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authorMickaël Salaün <mic@digikod.net>2024-02-27 12:05:50 +0100
committerMickaël Salaün <mic@digikod.net>2024-03-07 11:29:46 +0100
commit782191c74875cc33b50263e21d76080b1411884d (patch)
tree2ae6128bca47d8fa818f40032df2afd7a265539f /security
parent0e89ef6f790144504ef421dfc21960fc31abc783 (diff)
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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 This may be caused by boot loader configurations with outdated "lsm" kernel's command-line parameter. Cc: stable@vger.kernel.org Fixes: 265885daf3e5 ("landlock: Add syscall implementations") Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Günther Noack <gnoack3000@gmail.com> Link: https://lore.kernel.org/r/20240227110550.3702236-2-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
Diffstat (limited to 'security')
-rw-r--r--security/landlock/syscalls.c18
1 files changed, 15 insertions, 3 deletions
diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c
index 898358f57fa0..6788e73b6681 100644
--- a/security/landlock/syscalls.c
+++ b/security/landlock/syscalls.c
@@ -33,6 +33,18 @@
#include "ruleset.h"
#include "setup.h"
+static bool is_initialized(void)
+{
+ if (likely(landlock_initialized))
+ return true;
+
+ pr_warn_once(
+ "Disabled but requested by user space. "
+ "You should enable Landlock at boot time: "
+ "https://docs.kernel.org/userspace-api/landlock.html#boot-time-configuration\n");
+ return false;
+}
+
/**
* 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_initialized())
return -EOPNOTSUPP;
if (flags) {
@@ -398,7 +410,7 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd,
struct landlock_ruleset *ruleset;
int err;
- if (!landlock_initialized)
+ if (!is_initialized())
return -EOPNOTSUPP;
/* No flag for now. */
@@ -458,7 +470,7 @@ SYSCALL_DEFINE2(landlock_restrict_self, const int, ruleset_fd, const __u32,
struct landlock_cred_security *new_llcred;
int err;
- if (!landlock_initialized)
+ if (!is_initialized())
return -EOPNOTSUPP;
/*