]> git.ipfire.org Git - thirdparty/git.git/blobdiff - http.c
path: create path.h
[thirdparty/git.git] / http.c
diff --git a/http.c b/http.c
index d8e427b69b43a8cc0607893e59891fc8a4356f51..013bb0cc650888426156fd1c8d173544c1ec90e1 100644 (file)
--- a/http.c
+++ b/http.c
@@ -1,5 +1,6 @@
 #include "git-compat-util.h"
 #include "http.h"
+#include "config.h"
 #include "pack.h"
 #include "sideband.h"
 #include "run-command.h"
@@ -11,6 +12,7 @@
 #include "gettext.h"
 #include "transport.h"
 
+static struct trace_key trace_curl = TRACE_KEY_INIT(CURL);
 #if LIBCURL_VERSION_NUM >= 0x070a08
 long int git_curl_ipresolve = CURL_IPRESOLVE_WHATEVER;
 #else
@@ -18,7 +20,7 @@ long int git_curl_ipresolve;
 #endif
 int active_requests;
 int http_is_verbose;
-size_t http_post_buffer = 16 * LARGE_PACKET_MAX;
+ssize_t http_post_buffer = 16 * LARGE_PACKET_MAX;
 
 #if LIBCURL_VERSION_NUM >= 0x070a06
 #define LIBCURL_CAN_HANDLE_AUTH_ANY
@@ -89,6 +91,18 @@ static struct {
         * here, too
         */
 };
+#if LIBCURL_VERSION_NUM >= 0x071600
+static const char *curl_deleg;
+static struct {
+       const char *name;
+       long curl_deleg_param;
+} curl_deleg_levels[] = {
+       { "none", CURLGSSAPI_DELEGATION_NONE },
+       { "policy", CURLGSSAPI_DELEGATION_POLICY_FLAG },
+       { "always", CURLGSSAPI_DELEGATION_FLAG },
+};
+#endif
+
 static struct credential proxy_auth = CREDENTIAL_INIT;
 static const char *curl_proxyuserpwd;
 static const char *curl_cookie_file;
@@ -96,7 +110,9 @@ static int curl_save_cookies;
 struct credential http_auth = CREDENTIAL_INIT;
 static int http_proactive_auth;
 static const char *user_agent;
-static int curl_empty_auth;
+static int curl_empty_auth = -1;
+
+enum http_follow_config http_follow_config = HTTP_FOLLOW_INITIAL;
 
 #if LIBCURL_VERSION_NUM >= 0x071700
 /* Use CURLOPT_KEYPASSWD as is */
@@ -110,6 +126,14 @@ static struct credential cert_auth = CREDENTIAL_INIT;
 static int ssl_cert_password_required;
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
 static unsigned long http_auth_methods = CURLAUTH_ANY;
+static int http_auth_methods_restricted;
+/* Modes for which empty_auth cannot actually help us. */
+static unsigned long empty_auth_useless =
+       CURLAUTH_BASIC
+#ifdef CURLAUTH_DIGEST_IE
+       | CURLAUTH_DIGEST_IE
+#endif
+       | CURLAUTH_DIGEST;
 #endif
 
 static struct curl_slist *pragma_header;
@@ -200,6 +224,13 @@ static void finish_active_slot(struct active_request_slot *slot)
                slot->callback_func(slot->callback_data);
 }
 
+static void xmulti_remove_handle(struct active_request_slot *slot)
+{
+#ifdef USE_CURL_MULTI
+       curl_multi_remove_handle(curlm, slot->curl);
+#endif
+}
+
 #ifdef USE_CURL_MULTI
 static void process_curl_messages(void)
 {
@@ -215,7 +246,7 @@ static void process_curl_messages(void)
                               slot->curl != curl_message->easy_handle)
                                slot = slot->next;
                        if (slot != NULL) {
-                               curl_multi_remove_handle(curlm, slot->curl);
+                               xmulti_remove_handle(slot);
                                slot->curl_result = curl_result;
                                finish_active_slot(slot);
                        } else {
@@ -301,7 +332,9 @@ static int http_options(const char *var, const char *value, void *cb)
        }
 
        if (!strcmp("http.postbuffer", var)) {
-               http_post_buffer = git_config_int(var, value);
+               http_post_buffer = git_config_ssize_t(var, value);
+               if (http_post_buffer < 0)
+                       warning(_("negative value for http.postbuffer; defaulting to %d"), LARGE_PACKET_MAX);
                if (http_post_buffer < LARGE_PACKET_MAX)
                        http_post_buffer = LARGE_PACKET_MAX;
                return 0;
@@ -311,8 +344,20 @@ static int http_options(const char *var, const char *value, void *cb)
                return git_config_string(&user_agent, var, value);
 
        if (!strcmp("http.emptyauth", var)) {
-               curl_empty_auth = git_config_bool(var, value);
+               if (value && !strcmp("auto", value))
+                       curl_empty_auth = -1;
+               else
+                       curl_empty_auth = git_config_bool(var, value);
+               return 0;
+       }
+
+       if (!strcmp("http.delegation", var)) {
+#if LIBCURL_VERSION_NUM >= 0x071600
+               return git_config_string(&curl_deleg, var, value);
+#else
+               warning(_("Delegation control is not supported with cURL < 7.22.0"));
                return 0;
+#endif
        }
 
        if (!strcmp("http.pinnedpubkey", var)) {
@@ -337,14 +382,51 @@ static int http_options(const char *var, const char *value, void *cb)
                return 0;
        }
 
+       if (!strcmp("http.followredirects", var)) {
+               if (value && !strcmp(value, "initial"))
+                       http_follow_config = HTTP_FOLLOW_INITIAL;
+               else if (git_config_bool(var, value))
+                       http_follow_config = HTTP_FOLLOW_ALWAYS;
+               else
+                       http_follow_config = HTTP_FOLLOW_NONE;
+               return 0;
+       }
+
        /* Fall back on the default ones */
        return git_default_config(var, value, cb);
 }
 
+static int curl_empty_auth_enabled(void)
+{
+       if (curl_empty_auth >= 0)
+               return curl_empty_auth;
+
+#ifndef LIBCURL_CAN_HANDLE_AUTH_ANY
+       /*
+        * Our libcurl is too old to do AUTH_ANY in the first place;
+        * just default to turning the feature off.
+        */
+#else
+       /*
+        * In the automatic case, kick in the empty-auth
+        * hack as long as we would potentially try some
+        * method more exotic than "Basic" or "Digest".
+        *
+        * But only do this when this is our second or
+        * subsequent request, as by then we know what
+        * methods are available.
+        */
+       if (http_auth_methods_restricted &&
+           (http_auth_methods & ~empty_auth_useless))
+               return 1;
+#endif
+       return 0;
+}
+
 static void init_curl_http_auth(CURL *result)
 {
-       if (!http_auth.username) {
-               if (curl_empty_auth)
+       if (!http_auth.username || !*http_auth.username) {
+               if (curl_empty_auth_enabled())
                        curl_easy_setopt(result, CURLOPT_USERPWD, ":");
                return;
        }
@@ -477,10 +559,143 @@ static void set_curl_keepalive(CURL *c)
 }
 #endif
 
+static void redact_sensitive_header(struct strbuf *header)
+{
+       const char *sensitive_header;
+
+       if (skip_prefix(header->buf, "Authorization:", &sensitive_header) ||
+           skip_prefix(header->buf, "Proxy-Authorization:", &sensitive_header)) {
+               /* The first token is the type, which is OK to log */
+               while (isspace(*sensitive_header))
+                       sensitive_header++;
+               while (*sensitive_header && !isspace(*sensitive_header))
+                       sensitive_header++;
+               /* Everything else is opaque and possibly sensitive */
+               strbuf_setlen(header,  sensitive_header - header->buf);
+               strbuf_addstr(header, " <redacted>");
+       }
+}
+
+static void curl_dump_header(const char *text, unsigned char *ptr, size_t size, int hide_sensitive_header)
+{
+       struct strbuf out = STRBUF_INIT;
+       struct strbuf **headers, **header;
+
+       strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+               text, (long)size, (long)size);
+       trace_strbuf(&trace_curl, &out);
+       strbuf_reset(&out);
+       strbuf_add(&out, ptr, size);
+       headers = strbuf_split_max(&out, '\n', 0);
+
+       for (header = headers; *header; header++) {
+               if (hide_sensitive_header)
+                       redact_sensitive_header(*header);
+               strbuf_insert((*header), 0, text, strlen(text));
+               strbuf_insert((*header), strlen(text), ": ", 2);
+               strbuf_rtrim((*header));
+               strbuf_addch((*header), '\n');
+               trace_strbuf(&trace_curl, (*header));
+       }
+       strbuf_list_free(headers);
+       strbuf_release(&out);
+}
+
+static void curl_dump_data(const char *text, unsigned char *ptr, size_t size)
+{
+       size_t i;
+       struct strbuf out = STRBUF_INIT;
+       unsigned int width = 60;
+
+       strbuf_addf(&out, "%s, %10.10ld bytes (0x%8.8lx)\n",
+               text, (long)size, (long)size);
+       trace_strbuf(&trace_curl, &out);
+
+       for (i = 0; i < size; i += width) {
+               size_t w;
+
+               strbuf_reset(&out);
+               strbuf_addf(&out, "%s: ", text);
+               for (w = 0; (w < width) && (i + w < size); w++) {
+                       unsigned char ch = ptr[i + w];
+
+                       strbuf_addch(&out,
+                                      (ch >= 0x20) && (ch < 0x80)
+                                      ? ch : '.');
+               }
+               strbuf_addch(&out, '\n');
+               trace_strbuf(&trace_curl, &out);
+       }
+       strbuf_release(&out);
+}
+
+static int curl_trace(CURL *handle, curl_infotype type, char *data, size_t size, void *userp)
+{
+       const char *text;
+       enum { NO_FILTER = 0, DO_FILTER = 1 };
+
+       switch (type) {
+       case CURLINFO_TEXT:
+               trace_printf_key(&trace_curl, "== Info: %s", data);
+       default:                /* we ignore unknown types by default */
+               return 0;
+
+       case CURLINFO_HEADER_OUT:
+               text = "=> Send header";
+               curl_dump_header(text, (unsigned char *)data, size, DO_FILTER);
+               break;
+       case CURLINFO_DATA_OUT:
+               text = "=> Send data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_SSL_DATA_OUT:
+               text = "=> Send SSL data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_HEADER_IN:
+               text = "<= Recv header";
+               curl_dump_header(text, (unsigned char *)data, size, NO_FILTER);
+               break;
+       case CURLINFO_DATA_IN:
+               text = "<= Recv data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       case CURLINFO_SSL_DATA_IN:
+               text = "<= Recv SSL data";
+               curl_dump_data(text, (unsigned char *)data, size);
+               break;
+       }
+       return 0;
+}
+
+void setup_curl_trace(CURL *handle)
+{
+       if (!trace_want(&trace_curl))
+               return;
+       curl_easy_setopt(handle, CURLOPT_VERBOSE, 1L);
+       curl_easy_setopt(handle, CURLOPT_DEBUGFUNCTION, curl_trace);
+       curl_easy_setopt(handle, CURLOPT_DEBUGDATA, NULL);
+}
+
+static long get_curl_allowed_protocols(int from_user)
+{
+       long allowed_protocols = 0;
+
+       if (is_transport_allowed("http", from_user))
+               allowed_protocols |= CURLPROTO_HTTP;
+       if (is_transport_allowed("https", from_user))
+               allowed_protocols |= CURLPROTO_HTTPS;
+       if (is_transport_allowed("ftp", from_user))
+               allowed_protocols |= CURLPROTO_FTP;
+       if (is_transport_allowed("ftps", from_user))
+               allowed_protocols |= CURLPROTO_FTPS;
+
+       return allowed_protocols;
+}
+
 static CURL *get_curl_handle(void)
 {
        CURL *result = curl_easy_init();
-       long allowed_protocols = 0;
 
        if (!result)
                die("curl_easy_init failed");
@@ -502,6 +717,22 @@ static CURL *get_curl_handle(void)
        curl_easy_setopt(result, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
 #endif
 
+#if LIBCURL_VERSION_NUM >= 0x071600
+       if (curl_deleg) {
+               int i;
+               for (i = 0; i < ARRAY_SIZE(curl_deleg_levels); i++) {
+                       if (!strcmp(curl_deleg, curl_deleg_levels[i].name)) {
+                               curl_easy_setopt(result, CURLOPT_GSSAPI_DELEGATION,
+                                               curl_deleg_levels[i].curl_deleg_param);
+                               break;
+                       }
+               }
+               if (i == ARRAY_SIZE(curl_deleg_levels))
+                       warning("Unknown delegation method '%s': using default",
+                               curl_deleg);
+       }
+#endif
+
        if (http_proactive_auth)
                init_curl_http_auth(result);
 
@@ -553,7 +784,6 @@ static CURL *get_curl_handle(void)
                                 curl_low_speed_time);
        }
 
-       curl_easy_setopt(result, CURLOPT_FOLLOWLOCATION, 1);
        curl_easy_setopt(result, CURLOPT_MAXREDIRS, 20);
 #if LIBCURL_VERSION_NUM >= 0x071301
        curl_easy_setopt(result, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
@@ -561,23 +791,17 @@ static CURL *get_curl_handle(void)
        curl_easy_setopt(result, CURLOPT_POST301, 1);
 #endif
 #if LIBCURL_VERSION_NUM >= 0x071304
-       if (is_transport_allowed("http"))
-               allowed_protocols |= CURLPROTO_HTTP;
-       if (is_transport_allowed("https"))
-               allowed_protocols |= CURLPROTO_HTTPS;
-       if (is_transport_allowed("ftp"))
-               allowed_protocols |= CURLPROTO_FTP;
-       if (is_transport_allowed("ftps"))
-               allowed_protocols |= CURLPROTO_FTPS;
-       curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS, allowed_protocols);
+       curl_easy_setopt(result, CURLOPT_REDIR_PROTOCOLS,
+                        get_curl_allowed_protocols(0));
+       curl_easy_setopt(result, CURLOPT_PROTOCOLS,
+                        get_curl_allowed_protocols(-1));
 #else
-       if (transport_restrict_protocols())
-               warning("protocol restrictions not applied to curl redirects because\n"
-                       "your curl version is too old (>= 7.19.4)");
+       warning("protocol restrictions not applied to curl redirects because\n"
+               "your curl version is too old (>= 7.19.4)");
 #endif
-
        if (getenv("GIT_CURL_VERBOSE"))
-               curl_easy_setopt(result, CURLOPT_VERBOSE, 1);
+               curl_easy_setopt(result, CURLOPT_VERBOSE, 1L);
+       setup_curl_trace(result);
 
        curl_easy_setopt(result, CURLOPT_USERAGENT,
                user_agent ? user_agent : git_user_agent());
@@ -603,7 +827,7 @@ static CURL *get_curl_handle(void)
         * precedence here, as in CURL.
         */
        if (!curl_http_proxy) {
-               if (!strcmp(http_auth.protocol, "https")) {
+               if (http_auth.protocol && !strcmp(http_auth.protocol, "https")) {
                        var_override(&curl_http_proxy, getenv("HTTPS_PROXY"));
                        var_override(&curl_http_proxy, getenv("https_proxy"));
                } else {
@@ -615,8 +839,14 @@ static CURL *get_curl_handle(void)
                }
        }
 
-       if (curl_http_proxy) {
-               curl_easy_setopt(result, CURLOPT_PROXY, curl_http_proxy);
+       if (curl_http_proxy && curl_http_proxy[0] == '\0') {
+               /*
+                * Handle case with the empty http.proxy value here to keep
+                * common code clean.
+                * NB: empty option disables proxying at all.
+                */
+               curl_easy_setopt(result, CURLOPT_PROXY, "");
+       } else if (curl_http_proxy) {
 #if LIBCURL_VERSION_NUM >= 0x071800
                if (starts_with(curl_http_proxy, "socks5h"))
                        curl_easy_setopt(result,
@@ -640,6 +870,9 @@ static CURL *get_curl_handle(void)
                        strbuf_release(&url);
                }
 
+               if (!proxy_auth.host)
+                       die("Invalid proxy URL '%s'", curl_http_proxy);
+
                curl_easy_setopt(result, CURLOPT_PROXY, proxy_auth.host);
 #if LIBCURL_VERSION_NUM >= 0x071304
                var_override(&curl_no_proxy, getenv("NO_PROXY"));
@@ -761,9 +994,7 @@ void http_cleanup(void)
        while (slot != NULL) {
                struct active_request_slot *next = slot->next;
                if (slot->curl != NULL) {
-#ifdef USE_CURL_MULTI
-                       curl_multi_remove_handle(curlm, slot->curl);
-#endif
+                       xmulti_remove_handle(slot);
                        curl_easy_cleanup(slot->curl);
                }
                free(slot);
@@ -882,13 +1113,23 @@ struct active_request_slot *get_active_slot(void)
        curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 1);
        curl_easy_setopt(slot->curl, CURLOPT_RANGE, NULL);
 
+       /*
+        * Default following to off unless "ALWAYS" is configured; this gives
+        * callers a sane starting point, and they can tweak for individual
+        * HTTP_FOLLOW_* cases themselves.
+        */
+       if (http_follow_config == HTTP_FOLLOW_ALWAYS)
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
+       else
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 0);
+
 #if LIBCURL_VERSION_NUM >= 0x070a08
        curl_easy_setopt(slot->curl, CURLOPT_IPRESOLVE, git_curl_ipresolve);
 #endif
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
        curl_easy_setopt(slot->curl, CURLOPT_HTTPAUTH, http_auth_methods);
 #endif
-       if (http_auth.password || curl_empty_auth)
+       if (http_auth.password || curl_empty_auth_enabled())
                init_curl_http_auth(slot->curl);
 
        return slot;
@@ -902,6 +1143,8 @@ int start_active_slot(struct active_request_slot *slot)
 
        if (curlm_result != CURLM_OK &&
            curlm_result != CURLM_CALL_MULTI_PERFORM) {
+               warning("curl_multi_add_handle failed: %s",
+                       curl_multi_strerror(curlm_result));
                active_requests--;
                slot->in_use = 0;
                return 0;
@@ -1041,13 +1284,13 @@ void run_active_slot(struct active_request_slot *slot)
 static void release_active_slot(struct active_request_slot *slot)
 {
        closedown_active_slot(slot);
-       if (slot->curl && curl_session_count > min_curl_sessions) {
-#ifdef USE_CURL_MULTI
-               curl_multi_remove_handle(curlm, slot->curl);
-#endif
-               curl_easy_cleanup(slot->curl);
-               slot->curl = NULL;
-               curl_session_count--;
+       if (slot->curl) {
+               xmulti_remove_handle(slot);
+               if (curl_session_count > min_curl_sessions) {
+                       curl_easy_cleanup(slot->curl);
+                       slot->curl = NULL;
+                       curl_session_count--;
+               }
        }
 #ifdef USE_CURL_MULTI
        fill_active_slots();
@@ -1122,9 +1365,12 @@ static int handle_curl_result(struct slot_results *results)
         * If we see a failing http code with CURLE_OK, we have turned off
         * FAILONERROR (to keep the server's custom error response), and should
         * translate the code into failure here.
+        *
+        * Likewise, if we see a redirect (30x code), that means we turned off
+        * redirect-following, and we should treat the result as an error.
         */
        if (results->curl_result == CURLE_OK &&
-           results->http_code >= 400) {
+           results->http_code >= 300) {
                results->curl_result = CURLE_HTTP_RETURNED_ERROR;
                /*
                 * Normally curl will already have put the "reason phrase"
@@ -1132,9 +1378,9 @@ static int handle_curl_result(struct slot_results *results)
                 * FAILONERROR it is lost, so we can give only the numeric
                 * status code.
                 */
-               snprintf(curl_errorstr, sizeof(curl_errorstr),
-                        "The requested URL returned error: %ld",
-                        results->http_code);
+               xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+                         "The requested URL returned error: %ld",
+                         results->http_code);
        }
 
        if (results->curl_result == CURLE_OK) {
@@ -1151,6 +1397,10 @@ static int handle_curl_result(struct slot_results *results)
                } else {
 #ifdef LIBCURL_CAN_HANDLE_AUTH_ANY
                        http_auth_methods &= ~CURLAUTH_GSSNEGOTIATE;
+                       if (results->auth_avail) {
+                               http_auth_methods &= results->auth_avail;
+                               http_auth_methods_restricted = 1;
+                       }
 #endif
                        return HTTP_REAUTH;
                }
@@ -1172,8 +1422,8 @@ int run_one_slot(struct active_request_slot *slot,
 {
        slot->results = results;
        if (!start_active_slot(slot)) {
-               snprintf(curl_errorstr, sizeof(curl_errorstr),
-                        "failed to start HTTP request");
+               xsnprintf(curl_errorstr, sizeof(curl_errorstr),
+                         "failed to start HTTP request");
                return HTTP_START_FAILED;
        }
 
@@ -1443,6 +1693,9 @@ static int http_request(const char *url,
                strbuf_addstr(&buf, " no-cache");
        if (options && options->keep_error)
                curl_easy_setopt(slot->curl, CURLOPT_FAILONERROR, 0);
+       if (options && options->initial_request &&
+           http_follow_config == HTTP_FOLLOW_INITIAL)
+               curl_easy_setopt(slot->curl, CURLOPT_FOLLOWLOCATION, 1);
 
        headers = curl_slist_append(headers, buf.buf);
 
@@ -1491,16 +1744,16 @@ static int http_request(const char *url,
  *
  * Note that this assumes a sane redirect scheme. It's entirely possible
  * in the example above to end up at a URL that does not even end in
- * "info/refs".  In such a case we simply punt, as there is not much we can
- * do (and such a scheme is unlikely to represent a real git repository,
- * which means we are likely about to abort anyway).
+ * "info/refs".  In such a case we die. There's not much we can do, such a
+ * scheme is unlikely to represent a real git repository, and failing to
+ * rewrite the base opens options for malicious redirects to do funny things.
  */
 static int update_url_from_redirect(struct strbuf *base,
                                    const char *asked,
                                    const struct strbuf *got)
 {
        const char *tail;
-       size_t tail_len;
+       size_t new_len;
 
        if (!strcmp(asked, got->buf))
                return 0;
@@ -1509,14 +1762,16 @@ static int update_url_from_redirect(struct strbuf *base,
                die("BUG: update_url_from_redirect: %s is not a superset of %s",
                    asked, base->buf);
 
-       tail_len = strlen(tail);
-
-       if (got->len < tail_len ||
-           strcmp(tail, got->buf + got->len - tail_len))
-               return 0; /* insane redirect scheme */
+       new_len = got->len;
+       if (!strip_suffix_mem(got->buf, &new_len, tail))
+               die(_("unable to update url base from redirection:\n"
+                     "  asked for: %s\n"
+                     "   redirect: %s"),
+                   asked, got->buf);
 
        strbuf_reset(base);
-       strbuf_add(base, got->buf, got->len - tail_len);
+       strbuf_add(base, got->buf, new_len);
+
        return 1;
 }
 
@@ -1526,6 +1781,9 @@ static int http_request_reauth(const char *url,
 {
        int ret = http_request(url, result, target, options);
 
+       if (ret != HTTP_OK && ret != HTTP_REAUTH)
+               return ret;
+
        if (options && options->effective_url && options->base_url) {
                if (update_url_from_redirect(options->base_url,
                                             url, options->effective_url)) {
@@ -1855,8 +2113,19 @@ static size_t fwrite_sha1_file(char *ptr, size_t eltsize, size_t nmemb,
        unsigned char expn[4096];
        size_t size = eltsize * nmemb;
        int posn = 0;
-       struct http_object_request *freq =
-               (struct http_object_request *)data;
+       struct http_object_request *freq = data;
+       struct active_request_slot *slot = freq->slot;
+
+       if (slot) {
+               CURLcode c = curl_easy_getinfo(slot->curl, CURLINFO_HTTP_CODE,
+                                               &slot->http_code);
+               if (c != CURLE_OK)
+                       die("BUG: curl_easy_getinfo for HTTP code failed: %s",
+                               curl_easy_strerror(c));
+               if (slot->http_code >= 300)
+                       return size;
+       }
+
        do {
                ssize_t retval = xwrite(freq->localfile,
                                        (char *) ptr + posn, size - posn);
@@ -1977,6 +2246,7 @@ struct http_object_request *new_http_object_request(const char *base_url,
        freq->slot = get_active_slot();
 
        curl_easy_setopt(freq->slot->curl, CURLOPT_FILE, freq);
+       curl_easy_setopt(freq->slot->curl, CURLOPT_FAILONERROR, 0);
        curl_easy_setopt(freq->slot->curl, CURLOPT_WRITEFUNCTION, fwrite_sha1_file);
        curl_easy_setopt(freq->slot->curl, CURLOPT_ERRORBUFFER, freq->errorstr);
        curl_easy_setopt(freq->slot->curl, CURLOPT_URL, freq->url);