Support a modicum of path validation, and allow an export all trees option.

diff --git a/daemon.c b/daemon.c
index fe46d3e..0ca6cef 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -12,7 +12,13 @@
 static int log_syslog;
 static int verbose;
 
-static const char daemon_usage[] = "git-daemon [--verbose] [--syslog] [--inetd | --port=n]";
+static const char daemon_usage[] = "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all] [directory...]";
+
+/* List of acceptable pathname prefixes */
+static char **ok_paths = NULL;
+
+/* If this is set, git-daemon-export-ok is not required */
+static int export_all_trees = 0;
 
 
 static void logreport(int priority, const char *err, va_list params)
@@ -69,15 +75,61 @@ void loginfo(const char *err, ...)
        va_end(params);
 }
 
+static int path_ok(const char *dir)
+{
+       const char *p = dir;
+       char **pp;
+       int sl = 1, ndot = 0;
+
+       for (;;) {
+               if ( *p == '.' ) {
+                       ndot++;
+               } else if ( *p == '/' || *p == '\0' ) {
+                       if ( sl && ndot > 0 && ndot < 3 )
+                               return 0; /* . or .. in path */
+                       sl = 1;
+                       if ( *p == '\0' )
+                               break; /* End of string and all is good */
+               } else {
+                       sl = ndot = 0;
+               }
+               p++;
+       }
+
+       if ( ok_paths && *ok_paths ) {
+               int ok = 0;
+               int dirlen = strlen(dir); /* read_packet_line can return embedded \0 */
+
+               for ( pp = ok_paths ; *pp ; pp++ ) {
+                       int len = strlen(*pp);
+                       if ( len <= dirlen &&
+                            !strncmp(*pp, dir, len) &&
+                            (dir[len] == '/' || dir[len] == '\0') ) {
+                               ok = 1;
+                               break;
+                       }
+               }
+
+               if ( !ok )
+                       return 0; /* Path not in whitelist */
+       }
+
+       return 1;               /* Path acceptable */
+}
 
 static int upload(char *dir, int dirlen)
 {
        loginfo("Request for '%s'", dir);
+
+       if (!path_ok(dir)) {
+               logerror("Forbidden directory: %s\n", dir);
+               return -1;
+       }
+
        if (chdir(dir) < 0) {
                logerror("Cannot chdir('%s'): %s", dir, strerror(errno));
                return -1;
        }
-       chdir(".git");
 
        /*
         * Security on the cheap.
@@ -86,10 +138,10 @@ static int upload(char *dir, int dirlen)
         * a "git-daemon-export-ok" flag that says that the other side
         * is ok with us doing this.
         */
-       if (access("git-daemon-export-ok", F_OK) ||
+       if ((!export_all_trees && access("git-daemon-export-ok", F_OK)) ||
            access("objects/00", X_OK) ||
            access("HEAD", R_OK)) {
-               logerror("Not a valid gitd-enabled repository: '%s'", dir);
+               logerror("Not a valid git-daemon-enabled repository: '%s'", dir);
                return -1;
        }
 
@@ -441,7 +493,6 @@ int main(int argc, char **argv)
                                continue;
                        }
                }
-
                if (!strcmp(arg, "--inetd")) {
                        inetd_mode = 1;
                        continue;
@@ -455,6 +506,17 @@ int main(int argc, char **argv)
                        openlog("git-daemon", 0, LOG_DAEMON);
                        continue;
                }
+               if (!strcmp(arg, "--export-all")) {
+                       export_all_trees = 1;
+                       continue;
+               }
+               if (!strcmp(arg, "--")) {
+                       ok_paths = &argv[i+1];
+                       break;
+               } else if (arg[0] != '-') {
+                       ok_paths = &argv[i];
+                       break;
+               }
 
                usage(daemon_usage);
        }