From: grid <grigorii.demidov@nic.cz>
Date: Wed, 13 Dec 2017 09:20:53 +0000 (+0100)
Subject: daemon/tls: tls_push() can fall into endless loop in some circumstances; prevent it
X-Git-Tag: v2.0.0~43^2~9
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d320ef11450427d3afbd258afe9b0dda69721a91;p=thirdparty%2Fknot-resolver.git

daemon/tls: tls_push() can fall into endless loop in some circumstances; prevent it
---

diff --git a/daemon/tls.c b/daemon/tls.c
index 88d7ce430..2f2226e3e 100644
--- a/daemon/tls.c
+++ b/daemon/tls.c
@@ -231,6 +231,7 @@ int tls_push(struct qr_task *task, uv_handle_t *handle, knot_pkt_t *pkt)
 	}
 
 	ssize_t submitted = 0;
+	ssize_t retries = 0;
 	do {
 		count = gnutls_record_uncork(tls_p->session, 0);
 		if (count < 0) {
@@ -239,7 +240,13 @@ int tls_push(struct qr_task *task, uv_handle_t *handle, knot_pkt_t *pkt)
 				             gnutls_strerror_name(count), count);
 				return kr_error(EIO);
 			}
+			if (++retries > TLS_MAX_UNCORK_RETRIES) {
+				kr_log_error("[tls] gnutls_record_uncork: too many sequential non-fatal errors (%zd), last error is: %s (%zd)\n",
+				             retries, gnutls_strerror_name(count), count);
+				return kr_error(EIO);
+			}
 		} else {
+			retries = 0;
 			submitted += count;
 			if (count == 0 && submitted != sizeof(pkt_size) + pkt->size) {
 				kr_log_error("[tls] gnutls_record_uncork didn't send all data: %s (%zd)\n",
diff --git a/daemon/tls.h b/daemon/tls.h
index 20d1efc52..d13b70ebf 100644
--- a/daemon/tls.h
+++ b/daemon/tls.h
@@ -24,6 +24,7 @@
 #include "lib/generic/map.h"
 
 #define MAX_TLS_PADDING KR_EDNS_PAYLOAD
+#define TLS_MAX_UNCORK_RETRIES 100
 
 struct tls_ctx_t;
 struct tls_client_ctx_t;