Only set an error from libssl related code, if an error has not already

been set by libtls code. This avoids the situation where a libtls callback
has set an error, only to have it replaced by a less useful libssl based
error.

ok beck@

2 files changed, 47 insertions, 7 deletions

diff --git a/lib/libtls/tls.c b/lib/libtls/tls.c
index cccdb00531a..6893e95b083 100644
--- a/lib/libtls/tls.c
+++ b/lib/libtls/tls.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.c,v 1.50 2016/11/02 15:18:42 beck Exp $ */
+/* $OpenBSD: tls.c,v 1.51 2016/11/03 10:05:32 jsing Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -61,15 +61,25 @@ tls_error(struct tls *ctx)
 	return ctx->error.msg;
 }
 
+void
+tls_error_clear(struct tls_error *error)
+{
+	free(error->msg);
+	error->msg = NULL;
+	error->num = 0;
+	error->tls = 0;
+}
+
 static int
 tls_error_vset(struct tls_error *error, int errnum, const char *fmt, va_list ap)
 {
 	char *errmsg = NULL;
 	int rv = -1;
 
-	free(error->msg);
-	error->msg = NULL;
+	tls_error_clear(error);
+
 	error->num = errnum;
+	error->tls = 1;
 
 	if (vasprintf(&errmsg, fmt, ap) == -1) {
 		errmsg = NULL;
@@ -177,6 +187,23 @@ tls_set_errorx(struct tls *ctx, const char *fmt, ...)
 	return (rv);
 }
 
+int
+tls_set_ssl_errorx(struct tls *ctx, const char *fmt, ...)
+{
+	va_list ap;
+	int rv;
+
+	/* Only set an error if a more specific one does not already exist. */
+	if (ctx->error.tls != 0)
+		return (0);
+
+	va_start(ap, fmt);
+	rv = tls_error_vset(&ctx->error, -1, fmt, ap);
+	va_end(ap);
+
+	return (rv);
+}
+
 struct tls_sni_ctx *
 tls_sni_ctx_new(void)
 {
@@ -464,21 +491,21 @@ tls_ssl_error(struct tls *ctx, SSL *ssl_conn, int ssl_ret, const char *prefix)
 		} else if (ssl_ret == -1) {
 			errstr = strerror(errno);
 		}
-		tls_set_errorx(ctx, "%s failed: %s", prefix, errstr);
+		tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
 		return (-1);
 
 	case SSL_ERROR_SSL:
 		if ((err = ERR_peek_error()) != 0) {
 			errstr = ERR_error_string(err, NULL);
 		}
-		tls_set_errorx(ctx, "%s failed: %s", prefix, errstr);
+		tls_set_ssl_errorx(ctx, "%s failed: %s", prefix, errstr);
 		return (-1);
 
 	case SSL_ERROR_WANT_CONNECT:
 	case SSL_ERROR_WANT_ACCEPT:
 	case SSL_ERROR_WANT_X509_LOOKUP:
 	default:
-		tls_set_errorx(ctx, "%s failed (%i)", prefix, ssl_err);
+		tls_set_ssl_errorx(ctx, "%s failed (%i)", prefix, ssl_err);
 		return (-1);
 	}
 }
@@ -488,6 +515,8 @@ tls_handshake(struct tls *ctx)
 {
 	int rv = -1;
 
+	tls_error_clear(&ctx->error);
+
 	if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
 		tls_set_errorx(ctx, "invalid operation for context");
 		goto out;
@@ -517,6 +546,8 @@ tls_read(struct tls *ctx, void *buf, size_t buflen)
 	ssize_t rv = -1;
 	int ssl_ret;
 
+	tls_error_clear(&ctx->error);
+
 	if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
 		if ((rv = tls_handshake(ctx)) != 0)
 			goto out;
@@ -546,6 +577,8 @@ tls_write(struct tls *ctx, const void *buf, size_t buflen)
 	ssize_t rv = -1;
 	int ssl_ret;
 
+	tls_error_clear(&ctx->error);
+
 	if ((ctx->state & TLS_HANDSHAKE_COMPLETE) == 0) {
 		if ((rv = tls_handshake(ctx)) != 0)
 			goto out;
@@ -575,6 +608,8 @@ tls_close(struct tls *ctx)
 	int ssl_ret;
 	int rv = 0;
 
+	tls_error_clear(&ctx->error);
+
 	if ((ctx->flags & (TLS_CLIENT | TLS_SERVER_CONN)) == 0) {
 		tls_set_errorx(ctx, "invalid operation for context");
 		rv = -1;
diff --git a/lib/libtls/tls_internal.h b/lib/libtls/tls_internal.h
index df35db37f2e..fde4066f7cc 100644
--- a/lib/libtls/tls_internal.h
+++ b/lib/libtls/tls_internal.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls_internal.h,v 1.44 2016/11/02 15:18:42 beck Exp $ */
+/* $OpenBSD: tls_internal.h,v 1.45 2016/11/03 10:05:32 jsing Exp $ */
 /*
  * Copyright (c) 2014 Jeremie Courreges-Anglas <jca@openbsd.org>
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
@@ -39,6 +39,7 @@ union tls_addr {
 struct tls_error {
 	char *msg;
 	int num;
+	int tls;
 };
 
 struct tls_keypair {
@@ -174,6 +175,7 @@ int tls_host_port(const char *hostport, char **host, char **port);
 int tls_set_cbs(struct tls *ctx,
     tls_read_cb read_cb, tls_write_cb write_cb, void *cb_arg);
 
+void tls_error_clear(struct tls_error *error);
 int tls_error_set(struct tls_error *error, const char *fmt, ...)
     __attribute__((__format__ (printf, 2, 3)))
     __attribute__((__nonnull__ (2)));
@@ -192,6 +194,9 @@ int tls_set_error(struct tls *ctx, const char *fmt, ...)
 int tls_set_errorx(struct tls *ctx, const char *fmt, ...)
     __attribute__((__format__ (printf, 2, 3)))
     __attribute__((__nonnull__ (2)));
+int tls_set_ssl_errorx(struct tls *ctx, const char *fmt, ...)
+    __attribute__((__format__ (printf, 2, 3)))
+    __attribute__((__nonnull__ (2)));
 
 int tls_ssl_error(struct tls *ctx, SSL *ssl_conn, int ssl_ret,
     const char *prefix);