diff options
Diffstat (limited to 'src/libgit2/transports/http.c')
| -rw-r--r-- | src/libgit2/transports/http.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/src/libgit2/transports/http.c b/src/libgit2/transports/http.c new file mode 100644 index 000000000..7db5582ca --- /dev/null +++ b/src/libgit2/transports/http.c @@ -0,0 +1,760 @@ +/* + * 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 "common.h" + +#ifndef GIT_WINHTTP + +#include "http_parser.h" +#include "net.h" +#include "netops.h" +#include "remote.h" +#include "smart.h" +#include "auth.h" +#include "http.h" +#include "auth_negotiate.h" +#include "auth_ntlm.h" +#include "trace.h" +#include "streams/tls.h" +#include "streams/socket.h" +#include "httpclient.h" +#include "git2/sys/credential.h" + +bool git_http__expect_continue = false; + +typedef enum { + HTTP_STATE_NONE = 0, + HTTP_STATE_SENDING_REQUEST, + HTTP_STATE_RECEIVING_RESPONSE, + HTTP_STATE_DONE +} http_state; + +typedef struct { + git_http_method method; + const char *url; + const char *request_type; + const char *response_type; + unsigned int initial : 1, + chunked : 1; +} http_service; + +typedef struct { + git_smart_subtransport_stream parent; + const http_service *service; + http_state state; + unsigned replay_count; +} http_stream; + +typedef struct { + git_net_url url; + + git_credential *cred; + unsigned auth_schemetypes; + unsigned url_cred_presented : 1; +} http_server; + +typedef struct { + git_smart_subtransport parent; + transport_smart *owner; + + http_server server; + http_server proxy; + + git_http_client *http_client; +} http_subtransport; + +static const http_service upload_pack_ls_service = { + GIT_HTTP_METHOD_GET, "/info/refs?service=git-upload-pack", + NULL, + "application/x-git-upload-pack-advertisement", + 1, + 0 +}; +static const http_service upload_pack_service = { + GIT_HTTP_METHOD_POST, "/git-upload-pack", + "application/x-git-upload-pack-request", + "application/x-git-upload-pack-result", + 0, + 0 +}; +static const http_service receive_pack_ls_service = { + GIT_HTTP_METHOD_GET, "/info/refs?service=git-receive-pack", + NULL, + "application/x-git-receive-pack-advertisement", + 1, + 0 +}; +static const http_service receive_pack_service = { + GIT_HTTP_METHOD_POST, "/git-receive-pack", + "application/x-git-receive-pack-request", + "application/x-git-receive-pack-result", + 0, + 1 +}; + +#define SERVER_TYPE_REMOTE "remote" +#define SERVER_TYPE_PROXY "proxy" + +#define OWNING_SUBTRANSPORT(s) ((http_subtransport *)(s)->parent.subtransport) + +static int apply_url_credentials( + git_credential **cred, + unsigned int allowed_types, + const char *username, + const char *password) +{ + GIT_ASSERT_ARG(username); + + if (!password) + password = ""; + + if (allowed_types & GIT_CREDENTIAL_USERPASS_PLAINTEXT) + return git_credential_userpass_plaintext_new(cred, username, password); + + if ((allowed_types & GIT_CREDENTIAL_DEFAULT) && *username == '\0' && *password == '\0') + return git_credential_default_new(cred); + + return GIT_PASSTHROUGH; +} + +GIT_INLINE(void) free_cred(git_credential **cred) +{ + if (*cred) { + git_credential_free(*cred); + (*cred) = NULL; + } +} + +static int handle_auth( + http_server *server, + const char *server_type, + const char *url, + unsigned int allowed_schemetypes, + unsigned int allowed_credtypes, + git_credential_acquire_cb callback, + void *callback_payload) +{ + int error = 1; + + if (server->cred) + free_cred(&server->cred); + + /* Start with URL-specified credentials, if there were any. */ + if ((allowed_credtypes & GIT_CREDENTIAL_USERPASS_PLAINTEXT) && + !server->url_cred_presented && + server->url.username) { + error = apply_url_credentials(&server->cred, allowed_credtypes, server->url.username, server->url.password); + server->url_cred_presented = 1; + + /* treat GIT_PASSTHROUGH as if callback isn't set */ + if (error == GIT_PASSTHROUGH) + error = 1; + } + + if (error > 0 && callback) { + error = callback(&server->cred, url, server->url.username, allowed_credtypes, callback_payload); + + /* treat GIT_PASSTHROUGH as if callback isn't set */ + if (error == GIT_PASSTHROUGH) + error = 1; + } + + if (error > 0) { + git_error_set(GIT_ERROR_HTTP, "%s authentication required but no callback set", server_type); + error = GIT_EAUTH; + } + + if (!error) + server->auth_schemetypes = allowed_schemetypes; + + return error; +} + +GIT_INLINE(int) handle_remote_auth( + http_stream *stream, + git_http_response *response) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_remote_connect_options *connect_opts = &transport->owner->connect_opts; + + if (response->server_auth_credtypes == 0) { + git_error_set(GIT_ERROR_HTTP, "server requires authentication that we do not support"); + return GIT_EAUTH; + } + + /* Otherwise, prompt for credentials. */ + return handle_auth( + &transport->server, + SERVER_TYPE_REMOTE, + transport->owner->url, + response->server_auth_schemetypes, + response->server_auth_credtypes, + connect_opts->callbacks.credentials, + connect_opts->callbacks.payload); +} + +GIT_INLINE(int) handle_proxy_auth( + http_stream *stream, + git_http_response *response) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_remote_connect_options *connect_opts = &transport->owner->connect_opts; + + if (response->proxy_auth_credtypes == 0) { + git_error_set(GIT_ERROR_HTTP, "proxy requires authentication that we do not support"); + return GIT_EAUTH; + } + + /* Otherwise, prompt for credentials. */ + return handle_auth( + &transport->proxy, + SERVER_TYPE_PROXY, + connect_opts->proxy_opts.url, + response->server_auth_schemetypes, + response->proxy_auth_credtypes, + connect_opts->proxy_opts.credentials, + connect_opts->proxy_opts.payload); +} + +static bool allow_redirect(http_stream *stream) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + + switch (transport->owner->connect_opts.follow_redirects) { + case GIT_REMOTE_REDIRECT_INITIAL: + return (stream->service->initial == 1); + case GIT_REMOTE_REDIRECT_ALL: + return true; + default: + return false; + } +} + +static int handle_response( + bool *complete, + http_stream *stream, + git_http_response *response, + bool allow_replay) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + int error; + + *complete = false; + + if (allow_replay && git_http_response_is_redirect(response)) { + if (!response->location) { + git_error_set(GIT_ERROR_HTTP, "redirect without location"); + return -1; + } + + if (git_net_url_apply_redirect(&transport->server.url, response->location, allow_redirect(stream), stream->service->url) < 0) { + return -1; + } + + return 0; + } else if (git_http_response_is_redirect(response)) { + git_error_set(GIT_ERROR_HTTP, "unexpected redirect"); + return -1; + } + + /* If we're in the middle of challenge/response auth, continue. */ + if (allow_replay && response->resend_credentials) { + return 0; + } else if (allow_replay && response->status == GIT_HTTP_STATUS_UNAUTHORIZED) { + if ((error = handle_remote_auth(stream, response)) < 0) + return error; + + return git_http_client_skip_body(transport->http_client); + } else if (allow_replay && response->status == GIT_HTTP_STATUS_PROXY_AUTHENTICATION_REQUIRED) { + if ((error = handle_proxy_auth(stream, response)) < 0) + return error; + + return git_http_client_skip_body(transport->http_client); + } else if (response->status == GIT_HTTP_STATUS_UNAUTHORIZED || + response->status == GIT_HTTP_STATUS_PROXY_AUTHENTICATION_REQUIRED) { + git_error_set(GIT_ERROR_HTTP, "unexpected authentication failure"); + return GIT_EAUTH; + } + + if (response->status != GIT_HTTP_STATUS_OK) { + git_error_set(GIT_ERROR_HTTP, "unexpected http status code: %d", response->status); + return -1; + } + + /* The response must contain a Content-Type header. */ + if (!response->content_type) { + git_error_set(GIT_ERROR_HTTP, "no content-type header in response"); + return -1; + } + + /* The Content-Type header must match our expectation. */ + if (strcmp(response->content_type, stream->service->response_type) != 0) { + git_error_set(GIT_ERROR_HTTP, "invalid content-type: '%s'", response->content_type); + return -1; + } + + *complete = true; + stream->state = HTTP_STATE_RECEIVING_RESPONSE; + return 0; +} + +static int lookup_proxy( + bool *out_use, + http_subtransport *transport) +{ + git_remote_connect_options *connect_opts = &transport->owner->connect_opts; + const char *proxy; + git_remote *remote; + char *config = NULL; + int error = 0; + + *out_use = false; + git_net_url_dispose(&transport->proxy.url); + + switch (connect_opts->proxy_opts.type) { + case GIT_PROXY_SPECIFIED: + proxy = connect_opts->proxy_opts.url; + break; + + case GIT_PROXY_AUTO: + remote = transport->owner->owner; + + error = git_remote__http_proxy(&config, remote, &transport->server.url); + + if (error || !config) + goto done; + + proxy = config; + break; + + default: + return 0; + } + + if (!proxy || + (error = git_net_url_parse(&transport->proxy.url, proxy)) < 0) + goto done; + + *out_use = true; + +done: + git__free(config); + return error; +} + +static int generate_request( + git_net_url *url, + git_http_request *request, + http_stream *stream, + size_t len) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + bool use_proxy = false; + int error; + + if ((error = git_net_url_joinpath(url, + &transport->server.url, stream->service->url)) < 0 || + (error = lookup_proxy(&use_proxy, transport)) < 0) + return error; + + request->method = stream->service->method; + request->url = url; + request->credentials = transport->server.cred; + request->proxy = use_proxy ? &transport->proxy.url : NULL; + request->proxy_credentials = transport->proxy.cred; + request->custom_headers = &transport->owner->connect_opts.custom_headers; + + if (stream->service->method == GIT_HTTP_METHOD_POST) { + request->chunked = stream->service->chunked; + request->content_length = stream->service->chunked ? 0 : len; + request->content_type = stream->service->request_type; + request->accept = stream->service->response_type; + request->expect_continue = git_http__expect_continue; + } + + return 0; +} + +/* + * Read from an HTTP transport - for the first invocation of this function + * (ie, when stream->state == HTTP_STATE_NONE), we'll send a GET request + * to the remote host. We will stream that data back on all subsequent + * calls. + */ +static int http_stream_read( + git_smart_subtransport_stream *s, + char *buffer, + size_t buffer_size, + size_t *out_len) +{ + http_stream *stream = (http_stream *)s; + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_net_url url = GIT_NET_URL_INIT; + git_net_url proxy_url = GIT_NET_URL_INIT; + git_http_request request = {0}; + git_http_response response = {0}; + bool complete; + int error; + + *out_len = 0; + + if (stream->state == HTTP_STATE_NONE) { + stream->state = HTTP_STATE_SENDING_REQUEST; + stream->replay_count = 0; + } + + /* + * Formulate the URL, send the request and read the response + * headers. Some of the request body may also be read. + */ + while (stream->state == HTTP_STATE_SENDING_REQUEST && + stream->replay_count < GIT_HTTP_REPLAY_MAX) { + git_net_url_dispose(&url); + git_net_url_dispose(&proxy_url); + git_http_response_dispose(&response); + + if ((error = generate_request(&url, &request, stream, 0)) < 0 || + (error = git_http_client_send_request( + transport->http_client, &request)) < 0 || + (error = git_http_client_read_response( + &response, transport->http_client)) < 0 || + (error = handle_response(&complete, stream, &response, true)) < 0) + goto done; + + if (complete) + break; + + stream->replay_count++; + } + + if (stream->state == HTTP_STATE_SENDING_REQUEST) { + git_error_set(GIT_ERROR_HTTP, "too many redirects or authentication replays"); + error = GIT_ERROR; /* not GIT_EAUTH, because the exact cause is unclear */ + goto done; + } + + GIT_ASSERT(stream->state == HTTP_STATE_RECEIVING_RESPONSE); + + error = git_http_client_read_body(transport->http_client, buffer, buffer_size); + + if (error > 0) { + *out_len = error; + error = 0; + } + +done: + git_net_url_dispose(&url); + git_net_url_dispose(&proxy_url); + git_http_response_dispose(&response); + + return error; +} + +static bool needs_probe(http_stream *stream) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + + return (transport->server.auth_schemetypes == GIT_HTTP_AUTH_NTLM || + transport->server.auth_schemetypes == GIT_HTTP_AUTH_NEGOTIATE); +} + +static int send_probe(http_stream *stream) +{ + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_http_client *client = transport->http_client; + const char *probe = "0000"; + size_t len = 4; + git_net_url url = GIT_NET_URL_INIT; + git_http_request request = {0}; + git_http_response response = {0}; + bool complete = false; + size_t step, steps = 1; + int error; + + /* NTLM requires a full challenge/response */ + if (transport->server.auth_schemetypes == GIT_HTTP_AUTH_NTLM) + steps = GIT_AUTH_STEPS_NTLM; + + /* + * Send at most two requests: one without any authentication to see + * if we get prompted to authenticate. If we do, send a second one + * with the first authentication message. The final authentication + * message with the response will occur with the *actual* POST data. + */ + for (step = 0; step < steps && !complete; step++) { + git_net_url_dispose(&url); + git_http_response_dispose(&response); + + if ((error = generate_request(&url, &request, stream, len)) < 0 || + (error = git_http_client_send_request(client, &request)) < 0 || + (error = git_http_client_send_body(client, probe, len)) < 0 || + (error = git_http_client_read_response(&response, client)) < 0 || + (error = git_http_client_skip_body(client)) < 0 || + (error = handle_response(&complete, stream, &response, true)) < 0) + goto done; + } + +done: + git_http_response_dispose(&response); + git_net_url_dispose(&url); + return error; +} + +/* +* Write to an HTTP transport - for the first invocation of this function +* (ie, when stream->state == HTTP_STATE_NONE), we'll send a POST request +* to the remote host. If we're sending chunked data, then subsequent calls +* will write the additional data given in the buffer. If we're not chunking, +* then the caller should have given us all the data in the original call. +* The caller should call http_stream_read_response to get the result. +*/ +static int http_stream_write( + git_smart_subtransport_stream *s, + const char *buffer, + size_t len) +{ + http_stream *stream = GIT_CONTAINER_OF(s, http_stream, parent); + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_net_url url = GIT_NET_URL_INIT; + git_http_request request = {0}; + git_http_response response = {0}; + int error; + + while (stream->state == HTTP_STATE_NONE && + stream->replay_count < GIT_HTTP_REPLAY_MAX) { + + git_net_url_dispose(&url); + git_http_response_dispose(&response); + + /* + * If we're authenticating with a connection-based mechanism + * (NTLM, Kerberos), send a "probe" packet. Servers SHOULD + * authenticate an entire keep-alive connection, so ideally + * we should not need to authenticate but some servers do + * not support this. By sending a probe packet, we'll be + * able to follow up with a second POST using the actual + * data (and, in the degenerate case, the authentication + * header as well). + */ + if (needs_probe(stream) && (error = send_probe(stream)) < 0) + goto done; + + /* Send the regular POST request. */ + if ((error = generate_request(&url, &request, stream, len)) < 0 || + (error = git_http_client_send_request( + transport->http_client, &request)) < 0) + goto done; + + if (request.expect_continue && + git_http_client_has_response(transport->http_client)) { + bool complete; + + /* + * If we got a response to an expect/continue, then + * it's something other than a 100 and we should + * deal with the response somehow. + */ + if ((error = git_http_client_read_response(&response, transport->http_client)) < 0 || + (error = handle_response(&complete, stream, &response, true)) < 0) + goto done; + } else { + stream->state = HTTP_STATE_SENDING_REQUEST; + } + + stream->replay_count++; + } + + if (stream->state == HTTP_STATE_NONE) { + git_error_set(GIT_ERROR_HTTP, + "too many redirects or authentication replays"); + error = GIT_ERROR; /* not GIT_EAUTH because the exact cause is unclear */ + goto done; + } + + GIT_ASSERT(stream->state == HTTP_STATE_SENDING_REQUEST); + + error = git_http_client_send_body(transport->http_client, buffer, len); + +done: + git_http_response_dispose(&response); + git_net_url_dispose(&url); + return error; +} + +/* +* Read from an HTTP transport after it has been written to. This is the +* response from a POST request made by http_stream_write. +*/ +static int http_stream_read_response( + git_smart_subtransport_stream *s, + char *buffer, + size_t buffer_size, + size_t *out_len) +{ + http_stream *stream = (http_stream *)s; + http_subtransport *transport = OWNING_SUBTRANSPORT(stream); + git_http_client *client = transport->http_client; + git_http_response response = {0}; + bool complete; + int error; + + *out_len = 0; + + if (stream->state == HTTP_STATE_SENDING_REQUEST) { + if ((error = git_http_client_read_response(&response, client)) < 0 || + (error = handle_response(&complete, stream, &response, false)) < 0) + goto done; + + GIT_ASSERT(complete); + stream->state = HTTP_STATE_RECEIVING_RESPONSE; + } + + error = git_http_client_read_body(client, buffer, buffer_size); + + if (error > 0) { + *out_len = error; + error = 0; + } + +done: + git_http_response_dispose(&response); + return error; +} + +static void http_stream_free(git_smart_subtransport_stream *stream) +{ + http_stream *s = GIT_CONTAINER_OF(stream, http_stream, parent); + git__free(s); +} + +static const http_service *select_service(git_smart_service_t action) +{ + switch (action) { + case GIT_SERVICE_UPLOADPACK_LS: + return &upload_pack_ls_service; + case GIT_SERVICE_UPLOADPACK: + return &upload_pack_service; + case GIT_SERVICE_RECEIVEPACK_LS: + return &receive_pack_ls_service; + case GIT_SERVICE_RECEIVEPACK: + return &receive_pack_service; + } + + return NULL; +} + +static int http_action( + git_smart_subtransport_stream **out, + git_smart_subtransport *t, + const char *url, + git_smart_service_t action) +{ + http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent); + git_remote_connect_options *connect_opts = &transport->owner->connect_opts; + http_stream *stream; + const http_service *service; + int error; + + GIT_ASSERT_ARG(out); + GIT_ASSERT_ARG(t); + + *out = NULL; + + /* + * If we've seen a redirect then preserve the location that we've + * been given. This is important to continue authorization against + * the redirect target, not the user-given source; the endpoint may + * have redirected us from HTTP->HTTPS and is using an auth mechanism + * that would be insecure in plaintext (eg, HTTP Basic). + */ + if (!git_net_url_valid(&transport->server.url) && + (error = git_net_url_parse(&transport->server.url, url)) < 0) + return error; + + if ((service = select_service(action)) == NULL) { + git_error_set(GIT_ERROR_HTTP, "invalid action"); + return -1; + } + + stream = git__calloc(sizeof(http_stream), 1); + GIT_ERROR_CHECK_ALLOC(stream); + + if (!transport->http_client) { + git_http_client_options opts = {0}; + + opts.server_certificate_check_cb = connect_opts->callbacks.certificate_check; + opts.server_certificate_check_payload = connect_opts->callbacks.payload; + opts.proxy_certificate_check_cb = connect_opts->proxy_opts.certificate_check; + opts.proxy_certificate_check_payload = connect_opts->proxy_opts.payload; + + if (git_http_client_new(&transport->http_client, &opts) < 0) + return -1; + } + + stream->service = service; + stream->parent.subtransport = &transport->parent; + + if (service->method == GIT_HTTP_METHOD_GET) { + stream->parent.read = http_stream_read; + } else { + stream->parent.write = http_stream_write; + stream->parent.read = http_stream_read_response; + } + + stream->parent.free = http_stream_free; + + *out = (git_smart_subtransport_stream *)stream; + return 0; +} + +static int http_close(git_smart_subtransport *t) +{ + http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent); + + free_cred(&transport->server.cred); + free_cred(&transport->proxy.cred); + + transport->server.url_cred_presented = false; + transport->proxy.url_cred_presented = false; + + git_net_url_dispose(&transport->server.url); + git_net_url_dispose(&transport->proxy.url); + + return 0; +} + +static void http_free(git_smart_subtransport *t) +{ + http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent); + + git_http_client_free(transport->http_client); + + http_close(t); + git__free(transport); +} + +int git_smart_subtransport_http(git_smart_subtransport **out, git_transport *owner, void *param) +{ + http_subtransport *transport; + + GIT_UNUSED(param); + + GIT_ASSERT_ARG(out); + + transport = git__calloc(sizeof(http_subtransport), 1); + GIT_ERROR_CHECK_ALLOC(transport); + + transport->owner = (transport_smart *)owner; + transport->parent.action = http_action; + transport->parent.close = http_close; + transport->parent.free = http_free; + + *out = (git_smart_subtransport *) transport; + return 0; +} + +#endif /* !GIT_WINHTTP */ |