[PATCH v2 4/5] lib: mbedtls: sha256: add support of key derivation
Philippe Reynes
philippe.reynes at softathome.com
Wed Dec 4 18:54:36 CET 2024
Adds the support of key derivation using the scheme hkdf.
This scheme is defined in rfc5869.
Signed-off-by: Philippe Reynes <philippe.reynes at softathome.com>
---
include/u-boot/sha256.h | 5 +++++
lib/mbedtls/sha256.c | 18 ++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/include/u-boot/sha256.h b/include/u-boot/sha256.h
index 77dbcd4553a..0a6e309e3ab 100644
--- a/include/u-boot/sha256.h
+++ b/include/u-boot/sha256.h
@@ -48,4 +48,9 @@ void sha256_hmac(const unsigned char *key, int keylen,
const unsigned char *input, unsigned int ilen,
unsigned char *output);
+int sha256_hkdf(const unsigned char *salt, int saltlen,
+ const unsigned char *ikm, int ikmlen,
+ const unsigned char *info, int infolen,
+ unsigned char *output, int outputlen);
+
#endif /* _SHA256_H */
diff --git a/lib/mbedtls/sha256.c b/lib/mbedtls/sha256.c
index 1b9fc1a8503..c38e3e5818c 100644
--- a/lib/mbedtls/sha256.c
+++ b/lib/mbedtls/sha256.c
@@ -11,6 +11,9 @@
#include <string.h>
#include <u-boot/sha256.h>
+#include <mbedtls/md.h>
+#include <mbedtls/hkdf.h>
+
const u8 sha256_der_prefix[SHA256_DER_LEN] = {
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86,
0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05,
@@ -98,3 +101,18 @@ void sha256_hmac(const unsigned char *key, int keylen,
memset(tmpbuf, 0, sizeof(tmpbuf));
memset(&ctx, 0, sizeof(sha256_context));
}
+
+int sha256_hkdf(const unsigned char *salt, int saltlen,
+ const unsigned char *ikm, int ikmlen,
+ const unsigned char *info, int infolen,
+ unsigned char *output, int outputlen)
+{
+ const mbedtls_md_info_t *md;
+
+ md = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
+
+ return mbedtls_hkdf(md, salt, saltlen,
+ ikm, ikmlen,
+ info, infolen,
+ output, outputlen);
+}
--
2.25.1
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