Add size_t to int checks for SSL functions.

libtls accepts size_t for lengths but libssl accepts int.  This verifies
that the input does not exceed INT_MAX.  It also avoids truncating size_t
when comparing with int and adds printf-style attributes for
tls_set_error().

with input from deraadt@ and tedu@
ok tedu@

1 files changed, 22 insertions, 1 deletions

diff --git a/src/lib/libtls/tls.c b/src/lib/libtls/tls.c
index 6dae066922..0b9f12511d 100644
--- a/src/lib/libtls/tls.c
+++ b/src/lib/libtls/tls.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.c,v 1.3 2014/12/07 15:48:02 bcook Exp $ */
+/* $OpenBSD: tls.c,v 1.4 2014/12/17 17:51:33 doug Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -18,6 +18,7 @@
 #include <sys/socket.h>
 
 #include <errno.h>
+#include <limits.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -110,6 +111,11 @@ tls_configure_keypair(struct tls *ctx)
         BIO *bio = NULL;
 
         if (ctx->config->cert_mem != NULL) {
+                if (ctx->config->cert_len > INT_MAX) {
+                        tls_set_error(ctx, "certificate too long");
+                        goto err;
+                }
+
                 if (SSL_CTX_use_certificate_chain(ctx->ssl_ctx,
                     ctx->config->cert_mem, ctx->config->cert_len) != 1) {
                         tls_set_error(ctx, "failed to load certificate");
@@ -118,6 +124,11 @@ tls_configure_keypair(struct tls *ctx)
                 cert = NULL;
         }
         if (ctx->config->key_mem != NULL) {
+                if (ctx->config->key_len > INT_MAX) {
+                        tls_set_error(ctx, "key too long");
+                        goto err;
+                }
+
                 if ((bio = BIO_new_mem_buf(ctx->config->key_mem,
                     ctx->config->key_len)) == NULL) {
                         tls_set_error(ctx, "failed to create buffer");
@@ -229,6 +240,11 @@ tls_read(struct tls *ctx, void *buf, size_t buflen, size_t *outlen)
 {
         int ret, ssl_err;
 
+        if (buflen > INT_MAX) {
+                tls_set_error(ctx, "buflen too long");
+                return (-1);
+        }
+
         ret = SSL_read(ctx->ssl_conn, buf, buflen);
         if (ret > 0) {
                 *outlen = (size_t)ret;
@@ -252,6 +268,11 @@ tls_write(struct tls *ctx, const void *buf, size_t buflen, size_t *outlen)
 {
         int ret, ssl_err;
 
+        if (buflen > INT_MAX) {
+                tls_set_error(ctx, "buflen too long");
+                return (-1);
+        }
+
         ret = SSL_write(ctx->ssl_conn, buf, buflen);
         if (ret > 0) {
                 *outlen = (size_t)ret;