Adds the support of the hmac based on sha256.
This implementation is based on rfc2104.
Signed-off-by: Philippe Reynes <philippe.rey...@softathome.com>
---
include/u-boot/sha256.h | 4 ++++
lib/sha256.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 44 insertions(+)
diff --git a/include/u-boot/sha256.h b/include/u-boot/sha256.h
index a4fe176c0b4..7aa4c54d0d4 100644
--- a/include/u-boot/sha256.h
+++ b/include/u-boot/sha256.h
@@ -24,4 +24,8 @@ void sha256_finish(sha256_context * ctx, uint8_t
digest[SHA256_SUM_LEN]);
void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
unsigned char *output, unsigned int chunk_sz);
+void sha256_hmac(const unsigned char *key, int keylen,
+ const unsigned char *input, unsigned int ilen,
+ unsigned char *output);
+
#endif /* _SHA256_H */
diff --git a/lib/sha256.c b/lib/sha256.c
index 665ba6f152e..64f6b48974b 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -298,3 +298,43 @@ 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));
+}
--
2.25.1
