diff -urN squid-2.5.STABLE5.orig/helpers/ntlm_auth/SMB/libntlmssp.c squid-2.5.STABLE5/helpers/ntlm_auth/SMB/libntlmssp.c
--- squid-2.5.STABLE5.orig/helpers/ntlm_auth/SMB/libntlmssp.c	2001-11-30 11:50:28 +0200
+++ squid-2.5.STABLE5/helpers/ntlm_auth/SMB/libntlmssp.c	2004-06-10 11:49:23 +0300
@@ -161,8 +161,10 @@
 #define min(A,B) (A<B?A:B)
 
 int ntlm_errno;
-static char credentials[1024];	/* we can afford to waste */
-
+#define MAX_USERNAME_LEN 255
+#define MAX_DOMAIN_LEN 255
+#define MAX_PASSWD_LEN 31
+static char credentials[MAX_USERNAME_LEN+MAX_DOMAIN_LEN+2];    /* we can afford to waste */
 
 /* Fetches the user's credentials from the challenge.
  * Returns NULL if domain or user is not defined
@@ -197,7 +199,7 @@
 ntlm_check_auth(ntlm_authenticate * auth, int auth_length)
 {
     int rv;
-    char pass[25] /*, encrypted_pass[40] */;
+    char pass[MAX_PASSWD_LEN+1];
     char *domain = credentials;
     char *user;
     lstring tmp;
@@ -215,8 +217,13 @@
 	ntlm_errno = NTLM_LOGON_ERROR;
 	return NULL;
     }
+    if (tmp.l > MAX_DOMAIN_LEN) {
+    	debug("Domain string exceeds %d bytes, rejecting\n", MAX_DOMAIN_LEN);
+	ntlm_errno = NTLM_LOGON_ERROR;
+	return NULL;
+    }
     memcpy(domain, tmp.str, tmp.l);
-    user = domain + tmp.l;
+    user = domain + tmp.l + 1;
     *user++ = '\0';
 
 /*      debug("fetching user name\n"); */
@@ -226,6 +233,11 @@
 	ntlm_errno = NTLM_LOGON_ERROR;
 	return NULL;
     }
+    if (tmp.l > MAX_USERNAME_LEN) {
+    	debug("Username string exceeds %d bytes, rejecting\n", MAX_USERNAME_LEN);
+	ntlm_errno = NTLM_LOGON_ERROR;
+	return NULL;
+    }
     memcpy(user, tmp.str, tmp.l);
     *(user + tmp.l) = '\0';
 
@@ -237,9 +249,14 @@
 	ntlm_errno = NTLM_LOGON_ERROR;
 	return NULL;
     }
+    if (tmp.l > MAX_PASSWD_LEN) {
+    	debug("Password string exceeds %d bytes, rejecting\n", MAX_PASSWD_LEN);
+	ntlm_errno = NTLM_LOGON_ERROR;
+	return NULL;
+    }
 		
     memcpy(pass, tmp.str, tmp.l);
-    pass[25] = '\0';
+    pass[min(MAX_PASSWD_LEN,tmp.l)] = '\0';
 
 #if 1
 		debug ("Empty LM pass detection: user: '%s', ours:'%s', his: '%s'"