Thread (41 messages) 41 messages, 7 authors, 2018-06-06

[PATCH v4a 8/8] module: replace the existing LSM hook in init_module

From: Kees Cook <hidden>
Date: 2018-06-05 19:45:13
Also in: kexec, linux-integrity, lkml

On Thu, May 31, 2018 at 8:23 AM, Mimi Zohar [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 5fa191252c8f..a9c07bfbc338 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -173,9 +173,24 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
        return 0;
 }

+static int loadpin_load_data(enum kernel_load_data_id id)
+{
+       int rc = 0;
+
+       switch (id) {
+       case LOADING_MODULE:
+               rc = loadpin_read_file(NULL, READING_MODULE);
+       default:
+               break;
+       }
+
+       return rc;
+}
Is it worth keeping the same enum between the two hooks? That would
simplify this a bit since it could just pass the id without remapping.

And if you must have a separate enum, please change this to fail
closed instead of open (and mark the fall-through):

int rc = -EPERM;

switch (id) {
case LOADING_MODULE:
    rc = loadpin_read_file(NULL, READING_MODULE);
    /* Fall-through */
default:
    break;
}

Thanks!

-Kees
quoted hunk ↗ jump to hunk
+
 static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {
        LSM_HOOK_INIT(sb_free_security, loadpin_sb_free_security),
        LSM_HOOK_INIT(kernel_read_file, loadpin_read_file),
+       LSM_HOOK_INIT(kernel_load_data, loadpin_load_data),
 };

 void __init loadpin_add_hooks(void)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 02ebd1585eaf..475aed9ee2c7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4059,6 +4059,20 @@ static int selinux_kernel_read_file(struct file *file,
        return rc;
 }

+static int selinux_kernel_load_data(enum kernel_load_data_id id)
+{
+       int rc = 0;
+
+       switch (id) {
+       case LOADING_MODULE:
+               rc = selinux_kernel_module_from_file(NULL);
+       default:
+               break;
+       }
+
+       return rc;
+}
+
 static int selinux_task_setpgid(struct task_struct *p, pid_t pgid)
 {
        return avc_has_perm(&selinux_state,
@@ -6950,6 +6964,7 @@ static struct security_hook_list selinux_hooks[] __lsm_ro_after_init = {
        LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as),
        LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as),
        LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request),
+       LSM_HOOK_INIT(kernel_load_data, selinux_kernel_load_data),
        LSM_HOOK_INIT(kernel_read_file, selinux_kernel_read_file),
        LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid),
        LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid),
--
2.7.5


-- 
Kees Cook
Pixel Security
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