auth/credentials: add cli_credentials_set_utf16_password()

We need a way to initialize the cli_credentials from the raw utf16 blob,
which might not be completely valid utf16, which means the conversion
from CH_UTF16MUNGED to CH_UTF8 might loose information.

This would result in an invalid nt_hash, when we convert back
from CH_UTF8 to CH_UTF16LE.

Bug: https://bugzilla.samba.org/show_bug.cgi?id=11016

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

3 files changed, 65 insertions, 6 deletions

diff --git a/auth/credentials/credentials.c b/auth/credentials/credentials.c
index 78b59556ea..a9e4fc864d 100644
--- a/auth/credentials/credentials.c
+++ b/auth/credentials/credentials.c
@@ -496,24 +496,27 @@ _PUBLIC_ bool cli_credentials_set_old_password(struct cli_credentials *cred,
 _PUBLIC_ struct samr_Password *cli_credentials_get_nt_hash(struct cli_credentials *cred,
 							   TALLOC_CTX *mem_ctx)
 {
-	const char *password = cli_credentials_get_password(cred);
+	const char *password = NULL;
 
-	if (password) {
+	if (cred->nt_hash != NULL) {
 		struct samr_Password *nt_hash = talloc(mem_ctx, struct samr_Password);
 		if (!nt_hash) {
 			return NULL;
 		}
 
-		E_md4hash(password, nt_hash->hash);    
+		*nt_hash = *cred->nt_hash;
 
 		return nt_hash;
-	} else if (cred->nt_hash != NULL) {
+	}
+
+	password = cli_credentials_get_password(cred);
+	if (password) {
 		struct samr_Password *nt_hash = talloc(mem_ctx, struct samr_Password);
 		if (!nt_hash) {
 			return NULL;
 		}
 
-		*nt_hash = *cred->nt_hash;
+		E_md4hash(password, nt_hash->hash);
 
 		return nt_hash;
 	}
diff --git a/auth/credentials/credentials.h b/auth/credentials/credentials.h
index 2da47d2cac..814f01648b 100644
--- a/auth/credentials/credentials.h
+++ b/auth/credentials/credentials.h
@@ -191,6 +191,9 @@ enum netr_SchannelType cli_credentials_get_secure_channel_type(struct cli_creden
 time_t cli_credentials_get_password_last_changed_time(struct cli_credentials *cred);
 void cli_credentials_set_kvno(struct cli_credentials *cred,
 			      int kvno);
+bool cli_credentials_set_utf16_password(struct cli_credentials *cred,
+					const DATA_BLOB *password_utf16,
+					enum credentials_obtained obtained);
 bool cli_credentials_set_nt_hash(struct cli_credentials *cred,
 				 const struct samr_Password *nt_hash, 
 				 enum credentials_obtained obtained);
diff --git a/auth/credentials/credentials_ntlm.c b/auth/credentials/credentials_ntlm.c
index 8c6be39522..5e9aeeda95 100644
--- a/auth/credentials/credentials_ntlm.c
+++ b/auth/credentials/credentials_ntlm.c
@@ -214,7 +214,60 @@ _PUBLIC_ NTSTATUS cli_credentials_get_ntlm_response(struct cli_credentials *cred
 	}
 	return NT_STATUS_OK;
 }
-	
+
+/*
+ * Set a utf16 password on the credentials context, including an indication
+ * of 'how' the password was obtained
+ *
+ * This is required because the nt_hash is calculated over the raw utf16 blob,
+ * which might not be completely valid utf16, which means the conversion
+ * from CH_UTF16MUNGED to CH_UTF8 might loose information.
+ */
+_PUBLIC_ bool cli_credentials_set_utf16_password(struct cli_credentials *cred,
+						 const DATA_BLOB *password_utf16,
+						 enum credentials_obtained obtained)
+{
+	if (password_utf16 == NULL) {
+		return cli_credentials_set_password(cred, NULL, obtained);
+	}
+
+	if (obtained >= cred->password_obtained) {
+		struct samr_Password *nt_hash = NULL;
+		char *password_talloc = NULL;
+		size_t password_len = 0;
+		bool ok;
+
+		nt_hash = talloc(cred, struct samr_Password);
+		if (nt_hash == NULL) {
+			return false;
+		}
+
+		ok = convert_string_talloc(cred,
+					   CH_UTF16MUNGED, CH_UTF8,
+					   password_utf16->data,
+					   password_utf16->length,
+					   (void *)&password_talloc,
+					   &password_len);
+		if (!ok) {
+			TALLOC_FREE(nt_hash);
+			return false;
+		}
+
+		ok = cli_credentials_set_password(cred, password_talloc, obtained);
+		TALLOC_FREE(password_talloc);
+		if (!ok) {
+			TALLOC_FREE(nt_hash);
+			return false;
+		}
+
+		mdfour(nt_hash->hash, password_utf16->data, password_utf16->length);
+		cred->nt_hash = nt_hash;
+		return true;
+	}
+
+	return false;
+}
+
 _PUBLIC_ bool cli_credentials_set_nt_hash(struct cli_credentials *cred,
 				 const struct samr_Password *nt_hash, 
 				 enum credentials_obtained obtained)