ima: Support platform keyring for kernel appraisal

On secure boot enabled systems, the bootloader verifies the kernel
image and possibly the initramfs signatures based on a set of keys. A
soft reboot(kexec) of the system, with the same kernel image and
initramfs, requires access to the original keys to verify the
signatures.

This patch allows IMA-appraisal access to those original keys, now
loaded on the platform keyring, needed for verifying the kernel image
and initramfs signatures.

Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index deec1804a00aa488d02b307371cfc18475127bc3..e8f520450895cd0195cd816cfd809adec4108587 100644 (file)
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -289,12 +289,21 @@ int ima_appraise_measurement(enum ima_hooks func,
        case EVM_IMA_XATTR_DIGSIG:
                set_bit(IMA_DIGSIG, &iint->atomic_flags);
                rc = integrity_digsig_verify(INTEGRITY_KEYRING_IMA,
-                                            (const char *)xattr_value, rc,
+                                            (const char *)xattr_value,
+                                            xattr_len,
                                             iint->ima_hash->digest,
                                             iint->ima_hash->length);
                if (rc == -EOPNOTSUPP) {
                        status = INTEGRITY_UNKNOWN;
-               } else if (rc) {
+                       break;
+               }
+               if (rc && func == KEXEC_KERNEL_CHECK)
+                       rc = integrity_digsig_verify(INTEGRITY_KEYRING_PLATFORM,
+                                                    (const char *)xattr_value,
+                                                    xattr_len,
+                                                    iint->ima_hash->digest,
+                                                    iint->ima_hash->length);
+               if (rc) {
                        cause = "invalid-signature";
                        status = INTEGRITY_FAIL;
                } else {