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
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.