core: fix possible buffer overflow in command /color alias (issue #2330)

Fix: c.lang.security.insecure-use-strcat-fn.insecure-use-strcat-fn security vulnerability

Automated security fix generated by OrbisAI Security

CHANGELOG.md

@@ -31,6 +31,7 @@ SPDX-License-Identifier: GPL-3.0-or-later
 
 - core: fix option weechat.look.color_real_white not applied when color is "white" on 16+ colors terminals ([#1742](https://github.com/weechat/weechat/issues/1742))
 - core: fix buffer overflow in connection to SOCKS5 proxy ([#2325](https://github.com/weechat/weechat/issues/2325))
+- core: fix possible buffer overflow in command /color alias ([#2330](https://github.com/weechat/weechat/issues/2330))
 - api: fix infinite loop in function string_replace when the search string is empty
 - irc: fix tag in message with list of names when joining a channel
 - fset: remove error displayed in core buffer when clicking with the mouse below the last option displayed

src/core/core-command.c

@@ -1700,17 +1700,12 @@ COMMAND_CALLBACK(color)
             else
                 str_alias = argv[i];
         }
-        str_color[0] = '\0';
-        if (str_alias)
-        {
-            strcat (str_color, ";");
-            strcat (str_color, str_alias);
-        }
-        if (str_rgb)
-        {
-            strcat (str_color, ";");
-            strcat (str_color, str_rgb);
-        }
+        snprintf (str_color, sizeof (str_color),
+                  "%s%s%s%s",
+                  (str_alias) ? ";" : "",
+                  (str_alias) ? str_alias : "",
+                  (str_rgb) ? ";" : "",
+                  (str_rgb) ? str_rgb : "");
 
         /* add color alias */
         snprintf (str_command, sizeof (str_command),