diff options
| -rw-r--r-- | libcli/smb/smb2_signing.c | 32 | ||||
| -rw-r--r-- | libcli/smb/smb2_signing.h | 5 |
2 files changed, 37 insertions, 0 deletions
diff --git a/libcli/smb/smb2_signing.c b/libcli/smb/smb2_signing.c index 30172772b7..62a5ade043 100644 --- a/libcli/smb/smb2_signing.c +++ b/libcli/smb/smb2_signing.c @@ -135,3 +135,35 @@ NTSTATUS smb2_signing_check_pdu(DATA_BLOB signing_key, return NT_STATUS_OK; } + +void smb2_key_deviration(const uint8_t *KI, size_t KI_len, + const uint8_t *Label, size_t Label_len, + const uint8_t *Context, size_t Context_len, + uint8_t KO[16]) +{ + struct HMACSHA256Context ctx; + uint8_t buf[4]; + static const uint8_t zero = 0; + uint8_t digest[SHA256_DIGEST_LENGTH]; + uint32_t i = 1; + uint32_t L = 128; + + /* + * a simplified version of + * "NIST Special Publication 800-108" section 5.1 + * using hmac-sha256. + */ + hmac_sha256_init(KI, KI_len, &ctx); + + RSIVAL(buf, 0, i); + hmac_sha256_update(buf, sizeof(buf), &ctx); + hmac_sha256_update(Label, Label_len, &ctx); + hmac_sha256_update(&zero, 1, &ctx); + hmac_sha256_update(Context, Context_len, &ctx); + RSIVAL(buf, 0, L); + hmac_sha256_update(buf, sizeof(buf), &ctx); + + hmac_sha256_final(digest, &ctx); + + memcpy(KO, digest, 16); +} diff --git a/libcli/smb/smb2_signing.h b/libcli/smb/smb2_signing.h index ba2b1ca302..34d8ba2f4e 100644 --- a/libcli/smb/smb2_signing.h +++ b/libcli/smb/smb2_signing.h @@ -33,4 +33,9 @@ NTSTATUS smb2_signing_check_pdu(DATA_BLOB signing_key, const struct iovec *vector, int count); +void smb2_key_deviration(const uint8_t *KI, size_t KI_len, + const uint8_t *Label, size_t Label_len, + const uint8_t *Context, size_t Context_len, + uint8_t KO[16]); + #endif /* _LIBCLI_SMB_SMB2_SIGNING_H_ */ |