MA-15015 Add sha256_hmac support

Add sha256 hmac support in u-boot.

Test: hmac calculation.

Change-Id: I0f1438fed8290620a1bb0663d19c21e20098eb5a
Signed-off-by: Ji Luo <ji.luo@nxp.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/lib/sha256.c b/lib/sha256.c
index 7f5a3618d0..f9b6bce72e 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -290,3 +290,43 @@ void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
 
 	sha256_finish(&ctx, output);
 }
+
+/*
+ * Output = HMAC-SHA-256( input buffer, hmac key )
+ */
+void sha256_hmac(const unsigned char *key, int keylen,
+	       const unsigned char *input, unsigned int ilen,
+	       unsigned char *output)
+{
+	int i;
+	sha256_context ctx;
+	unsigned char k_ipad[64];
+	unsigned char k_opad[64];
+	unsigned char tmpbuf[32];
+
+	memset (k_ipad, 0x36, 64);
+	memset (k_opad, 0x5C, 64);
+
+	for (i = 0; i < keylen; i++) {
+		if (i >= 64)
+			break;
+
+		k_ipad[i] ^= key[i];
+		k_opad[i] ^= key[i];
+	}
+
+	sha256_starts (&ctx);
+	sha256_update (&ctx, k_ipad, 64);
+	sha256_update (&ctx, input, ilen);
+	sha256_finish (&ctx, tmpbuf);
+
+	sha256_starts (&ctx);
+	sha256_update (&ctx, k_opad, 64);
+	sha256_update (&ctx, tmpbuf, 32);
+	sha256_finish (&ctx, output);
+
+	memset (k_ipad, 0, 64);
+	memset (k_opad, 0, 64);
+	memset (tmpbuf, 0, 32);
+	memset (&ctx, 0, sizeof (sha256_context));
+}