Re: [PATCH 2/3] lsm: introduce security_lsm_manage_policy hook

From
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date
2025-05-07 10:40:32
Also in
linux-security-module, lkml
Reply to
Maxime Bélair, 2025-05-06
On 2025/05/06 23:32, Maxime Bélair wrote:
quoted hunk ↗ jump to hunk
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c
index dcaad8818679..b39e6635a7d5 100644
--- a/security/lsm_syscalls.c
+++ b/security/lsm_syscalls.c
@@ -122,5 +122,10 @@ SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, u32 __user *, size,
 SYSCALL_DEFINE5(lsm_manage_policy, u32, lsm_id, u32, op, void __user *, buf, u32
 		__user *, size, u32, flags)
 {
-	return 0;
+	size_t usize;
+
+	if (get_user(usize, size))
+		return -EFAULT;
+
+	return security_lsm_manage_policy(lsm_id, op, buf, usize, flags);
 }
syzbot will report user-controlled unbounded huge size memory allocation attempt. ;-)

This interface might be fine for AppArmor, but TOMOYO won't use this interface because
TOMOYO's policy is line-oriented ASCII text data where the destination is switched via
pseudo‑filesystem's filename; use of filename helps restricting which type of policy
can be manipulated by which process.
Thread (36 messages) 36 messages, 8 authors, last reply 2025-05-17
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