Merge pull request #2497 from ethomson/kerberos3

SPNEGO authentication via GSSAPI

14 files changed, 1048 insertions, 98 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6f1a97edb..76cca4f22 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,6 +36,7 @@ OPTION( ANDROID				"Build for android NDK"	 				OFF )
 
 OPTION( USE_ICONV			"Link with and use iconv library" 		OFF )
 OPTION( USE_SSH				"Link with libssh to enable SSH support" ON )
+OPTION( USE_GSSAPI			"Link with libgssapi for SPNEGO auth"   OFF )
 OPTION( VALGRIND			"Configure build for valgrind"			OFF )
 
 IF(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
@@ -208,6 +209,14 @@ IF (LIBSSH2_FOUND)
 	SET(SSH_LIBRARIES ${LIBSSH2_LIBRARIES})
 ENDIF()
 
+# Optional external dependency: libgssapi
+IF (USE_GSSAPI)
+	FIND_PACKAGE(GSSAPI)
+ENDIF()
+IF (GSSAPI_FOUND)
+	ADD_DEFINITIONS(-DGIT_GSSAPI)
+ENDIF()
+
 # Optional external dependency: iconv
 IF (USE_ICONV)
 	FIND_PACKAGE(Iconv)
@@ -387,6 +396,7 @@ ENDIF()
 ADD_LIBRARY(git2 ${SRC_H} ${SRC_GIT2} ${SRC_OS} ${SRC_ZLIB} ${SRC_HTTP} ${SRC_REGEX} ${SRC_SHA1} ${WIN_RC})
 TARGET_LINK_LIBRARIES(git2 ${SSL_LIBRARIES})
 TARGET_LINK_LIBRARIES(git2 ${SSH_LIBRARIES})
+TARGET_LINK_LIBRARIES(git2 ${GSSAPI_LIBRARIES})
 TARGET_LINK_LIBRARIES(git2 ${ICONV_LIBRARIES})
 TARGET_OS_LIBRARIES(git2)
 
@@ -453,6 +463,7 @@ IF (BUILD_CLAR)
 
 	TARGET_LINK_LIBRARIES(libgit2_clar ${SSL_LIBRARIES})
 	TARGET_LINK_LIBRARIES(libgit2_clar ${SSH_LIBRARIES})
+	TARGET_LINK_LIBRARIES(libgit2_clar ${GSSAPI_LIBRARIES})
 	TARGET_LINK_LIBRARIES(libgit2_clar ${ICONV_LIBRARIES})
 	TARGET_OS_LIBRARIES(libgit2_clar)
 	MSVC_SPLIT_SOURCES(libgit2_clar)
diff --git a/cmake/Modules/FindGSSAPI.cmake b/cmake/Modules/FindGSSAPI.cmake
new file mode 100644
index 000000000..8520d35df
--- /dev/null
+++ b/cmake/Modules/FindGSSAPI.cmake
@@ -0,0 +1,324 @@
+# - Try to find GSSAPI
+# Once done this will define
+#
+#  KRB5_CONFIG - Path to krb5-config
+#  GSSAPI_ROOT_DIR - Set this variable to the root installation of GSSAPI
+#
+# Read-Only variables:
+#  GSSAPI_FLAVOR_MIT - set to TURE if MIT Kerberos has been found
+#  GSSAPI_FLAVOR_HEIMDAL - set to TRUE if Heimdal Keberos has been found
+#  GSSAPI_FOUND - system has GSSAPI
+#  GSSAPI_INCLUDE_DIR - the GSSAPI include directory
+#  GSSAPI_LIBRARIES - Link these to use GSSAPI
+#  GSSAPI_DEFINITIONS - Compiler switches required for using GSSAPI
+#
+#=============================================================================
+#  Copyright (c) 2013 Andreas Schneider <asn@cryptomilk.org>
+#
+#  Distributed under the OSI-approved BSD License (the "License");
+#  see accompanying file Copyright.txt for details.
+#
+#  This software is distributed WITHOUT ANY WARRANTY; without even the
+#  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+#  See the License for more information.
+#=============================================================================
+#
+
+find_path(GSSAPI_ROOT_DIR
+    NAMES
+        include/gssapi.h
+        include/gssapi/gssapi.h
+    HINTS
+        ${_GSSAPI_ROOT_HINTS}
+    PATHS
+        ${_GSSAPI_ROOT_PATHS}
+)
+mark_as_advanced(GSSAPI_ROOT_DIR)
+
+if (UNIX)
+    find_program(KRB5_CONFIG
+        NAMES
+            krb5-config
+        PATHS
+            ${GSSAPI_ROOT_DIR}/bin
+            /opt/local/bin)
+    mark_as_advanced(KRB5_CONFIG)
+
+    if (KRB5_CONFIG)
+        # Check if we have MIT KRB5
+        execute_process(
+            COMMAND
+                ${KRB5_CONFIG} --vendor
+            RESULT_VARIABLE
+                _GSSAPI_VENDOR_RESULT
+            OUTPUT_VARIABLE
+                _GSSAPI_VENDOR_STRING)
+
+        if (_GSSAPI_VENDOR_STRING MATCHES ".*Massachusetts.*")
+            set(GSSAPI_FLAVOR_MIT TRUE)
+        else()
+            execute_process(
+                COMMAND
+                    ${KRB5_CONFIG} --libs gssapi
+                RESULT_VARIABLE
+                    _GSSAPI_LIBS_RESULT
+                OUTPUT_VARIABLE
+                    _GSSAPI_LIBS_STRING)
+
+            if (_GSSAPI_LIBS_STRING MATCHES ".*roken.*")
+                set(GSSAPI_FLAVOR_HEIMDAL TRUE)
+            endif()
+        endif()
+
+        # Get the include dir
+        execute_process(
+            COMMAND
+                ${KRB5_CONFIG} --cflags gssapi
+            RESULT_VARIABLE
+                _GSSAPI_INCLUDE_RESULT
+            OUTPUT_VARIABLE
+                _GSSAPI_INCLUDE_STRING)
+        string(REGEX REPLACE "(\r?\n)+$" "" _GSSAPI_INCLUDE_STRING "${_GSSAPI_INCLUDE_STRING}")
+        string(REGEX REPLACE " *-I" "" _GSSAPI_INCLUDEDIR "${_GSSAPI_INCLUDE_STRING}")
+    endif()
+
+    if (NOT GSSAPI_FLAVOR_MIT AND NOT GSSAPI_FLAVOR_HEIMDAL)
+        # Check for HEIMDAL
+        find_package(PkgConfig)
+        if (PKG_CONFIG_FOUND)
+            pkg_check_modules(_GSSAPI heimdal-gssapi)
+        endif (PKG_CONFIG_FOUND)
+
+        if (_GSSAPI_FOUND)
+            set(GSSAPI_FLAVOR_HEIMDAL TRUE)
+        else()
+            find_path(_GSSAPI_ROKEN
+                NAMES
+                    roken.h
+                PATHS
+                    ${GSSAPI_ROOT_DIR}/include
+                    ${_GSSAPI_INCLUDEDIR})
+            if (_GSSAPI_ROKEN)
+                set(GSSAPI_FLAVOR_HEIMDAL TRUE)
+            endif()
+        endif ()
+    endif()
+endif (UNIX)
+
+find_path(GSSAPI_INCLUDE_DIR
+    NAMES
+        gssapi.h
+        gssapi/gssapi.h
+    PATHS
+        ${GSSAPI_ROOT_DIR}/include
+        ${_GSSAPI_INCLUDEDIR}
+)
+
+if (GSSAPI_FLAVOR_MIT)
+    find_library(GSSAPI_LIBRARY
+        NAMES
+            gssapi_krb5
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(KRB5_LIBRARY
+        NAMES
+            krb5
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(K5CRYPTO_LIBRARY
+        NAMES
+            k5crypto
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(COM_ERR_LIBRARY
+        NAMES
+            com_err
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    if (GSSAPI_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${GSSAPI_LIBRARY}
+        )
+    endif (GSSAPI_LIBRARY)
+
+    if (KRB5_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${KRB5_LIBRARY}
+        )
+    endif (KRB5_LIBRARY)
+
+    if (K5CRYPTO_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${K5CRYPTO_LIBRARY}
+        )
+    endif (K5CRYPTO_LIBRARY)
+
+    if (COM_ERR_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${COM_ERR_LIBRARY}
+        )
+    endif (COM_ERR_LIBRARY)
+endif (GSSAPI_FLAVOR_MIT)
+
+if (GSSAPI_FLAVOR_HEIMDAL)
+    find_library(GSSAPI_LIBRARY
+        NAMES
+            gssapi
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(KRB5_LIBRARY
+        NAMES
+            krb5
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(HCRYPTO_LIBRARY
+        NAMES
+            hcrypto
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(COM_ERR_LIBRARY
+        NAMES
+            com_err
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(HEIMNTLM_LIBRARY
+        NAMES
+            heimntlm
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(HX509_LIBRARY
+        NAMES
+            hx509
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(ASN1_LIBRARY
+        NAMES
+            asn1
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(WIND_LIBRARY
+        NAMES
+            wind
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    find_library(ROKEN_LIBRARY
+        NAMES
+            roken
+        PATHS
+            ${GSSAPI_ROOT_DIR}/lib
+            ${_GSSAPI_LIBDIR}
+    )
+
+    if (GSSAPI_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${GSSAPI_LIBRARY}
+        )
+    endif (GSSAPI_LIBRARY)
+
+    if (KRB5_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${KRB5_LIBRARY}
+        )
+    endif (KRB5_LIBRARY)
+
+    if (HCRYPTO_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${HCRYPTO_LIBRARY}
+        )
+    endif (HCRYPTO_LIBRARY)
+
+    if (COM_ERR_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${COM_ERR_LIBRARY}
+        )
+    endif (COM_ERR_LIBRARY)
+
+    if (HEIMNTLM_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${HEIMNTLM_LIBRARY}
+        )
+    endif (HEIMNTLM_LIBRARY)
+
+    if (HX509_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${HX509_LIBRARY}
+        )
+    endif (HX509_LIBRARY)
+
+    if (ASN1_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${ASN1_LIBRARY}
+        )
+    endif (ASN1_LIBRARY)
+
+    if (WIND_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${WIND_LIBRARY}
+        )
+    endif (WIND_LIBRARY)
+
+    if (ROKEN_LIBRARY)
+        set(GSSAPI_LIBRARIES
+            ${GSSAPI_LIBRARIES}
+            ${WIND_LIBRARY}
+        )
+    endif (ROKEN_LIBRARY)
+endif (GSSAPI_FLAVOR_HEIMDAL)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(GSSAPI DEFAULT_MSG GSSAPI_LIBRARIES GSSAPI_INCLUDE_DIR)
+
+if (GSSAPI_INCLUDE_DIRS AND GSSAPI_LIBRARIES)
+    set(GSSAPI_FOUND TRUE)
+endif (GSSAPI_INCLUDE_DIRS AND GSSAPI_LIBRARIES)
+
+# show the GSSAPI_INCLUDE_DIRS and GSSAPI_LIBRARIES variables only in the advanced view
+mark_as_advanced(GSSAPI_INCLUDE_DIRS GSSAPI_LIBRARIES)
diff --git a/src/buffer.c b/src/buffer.c
index 1bee9d70b..e9c420e16 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -189,10 +189,10 @@ int git_buf_puts(git_buf *buf, const char *string)
 	return git_buf_put(buf, string, strlen(string));
 }
 
-static const char b64str[] =
+static const char base64_encode[] =
 	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
-int git_buf_put_base64(git_buf *buf, const char *data, size_t len)
+int git_buf_encode_base64(git_buf *buf, const char *data, size_t len)
 {
 	size_t extra = len % 3;
 	uint8_t *write, a, b, c;
@@ -207,19 +207,19 @@ int git_buf_put_base64(git_buf *buf, const char *data, size_t len)
 		b = *read++;
 		c = *read++;
 
-		*write++ = b64str[a >> 2];
-		*write++ = b64str[(a & 0x03) << 4 | b >> 4];
-		*write++ = b64str[(b & 0x0f) << 2 | c >> 6];
-		*write++ = b64str[c & 0x3f];
+		*write++ = base64_encode[a >> 2];
+		*write++ = base64_encode[(a & 0x03) << 4 | b >> 4];
+		*write++ = base64_encode[(b & 0x0f) << 2 | c >> 6];
+		*write++ = base64_encode[c & 0x3f];
 	}
 
 	if (extra > 0) {
 		a = *read++;
 		b = (extra > 1) ? *read++ : 0;
 
-		*write++ = b64str[a >> 2];
-		*write++ = b64str[(a & 0x03) << 4 | b >> 4];
-		*write++ = (extra > 1) ? b64str[(b & 0x0f) << 2] : '=';
+		*write++ = base64_encode[a >> 2];
+		*write++ = base64_encode[(a & 0x03) << 4 | b >> 4];
+		*write++ = (extra > 1) ? base64_encode[(b & 0x0f) << 2] : '=';
 		*write++ = '=';
 	}
 
@@ -229,10 +229,56 @@ int git_buf_put_base64(git_buf *buf, const char *data, size_t len)
 	return 0;
 }
 
+/* The inverse of base64_encode, offset by '+' == 43. */
+static const int8_t base64_decode[] = {
+	62,
+	-1, -1, -1,
+	63,
+	52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
+	-1, -1, -1, 0, -1, -1, -1,
+	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
+	13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
+	-1, -1, -1, -1, -1, -1,
+	26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
+	39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
+};
+
+#define BASE64_DECODE_VALUE(c) (((c) < 43 || (c) > 122) ? -1 : base64_decode[c - 43])
+
+int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
+{
+	size_t i;
+	int8_t a, b, c, d;
+	size_t orig_size = buf->size;
+
+	assert(len % 4 == 0);
+	ENSURE_SIZE(buf, buf->size + (len / 4 * 3) + 1);
+
+	for (i = 0; i < len; i += 4) {
+		if ((a = BASE64_DECODE_VALUE(base64[i])) < 0 ||
+			(b = BASE64_DECODE_VALUE(base64[i+1])) < 0 ||
+			(c = BASE64_DECODE_VALUE(base64[i+2])) < 0 ||
+			(d = BASE64_DECODE_VALUE(base64[i+3])) < 0) {
+			buf->size = orig_size;
+			buf->ptr[buf->size] = '\0';
+
+			giterr_set(GITERR_INVALID, "Invalid base64 input");
+			return -1;
+		}
+
+		buf->ptr[buf->size++] = ((a << 2) | (b & 0x30) >> 4);
+		buf->ptr[buf->size++] = ((b & 0x0f) << 4) | ((c & 0x3c) >> 2);
+		buf->ptr[buf->size++] = (c & 0x03) << 6 | (d & 0x3f);
+	}
+
+	buf->ptr[buf->size] = '\0';
+	return 0;
+}
+
 static const char b85str[] =
 	"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
 
-int git_buf_put_base85(git_buf *buf, const char *data, size_t len)
+int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
 {
 	ENSURE_SIZE(buf, buf->size + (5 * ((len / 4) + !!(len % 4))) + 1);
 
diff --git a/src/buffer.h b/src/buffer.h
index 70d6d73b3..8ee4b532c 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -156,10 +156,12 @@ void git_buf_rtrim(git_buf *buf);
 int git_buf_cmp(const git_buf *a, const git_buf *b);
 
 /* Write data as base64 encoded in buffer */
-int git_buf_put_base64(git_buf *buf, const char *data, size_t len);
+int git_buf_encode_base64(git_buf *buf, const char *data, size_t len);
+/* Decode the given bas64 and write the result to the buffer */
+int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len);
 
 /* Write data as "base85" encoded in buffer */
-int git_buf_put_base85(git_buf *buf, const char *data, size_t len);
+int git_buf_encode_base85(git_buf *buf, const char *data, size_t len);
 
 /*
  * Insert, remove or replace a portion of the buffer.
diff --git a/src/diff_print.c b/src/diff_print.c
index fb62a5fc1..43a90b3d8 100644
--- a/src/diff_print.c
+++ b/src/diff_print.c
@@ -352,7 +352,7 @@ static int print_binary_hunk(diff_print_info *pi, git_blob *old, git_blob *new)
 		else
 			git_buf_putc(pi->buf, (char)chunk_len - 26 + 'a' - 1);
 
-		git_buf_put_base85(pi->buf, scan, chunk_len);
+		git_buf_encode_base85(pi->buf, scan, chunk_len);
 		git_buf_putc(pi->buf, '\n');
 
 		if (git_buf_oom(pi->buf)) {
diff --git a/src/transports/auth.c b/src/transports/auth.c
new file mode 100644
index 000000000..c1154db34
--- /dev/null
+++ b/src/transports/auth.c
@@ -0,0 +1,71 @@
+/*
+ * 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 "git2.h"
+#include "buffer.h"
+#include "auth.h"
+
+static int basic_next_token(
+	git_buf *out, git_http_auth_context *ctx, git_cred *c)
+{
+	git_cred_userpass_plaintext *cred;
+	git_buf raw = GIT_BUF_INIT;
+	int error = -1;
+
+	GIT_UNUSED(ctx);
+
+	if (c->credtype != GIT_CREDTYPE_USERPASS_PLAINTEXT) {
+		giterr_set(GITERR_INVALID, "invalid credential type for basic auth");
+		goto on_error;
+	}
+
+	cred = (git_cred_userpass_plaintext *)c;
+
+	git_buf_printf(&raw, "%s:%s", cred->username, cred->password);
+
+	if (git_buf_oom(&raw) ||
+		git_buf_puts(out, "Authorization: Basic ") < 0 ||
+		git_buf_encode_base64(out, git_buf_cstr(&raw), raw.size) < 0 ||
+		git_buf_puts(out, "\r\n") < 0)
+		goto on_error;
+
+	error = 0;
+
+on_error:
+	if (raw.size)
+		git__memzero(raw.ptr, raw.size);
+
+	git_buf_free(&raw);
+	return error;
+}
+
+static git_http_auth_context basic_context = {
+	GIT_AUTHTYPE_BASIC,
+	GIT_CREDTYPE_USERPASS_PLAINTEXT,
+	NULL,
+	basic_next_token,
+	NULL
+};
+
+int git_http_auth_basic(
+	git_http_auth_context **out, const gitno_connection_data *connection_data)
+{
+	GIT_UNUSED(connection_data);
+
+	*out = &basic_context;
+	return 0;
+}
+
+int git_http_auth_dummy(
+	git_http_auth_context **out, const gitno_connection_data *connection_data)
+{
+	GIT_UNUSED(connection_data);
+
+	*out = NULL;
+	return 0;
+}
+
diff --git a/src/transports/auth.h b/src/transports/auth.h
new file mode 100644
index 000000000..52138cf8f
--- /dev/null
+++ b/src/transports/auth.h
@@ -0,0 +1,63 @@
+/*
+ * 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.
+ */
+
+#ifndef INCLUDE_http_auth_h__
+#define INCLUDE_http_auth_h__
+
+#include "git2.h"
+#include "netops.h"
+
+typedef enum {
+	GIT_AUTHTYPE_BASIC = 1,
+	GIT_AUTHTYPE_NEGOTIATE = 2,
+} git_http_authtype_t;
+
+typedef struct git_http_auth_context git_http_auth_context;
+
+struct git_http_auth_context {
+	/** Type of scheme */
+	git_http_authtype_t type;
+
+	/** Supported credentials */
+	git_credtype_t credtypes;
+
+	/** Sets the challenge on the authentication context */
+	int (*set_challenge)(git_http_auth_context *ctx, const char *challenge);
+
+	/** Gets the next authentication token from the context */
+	int (*next_token)(git_buf *out, git_http_auth_context *ctx, git_cred *cred);
+
+	/** Frees the authentication context */
+	void (*free)(git_http_auth_context *ctx);
+};
+
+typedef struct {
+	/** Type of scheme */
+	git_http_authtype_t type;
+
+	/** Name of the scheme (as used in the Authorization header) */
+	const char *name;
+
+	/** Credential types this scheme supports */
+	git_credtype_t credtypes;
+
+	/** Function to initialize an authentication context */
+	int (*init_context)(
+		git_http_auth_context **out,
+		const gitno_connection_data *connection_data);
+} git_http_auth_scheme;
+
+int git_http_auth_dummy(
+	git_http_auth_context **out,
+	const gitno_connection_data *connection_data);
+
+int git_http_auth_basic(
+	git_http_auth_context **out,
+	const gitno_connection_data *connection_data);
+
+#endif
+
diff --git a/src/transports/auth_negotiate.c b/src/transports/auth_negotiate.c
new file mode 100644
index 000000000..8b99fc735
--- /dev/null
+++ b/src/transports/auth_negotiate.c
@@ -0,0 +1,275 @@
+/*
+ * 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.
+ */
+
+#ifdef GIT_GSSAPI
+
+#include "git2.h"
+#include "common.h"
+#include "buffer.h"
+#include "auth.h"
+
+#include <gssapi.h>
+#include <krb5.h>
+
+static gss_OID_desc negotiate_oid_spnego =
+	{ 6, (void *) "\x2b\x06\x01\x05\x05\x02" };
+static gss_OID_desc negotiate_oid_krb5 =
+	{ 9, (void *) "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" };
+
+static gss_OID negotiate_oids[] =
+	{ &negotiate_oid_spnego, &negotiate_oid_krb5, NULL };
+
+typedef struct {
+	git_http_auth_context parent;
+	unsigned configured : 1,
+		complete : 1;
+	git_buf target;
+	char *challenge;
+	gss_ctx_id_t gss_context;
+	gss_OID oid;
+} http_auth_negotiate_context;
+
+static void negotiate_err_set(
+	OM_uint32 status_major,
+	OM_uint32 status_minor,
+	const char *message)
+{
+	gss_buffer_desc buffer = GSS_C_EMPTY_BUFFER;
+	OM_uint32 status_display, context = 0;
+
+	if (gss_display_status(&status_display, status_major, GSS_C_GSS_CODE,
+		GSS_C_NO_OID, &context, &buffer) == GSS_S_COMPLETE) {
+		giterr_set(GITERR_NET, "%s: %.*s (%d.%d)",
+			message, (int)buffer.length, (const char *)buffer.value,
+			status_major, status_minor);
+		gss_release_buffer(&status_minor, &buffer);
+	} else {
+		giterr_set(GITERR_NET, "%s: unknown negotiate error (%d.%d)",
+			message, status_major, status_minor);
+	}
+}
+
+static int negotiate_set_challenge(
+	git_http_auth_context *c,
+	const char *challenge)
+{
+	http_auth_negotiate_context *ctx = (http_auth_negotiate_context *)c;
+
+	assert(ctx && ctx->configured && challenge);
+
+	git__free(ctx->challenge);
+
+	ctx->challenge = git__strdup(challenge);
+	GITERR_CHECK_ALLOC(ctx->challenge);
+
+	return 0;
+}
+
+static int negotiate_next_token(
+	git_buf *buf,
+	git_http_auth_context *c,
+	git_cred *cred)
+{
+	http_auth_negotiate_context *ctx = (http_auth_negotiate_context *)c;
+	OM_uint32 status_major, status_minor;
+	gss_buffer_desc target_buffer = GSS_C_EMPTY_BUFFER,
+		input_token = GSS_C_EMPTY_BUFFER,
+		output_token = GSS_C_EMPTY_BUFFER;
+	gss_buffer_t input_token_ptr = GSS_C_NO_BUFFER;
+	git_buf input_buf = GIT_BUF_INIT;
+	gss_name_t server = NULL;
+	gss_OID mech;
+	size_t challenge_len;
+	int error = 0;
+
+	assert(buf && ctx && ctx->configured && cred && cred->credtype == GIT_CREDTYPE_DEFAULT);
+
+	if (ctx->complete)
+		return 0;
+
+	target_buffer.value = (void *)ctx->target.ptr;
+	target_buffer.length = ctx->target.size;
+
+	status_major = gss_import_name(&status_minor, &target_buffer,
+		GSS_C_NT_HOSTBASED_SERVICE, &server);
+
+	if (GSS_ERROR(status_major)) {
+		negotiate_err_set(status_major, status_minor,
+			"Could not parse principal");
+		error = -1;
+		goto done;
+	}
+
+	challenge_len = ctx->challenge ? strlen(ctx->challenge) : 0;
+
+	if (challenge_len < 9) {
+		giterr_set(GITERR_NET, "No negotiate challenge sent from server");
+		error = -1;
+		goto done;
+	} else if (challenge_len > 9) {
+		if (git_buf_decode_base64(&input_buf,
+				ctx->challenge + 10, challenge_len - 10) < 0) {
+			giterr_set(GITERR_NET, "Invalid negotiate challenge from server");
+			error = -1;
+			goto done;
+		}
+
+		input_token.value = input_buf.ptr;
+		input_token.length = input_buf.size;
+		input_token_ptr = &input_token;
+	} else if (ctx->gss_context != GSS_C_NO_CONTEXT) {
+		giterr_set(GITERR_NET, "Could not restart authentication");
+		error = -1;
+		goto done;
+	}
+
+	mech = &negotiate_oid_spnego;
+
+	if (GSS_ERROR(status_major = gss_init_sec_context(
+		&status_minor,
+		GSS_C_NO_CREDENTIAL,
+		&ctx->gss_context,
+		server,
+		mech,
+		GSS_C_DELEG_FLAG | GSS_C_MUTUAL_FLAG,
+		GSS_C_INDEFINITE,
+		GSS_C_NO_CHANNEL_BINDINGS,
+		input_token_ptr,
+		NULL,
+		&output_token,
+		NULL,
+		NULL))) {
+		negotiate_err_set(status_major, status_minor, "Negotiate failure");
+		error = -1;
+		goto done;
+	}
+
+	/* This message merely told us auth was complete; we do not respond. */
+	if (status_major == GSS_S_COMPLETE) {
+		ctx->complete = 1;
+		goto done;
+	}
+
+	git_buf_puts(buf, "Authorization: Negotiate ");
+	git_buf_encode_base64(buf, output_token.value, output_token.length);
+	git_buf_puts(buf, "\r\n");
+
+	if (git_buf_oom(buf))
+		error = -1;
+
+done:
+	gss_release_name(&status_minor, &server);
+	gss_release_buffer(&status_minor, (gss_buffer_t) &output_token);
+	git_buf_free(&input_buf);
+	return error;
+}
+
+static void negotiate_context_free(git_http_auth_context *c)
+{
+	http_auth_negotiate_context *ctx = (http_auth_negotiate_context *)c;
+	OM_uint32 status_minor;
+
+	if (ctx->gss_context != GSS_C_NO_CONTEXT) {
+		gss_delete_sec_context(
+			&status_minor, &ctx->gss_context, GSS_C_NO_BUFFER);
+		ctx->gss_context = GSS_C_NO_CONTEXT;
+	}
+
+	git_buf_free(&ctx->target);
+
+	git__free(ctx->challenge);
+
+	ctx->configured = 0;
+	ctx->complete = 0;
+	ctx->oid = NULL;
+
+	git__free(ctx);
+}
+
+static int negotiate_init_context(
+	http_auth_negotiate_context *ctx,
+	const gitno_connection_data *connection_data)
+{
+	OM_uint32 status_major, status_minor;
+	gss_OID item, *oid;
+	gss_OID_set mechanism_list;
+	size_t i;
+
+	/* Query supported mechanisms looking for SPNEGO) */
+	if (GSS_ERROR(status_major =
+		gss_indicate_mechs(&status_minor, &mechanism_list))) {
+		negotiate_err_set(status_major, status_minor,
+			"could not query mechanisms");
+		return -1;
+	}
+
+	if (mechanism_list) {
+		for (oid = negotiate_oids; *oid; oid++) {
+			for (i = 0; i < mechanism_list->count; i++) {
+				item = &mechanism_list->elements[i];
+
+				if (item->length == (*oid)->length &&
+					memcmp(item->elements, (*oid)->elements, item->length) == 0) {
+					ctx->oid = *oid;
+					break;
+				}
+
+			}
+
+			if (ctx->oid)
+				break;
+		}
+	}
+
+	gss_release_oid_set(&status_minor, &mechanism_list);
+
+	if (!ctx->oid) {
+		giterr_set(GITERR_NET, "Negotiate authentication is not supported");
+		return -1;
+	}
+
+	git_buf_puts(&ctx->target, "HTTP@");
+	git_buf_puts(&ctx->target, connection_data->host);
+
+	if (git_buf_oom(&ctx->target))
+		return -1;
+
+	ctx->gss_context = GSS_C_NO_CONTEXT;
+	ctx->configured = 1;
+
+	return 0;
+}
+
+int git_http_auth_negotiate(
+	git_http_auth_context **out,
+	const gitno_connection_data *connection_data)
+{
+	http_auth_negotiate_context *ctx;
+
+	*out = NULL;
+
+	ctx = git__calloc(1, sizeof(http_auth_negotiate_context));
+	GITERR_CHECK_ALLOC(ctx);
+
+	if (negotiate_init_context(ctx, connection_data) < 0) {
+		git__free(ctx);
+		return -1;
+	}
+
+	ctx->parent.type = GIT_AUTHTYPE_NEGOTIATE;
+	ctx->parent.credtypes = GIT_CREDTYPE_DEFAULT;
+	ctx->parent.set_challenge = negotiate_set_challenge;
+	ctx->parent.next_token = negotiate_next_token;
+	ctx->parent.free = negotiate_context_free;
+
+	*out = (git_http_auth_context *)ctx;
+
+	return 0;
+}
+
+#endif /* GIT_GSSAPI */
+
diff --git a/src/transports/auth_negotiate.h b/src/transports/auth_negotiate.h
new file mode 100644
index 000000000..d7270b7ab
--- /dev/null
+++ b/src/transports/auth_negotiate.h
@@ -0,0 +1,27 @@
+/*
+ * 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.
+ */
+
+#ifndef INCLUDE_auth_negotiate_h__
+#define INCLUDE_auth_negotiate_h__
+
+#include "git2.h"
+#include "auth.h"
+
+#ifdef GIT_GSSAPI
+
+extern int git_http_auth_negotiate(
+	git_http_auth_context **out,
+	const gitno_connection_data *connection_data);
+
+#else
+
+#define git_http_auth_negotiate git_http_auth_dummy
+
+#endif /* GIT_GSSAPI */
+
+#endif
+
diff --git a/src/transports/http.c b/src/transports/http.c
index ae608ab3d..5c5e5d391 100644
--- a/src/transports/http.c
+++ b/src/transports/http.c
@@ -11,6 +11,13 @@
 #include "buffer.h"
 #include "netops.h"
 #include "smart.h"
+#include "auth.h"
+#include "auth_negotiate.h"
+
+git_http_auth_scheme auth_schemes[] = {
+	{ GIT_AUTHTYPE_NEGOTIATE, "Negotiate", GIT_CREDTYPE_DEFAULT, git_http_auth_negotiate },
+	{ GIT_AUTHTYPE_BASIC, "Basic", GIT_CREDTYPE_USERPASS_PLAINTEXT, git_http_auth_basic },
+};
 
 static const char *upload_pack_service = "upload-pack";
 static const char *upload_pack_ls_service_url = "/info/refs?service=git-upload-pack";
@@ -20,7 +27,6 @@ static const char *receive_pack_ls_service_url = "/info/refs?service=git-receive
 static const char *receive_pack_service_url = "/git-receive-pack";
 static const char *get_verb = "GET";
 static const char *post_verb = "POST";
-static const char *basic_authtype = "Basic";
 
 #define OWNING_SUBTRANSPORT(s) ((http_subtransport *)(s)->parent.subtransport)
 
@@ -35,10 +41,6 @@ enum last_cb {
 	VALUE
 };
 
-typedef enum {
-	GIT_HTTP_AUTH_BASIC = 1,
-} http_authmechanism_t;
-
 typedef struct {
 	git_smart_subtransport_stream parent;
 	const char *service;
@@ -58,9 +60,6 @@ typedef struct {
 	transport_smart *owner;
 	gitno_socket socket;
 	gitno_connection_data connection_data;
-	git_cred *cred;
-	git_cred *url_cred;
-	http_authmechanism_t auth_mechanism;
 	bool connected;
 
 	/* Parser structures */
@@ -76,6 +75,11 @@ typedef struct {
 	enum last_cb last_cb;
 	int parse_error;
 	unsigned parse_finished : 1;
+
+	/* Authentication */
+	git_cred *cred;
+	git_cred *url_cred;
+	git_vector auth_contexts;
 } http_subtransport;
 
 typedef struct {
@@ -88,28 +92,91 @@ typedef struct {
 	size_t *bytes_read;
 } parser_context;
 
-static int apply_basic_credential(git_buf *buf, git_cred *cred)
+static bool credtype_match(git_http_auth_scheme *scheme, void *data)
 {
-	git_cred_userpass_plaintext *c = (git_cred_userpass_plaintext *)cred;
-	git_buf raw = GIT_BUF_INIT;
-	int error = -1;
+	unsigned int credtype = *(unsigned int *)data;
 
-	git_buf_printf(&raw, "%s:%s", c->username, c->password);
+	return !!(scheme->credtypes & credtype);
+}
 
-	if (git_buf_oom(&raw) ||
-		git_buf_puts(buf, "Authorization: Basic ") < 0 ||
-		git_buf_put_base64(buf, git_buf_cstr(&raw), raw.size) < 0 ||
-		git_buf_puts(buf, "\r\n") < 0)
-		goto on_error;
+static bool challenge_match(git_http_auth_scheme *scheme, void *data)
+{
+	const char *scheme_name = scheme->name;
+	const char *challenge = (const char *)data;
+	size_t scheme_len;
 
-	error = 0;
+	scheme_len = strlen(scheme_name);
+	return (strncmp(challenge, scheme_name, scheme_len) == 0 &&
+		(challenge[scheme_len] == '\0' || challenge[scheme_len] == ' '));
+}
 
-on_error:
-	if (raw.size)
-		memset(raw.ptr, 0x0, raw.size);
+static int auth_context_match(
+	git_http_auth_context **out,
+	http_subtransport *t,
+	bool (*scheme_match)(git_http_auth_scheme *scheme, void *data),
+	void *data)
+{
+	git_http_auth_scheme *scheme = NULL;
+	git_http_auth_context *context = NULL, *c;
+	size_t i;
 
-	git_buf_free(&raw);
-	return error;
+	*out = NULL;
+
+	for (i = 0; i < ARRAY_SIZE(auth_schemes); i++) {
+		if (scheme_match(&auth_schemes[i], data)) {
+			scheme = &auth_schemes[i];
+			break;
+		}
+	}
+
+	if (!scheme)
+		return 0;
+
+	/* See if authentication has already started for this scheme */
+	git_vector_foreach(&t->auth_contexts, i, c) {
+		if (c->type == scheme->type) {
+			context = c;
+			break;
+		}
+	}
+
+	if (!context) {
+		if (scheme->init_context(&context, &t->connection_data) < 0)
+			return -1;
+		else if (!context)
+			return 0;
+		else if (git_vector_insert(&t->auth_contexts, context) < 0)
+			return -1;
+	}
+
+	*out = context;
+
+	return 0;
+}
+
+static int apply_credentials(git_buf *buf, http_subtransport *t)
+{
+	git_cred *cred = t->cred;
+	git_http_auth_context *context;
+
+	/* Apply the credentials given to us in the URL */
+	if (!cred && t->connection_data.user && t->connection_data.pass) {
+		if (!t->url_cred &&
+			git_cred_userpass_plaintext_new(&t->url_cred,
+				t->connection_data.user, t->connection_data.pass) < 0)
+			return -1;
+
+		cred = t->url_cred;
+	}
+
+	if (!cred)
+		return 0;
+
+	/* Get or create a context for the best scheme for this cred type */
+	if (auth_context_match(&context, t, credtype_match, &cred->credtype) < 0)
+		return -1;
+
+	return context->next_token(buf, context, cred);
 }
 
 static int gen_request(
@@ -137,19 +204,9 @@ static int gen_request(
 		git_buf_puts(buf, "Accept: */*\r\n");
 
 	/* Apply credentials to the request */
-	if (t->cred && t->cred->credtype == GIT_CREDTYPE_USERPASS_PLAINTEXT &&
-		t->auth_mechanism == GIT_HTTP_AUTH_BASIC &&
-		apply_basic_credential(buf, t->cred) < 0)
+	if (apply_credentials(buf, t) < 0)
 		return -1;
 
-	/* Use url-parsed basic auth if username and password are both provided */
-	if (!t->cred && t->connection_data.user && t->connection_data.pass) {
-		if (!t->url_cred && git_cred_userpass_plaintext_new(&t->url_cred,
-					t->connection_data.user, t->connection_data.pass) < 0)
-			return -1;
-		if (apply_basic_credential(buf, t->url_cred) < 0) return -1;
-	}
-
 	git_buf_puts(buf, "\r\n");
 
 	if (git_buf_oom(buf))
@@ -158,20 +215,26 @@ static int gen_request(
 	return 0;
 }
 
-static int parse_unauthorized_response(
+static int parse_authenticate_response(
 	git_vector *www_authenticate,
-	int *allowed_types,
-	http_authmechanism_t *auth_mechanism)
+	http_subtransport *t,
+	int *allowed_types)
 {
-	unsigned i;
-	char *entry;
-
-	git_vector_foreach(www_authenticate, i, entry) {
-		if (!strncmp(entry, basic_authtype, 5) &&
-			(entry[5] == '\0' || entry[5] == ' ')) {
-			*allowed_types |= GIT_CREDTYPE_USERPASS_PLAINTEXT;
-			*auth_mechanism = GIT_HTTP_AUTH_BASIC;
-		}
+	git_http_auth_context *context;
+	char *challenge;
+	size_t i;
+
+	git_vector_foreach(www_authenticate, i, challenge) {
+		if (auth_context_match(&context, t, challenge_match, challenge) < 0)
+			return -1;
+		else if (!context)
+			continue;
+
+		if (context->set_challenge &&
+			context->set_challenge(context, challenge) < 0)
+			return -1;
+
+		*allowed_types |= context->credtypes;
 	}
 
 	return 0;
@@ -248,7 +311,7 @@ static int on_headers_complete(http_parser *parser)
 	http_subtransport *t = ctx->t;
 	http_stream *s = ctx->s;
 	git_buf buf = GIT_BUF_INIT;
-	int error = 0, no_callback = 0;
+	int error = 0, no_callback = 0, allowed_auth_types = 0;
 
 	/* Both parse_header_name and parse_header_value are populated
 	 * and ready for consumption. */
@@ -256,26 +319,26 @@ static int on_headers_complete(http_parser *parser)
 		if (on_header_ready(t) < 0)
 			return t->parse_error = PARSE_ERROR_GENERIC;
 
-	/* Check for an authentication failure. */
+	/* Capture authentication headers which may be a 401 (authentication
+	 * is not complete) or a 200 (simply informing us that auth *is*
+	 * complete.)
+	 */
+	if (parse_authenticate_response(&t->www_authenticate, t,
+			&allowed_auth_types) < 0)
+		return t->parse_error = PARSE_ERROR_GENERIC;
 
-	if (parser->status_code == 401 &&
-	    get_verb == s->verb) {
+	/* Check for an authentication failure. */
+	if (parser->status_code == 401 && get_verb == s->verb) {
 		if (!t->owner->cred_acquire_cb) {
 			no_callback = 1;
 		} else {
-			int allowed_types = 0;
-
-			if (parse_unauthorized_response(&t->www_authenticate,
-							&allowed_types, &t->auth_mechanism) < 0)
-				return t->parse_error = PARSE_ERROR_GENERIC;
-
-			if (allowed_types &&
-			    (!t->cred || 0 == (t->cred->credtype & allowed_types))) {
+			if (allowed_auth_types &&
+			    (!t->cred || 0 == (t->cred->credtype & allowed_auth_types))) {
 
 				error = t->owner->cred_acquire_cb(&t->cred,
 								  t->owner->url,
 								  t->connection_data.user,
-								  allowed_types,
+								  allowed_auth_types,
 								  t->owner->cred_acquire_payload);
 
 				if (error == GIT_PASSTHROUGH) {
@@ -286,7 +349,8 @@ static int on_headers_complete(http_parser *parser)
 					assert(t->cred);
 
 					/* Successfully acquired a credential. */
-					return t->parse_error = PARSE_ERROR_REPLAY;
+					t->parse_error = PARSE_ERROR_REPLAY;
+					return 0;
 				}
 			}
 		}
@@ -324,7 +388,8 @@ static int on_headers_complete(http_parser *parser)
 		t->connected = 0;
 		s->redirect_count++;
 
-		return t->parse_error = PARSE_ERROR_REPLAY;
+		t->parse_error = PARSE_ERROR_REPLAY;
+		return 0;
 	}
 
 	/* Check for a 200 HTTP status code. */
@@ -382,6 +447,13 @@ static int on_body_fill_buffer(http_parser *parser, const char *str, size_t len)
 	parser_context *ctx = (parser_context *) parser->data;
 	http_subtransport *t = ctx->t;
 
+	/* If our goal is to replay the request (either an auth failure or
+	 * a redirect) then don't bother buffering since we're ignoring the
+	 * content anyway.
+	 */
+	if (t->parse_error == PARSE_ERROR_REPLAY)
+		return 0;
+
 	if (ctx->buf_size < len) {
 		giterr_set(GITERR_NET, "Can't fit data in the buffer");
 		return t->parse_error = PARSE_ERROR_GENERIC;
@@ -456,7 +528,7 @@ static int http_connect(http_subtransport *t)
 
 	if (t->connected &&
 		http_should_keep_alive(&t->parser) &&
-		http_body_is_final(&t->parser))
+		t->parse_finished)
 		return 0;
 
 	if (t->socket.socket)
@@ -502,10 +574,8 @@ replay:
 
 		clear_parser_state(t);
 
-		if (gen_request(&request, s, 0) < 0) {
-			giterr_set(GITERR_NET, "Failed to generate request");
+		if (gen_request(&request, s, 0) < 0)
 			return -1;
-		}
 
 		if (gitno_send(&t->socket, request.ptr, request.size, 0) < 0) {
 			git_buf_free(&request);
@@ -604,10 +674,8 @@ static int http_stream_write_chunked(
 
 		clear_parser_state(t);
 
-		if (gen_request(&request, s, 0) < 0) {
-			giterr_set(GITERR_NET, "Failed to generate request");
+		if (gen_request(&request, s, 0) < 0)
 			return -1;
-		}
 
 		if (gitno_send(&t->socket, request.ptr, request.size, 0) < 0) {
 			git_buf_free(&request);
@@ -679,10 +747,8 @@ static int http_stream_write_single(
 
 	clear_parser_state(t);
 
-	if (gen_request(&request, s, len) < 0) {
-		giterr_set(GITERR_NET, "Failed to generate request");
+	if (gen_request(&request, s, len) < 0)
 		return -1;
-	}
 
 	if (gitno_send(&t->socket, request.ptr, request.size, 0) < 0)
 		goto on_error;
@@ -849,6 +915,8 @@ static int http_action(
 static int http_close(git_smart_subtransport *subtransport)
 {
 	http_subtransport *t = (http_subtransport *) subtransport;
+	git_http_auth_context *context;
+	size_t i;
 
 	clear_parser_state(t);
 
@@ -867,6 +935,13 @@ static int http_close(git_smart_subtransport *subtransport)
 		t->url_cred = NULL;
 	}
 
+	git_vector_foreach(&t->auth_contexts, i, context) {
+		if (context->free)
+			context->free(context);
+	}
+
+	git_vector_clear(&t->auth_contexts);
+
 	gitno_connection_data_free_ptrs(&t->connection_data);
 
 	return 0;
@@ -878,6 +953,7 @@ static void http_free(git_smart_subtransport *subtransport)
 
 	http_close(subtransport);
 
+	git_vector_free(&t->auth_contexts);
 	git__free(t);
 }
 
diff --git a/src/transports/winhttp.c b/src/transports/winhttp.c
index 32641cd64..1e46dfaee 100644
--- a/src/transports/winhttp.c
+++ b/src/transports/winhttp.c
@@ -101,7 +101,7 @@ static int apply_basic_credential(HINTERNET request, git_cred *cred)
 
 	if (git_buf_oom(&raw) ||
 		git_buf_puts(&buf, "Authorization: Basic ") < 0 ||
-		git_buf_put_base64(&buf, git_buf_cstr(&raw), raw.size) < 0)
+		git_buf_encode_base64(&buf, git_buf_cstr(&raw), raw.size) < 0)
 		goto on_error;
 
 	if ((wide_len = git__utf8_to_16_alloc(&wide, git_buf_cstr(&buf))) < 0) {
diff --git a/tests/core/buffer.c b/tests/core/buffer.c
index 8310deae1..7482dadbe 100644
--- a/tests/core/buffer.c
+++ b/tests/core/buffer.c
@@ -748,7 +748,7 @@ void test_core_buffer__unescape(void)
 	assert_unescape("", "");
 }
 
-void test_core_buffer__base64(void)
+void test_core_buffer__encode_base64(void)
 {
 	git_buf buf = GIT_BUF_INIT;
 
@@ -759,33 +759,54 @@ void test_core_buffer__base64(void)
 	 * 0x 1d 06 21 29 1c 30
 	 *     d  G  h  p  c  w
 	 */
-	cl_git_pass(git_buf_put_base64(&buf, "this", 4));
+	cl_git_pass(git_buf_encode_base64(&buf, "this", 4));
 	cl_assert_equal_s("dGhpcw==", buf.ptr);
 
 	git_buf_clear(&buf);
-	cl_git_pass(git_buf_put_base64(&buf, "this!", 5));
+	cl_git_pass(git_buf_encode_base64(&buf, "this!", 5));
 	cl_assert_equal_s("dGhpcyE=", buf.ptr);
 
 	git_buf_clear(&buf);
-	cl_git_pass(git_buf_put_base64(&buf, "this!\n", 6));
+	cl_git_pass(git_buf_encode_base64(&buf, "this!\n", 6));
 	cl_assert_equal_s("dGhpcyEK", buf.ptr);
 
 	git_buf_free(&buf);
 }
 
-void test_core_buffer__base85(void)
+void test_core_buffer__decode_base64(void)
 {
 	git_buf buf = GIT_BUF_INIT;
 
-	cl_git_pass(git_buf_put_base85(&buf, "this", 4));
+	cl_git_pass(git_buf_decode_base64(&buf, "dGhpcw==", 8));
+	cl_assert_equal_s("this", buf.ptr);
+
+	git_buf_clear(&buf);
+	cl_git_pass(git_buf_decode_base64(&buf, "dGhpcyE=", 8));
+	cl_assert_equal_s("this!", buf.ptr);
+
+	git_buf_clear(&buf);
+	cl_git_pass(git_buf_decode_base64(&buf, "dGhpcyEK", 8));
+	cl_assert_equal_s("this!\n", buf.ptr);
+
+	cl_git_fail(git_buf_decode_base64(&buf, "This is not a valid base64 string!!!", 36));
+	cl_assert_equal_s("this!\n", buf.ptr);
+
+	git_buf_free(&buf);
+}
+
+void test_core_buffer__encode_base85(void)
+{
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_buf_encode_base85(&buf, "this", 4));
 	cl_assert_equal_s("bZBXF", buf.ptr);
 	git_buf_clear(&buf);
 
-	cl_git_pass(git_buf_put_base85(&buf, "two rnds", 8));
+	cl_git_pass(git_buf_encode_base85(&buf, "two rnds", 8));
 	cl_assert_equal_s("ba!tca&BaE", buf.ptr);
 	git_buf_clear(&buf);
 
-	cl_git_pass(git_buf_put_base85(&buf, "this is base 85 encoded",
+	cl_git_pass(git_buf_encode_base85(&buf, "this is base 85 encoded",
 		strlen("this is base 85 encoded")));
 	cl_assert_equal_s("bZBXFAZc?TVqtS-AUHK3Wo~0{WMyOk", buf.ptr);
 	git_buf_clear(&buf);
diff --git a/tests/online/clone.c b/tests/online/clone.c
index b672a099a..0cd0f3115 100644
--- a/tests/online/clone.c
+++ b/tests/online/clone.c
@@ -226,9 +226,28 @@ void test_online_clone__cred_callback_failure_return_code_is_tunnelled(void)
 	cl_git_fail_with(git_clone(&g_repo, remote_url, "./foo", &g_options), -1);
 }
 
+int cred_default(
+	git_cred **cred,
+	const char *url,
+	const char *user_from_url,
+	unsigned int allowed_types,
+	void *payload)
+{
+	GIT_UNUSED(url);
+	GIT_UNUSED(user_from_url);
+	GIT_UNUSED(payload);
+
+	if (!(allowed_types & GIT_CREDTYPE_DEFAULT))
+		return 0;
+
+	return git_cred_default_new(cred);
+}
+
 void test_online_clone__credentials(void)
 {
-	/* Remote URL environment variable must be set.  User and password are optional.  */
+	/* Remote URL environment variable must be set.
+	 * User and password are optional.
+	 */
 	const char *remote_url = cl_getenv("GITTEST_REMOTE_URL");
 	git_cred_userpass_payload user_pass = {
 		cl_getenv("GITTEST_REMOTE_USER"),
@@ -237,8 +256,12 @@ void test_online_clone__credentials(void)
 
 	if (!remote_url) return;
 
-	g_options.remote_callbacks.credentials = git_cred_userpass;
-	g_options.remote_callbacks.payload = &user_pass;
+	if (cl_getenv("GITTEST_REMOTE_DEFAULT")) {
+		g_options.remote_callbacks.credentials = cred_default;
+	} else {
+		g_options.remote_callbacks.credentials = git_cred_userpass;
+		g_options.remote_callbacks.payload = &user_pass;
+	}
 
 	cl_git_pass(git_clone(&g_repo, remote_url, "./foo", &g_options));
 	git_repository_free(g_repo); g_repo = NULL;
@@ -346,7 +369,7 @@ void test_online_clone__ssh_with_paths(void)
 	const char *remote_url = cl_getenv("GITTEST_REMOTE_URL");
 	const char *remote_user = cl_getenv("GITTEST_REMOTE_USER");
 
-	if (!remote_url || !remote_user)
+	if (!remote_url || !remote_user || strncmp(remote_url, "ssh://", 5) != 0)
 		clar__skip();
 
 	g_options.remote_cb = custom_remote_ssh_with_paths;
diff --git a/tests/online/push.c b/tests/online/push.c
index 6da27bb96..c351827d9 100644
--- a/tests/online/push.c
+++ b/tests/online/push.c
@@ -204,6 +204,8 @@ static void verify_tracking_branches(git_remote *remote, expected_ref expected_r
 		cl_assert_equal_i(branch_type, GIT_BRANCH_REMOTE);
 
 		cl_git_pass(git_vector_insert(&actual_refs, git__strdup(git_reference_name(ref))));
+
+		git_reference_free(ref);
 	}
 
 	cl_assert_equal_i(error, GIT_ITEROVER);
@@ -852,6 +854,9 @@ void test_online_push__notes(void)
 	const char *specs[] = { "refs/notes/commits:refs/notes/commits" };
 	push_status exp_stats[] = { { "refs/notes/commits", 1 } };
 	expected_ref exp_refs[] = { { "refs/notes/commits", &expected_oid } };
+	const char *specs_del[] = { ":refs/notes/commits" };
+	expected_ref exp_refs_del[] = { };
+
 	git_oid_fromstr(&expected_oid, "8461a99b27b7043e58ff6e1f5d2cf07d282534fb");
 
 	target_oid = &_oid_b6;
@@ -864,5 +869,11 @@ void test_online_push__notes(void)
 		exp_stats, ARRAY_SIZE(exp_stats),
 		exp_refs, ARRAY_SIZE(exp_refs), 0, 1, 1);
 
+	/* And make sure to delete the note */
+
+	do_push(specs_del, ARRAY_SIZE(specs_del),
+		exp_stats, 1,
+		exp_refs_del, ARRAY_SIZE(exp_refs_del), 0, 0, 0);
+
 	git_signature_free(signature);
 }