Make path-limiting be incremental when possible.

diff --git a/daemon.c b/daemon.c
index dab8c2c64506e5d9ff1f4d2120e0dc00020eb9e9..a1ccda30e2211368c66c1186437891f548f0e338 100644 (file)
--- a/daemon.c
+++ b/daemon.c
@@ -18,7 +18,8 @@ static int reuseaddr;
 static const char daemon_usage[] =
 "git-daemon [--verbose] [--syslog] [--inetd | --port=n] [--export-all]\n"
 "           [--timeout=n] [--init-timeout=n] [--strict-paths]\n"
-"           [--base-path=path] [--reuseaddr] [directory...]";
+"           [--base-path=path] [--user-path | --user-path=path]\n"
+"           [--reuseaddr] [directory...]";
 
 /* List of acceptable pathname prefixes */
 static char **ok_paths = NULL;
@@ -30,6 +31,12 @@ static int export_all_trees = 0;
 /* Take all paths relative to this one if non-NULL */
 static char *base_path = NULL;
 
+/* If defined, ~user notation is allowed and the string is inserted
+ * after ~user/.  E.g. a request to git://host/~alice/frotz would
+ * go to /home/alice/pub_git/frotz with --user-path=pub_git.
+ */
+static char *user_path = NULL;
+
 /* Timeout, and initial timeout */
 static unsigned int timeout = 0;
 static unsigned int init_timeout = 0;
@@ -137,6 +144,7 @@ static int avoid_alias(char *p)
 
 static char *path_ok(char *dir)
 {
+       static char rpath[PATH_MAX];
        char *path;
 
        if (avoid_alias(dir)) {
@@ -144,12 +152,31 @@ static char *path_ok(char *dir)
                return NULL;
        }
 
-       if (base_path) {
-               static char rpath[PATH_MAX];
-               if (!strict_paths && *dir == '~')
-                       ; /* allow user relative paths */
-               else if (*dir != '/') {
-                       /* otherwise allow only absolute */
+       if (*dir == '~') {
+               if (!user_path) {
+                       logerror("'%s': User-path not allowed", dir);
+                       return NULL;
+               }
+               if (*user_path) {
+                       /* Got either "~alice" or "~alice/foo";
+                        * rewrite them to "~alice/%s" or
+                        * "~alice/%s/foo".
+                        */
+                       int namlen, restlen = strlen(dir);
+                       char *slash = strchr(dir, '/');
+                       if (!slash)
+                               slash = dir + restlen;
+                       namlen = slash - dir;
+                       restlen -= namlen;
+                       loginfo("userpath <%s>, request <%s>, namlen %d, restlen %d, slash <%s>", user_path, dir, namlen, restlen, slash);
+                       snprintf(rpath, PATH_MAX, "%.*s/%s%.*s",
+                                namlen, dir, user_path, restlen, slash);
+                       dir = rpath;
+               }
+       }
+       else if (base_path) {
+               if (*dir != '/') {
+                       /* Allow only absolute */
                        logerror("'%s': Non-absolute path denied (base-path active)", dir);
                        return NULL;
                }
@@ -688,6 +715,14 @@ int main(int argc, char **argv)
                        reuseaddr = 1;
                        continue;
                }
+               if (!strcmp(arg, "--user-path")) {
+                       user_path = "";
+                       continue;
+               }
+               if (!strncmp(arg, "--user-path=", 12)) {
+                       user_path = arg + 12;
+                       continue;
+               }
                if (!strcmp(arg, "--")) {
                        ok_paths = &argv[i+1];
                        break;