[Skiboot] [PATCH 08/19] libstb/cvc.c: import softrom behavior from drivers/sw_driver.c

[Claudio Carvalho]

Softrom is used only for testing with mambo. By setting
compatible="ibm,secureboot-v1-softrom" in the "ibm,secureboot" node,
firmware images can be properly measured even if the
Container-Verification-Code (CVC) is not available. In this case, the
mbedtls_sha512() function is used to calculate the sha512 hash of the
firmware images.

This imports the softrom behavior from libstb/drivers/sw_driver.c code
into cvc.c, but now softrom is implemented as a flag. When the flag is
set, the wrappers for the CVC services work the same way as in
sw_driver.c.

Signed-off-by: Claudio Carvalho <cclaudio at linux.vnet.ibm.com>
---
 libstb/cvc.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/libstb/cvc.c b/libstb/cvc.c
index ddb6a1c..5f46e5e 100644
--- a/libstb/cvc.c
+++ b/libstb/cvc.c
@@ -25,6 +25,7 @@
 #include <xscom.h>
 #include "container.h"
 #include "cvc.h"
+#include "mbedtls/sha512.h"
 
 /*
  * Assembly interfaces to call into the Container Verification Code.
@@ -251,6 +252,15 @@ int call_cvc_sha512(const uint8_t *data, size_t data_len, uint8_t *digest,
 		return OPAL_SUCCESS;
 
 	memset(digest, 0, SHA512_DIGEST_LENGTH);
+	if (softrom) {
+		mbedtls_sha512_context ctx;
+		mbedtls_sha512_init(&ctx);
+		mbedtls_sha512_starts(&ctx, 0); // SHA512 = 0
+		mbedtls_sha512_update(&ctx, data, data_len);
+		mbedtls_sha512_finish(&ctx, digest);
+		mbedtls_sha512_free(&ctx);
+		return OPAL_SUCCESS;
+	}
 
 	service = cvc_find_service(CVC_SHA512_SERVICE);
 
@@ -276,6 +286,9 @@ int call_cvc_verify(void *container, size_t len, const void *hw_key_hash,
 	    !hw_key_hash || hw_key_hash_size <= 0)
 		return OPAL_PARAMETER;
 
+	if (softrom)
+		return OPAL_RESOURCE;
+
 	service = cvc_find_service(CVC_VERIFY_SERVICE);
 
 	if (!service)
-- 
2.7.4