[PATCH v4 2/7] lib: crypto: enable x509_check_for_self_signed()

[AKASHI Takahiro]

When the file, x509_public_key.c, was imported from linux code in
    commit b4adf627d5b7 ("lib: crypto: add x509 parser"),
x509_check_for_self_signed() was commented out for simplicity.

Now it need be enabled in order to make pkcs7_verify_one(), which will be
imported in a later patch, functional.

Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
 lib/crypto/x509_cert_parser.c |  2 --
 lib/crypto/x509_public_key.c  | 33 +++++++++++++++++++++++++--------
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/lib/crypto/x509_cert_parser.c b/lib/crypto/x509_cert_parser.c
index 5f984b9dfdae..eb24349460c2 100644
--- a/lib/crypto/x509_cert_parser.c
+++ b/lib/crypto/x509_cert_parser.c
@@ -142,12 +142,10 @@ struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
 	}
 	cert->id = kid;
 
-#ifndef __UBOOT__
 	/* Detect self-signed certificates */
 	ret = x509_check_for_self_signed(cert);
 	if (ret < 0)
 		goto error_decode;
-#endif
 
 	kfree(ctx);
 	return cert;
diff --git a/lib/crypto/x509_public_key.c b/lib/crypto/x509_public_key.c
index 571af9a0adf9..91810a864049 100644
--- a/lib/crypto/x509_public_key.c
+++ b/lib/crypto/x509_public_key.c
@@ -8,6 +8,7 @@
 #define pr_fmt(fmt) "X.509: "fmt
 #ifdef __UBOOT__
 #include <common.h>
+#include <image.h>
 #include <dm/devres.h>
 #include <linux/compat.h>
 #include <linux/err.h>
@@ -18,6 +19,7 @@
 #include <linux/kernel.h>
 #ifdef __UBOOT__
 #include <crypto/x509_parser.h>
+#include <u-boot/rsa-checksum.h>
 #else
 #include <linux/slab.h>
 #include <keys/asymmetric-subtype.h>
@@ -35,7 +37,9 @@
 int x509_get_sig_params(struct x509_certificate *cert)
 {
 	struct public_key_signature *sig = cert->sig;
-#ifndef __UBOOT__
+#ifdef __UBOOT__
+	struct image_region region;
+#else
 	struct crypto_shash *tfm;
 	struct shash_desc *desc;
 	size_t desc_size;
@@ -63,12 +67,25 @@ int x509_get_sig_params(struct x509_certificate *cert)
 	sig->s_size = cert->raw_sig_size;
 
 #ifdef __UBOOT__
-	/*
-	 * Note:
-	 * This part (filling sig->digest) should be implemented if
-	 * x509_check_for_self_signed() is enabled x509_cert_parse().
-	 * Currently, this check won't affect UEFI secure boot.
-	 */
+	if (!sig->hash_algo)
+		return -ENOPKG;
+	if (!strcmp(sig->hash_algo, "sha256"))
+		sig->digest_size = SHA256_SUM_LEN;
+	else if (!strcmp(sig->hash_algo, "sha1"))
+		sig->digest_size = SHA1_SUM_LEN;
+	else
+		return -ENOPKG;
+
+	sig->digest = calloc(1, sig->digest_size);
+	if (!sig->digest)
+		return -ENOMEM;
+
+	region.data = cert->tbs;
+	region.size = cert->tbs_size;
+	hash_calculate(sig->hash_algo, &region, 1, sig->digest);
+
+	/* TODO: is_hash_blacklisted()? */
+
 	ret = 0;
 #else
 	/* Allocate the hashing algorithm we're going to need and find out how
@@ -118,7 +135,6 @@ error:
 	return ret;
 }
 
-#ifndef __UBOOT__
 /*
  * Check for self-signedness in an X.509 cert and if found, check the signature
  * immediately if we can.
@@ -175,6 +191,7 @@ not_self_signed:
 	return 0;
 }
 
+#ifndef __UBOOT__
 /*
  * Attempt to parse a data blob for a key as an X509 certificate.
  */
-- 
2.27.0