path: safeguard `.git` against NTFS Alternate Streams Accesses

[thirdparty/git.git] / http-walker.c

diff --git a/http-walker.c b/http-walker.c
index c2f81cd6af9d9da0f10fa2e657e6fe62bdbdc4bc..ee049cb13df6ed6a64b1980004100a5dd55dde51 100644 (file)
--- a/http-walker.c
+++ b/http-walker.c
@@ -3,6 +3,7 @@
 #include "walker.h"
 #include "http.h"
 #include "list.h"
+#include "transport.h"
 
 struct alt_base {
        char *base;
@@ -160,6 +161,37 @@ static void prefetch(struct walker *walker, unsigned char *sha1)
 #endif
 }
 
+static int is_alternate_allowed(const char *url)
+{
+       const char *protocols[] = {
+               "http", "https", "ftp", "ftps"
+       };
+       int i;
+
+       if (http_follow_config != HTTP_FOLLOW_ALWAYS) {
+               warning("alternate disabled by http.followRedirects: %s", url);
+               return 0;
+       }
+
+       for (i = 0; i < ARRAY_SIZE(protocols); i++) {
+               const char *end;
+               if (skip_prefix(url, protocols[i], &end) &&
+                   starts_with(end, "://"))
+                       break;
+       }
+
+       if (i >= ARRAY_SIZE(protocols)) {
+               warning("ignoring alternate with unknown protocol: %s", url);
+               return 0;
+       }
+       if (!is_transport_allowed(protocols[i], 0)) {
+               warning("ignoring alternate with restricted protocol: %s", url);
+               return 0;
+       }
+
+       return 1;
+}
+
 static void process_alternates_response(void *callback_data)
 {
        struct alternates_request *alt_req =
@@ -269,22 +301,30 @@ static void process_alternates_response(void *callback_data)
                                        okay = 1;
                                }
                        }
-                       /* skip "objects\n" at end */
                        if (okay) {
                                struct strbuf target = STRBUF_INIT;
                                strbuf_add(&target, base, serverlen);
-                               strbuf_add(&target, data + i, posn - i - 7);
-                               warning("adding alternate object store: %s",
-                                       target.buf);
-                               newalt = xmalloc(sizeof(*newalt));
-                               newalt->next = NULL;
-                               newalt->base = strbuf_detach(&target, NULL);
-                               newalt->got_indices = 0;
-                               newalt->packs = NULL;
-
-                               while (tail->next != NULL)
-                                       tail = tail->next;
-                               tail->next = newalt;
+                               strbuf_add(&target, data + i, posn - i);
+                               if (!strbuf_strip_suffix(&target, "objects")) {
+                                       warning("ignoring alternate that does"
+                                               " not end in 'objects': %s",
+                                               target.buf);
+                                       strbuf_release(&target);
+                               } else if (is_alternate_allowed(target.buf)) {
+                                       warning("adding alternate object store: %s",
+                                               target.buf);
+                                       newalt = xmalloc(sizeof(*newalt));
+                                       newalt->next = NULL;
+                                       newalt->base = strbuf_detach(&target, NULL);
+                                       newalt->got_indices = 0;
+                                       newalt->packs = NULL;
+
+                                       while (tail->next != NULL)
+                                               tail = tail->next;
+                                       tail->next = newalt;
+                               } else {
+                                       strbuf_release(&target);
+                               }
                        }
                }
                i = posn + 1;
@@ -301,9 +341,6 @@ static void fetch_alternates(struct walker *walker, const char *base)
        struct alternates_request alt_req;
        struct walker_data *cdata = walker->data;
 
-       if (http_follow_config != HTTP_FOLLOW_ALWAYS)
-               return;
-
        /*
         * If another request has already started fetching alternates,
         * wait for them to arrive and return to processing this request's