Adds the support of key derivation using the scheme hkdf. This scheme is defined in rfc5869.
Signed-off-by: Philippe Reynes philippe.reynes@softathome.com --- include/u-boot/sha256.h | 20 ++++++++++++++++++++ lib/mbedtls/sha256.c | 23 +++++++++++++++++++++++ 2 files changed, 43 insertions(+)
diff --git a/include/u-boot/sha256.h b/include/u-boot/sha256.h index 99cf78e204c..d7a3403270b 100644 --- a/include/u-boot/sha256.h +++ b/include/u-boot/sha256.h @@ -1,6 +1,8 @@ #ifndef _SHA256_H #define _SHA256_H
+#include <linux/compiler_attributes.h> +#include <linux/errno.h> #include <linux/kconfig.h> #include <linux/types.h>
@@ -49,4 +51,22 @@ int sha256_hmac(const unsigned char *key, int keylen, const unsigned char *input, unsigned int ilen, unsigned char *output);
+#if CONFIG_IS_ENABLED(HKDF_MBEDTLS) +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); +#else +static inline int sha256_hkdf(const unsigned char __always_unused *salt, + int __always_unused saltlen, + const unsigned char __always_unused *ikm, + int __always_unused ikmlen, + const unsigned char __always_unused *info, + int __always_unused infolen, + unsigned char __always_unused *output, + int __always_unused outputlen) { + return -EOPNOTSUPP; +} +#endif + #endif /* _SHA256_H */ diff --git a/lib/mbedtls/sha256.c b/lib/mbedtls/sha256.c index 7d456a82017..59edcb517df 100644 --- a/lib/mbedtls/sha256.c +++ b/lib/mbedtls/sha256.c @@ -12,6 +12,10 @@
#include <mbedtls/md.h>
+#if CONFIG_IS_ENABLED(HKDF_MBEDTLS) +#include <mbedtls/hkdf.h> +#endif + const u8 sha256_der_prefix[SHA256_DER_LEN] = { 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, @@ -48,3 +52,22 @@ int sha256_hmac(const unsigned char *key, int keylen,
return mbedtls_md_hmac(md, key, keylen, input, ilen, output); } + +#if CONFIG_IS_ENABLED(HKDF_MBEDTLS) +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); + if (!md) + return MBEDTLS_ERR_MD_FEATURE_UNAVAILABLE; + + return mbedtls_hkdf(md, salt, saltlen, + ikm, ikmlen, + info, infolen, + output, outputlen); +} +#endif