security: fix remotely triggerable crash in SSL/TLS code

When a server is running with SSL/TLS support compiled in,
it is trivial to crash the server by sending an MOTD request
via another server in the network.

- ONLY servers without ssl/tls support compiled in are not affected.
  Disabling SSL in the configuration (no ssl listening ports, etc)
  does NOT help.
- servers that are running standalone (i.e., not connected to any
  other servers) are not affected, either.

This affects all ngircd releases since ngircd 13 (earlier versions
have no SSL/TLS support).

diff --git a/src/ngircd/conn.c b/src/ngircd/conn.c
index 9752a6191c7e2da5b0df64779e9cc28ad1e6241c..c6095a31c613bc5ca127d55b8723e15b836f1cca 100644 (file)
--- a/src/ngircd/conn.c
+++ b/src/ngircd/conn.c
@@ -1951,6 +1951,9 @@ Conn_GetClient( CONN_ID Idx )
 GLOBAL bool
 Conn_GetCipherInfo(CONN_ID Idx, char *buf, size_t len)
 {
+       if (Idx < 0)
+               return false;
+       assert(Idx < (int) array_length(&My_ConnArray, sizeof(CONNECTION)));
        return ConnSSL_GetCipherInfo(&My_Connections[Idx], buf, len);
 }
 
@@ -1958,6 +1961,9 @@ Conn_GetCipherInfo(CONN_ID Idx, char *buf, size_t len)
 GLOBAL bool
 Conn_UsesSSL(CONN_ID Idx)
 {
+       if (Idx < 0)
+               return false;
+       assert(Idx < (int) array_length(&My_ConnArray, sizeof(CONNECTION)));
        return Conn_OPTION_ISSET(&My_Connections[Idx], CONN_SSL);
 }
 #endif