Re: [PATCH v1 7/8] LSM: Create lsm_module_list system call
From: Paul Moore <paul@paul-moore.com>
Date: 2022-11-09 23:35:53
Also in:
linux-security-module, lkml
Possibly related (same subject, not in this thread)
- 2022-11-23 · [PATCH v1 7/8] LSM: Create lsm_module_list system call · Casey Schaufler <casey@schaufler-ca.com>
On Tue, Oct 25, 2022 at 2:48 PM Casey Schaufler [off-list ref] wrote:
Create a system call to report the list of Linux Security Modules that are active on the system. The list is provided as an array of LSM ID numbers. The calling application can use this list determine what LSM specific actions it might take. That might include chosing an output format, determining required privilege or bypassing security module specific behavior. Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- include/linux/syscalls.h | 1 + kernel/sys_ni.c | 1 + security/lsm_syscalls.c | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 40 insertions(+)
...
quoted hunk ↗ jump to hunk
diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c index da0fab7065e2..cd5db370b974 100644 --- a/security/lsm_syscalls.c +++ b/security/lsm_syscalls.c@@ -154,3 +154,41 @@ SYSCALL_DEFINE3(lsm_self_attr, kfree(final); return rc; } + +/** + * lsm_module_list - Return a list of the active security modules + * @ids: the LSM module ids + * @size: size of @ids, updated on return + * @flags: reserved for future use, must be zero + * + * Returns a list of the active LSM ids. On success this function + * returns the number of @ids array elements. This value may be zero + * if there are no LSMs active. If @size is insufficient to contain + * the return data -E2BIG is returned and @size is set to the minimum + * required size. In all other cases a negative value indicating the + * error is returned. + */
Let's make a promise that for this syscall we will order the LSM IDs in the array in the same order as which they are configured/executed. I'm doubtful that only a *very* small number of applications will care about this (if any), but this is something we can do so let's do it now while we can.
+SYSCALL_DEFINE3(lsm_module_list, + unsigned int __user *, ids, + size_t __user *, size, + unsigned int, flags)
-- paul-moore.com