module: replace the existing LSM hook in init_module

Both the init_module and finit_module syscalls call either directly
or indirectly the security_kernel_read_file LSM hook.  This patch
replaces the direct call in init_module with a call to the new
security_kernel_load_data hook and makes the corresponding changes
in SELinux, LoadPin, and IMA.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>

4 files changed, 32 insertions, 14 deletions

diff --git a/kernel/module.c b/kernel/module.c
index f475f30eed8c..a7615d661910 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2876,7 +2876,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
         if (info->len < sizeof(*(info->hdr)))
                 return -ENOEXEC;
 
-        err = security_kernel_read_file(NULL, READING_MODULE);
+        err = security_kernel_load_data(LOADING_MODULE);
         if (err)
                 return err;
 
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index e467664965e7..ef349a761609 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -429,16 +429,6 @@ void ima_post_path_mknod(struct dentry *dentry)
  */
 int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
 {
-        bool sig_enforce = is_module_sig_enforced();
-
-        if (!file && read_id == READING_MODULE) {
-                if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
-                    (ima_appraise & IMA_APPRAISE_ENFORCE)) {
-                        pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
-                        return -EACCES; /* INTEGRITY_UNKNOWN */
-                }
-                return 0;       /* We rely on module signature checking */
-        }
         return 0;
 }
 
@@ -479,9 +469,6 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
                 return 0;
         }
 
-        if (!file && read_id == READING_MODULE) /* MODULE_SIG_FORCE enabled */
-                return 0;
-
         /* permit signed certs */
         if (!file && read_id == READING_X509_CERTIFICATE)
                 return 0;
@@ -510,6 +497,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
  */
 int ima_load_data(enum kernel_load_data_id id)
 {
+        bool sig_enforce;
+
         if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE)
                 return 0;
 
@@ -525,6 +514,14 @@ int ima_load_data(enum kernel_load_data_id id)
                         pr_err("Prevent firmware sysfs fallback loading.\n");
                         return -EACCES; /* INTEGRITY_UNKNOWN */
                 }
+                break;
+        case LOADING_MODULE:
+                sig_enforce = is_module_sig_enforced();
+
+                if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) {
+                        pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n");
+                        return -EACCES; /* INTEGRITY_UNKNOWN */
+                }
         default:
                 break;
         }
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 5fa191252c8f..0716af28808a 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -173,9 +173,15 @@ 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)
+{
+        return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
+}
+
 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 2b5ee5fbd652..a8bf324130f5 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4073,6 +4073,20 @@ 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,
@@ -6972,6 +6986,7 @@ 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),