added git_mbedtls_stream_new

libgit2 · joshtriplett · Oct 9, 2015 · Oct 9, 2015 · Oct 9, 2015 · Oct 9, 2015
commit ad2b2e2242da65f5f3fa37dbb02c1eb22a97fddb
diff --git a/src/mbedtls_stream.c b/src/mbedtls_stream.c
@@ -0,0 +1,303 @@
+/*
+ * 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_MBEDTLS
+
+#include <ctype.h>
+
+#include "global.h"
+#include "posix.h"
+#include "stream.h"
+#include "socket_stream.h"
+#include "netops.h"
+#include "git2/transport.h"
+
+#ifdef GIT_CURL
+# include "curl_stream.h"
+#endif
+
+#ifndef GIT_WIN32
+# include <sys/types.h>
+# include <sys/socket.h>
+# include <netinet/in.h>
+#endif
+
+#include <mbedtls/ssl.h>
+#include <mbedtls/x509.h>
+#include <mbedtls/error.h>
+
+static int bio_read(void *b, unsigned char *buf, size_t len)
+{
+    git_stream *io = (git_stream *) b;
+    return (int) git_stream_read(io, buf, len);
+}
+
+static int bio_write(void *b, const unsigned char *buf, size_t len)
+{
+    git_stream *io = (git_stream *) b;
+    return (int) git_stream_write(io, (const char *)buf, len, 0);
+}
+
+static int ssl_set_error(int error)
+{
+    char errbuf[512];
+
+    assert(error != MBEDTLS_ERR_SSL_WANT_READ);
+    assert(error != MBEDTLS_ERR_SSL_WANT_WRITE);
+
+    if (error == 0) {
+        giterr_set(GITERR_NET, "SSL error: unknown error");
+    } else {
+        mbedtls_strerror( error, errbuf, 512 );
+        giterr_set(GITERR_NET, "SSL error: %d - %s", error, errbuf);
+    }
+
+    return -1;
+}
+
+static int ssl_teardown(mbedtls_ssl_context *ssl)
+{
+    int ret = 0;
+
+    ret = mbedtls_ssl_close_notify(ssl);
+    if (ret < 0)
+        ret = ssl_set_error(ret);
+
+    mbedtls_ssl_free(ssl);
+    return ret;
+}
+
+static int verify_server_cert(mbedtls_ssl_context *ssl, const char *host)
+{
+    const mbedtls_x509_crt *cert;
+    int flags;
+    struct in6_addr addr6;
+    struct in_addr addr4;
+    void *addr;
+
+    if( ( flags = mbedtls_ssl_get_verify_result(ssl) ) != 0 )
+    {
+        char vrfy_buf[512];
+        mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), "  ! ", flags );
+        giterr_set(GITERR_SSL, "The SSL certificate is invalid: %s", vrfy_buf);
+        return GIT_ECERTIFICATE;
+    }
+
+    /* Try to parse the host as an IP address to see if it is */
+    if (p_inet_pton(AF_INET, host, &addr4)) {
+        addr = &addr4;
+    } else {
+        if(p_inet_pton(AF_INET6, host, &addr6)) {
+            addr = &addr6;
+        }
+    }
+
+    cert = mbedtls_ssl_get_peer_cert(ssl);
+    if (!cert) {
+        giterr_set(GITERR_SSL, "the server did not provide a certificate");
+        return -1;
+    }
+
+    /* Check the alternative names */
+    //TODO: cert->subject_alt_names
+
+    /* If no alternative names are available, check the common name */
+    /*TODO
+    mbedtls_x509_name peer_name = cert->subject;
+    if (peer_name == NULL)
+        goto on_error;
+    */
+
+    return 0;
+
+on_error:
+    return ssl_set_error(0);
+
+cert_fail_name:
+    giterr_set(GITERR_SSL, "hostname does not match certificate");
+    return GIT_ECERTIFICATE;
+}
+
+typedef struct {
+    git_stream parent;
+    git_stream *io;
+    bool connected;
+    char *host;
+    mbedtls_ssl_context *ssl;
+    git_cert_x509 cert_info;
+} mbedtls_stream;
+
+
+int mbedtls_connect(git_stream *stream)
+{
+    int ret;
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+
+    if ((ret = git_stream_connect(st->io)) < 0)
+        return ret;
+
+    st->connected = true;
+
+    mbedtls_ssl_set_bio(st->ssl, st->io, bio_write, bio_read, NULL);
+
+    /* specify the host in case SNI is needed */
+#ifdef SSL_CTRL_SET_TLSEXT_HOSTNAME
+    mbedtls_ssl_set_hostname(st->ssl, st->host);
+#endif
+
+    if ((ret = mbedtls_ssl_handshake(st->ssl)) != 0)
+        return ssl_set_error(ret);
+
+    return verify_server_cert(st->ssl, st->host);
+}
+
+int mbedtls_certificate(git_cert **out, git_stream *stream)
+{
+    unsigned char *encoded_cert;
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+
+    const mbedtls_x509_crt *cert = mbedtls_ssl_get_peer_cert(st->ssl);
+    if (!cert) {
+        giterr_set(GITERR_SSL, "the server did not provide a certificate");
+        return -1;
+    }
+
+    /* Retrieve the length of the certificate first */
+    if (cert->raw.len == 0) {
+        giterr_set(GITERR_NET, "failed to retrieve certificate information");
+        return -1;
+    }
+
+    encoded_cert = git__malloc(cert->raw.len);
+    GITERR_CHECK_ALLOC(encoded_cert);
+    memcpy(encoded_cert, cert->raw.p, cert->raw.len);
+
+    st->cert_info.parent.cert_type = GIT_CERT_X509;
+    st->cert_info.data = encoded_cert;
+    st->cert_info.len = cert->raw.len;
+
+    *out = &st->cert_info.parent;
+
+    return 0;
+}
+
+static int mbedtls_set_proxy(git_stream *stream, const char *proxy_url)
+{
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+
+    return git_stream_set_proxy(st->io, proxy_url);
+}
+
+ssize_t mbedtls_write(git_stream *stream, const char *data, size_t len, int flags)
+{
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+    int ret;
+
+    GIT_UNUSED(flags);
+
+    if ((ret = mbedtls_ssl_write(st->ssl, (const unsigned char *)data, len)) <= 0) {
+        return ssl_set_error(ret);
+    }
+
+    return ret;
+}
+
+ssize_t mbedtls_read(git_stream *stream, void *data, size_t len)
+{
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+    int ret;
+
+    if ((ret = mbedtls_ssl_read(st->ssl, (unsigned char *)data, len)) <= 0)
+        ssl_set_error(ret);
+
+    return ret;
+}
+
+int mbedtls_close(git_stream *stream)
+{
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+    int ret = 0;
+
+    if (st->connected && (ret = ssl_teardown(st->ssl)) != 0)
+        return -1;
+
+    st->connected = false;
+
+    return git_stream_close(st->io);
+}
+
+void mbedtls_free(git_stream *stream)
+{
+    mbedtls_stream *st = (mbedtls_stream *) stream;
+
+    git__free(st->host);
+    git__free(st->cert_info.data);
+    git_stream_free(st->io);
+    git__free(st->ssl);
+    git__free(st);
+}
+
+int git_mbedtls_stream_new(git_stream **out, const char *host, const char *port)
+{
+    int error;
+    mbedtls_stream *st;
+
+    st = git__calloc(1, sizeof(mbedtls_stream));
+    GITERR_CHECK_ALLOC(st);
+
+#ifdef GIT_CURL
+    error = git_curl_stream_new(&st->io, host, port);
+#else
+    error = git_socket_stream_new(&st->io, host, port);
+#endif
+
+    if (error < 0)
+        return error;
+
+    st->ssl = git__malloc(sizeof(mbedtls_ssl_context));
+    GITERR_CHECK_ALLOC(st->ssl);
+    mbedtls_ssl_init(st->ssl);
+    if( (error = mbedtls_ssl_setup(st->ssl, git__ssl_conf)) != 0 ) {
+        mbedtls_ssl_free(st->ssl);
+        giterr_set(GITERR_SSL, "failed to create ssl object");
+        return -1;
+    }
+
+    st->host = git__strdup(host);
+    GITERR_CHECK_ALLOC(st->host);
+
+    st->parent.version = GIT_STREAM_VERSION;
+    st->parent.encrypted = 1;
+    st->parent.proxy_support = git_stream_supports_proxy(st->io);
+    st->parent.connect = mbedtls_connect;
+    st->parent.certificate = mbedtls_certificate;
+    st->parent.set_proxy = mbedtls_set_proxy;
+    st->parent.read = mbedtls_read;
+    st->parent.write = mbedtls_write;
+    st->parent.close = mbedtls_close;
+    st->parent.free = mbedtls_free;
+
+    *out = (git_stream *) st;
+    return 0;
+}
+
+#else
+
+#include "stream.h"
+
+int git_mbedtls_stream_new(git_stream **out, const char *host, const char *port)
+{
+    GIT_UNUSED(out);
+    GIT_UNUSED(host);
+    GIT_UNUSED(port);
+
+    giterr_set(GITERR_SSL, "openssl is not supported in this version");
+    return -1;
+}
+
+#endif
+
diff --git a/src/mbedtls_stream.h b/src/mbedtls_stream.h
@@ -0,0 +1,14 @@
+/*
+ * 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_mbedtls_stream_h__
+#define INCLUDE_mbedtls_stream_h__
+
+#include "git2/sys/stream.h"
+
+extern int git_mbedtls_stream_new(git_stream **out, const char *host, const char *port);
+
+#endif