Allow specific libtls hostname validation errors to propagate.

Remove direct calls to printf from the tls_check_hostname() path. This allows
NUL byte error messages to bubble up to the caller, to be logged in a
program-appropriate way. It also removes non-portable calls to getprogname().

The semantics of tls_error() are changed slightly: the last error message is
not necessarily preserved between subsequent calls into the library.
When the previous call to libtls succeeds, client programs should treat the
return value of tls_error() as undefined.

ok tedu@

1 files changed, 10 insertions, 3 deletions

diff --git a/src/lib/libtls/tls.c b/src/lib/libtls/tls.c
index a7f612e40b..d3bb79b3fe 100644
--- a/src/lib/libtls/tls.c
+++ b/src/lib/libtls/tls.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls.c,v 1.1 2014/10/31 13:46:17 jsing Exp $ */
+/* $OpenBSD: tls.c,v 1.2 2014/12/07 15:00:32 bcook Exp $ */
 /*
  * Copyright (c) 2014 Joel Sing <jsing@openbsd.org>
  *
@@ -56,15 +56,22 @@ tls_error(struct tls *ctx)
         return ctx->errmsg;
 }
 
+void
+tls_clear_error(struct tls *ctx)
+{
+        ctx->err = 0;
+        free(ctx->errmsg);
+        ctx->errmsg = NULL;
+}
+
 int
 tls_set_error(struct tls *ctx, char *fmt, ...)
 {
         va_list ap;
         int rv;
 
+        tls_clear_error(ctx);
         ctx->err = errno;
-        free(ctx->errmsg);
-        ctx->errmsg = NULL;
 
         va_start(ap, fmt);
         rv = vasprintf(&ctx->errmsg, fmt, ap);