http: add SSPI authentication on Windows

Add support for SSPI on Windows, which offers NTLM and Negotiate
authentication.

cmake/SelectGSSAPI.cmake

@@ -29,7 +29,7 @@ if(USE_GSSAPI)
 		list(APPEND LIBGIT2_SYSTEM_LIBS ${GSSFRAMEWORK_LIBRARIES})
 
 		set(GIT_GSSFRAMEWORK 1)
-		add_feature_info(SPNEGO GIT_GSSFRAMEWORK "SPNEGO authentication support (${USE_GSSAPI})")
+		add_feature_info(GSSAPI GIT_GSSFRAMEWORK "GSSAPI support for SPNEGO authentication (${USE_GSSAPI})")
 	elseif(USE_GSSAPI STREQUAL "gssapi")
 		if(NOT GSSAPI_FOUND)
 			message(FATAL_ERROR "Asked for gssapi GSS backend, but it wasn't found")
@@ -38,11 +38,11 @@ if(USE_GSSAPI)
 		list(APPEND LIBGIT2_SYSTEM_LIBS ${GSSAPI_LIBRARIES})
 
 		set(GIT_GSSAPI 1)
-		add_feature_info(SPNEGO GIT_GSSAPI "SPNEGO authentication support (${USE_GSSAPI})")
+		add_feature_info(GSSAPI GIT_GSSAPI "GSSAPI support for SPNEGO authentication (${USE_GSSAPI})")
 	else()
 		message(FATAL_ERROR "Asked for backend ${USE_GSSAPI} but it wasn't found")
 	endif()
 else()
 	set(GIT_GSSAPI 0)
-	add_feature_info(SPNEGO NO "SPNEGO authentication support")
+	add_feature_info(GSSAPI NO "GSSAPI support for SPNEGO authentication")
 endif()

cmake/SelectHTTPSBackend.cmake

@@ -125,8 +125,8 @@ if(USE_HTTPS)
 			list(APPEND LIBGIT2_PC_LIBS "-lwinhttp")
 		endif()
 
-		list(APPEND LIBGIT2_SYSTEM_LIBS "rpcrt4" "crypt32" "ole32")
-		list(APPEND LIBGIT2_PC_LIBS "-lrpcrt4" "-lcrypt32" "-lole32")
+		list(APPEND LIBGIT2_SYSTEM_LIBS "rpcrt4" "crypt32" "ole32" "secur32")
+		list(APPEND LIBGIT2_PC_LIBS "-lrpcrt4" "-lcrypt32" "-lole32" "-lsecur32")
 	elseif(USE_HTTPS STREQUAL "OpenSSL-Dynamic")
 		set(GIT_OPENSSL 1)
 		set(GIT_OPENSSL_DYNAMIC 1)

src/libgit2/transports/auth_negotiate.h

@@ -12,7 +12,7 @@
 #include "git2.h"
 #include "auth.h"
 
-#if defined(GIT_GSSAPI) || defined(GIT_GSSFRAMEWORK)
+#if defined(GIT_GSSAPI) || defined(GIT_GSSFRAMEWORK) || defined(GIT_WIN32)
 
 extern int git_http_auth_negotiate(
 	git_http_auth_context **out,

src/libgit2/transports/auth_ntlm.h

@@ -5,15 +5,15 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 
-#ifndef INCLUDE_transports_auth_ntlmclient_h__
-#define INCLUDE_transports_auth_ntlmclient_h__
+#ifndef INCLUDE_transports_auth_ntlm_h__
+#define INCLUDE_transports_auth_ntlm_h__
 
 #include "auth.h"
 
 /* NTLM requires a full request/challenge/response */
 #define GIT_AUTH_STEPS_NTLM 2
 
-#ifdef GIT_NTLM
+#if defined(GIT_NTLM) || defined(GIT_WIN32)
 
 #if defined(GIT_OPENSSL)
 # define CRYPT_OPENSSL

src/libgit2/transports/auth_sspi.c

+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "auth_ntlm.h"
+#include "auth_negotiate.h"
+
+#ifdef GIT_WIN32
+
+#define SECURITY_WIN32
+
+#include "git2.h"
+#include "auth.h"
+#include "git2/sys/credential.h"
+
+#include <windows.h>
+#include <security.h>
+
+typedef struct {
+	git_http_auth_context parent;
+	wchar_t *target;
+
+	const char *package_name;
+	size_t package_name_len;
+	wchar_t *package_name_w;
+	SecPkgInfoW *package_info;
+	SEC_WINNT_AUTH_IDENTITY_W identity;
+	CredHandle cred;
+	CtxtHandle context;
+
+	int has_identity : 1,
+	    has_credentials : 1,
+	    has_context : 1,
+	    complete : 1;
+	git_str challenge;
+} http_auth_sspi_context;
+
+static void sspi_reset_context(http_auth_sspi_context *ctx)
+{
+	if (ctx->has_identity) {
+		git__free(ctx->identity.User);
+		git__free(ctx->identity.Domain);
+		git__free(ctx->identity.Password);
+
+		memset(&ctx->identity, 0, sizeof(SEC_WINNT_AUTH_IDENTITY_W));
+
+		ctx->has_identity = 0;
+	}
+
+	if (ctx->has_credentials) {
+		FreeCredentialsHandle(&ctx->cred);
+		memset(&ctx->cred, 0, sizeof(CredHandle));
+
+		ctx->has_credentials = 0;
+	}
+
+	if (ctx->has_context) {
+		DeleteSecurityContext(&ctx->context);
+		memset(&ctx->context, 0, sizeof(CtxtHandle));
+
+		ctx->has_context = 0;
+	}
+
+	ctx->complete = 0;
+
+	git_str_dispose(&ctx->challenge);
+}
+
+static int sspi_set_challenge(
+	git_http_auth_context *c,
+	const char *challenge)
+{
+	http_auth_sspi_context *ctx = (http_auth_sspi_context *)c;
+	size_t challenge_len = strlen(challenge);
+
+	git_str_clear(&ctx->challenge);
+
+	if (strncmp(challenge, ctx->package_name, ctx->package_name_len) != 0) {
+		git_error_set(GIT_ERROR_NET, "invalid %s challenge from server", ctx->package_name);
+		return -1;
+	}
+
+	/*
+	 * A package type indicator without a base64 payload indicates the
+	 * mechanism; it's not an actual challenge. Ignore it.
+	 */
+	if (challenge[ctx->package_name_len] == 0) {
+		return 0;
+	} else if (challenge[ctx->package_name_len] != ' ') {
+		git_error_set(GIT_ERROR_NET, "invalid %s challenge from server", ctx->package_name);
+		return -1;
+	}
+
+	if (git_str_decode_base64(&ctx->challenge,
+	                          challenge + (ctx->package_name_len + 1),
+	                          challenge_len - (ctx->package_name_len + 1)) < 0) {
+		git_error_set(GIT_ERROR_NET, "invalid %s challenge from server", ctx->package_name);
+		return -1;
+	}
+
+	GIT_ASSERT(ctx->challenge.size <= ULONG_MAX);
+	return 0;
+}
+
+static int create_identity(
+	SEC_WINNT_AUTH_IDENTITY_W **out,
+	http_auth_sspi_context *ctx,
+	git_credential *cred)
+{
+	git_credential_userpass_plaintext *userpass;
+	wchar_t *username = NULL, *domain = NULL, *password = NULL;
+	int username_len = 0, domain_len = 0, password_len = 0;
+	const char *sep;
+
+	if (cred->credtype == GIT_CREDENTIAL_DEFAULT) {
+		*out = NULL;
+		return 0;
+	}
+
+	if (cred->credtype != GIT_CREDENTIAL_USERPASS_PLAINTEXT) {
+		git_error_set(GIT_ERROR_NET, "unknown credential type: %d", cred->credtype);
+		return -1;
+	}
+
+	userpass = (git_credential_userpass_plaintext *)cred;
+
+	if ((sep = strchr(userpass->username, '\\')) != NULL) {
+		GIT_ASSERT(sep - userpass->username < INT_MAX);
+
+		username_len = git_utf8_to_16_alloc(&username, sep + 1);
+		domain_len = git_utf8_to_16_alloc_with_len(&domain,
+			userpass->username, (int)(sep - userpass->username));
+	} else {
+		username_len = git_utf8_to_16_alloc(&username,
+			userpass->username);
+	}
+
+	password_len = git_utf8_to_16_alloc(&password, userpass->password);
+
+	if (username_len < 0 || domain_len < 0 || password_len < 0) {
+		git__free(username);
+		git__free(domain);
+		git__free(password);
+		return -1;
+	}
+
+	ctx->identity.Flags = SEC_WINNT_AUTH_IDENTITY_UNICODE;
+	ctx->identity.User = username;
+	ctx->identity.UserLength = (unsigned long)username_len;
+	ctx->identity.Password = password;
+	ctx->identity.PasswordLength = (unsigned long)password_len;
+	ctx->identity.Domain = domain;
+	ctx->identity.DomainLength = (unsigned long)domain_len;
+
+	ctx->has_identity = 1;
+
+	*out = &ctx->identity;
+
+	return 0;
+}
+
+static int sspi_next_token(
+	git_str *buf,
+	git_http_auth_context *c,
+	git_credential *cred)
+{
+	http_auth_sspi_context *ctx = (http_auth_sspi_context *)c;
+	SEC_WINNT_AUTH_IDENTITY_W *identity = NULL;
+	TimeStamp timestamp;
+	DWORD context_flags;
+	SecBuffer input_buf = { 0, SECBUFFER_TOKEN, NULL };
+	SecBuffer output_buf = { 0, SECBUFFER_TOKEN, NULL };
+	SecBufferDesc input_buf_desc = { SECBUFFER_VERSION, 1, &input_buf };
+	SecBufferDesc output_buf_desc = { SECBUFFER_VERSION, 1, &output_buf };
+	SECURITY_STATUS status;
+
+	if (ctx->complete)
+		sspi_reset_context(ctx);
+
+	if (!ctx->has_context) {
+		if (create_identity(&identity, ctx, cred) < 0)
+			return -1;
+
+		status = AcquireCredentialsHandleW(NULL, ctx->package_name_w,
+				SECPKG_CRED_BOTH, NULL, identity, NULL,
+				NULL, &ctx->cred, &timestamp);
+
+		if (status != SEC_E_OK) {
+			git_error_set(GIT_ERROR_OS, "could not acquire credentials");
+			return -1;
+		}
+
+		ctx->has_credentials = 1;
+	}
+
+	context_flags = ISC_REQ_ALLOCATE_MEMORY |
+	                ISC_REQ_CONFIDENTIALITY |
+	                ISC_REQ_MUTUAL_AUTH;
+
+	if (ctx->challenge.size > 0) {
+		input_buf.BufferType = SECBUFFER_TOKEN;
+		input_buf.cbBuffer = (unsigned long)ctx->challenge.size;
+		input_buf.pvBuffer = ctx->challenge.ptr;
+	}
+
+	status = InitializeSecurityContextW(&ctx->cred,
+		ctx->has_context ? &ctx->context : NULL,
+		ctx->target,
+		context_flags,
+		0,
+		SECURITY_NETWORK_DREP,
+		ctx->has_context ? &input_buf_desc : NULL,
+		0,
+		ctx->has_context ? NULL : &ctx->context,
+		&output_buf_desc,
+		&context_flags,
+		NULL);
+
+	if (status == SEC_I_COMPLETE_AND_CONTINUE ||
+	    status == SEC_I_COMPLETE_NEEDED)
+		status = CompleteAuthToken(&ctx->context, &output_buf_desc);
+
+	if (status == SEC_E_OK) {
+		ctx->complete = 1;
+	} else if (status != SEC_I_CONTINUE_NEEDED) {
+		git_error_set(GIT_ERROR_OS, "could not initialize security context");
+		return -1;
+	}
+
+	ctx->has_context = 1;
+	git_str_clear(&ctx->challenge);
+
+	if (output_buf.cbBuffer > 0) {
+		git_str_put(buf, ctx->package_name, ctx->package_name_len);
+		git_str_putc(buf, ' ');
+		git_str_encode_base64(buf, output_buf.pvBuffer, output_buf.cbBuffer);
+
+		FreeContextBuffer(output_buf.pvBuffer);
+
+		if (git_str_oom(buf))
+			return -1;
+	}
+
+	return 0;
+}
+
+static int sspi_is_complete(git_http_auth_context *c)
+{
+	http_auth_sspi_context *ctx = (http_auth_sspi_context *)c;
+
+	return ctx->complete;
+}
+
+static void sspi_context_free(git_http_auth_context *c)
+{
+	http_auth_sspi_context *ctx = (http_auth_sspi_context *)c;
+
+	sspi_reset_context(ctx);
+
+	FreeContextBuffer(ctx->package_info);
+	git__free(ctx->target);
+	git__free(ctx);
+}
+
+static int sspi_init_context(
+	git_http_auth_context **out,
+	git_http_auth_t type,
+	const git_net_url *url)
+{
+	http_auth_sspi_context *ctx;
+	git_str target = GIT_STR_INIT;
+
+	*out = NULL;
+
+	ctx = git__calloc(1, sizeof(http_auth_sspi_context));
+	GIT_ERROR_CHECK_ALLOC(ctx);
+
+	switch (type) {
+	case GIT_HTTP_AUTH_NTLM:
+		ctx->package_name = "NTLM";
+		ctx->package_name_len = CONST_STRLEN("NTLM");
+		ctx->package_name_w = L"NTLM";
+		ctx->parent.credtypes = GIT_CREDENTIAL_USERPASS_PLAINTEXT |
+	                                GIT_CREDENTIAL_DEFAULT;
+		break;
+	case GIT_HTTP_AUTH_NEGOTIATE:
+		ctx->package_name = "Negotiate";
+		ctx->package_name_len = CONST_STRLEN("Negotiate");
+		ctx->package_name_w = L"Negotiate";
+		ctx->parent.credtypes = GIT_CREDENTIAL_DEFAULT;
+		break;
+	default:
+		git_error_set(GIT_ERROR_NET, "unknown SSPI auth type: %d", ctx->parent.type);
+		git__free(ctx);
+		return -1;
+	}
+
+	if (QuerySecurityPackageInfoW(ctx->package_name_w, &ctx->package_info) != SEC_E_OK) {
+		git_error_set(GIT_ERROR_OS, "could not query security package");
+		git__free(ctx);
+		return -1;
+	}
+
+	if (git_str_printf(&target, "http/%s", url->host) < 0 ||
+	    git_utf8_to_16_alloc(&ctx->target, target.ptr) < 0) {
+		FreeContextBuffer(ctx->package_info);
+		git__free(ctx);
+		return -1;
+	}
+
+	ctx->parent.type = type;
+	ctx->parent.connection_affinity = 1;
+	ctx->parent.set_challenge = sspi_set_challenge;
+	ctx->parent.next_token = sspi_next_token;
+	ctx->parent.is_complete = sspi_is_complete;
+	ctx->parent.free = sspi_context_free;
+
+	*out = (git_http_auth_context *)ctx;
+
+	git_str_dispose(&target);
+	return 0;
+}
+
+int git_http_auth_negotiate(
+	git_http_auth_context **out,
+	const git_net_url *url)
+{
+	return sspi_init_context(out, GIT_HTTP_AUTH_NEGOTIATE, url);
+}
+
+int git_http_auth_ntlm(
+	git_http_auth_context **out,
+	const git_net_url *url)
+{
+	return sspi_init_context(out, GIT_HTTP_AUTH_NTLM, url);
+}
+
+#endif /* GIT_WIN32 */