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 <na...@linux.ibm.com>
Reviewed-by: Mimi Zohar <zo...@linux.ibm.com>
---
 security/integrity/ima/ima_appraise.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/security/integrity/ima/ima_appraise.c 
b/security/integrity/ima/ima_appraise.c
index deec1804a00a..9c13585e7d3e 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -294,7 +294,16 @@ int ima_appraise_measurement(enum ima_hooks func,
                                             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 {
-- 
2.13.6

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