFIG} will
get replaced with the current definition of ADD_CONFIG which contains the
${ADD_CONFIG} and that will also try to get converted. ktest.pl will error
after 100 attempts of recursion and fail.

When replacing a variable with the default variable, if the default
variable contains itself, do not replace it.

Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
---
 tools/testing/ktest/ktest.pl | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/ktest/ktest.pl b/tools/testing/ktest/ktest.pl
index 075c386af5e5..b2971430d7e4 100755
--- a/tools/testing/ktest/ktest.pl
+++ b/tools/testing/ktest/ktest.pl
@@ -1394,7 +1394,10 @@ sub __eval_option {
 	# If a variable contains itself, use the default var
 	if (($var eq $name) && defined($opt{$var})) {
 	    $o = $opt{$var};
-	    $retval = "$retval$o";
+	    # Only append if the default doesn't contain itself
+	    if ($o !~ m/\$\{$var\}/) {
+		$retval = "$retval$o";
+	    }
 	} elsif (defined($opt{$o})) {
 	    $o = $opt{$o};
 	    $retval = "$retval$o";
-- 
2.47.2