security: introduce kernel_module_from_file hook
Now that kernel module origins can be reasoned about, provide a hook to
the LSMs to make policy decisions about the module file. This will let
Chrome OS enforce that loadable kernel modules can only come from its
read-only hash-verified root filesystem. Other LSMs can, for example,
read extended attributes for signatures, etc.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/include/linux/security.h b/include/linux/security.h
index 05e88bd..0f6afc6 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -694,6 +694,12 @@
* userspace to load a kernel module with the given name.
* @kmod_name name of the module requested by the kernel
* Return 0 if successful.
+ * @kernel_module_from_file:
+ * Load a kernel module from userspace.
+ * @file contains the file structure pointing to the file containing
+ * the kernel module to load. If the module is being loaded from a blob,
+ * this argument will be NULL.
+ * Return 0 if permission is granted.
* @task_fix_setuid:
* Update the module's state after setting one or more of the user
* identity attributes of the current process. The @flags parameter
@@ -1508,6 +1514,7 @@
int (*kernel_act_as)(struct cred *new, u32 secid);
int (*kernel_create_files_as)(struct cred *new, struct inode *inode);
int (*kernel_module_request)(char *kmod_name);
+ int (*kernel_module_from_file)(struct file *file);
int (*task_fix_setuid) (struct cred *new, const struct cred *old,
int flags);
int (*task_setpgid) (struct task_struct *p, pid_t pgid);
@@ -1765,6 +1772,7 @@
int security_kernel_act_as(struct cred *new, u32 secid);
int security_kernel_create_files_as(struct cred *new, struct inode *inode);
int security_kernel_module_request(char *kmod_name);
+int security_kernel_module_from_file(struct file *file);
int security_task_fix_setuid(struct cred *new, const struct cred *old,
int flags);
int security_task_setpgid(struct task_struct *p, pid_t pgid);
@@ -2278,6 +2286,11 @@
return 0;
}
+static inline int security_kernel_module_from_file(struct file *file)
+{
+ return 0;
+}
+
static inline int security_task_fix_setuid(struct cred *new,
const struct cred *old,
int flags)