ima: log message to module appraisal error

Simple but useful message log to the user in case of module appraise is
forced and fails due to the lack of file descriptor, that might be
caused by kmod calls to compressed modules.

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 0abc7d0db90b96e16a2a0b06dba6bcc74fb66a53..21330d0455b09b08964125a4add5e448dd9b057e 100644 (file)
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -404,8 +404,10 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
 
        if (!file && read_id == READING_MODULE) {
                if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES) &&
-                   (ima_appraise & IMA_APPRAISE_ENFORCE))
+                   (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;