ima: check signature enforcement against cmdline param instead of CONFIG

When the user requests MODULE_CHECK policy and its kernel is compiled
with CONFIG_MODULE_SIG_FORCE not set, all modules would not load, just
those loaded in initram time. One option the user would have would be
set a kernel cmdline param (module.sig_enforce) to true, but the IMA
module check code doesn't rely on this value, it checks just
CONFIG_MODULE_SIG_FORCE.

This patch solves this problem checking for the exported value of
module.sig_enforce cmdline param intead of CONFIG_MODULE_SIG_FORCE,
which holds the effective value (CONFIG || param).

Signed-off-by: Bruno E. O. Meneguele <brdeoliv@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index d6ddaad91e82115222c1f77c11a5b73cf29354d9..770654694efcb4d728dd6a0f23b2f8f21d6e90be 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -362,12 +362,12 @@ 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) {
-#ifndef CONFIG_MODULE_SIG_FORCE
-               if ((ima_appraise & IMA_APPRAISE_MODULES) &&
+               if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
                    (ima_appraise & IMA_APPRAISE_ENFORCE))
                        return -EACCES; /* INTEGRITY_UNKNOWN */
-#endif
                return 0;       /* We rely on module signature checking */
        }
        return 0;