Merge branch 'jk/maint-config-bogus-section'

"git config --rename-section" to rename an existing section into a
bogus one did not check the new name.

By Jeff King
* jk/maint-config-bogus-section:
config: reject bogus section names for --rename-section

diff --combined config.c
index 2bbf02d1e8c2c05f9fba1149c307c1b3b06517fd,9ef947e073f487c035d0317572fe3733de8f0ad5..ac69cb62935cfe86fec4b557ad6546366e6b7d70
--- 1/config.c
--- 2/config.c
+++ b/config.c
@@@ -37,11 -37,6 +37,11 @@@ static int handle_path_include(const ch
  {
        int ret = 0;
        struct strbuf buf = STRBUF_INIT;
 +      char *expanded = expand_user_path(path);
 +
 +      if (!expanded)
 +              return error("Could not expand include path '%s'", path);
 +      path = expanded;
  
        /*
         * Use an absolute path as-is, but interpret relative paths
@@@ -68,7 -63,6 +68,7 @@@
                inc->depth--;
        }
        strbuf_release(&buf);
 +      free(expanded);
        return ret;
  }
  
@@@ -1558,20 -1552,42 +1558,42 @@@ static int section_name_match (const ch
        return 0;
  }
  
+ static int section_name_is_ok(const char *name)
+ {
+       /* Empty section names are bogus. */
+       if (!*name)
+               return 0;
+ 
+       /*
+        * Before a dot, we must be alphanumeric or dash. After the first dot,
+        * anything goes, so we can stop checking.
+        */
+       for (; *name && *name != '.'; name++)
+               if (*name != '-' && !isalnum(*name))
+                       return 0;
+       return 1;
+ }
+ 
  /* if new_name == NULL, the section is removed instead */
  int git_config_rename_section_in_file(const char *config_filename,
                                      const char *old_name, const char *new_name)
  {
        int ret = 0, remove = 0;
        char *filename_buf = NULL;
-       struct lock_file *lock = xcalloc(sizeof(struct lock_file), 1);
+       struct lock_file *lock;
        int out_fd;
        char buf[1024];
        FILE *config_file;
  
+       if (new_name && !section_name_is_ok(new_name)) {
+               ret = error("invalid section name: %s", new_name);
+               goto out;
+       }
+ 
        if (!config_filename)
                config_filename = filename_buf = git_pathdup("config");
  
+       lock = xcalloc(sizeof(struct lock_file), 1);
        out_fd = hold_lock_file_for_update(lock, config_filename, 0);
        if (out_fd < 0) {
                ret = error("could not lock config file %s", config_filename);