Basic authentication for http and winhttp

include/git2/remote.h

@@ -287,6 +287,19 @@ GIT_EXTERN(int) git_remote_add(git_remote **out, git_repository *repo, const cha
 GIT_EXTERN(void) git_remote_check_cert(git_remote *remote, int check);
 
 /**
+ * Set a credentials acquisition callback for this remote. If the remote is
+ * not available for anonymous access, then you must set this callback in order
+ * to provide credentials to the transport at the time of authentication
+ * failure so that retry can be performed.
+ *
+ * @param remote the remote to configure
+ * @param The credentials acquisition callback to use (defaults to NULL)
+ */
+GIT_EXTERN(void) git_remote_set_cred_acquire_cb(
+	git_remote *remote,
+	git_cred_acquire_cb cred_acquire_cb);
+
+/**
  * Sets a custom transport for the remote. The caller can use this function
  * to bypass the automatic discovery of a transport by URL scheme (i.e.
  * http://, https://, git://) and supply their own transport to be used
@@ -297,7 +310,9 @@ GIT_EXTERN(void) git_remote_check_cert(git_remote *remote, int check);
  * @param remote the remote to configure
  * @param transport the transport object for the remote to use
  */
-GIT_EXTERN(int) git_remote_set_transport(git_remote *remote, git_transport *transport);
+GIT_EXTERN(int) git_remote_set_transport(
+	git_remote *remote,
+	git_transport *transport);
 
 /**
  * Argument to the completion callback which tells it which operation

include/git2/transport.h

@@ -20,6 +20,54 @@
 GIT_BEGIN_DECL
 
 /*
+ *** Begin interface for credentials acquisition ***
+ */
+
+typedef enum {
+	/* git_cred_userpass_plaintext */
+	GIT_CREDTYPE_USERPASS_PLAINTEXT = 1,
+} git_credtype_t;
+
+/* The base structure for all credential types */
+typedef struct git_cred {
+	git_credtype_t credtype;
+	void (*free)(
+		struct git_cred *cred);
+} git_cred;
+
+/* A plaintext username and password */
+typedef struct git_cred_userpass_plaintext {
+	git_cred parent;
+	char *username;
+	char *password;
+} git_cred_userpass_plaintext;
+
+/**
+ * Creates a new plain-text username and password credential object.
+ *
+ * @param cred The newly created credential object.
+ * @param username The username of the credential.
+ * @param password The password of the credential.
+ */
+GIT_EXTERN(int) git_cred_userpass_plaintext_new(
+	git_cred **cred,
+	const char *username,
+	const char *password);
+
+/**
+ * Signature of a function which acquires a credential object.
+ *
+ * @param cred The newly created credential object.
+ * @param url The resource for which we are demanding a credential.
+ * @param allowed_types A bitmask stating which cred types are OK to return.
+ */
+typedef int (*git_cred_acquire_cb)(
+	git_cred **cred,
+	const char *url,
+	int allowed_types);
+
+/*
+ *** End interface for credentials acquisition ***
  *** Begin base transport interface ***
  */
 
@@ -43,6 +91,7 @@ typedef struct git_transport {
 	 * direction. */
 	int (*connect)(struct git_transport *transport,
 		const char *url,
+		git_cred_acquire_cb cred_acquire_cb,
 		int direction,
 		int flags);
 

src/remote.c

@@ -492,7 +492,7 @@ int git_remote_connect(git_remote *remote, int direction)
 	if (!remote->check_cert)
 		flags |= GIT_TRANSPORTFLAGS_NO_CHECK_CERT;
 
-	if (t->connect(t, url, direction, flags) < 0)
+	if (t->connect(t, url, remote->cred_acquire_cb, direction, flags) < 0)
 		goto on_error;
 
 	remote->transport = t;
@@ -809,6 +809,15 @@ void git_remote_set_callbacks(git_remote *remote, git_remote_callbacks *callback
 			remote->callbacks.data);
 }
 
+void git_remote_set_cred_acquire_cb(
+	git_remote *remote,
+	git_cred_acquire_cb cred_acquire_cb)
+{
+	assert(remote);
+
+	remote->cred_acquire_cb = cred_acquire_cb;
+}
+
 int git_remote_set_transport(git_remote *remote, git_transport *transport)
 {
 	assert(remote && transport);

src/remote.h

@@ -22,6 +22,7 @@ struct git_remote {
 	git_vector refs;
 	struct git_refspec fetch;
 	struct git_refspec push;
+	git_cred_acquire_cb cred_acquire_cb;
 	git_transport *transport;
 	git_repository *repo;
 	git_remote_callbacks callbacks;

src/transports/cred.c

+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * 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 "git2.h"
+#include "smart.h"
+
+static void plaintext_free(struct git_cred *cred)
+{
+	git_cred_userpass_plaintext *c = (git_cred_userpass_plaintext *)cred;
+	int pass_len = strlen(c->password);
+
+	git__free(c->username);
+
+	/* Zero the memory which previously held the password */
+	memset(c->password, 0x0, pass_len);
+	git__free(c->password);
+
+	git__free(c);
+}
+
+int git_cred_userpass_plaintext_new(
+	git_cred **cred,
+	const char *username,
+	const char *password)
+{
+	git_cred_userpass_plaintext *c;
+
+	if (!cred)
+		return -1;
+
+	c = (git_cred_userpass_plaintext *)git__malloc(sizeof(git_cred_userpass_plaintext));
+	GITERR_CHECK_ALLOC(c);
+
+	c->parent.credtype = GIT_CREDTYPE_USERPASS_PLAINTEXT;
+	c->parent.free = plaintext_free;
+	c->username = git__strdup(username);
+
+	if (!c->username) {
+		git__free(c);
+		return -1;
+	}
+
+	c->password = git__strdup(password);
+
+	if (!c->password) {
+		git__free(c->username);
+		git__free(c);
+		return -1;
+	}
+
+	*cred = &c->parent;
+	return 0;
+}
\ No newline at end of file

src/transports/local.c

@@ -130,7 +130,11 @@ on_error:
  * Try to open the url as a git directory. The direction doesn't
  * matter in this case because we're calulating the heads ourselves.
  */
-static int local_connect(git_transport *transport, const char *url, int direction, int flags)
+static int local_connect(
+	git_transport *transport,
+	const char *url,
+	git_cred_acquire_cb cred_acquire_cb,
+	int direction, int flags)
 {
 	git_repository *repo;
 	int error;
@@ -138,6 +142,8 @@ static int local_connect(git_transport *transport, const char *url, int directio
 	const char *path;
 	git_buf buf = GIT_BUF_INIT;
 
+	GIT_UNUSED(cred_acquire_cb);
+
 	t->url = git__strdup(url);
 	GITERR_CHECK_ALLOC(t->url);
 	t->direction = direction;

src/transports/smart.c

@@ -52,7 +52,12 @@ static int git_smart__set_callbacks(
 	return 0;
 }
 
-static int git_smart__connect(git_transport *transport, const char *url, int direction, int flags)
+static int git_smart__connect(
+	git_transport *transport,
+	const char *url,
+	git_cred_acquire_cb cred_acquire_cb,
+	int direction,
+	int flags)
 {
 	transport_smart *t = (transport_smart *)transport;
 	git_smart_subtransport_stream *stream;
@@ -66,6 +71,7 @@ static int git_smart__connect(git_transport *transport, const char *url, int dir
 
 	t->direction = direction;
 	t->flags = flags;
+	t->cred_acquire_cb = cred_acquire_cb;
 
 	if (GIT_DIR_FETCH == direction)
 	{

src/transports/smart.h

@@ -99,6 +99,7 @@ typedef void (*packetsize_cb)(int received, void *payload);
 typedef struct {
 	git_transport parent;
 	char *url;
+	git_cred_acquire_cb cred_acquire_cb;
 	int direction;
 	int flags;
 	git_transport_message_cb progress_cb;

src/transports/winhttp.c

@@ -30,6 +30,7 @@ static const char *upload_pack_ls_service_url = "/info/refs?service=git-upload-p
 static const char *upload_pack_service_url = "/git-upload-pack";
 static const wchar_t *get_verb = L"GET";
 static const wchar_t *post_verb = L"POST";
+static const wchar_t *basic_authtype = L"Basic";
 static const wchar_t *pragma_nocache = L"Pragma: no-cache";
 static const int no_check_cert_flags = SECURITY_FLAG_IGNORE_CERT_CN_INVALID |
 	SECURITY_FLAG_IGNORE_CERT_DATE_INVALID |
@@ -37,6 +38,10 @@ static const int no_check_cert_flags = SECURITY_FLAG_IGNORE_CERT_CN_INVALID |
 
 #define OWNING_SUBTRANSPORT(s) ((winhttp_subtransport *)(s)->parent.subtransport)
 
+typedef enum {
+	GIT_WINHTTP_AUTH_BASIC = 1,
+} winhttp_authmechanism_t;
+
 typedef struct {
 	git_smart_subtransport_stream parent;
 	const char *service;
@@ -49,16 +54,75 @@ typedef struct {
 
 typedef struct {
 	git_smart_subtransport parent;
-	git_transport *owner;
+	transport_smart *owner;
 	const char *path;
 	char *host;
 	char *port;
+	git_cred *cred;
+	int auth_mechanism;
 	HINTERNET session;
 	HINTERNET connection;
 	unsigned use_ssl : 1,
 		no_check_cert : 1;
 } winhttp_subtransport;
 
+static int apply_basic_credential(HINTERNET request, git_cred *cred)
+{
+	git_cred_userpass_plaintext *c = (git_cred_userpass_plaintext *)cred;
+	git_buf buf = GIT_BUF_INIT, raw = GIT_BUF_INIT;
+	wchar_t *wide = NULL;
+	int error = -1, wide_len;
+
+	git_buf_printf(&raw, "%s:%s", c->username, c->password);
+
+	if (git_buf_oom(&raw) ||
+		git_buf_puts(&buf, "Authorization: Basic ") < 0 ||
+		git_buf_put_base64(&buf, git_buf_cstr(&raw), raw.size) < 0)
+		goto on_error;
+
+	wide_len = MultiByteToWideChar(CP_UTF8,	MB_ERR_INVALID_CHARS,
+		git_buf_cstr(&buf),	-1, NULL, 0);
+
+	if (!wide_len) {
+		giterr_set(GITERR_OS, "Failed to measure string for wide conversion");
+		goto on_error;
+	}
+
+	wide = (wchar_t *)git__malloc(wide_len * sizeof(wchar_t));
+
+	if (!wide)
+		goto on_error;
+
+	if (!MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS,
+		git_buf_cstr(&buf), -1, wide, wide_len)) {
+		giterr_set(GITERR_OS, "Failed to convert string to wide form");
+		goto on_error;
+	}
+
+	if (!WinHttpAddRequestHeaders(request, wide, (ULONG) -1L, WINHTTP_ADDREQ_FLAG_ADD)) {
+		giterr_set(GITERR_OS, "Failed to add a header to the request");
+		goto on_error;
+	}
+
+	error = 0;
+
+on_error:
+	/* We were dealing with plaintext passwords, so clean up after ourselves a bit. */
+	if (wide)
+		memset(wide, 0x0, wide_len * sizeof(wchar_t));
+
+	if (buf.size)
+		memset(buf.ptr, 0x0, buf.size);
+
+	if (raw.size)
+		memset(raw.ptr, 0x0, raw.size);
+
+	git__free(wide);
+	git_buf_free(&buf);
+	git_buf_free(&raw);
+	return error;
+}
+
 static int winhttp_stream_connect(winhttp_stream *s)
 {
 	winhttp_subtransport *t = OWNING_SUBTRANSPORT(s);
@@ -127,6 +191,13 @@ static int winhttp_stream_connect(winhttp_stream *s)
 		}
 	}
 
+	/* If we have a credential on the subtransport, apply it to the request */
+	if (t->cred &&
+		t->cred->credtype == GIT_CREDTYPE_USERPASS_PLAINTEXT &&
+		t->auth_mechanism == GIT_WINHTTP_AUTH_BASIC &&
+		apply_basic_credential(s->request, t->cred) < 0)
+		goto on_error;
+
 	/* We've done everything up to calling WinHttpSendRequest. */
 
 	return 0;
@@ -136,6 +207,64 @@ on_error:
 	return -1;
 }
 
+static int parse_unauthorized_response(
+	HINTERNET request,
+	int *allowed_types,
+	int *auth_mechanism)
+{
+	DWORD index, buf_size, last_error;
+	int error = 0;
+	wchar_t *buf = NULL;
+
+	*allowed_types = 0;
+
+	for (index = 0; ; index++) {
+		/* Make a first call to ask for the size of the buffer to allocate
+		 * to hold the WWW-Authenticate header */
+		if (!WinHttpQueryHeaders(request, WINHTTP_QUERY_WWW_AUTHENTICATE,
+			WINHTTP_HEADER_NAME_BY_INDEX, WINHTTP_NO_OUTPUT_BUFFER,
+			&buf_size, &index))
+		{
+			last_error = GetLastError();
+
+			if (ERROR_WINHTTP_HEADER_NOT_FOUND == last_error) {
+				/* End of enumeration */
+				break;
+			} else if (ERROR_INSUFFICIENT_BUFFER == last_error) {
+				git__free(buf);
+				buf = (wchar_t *)git__malloc(buf_size);
+
+				if (!buf) {
+					error = -1;
+					break;
+				}
+			} else {
+				giterr_set(GITERR_OS, "Failed to read WWW-Authenticate header");
+				error = -1;
+				break;
+			}
+		}
+
+		/* Actually receive the data into our now-allocated buffer */
+		if (!WinHttpQueryHeaders(request, WINHTTP_QUERY_WWW_AUTHENTICATE,
+			WINHTTP_HEADER_NAME_BY_INDEX, buf,
+			&buf_size, &index)) {
+			giterr_set(GITERR_OS, "Failed to read WWW-Authenticate header");
+			error = -1;
+			break;
+		}
+
+		if (!wcsncmp(buf, basic_authtype, 5) &&
+			(buf[5] == L'\0' || buf[5] == L' ')) {
+			*allowed_types |= GIT_CREDTYPE_USERPASS_PLAINTEXT;
+			*auth_mechanism = GIT_WINHTTP_AUTH_BASIC;
+		}
+	}
+
+	git__free(buf);
+	return error;
+}
+
 static int winhttp_stream_read(
 	git_smart_subtransport_stream *stream,
 	char *buffer,
@@ -145,6 +274,7 @@ static int winhttp_stream_read(
 	winhttp_stream *s = (winhttp_stream *)stream;
 	winhttp_subtransport *t = OWNING_SUBTRANSPORT(s);
 
+replay:
 	/* Connect if necessary */
 	if (!s->request && winhttp_stream_connect(s) < 0)
 		return -1;
@@ -182,6 +312,31 @@ static int winhttp_stream_read(
 				return -1;
 		}
 
+		/* Handle authentication failures */
+		if (HTTP_STATUS_DENIED == status_code &&
+			get_verb == s->verb && t->owner->cred_acquire_cb) {
+			int allowed_types;
+
+			if (parse_unauthorized_response(s->request, &allowed_types, &t->auth_mechanism) < 0)
+				return -1;
+
+			if (allowed_types &&
+				(!t->cred || 0 == (t->cred->credtype & allowed_types))) {
+
+				if (t->owner->cred_acquire_cb(&t->cred, t->owner->url, allowed_types) < 0)
+					return -1;
+
+				assert(t->cred);
+
+				WinHttpCloseHandle(s->request);
+				s->request = NULL;
+				s->sent_request = 0;
+
+				/* Successfully acquired a credential */
+				goto replay;
+			}
+		}
+
 		if (HTTP_STATUS_OK != status_code) {
 			giterr_set(GITERR_NET, "Request failed with status code: %d", status_code);
 			return -1;
@@ -432,6 +587,11 @@ static void winhttp_free(git_smart_subtransport *smart_transport)
 	git__free(t->host);
 	git__free(t->port);
 
+	if (t->cred) {
+		t->cred->free(t->cred);
+		t->cred = NULL;
+	}
+
 	if (t->connection) {
 		WinHttpCloseHandle(t->connection);
 		t->connection = NULL;
@@ -456,7 +616,7 @@ int git_smart_subtransport_http(git_smart_subtransport **out, git_transport *own
 	t = (winhttp_subtransport *)git__calloc(sizeof(winhttp_subtransport), 1);
 	GITERR_CHECK_ALLOC(t);
 
-	t->owner = owner;
+	t->owner = (transport_smart *)owner;
 	t->parent.action = winhttp_action;
 	t->parent.free = winhttp_free;