From 21ad547f18895f4b818376b9fc896b34848f4a18 Mon Sep 17 00:00:00 2001
From: Andreas Koepsel <andreas.koepsel@bisdn.de>
Date: Fri, 22 Jun 2018 13:40:56 +0200
Subject: [PATCH] Strings (#111) (#112)

* fix stringop-truncation

* pass correct len for strings in desc stats
---
 src/rofl/common/openflow/cofdescstats.cc     | 10 ++++----
 src/rofl/common/openflow/cofport.cc          | 24 +++++++++++++++++---
 src/rofl/common/openflow/coftablefeatures.cc |  5 +++-
 3 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/rofl/common/openflow/cofdescstats.cc b/src/rofl/common/openflow/cofdescstats.cc
index 3af6705f..7000d60c 100644
--- a/src/rofl/common/openflow/cofdescstats.cc
+++ b/src/rofl/common/openflow/cofdescstats.cc
@@ -68,11 +68,11 @@ void cofdesc_stats_reply::unpack(uint8_t *buf, size_t buflen) {
     struct openflow10::ofp_desc_stats *desc =
         (struct openflow10::ofp_desc_stats *)buf;
 
-    mfr_desc.assign(desc->mfr_desc, DESC_STR_LEN);
-    hw_desc.assign(desc->hw_desc, DESC_STR_LEN);
-    sw_desc.assign(desc->sw_desc, DESC_STR_LEN);
-    serial_num.assign(desc->serial_num, SERIAL_NUM_LEN);
-    dp_desc.assign(desc->dp_desc, DESC_STR_LEN);
+    mfr_desc.assign(desc->mfr_desc, strnlen(desc->mfr_desc, DESC_STR_LEN));
+    hw_desc.assign(desc->hw_desc, strnlen(desc->hw_desc, DESC_STR_LEN));
+    sw_desc.assign(desc->sw_desc, strnlen(desc->sw_desc, DESC_STR_LEN));
+    serial_num.assign(desc->serial_num, strnlen(desc->serial_num, SERIAL_NUM_LEN));
+    dp_desc.assign(desc->dp_desc, strnlen(desc->dp_desc, DESC_STR_LEN));
 
   } break;
   case rofl::openflow12::OFP_VERSION:
diff --git a/src/rofl/common/openflow/cofport.cc b/src/rofl/common/openflow/cofport.cc
index b8263be3..3b11d3b4 100644
--- a/src/rofl/common/openflow/cofport.cc
+++ b/src/rofl/common/openflow/cofport.cc
@@ -32,7 +32,19 @@ void cofport::pack(uint8_t *buf, size_t buflen) {
 
     hdr->port_no = htobe16(portno & 0x0000ffff);
     memcpy(hdr->hw_addr, hwaddr.somem(), OFP_ETH_ALEN);
-    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN);
+    static_assert(sizeof(hdr->name) == OFP_MAX_PORT_NAME_LEN, "invalid length of hdr->name");
+    // this is somewhat awkward
+#if __GNUC__ >= 8
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-overflow"
+#endif
+    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN - 1);
+#if __GNUC__ >= 8
+#pragma GCC diagnostic pop
+#endif
+    if (name.length() >= OFP_MAX_PORT_NAME_LEN) {
+      hdr->name[OFP_MAX_PORT_NAME_LEN - 1] = '\0';
+    }
     hdr->config = htobe32(config);
     hdr->state = htobe32(state);
     hdr->curr = htobe32(get_ethernet().get_curr());
@@ -49,7 +61,10 @@ void cofport::pack(uint8_t *buf, size_t buflen) {
 
     hdr->port_no = htobe32(portno);
     memcpy(hdr->hw_addr, hwaddr.somem(), OFP_ETH_ALEN);
-    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN);
+    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN - 1);
+    if (name.length() >= OFP_MAX_PORT_NAME_LEN) {
+      hdr->name[OFP_MAX_PORT_NAME_LEN - 1] = '\0';
+    }
     hdr->config = htobe32(config);
     hdr->state = htobe32(state);
     hdr->curr = htobe32(get_ethernet().get_curr());
@@ -67,7 +82,10 @@ void cofport::pack(uint8_t *buf, size_t buflen) {
 
     hdr->port_no = htobe32(portno);
     memcpy(hdr->hw_addr, hwaddr.somem(), OFP_ETH_ALEN);
-    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN);
+    strncpy(hdr->name, name.c_str(), OFP_MAX_PORT_NAME_LEN - 1);
+    if (name.length() >= OFP_MAX_PORT_NAME_LEN) {
+      hdr->name[OFP_MAX_PORT_NAME_LEN - 1] = '\0';
+    }
     hdr->config = htobe32(config);
     hdr->state = htobe32(state);
 
diff --git a/src/rofl/common/openflow/coftablefeatures.cc b/src/rofl/common/openflow/coftablefeatures.cc
index a7e19004..80fefe89 100644
--- a/src/rofl/common/openflow/coftablefeatures.cc
+++ b/src/rofl/common/openflow/coftablefeatures.cc
@@ -31,7 +31,10 @@ void coftable_features::pack(uint8_t *buf, size_t buflen) {
 
     hdr->length = htobe16(length());
     hdr->table_id = table_id;
-    strncpy(hdr->name, name.c_str(), OFP_MAX_TABLE_NAME_LEN);
+    strncpy(hdr->name, name.c_str(), OFP_MAX_TABLE_NAME_LEN - 1);
+    if (name.length() >= OFP_MAX_TABLE_NAME_LEN) {
+      hdr->name[OFP_MAX_TABLE_NAME_LEN - 1] = '\0';
+    }
     hdr->metadata_match = htobe64(metadata_match);
     hdr->metadata_write = htobe64(metadata_write);
     hdr->config = htobe32(config);