[PATCH v3 5/7] ima: based on policy require signed firmware (sysfs fallback)

[Mimi Zohar]

With an IMA policy requiring signed firmware, this patch prevents
the sysfs fallback method of loading firmware.

Signed-off-by: Mimi Zohar <zo...@linux.vnet.ibm.com>
Cc: Luis R. Rodriguez <mcg...@suse.com>
Cc: David Howells <dhowe...@redhat.com>
Cc: Matthew Garrett <mj...@google.com>
---
 security/integrity/ima/ima_main.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/security/integrity/ima/ima_main.c 
b/security/integrity/ima/ima_main.c
index fbbcc02a1380..dd1f263f950a 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -451,10 +451,17 @@ int ima_read_data(struct file *file, enum 
kernel_read_file_id read_id)
                        pr_err("impossible to appraise a kernel image without a 
file descriptor; try using kexec_file syscall.\n");
                        return -EACCES; /* INTEGRITY_UNKNOWN */
                }
+               break;
+       case READING_FIRMWARE_FALLBACK_SYSFS:
+               if (ima_appraise & IMA_APPRAISE_FIRMWARE) {
+                       pr_err("Prevent firmware sysfs fallback loading.\n");
+                       return -EACCES; /* INTEGRITY_UNKNOWN */
+               }
        default:
                break;
        }
        return 0;
+
 }
 
 static int read_idmap[READING_MAX_ID] = {
-- 
2.7.5