Fix a bug caused by the return value being set early to signal successful

DTLS cookie validation. This can mask a later failure and result in a
positive return value being returned from ssl3_get_client_hello(), when
it should return a negative value to propagate the error.

Ironically this was introduced in OpenSSL 2e9802b7a7b with the commit
message "Fix DTLS cookie management bugs".

Fix based on OpenSSL.

Issue reported by Nicolas Bouliane <nbouliane at jive dot com>.

ok beck@

diff --git a/lib/libssl/ssl_srvr.c b/lib/libssl/ssl_srvr.c
index 8ea1adf..ea1aed2 100644 (file)
--- a/lib/libssl/ssl_srvr.c
+++ b/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.14 2017/04/14 15:32:41 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.15 2017/04/29 23:38:49 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -720,7 +720,7 @@ ssl3_get_client_hello(SSL *s)
        uint16_t client_version;
        uint8_t comp_method;
        int comp_null;
-       int i, j, ok, al, ret = -1;
+       int i, j, ok, al, ret = -1, cookie_valid = 0;
        long n;
        unsigned long id;
        unsigned char *p, *d;
@@ -887,7 +887,7 @@ ssl3_get_client_hello(SSL *s)
                                SSLerror(s, SSL_R_COOKIE_MISMATCH);
                                goto f_err;
                        }
-                       ret = 2;
+                       cookie_valid = 1;
                }
        }
 
@@ -1059,8 +1059,8 @@ ssl3_get_client_hello(SSL *s)
                goto err;
        }
 
-       if (ret < 0)
-               ret = 1;
+       ret = cookie_valid ? 2 : 1;
+
        if (0) {
 truncated:
                al = SSL_AD_DECODE_ERROR;