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-next>] [day] [month] [year] [list]
Message-ID: <20240219191804.2978911-1-mic@digikod.net>
Date: Mon, 19 Feb 2024 20:18:04 +0100
From: Mickaël Salaün <mic@...ikod.net>
To: Günther Noack <gnoack@...gle.com>,
	Paul Moore <paul@...l-moore.com>,
	"Serge E . Hallyn" <serge@...lyn.com>
Cc: Mickaël Salaün <mic@...ikod.net>,
	Konstantin Meskhidze <konstantin.meskhidze@...wei.com>,
	Shervin Oloumi <enlightened@...omium.org>,
	linux-hardening@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH] landlock: Warn once if a Landlock action is requested while disabled

Because sandboxing can be used as an opportunistic security measure,
user space may not log unsupported features.  Let the system
administrator know if an application tries to use Landlock but failed
because it isn't enabled at boot time.  This may be caused by bootloader
configurations with outdated "lsm" kernel's command-line parameter.

Cc: Günther Noack <gnoack@...gle.com>
Cc: stable@...r.kernel.org
Fixes: 265885daf3e5 ("landlock: Add syscall implementations")
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
---
 security/landlock/syscalls.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index f0bc50003b46..b5b424819dee 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -33,6 +33,18 @@
 #include "ruleset.h"
 #include "setup.h"
 
+static bool is_not_initialized(void)
+{
+	if (likely(landlock_initialized))
+		return false;
+
+	pr_warn_once(
+		"Disabled but requested by user space. "
+		"You should enable Landlock at boot time: "
+		"https://docs.kernel.org/userspace-api/landlock.html#kernel-support\n");
+	return true;
+}
+
 /**
  * copy_min_struct_from_user - Safe future-proof argument copying
  *
@@ -173,7 +185,7 @@ SYSCALL_DEFINE3(landlock_create_ruleset,
 	/* Build-time checks. */
 	build_check_abi();
 
-	if (!landlock_initialized)
+	if (is_not_initialized())
 		return -EOPNOTSUPP;
 
 	if (flags) {
@@ -407,7 +419,7 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd,
 	struct landlock_ruleset *ruleset;
 	int err;
 
-	if (!landlock_initialized)
+	if (is_not_initialized())
 		return -EOPNOTSUPP;
 
 	/* No flag for now. */
@@ -467,7 +479,7 @@ SYSCALL_DEFINE2(landlock_restrict_self, const int, ruleset_fd, const __u32,
 	struct landlock_cred_security *new_llcred;
 	int err;
 
-	if (!landlock_initialized)
+	if (is_not_initialized())
 		return -EOPNOTSUPP;
 
 	/*
-- 
2.43.0


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ