[incubator-nuttx] branch master updated: net/dns:fix unaligned access in dns query

[xiaoxiang]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new 317bd40  net/dns:fix unaligned access in dns query
317bd40 is described below

commit 317bd40fecb88c28b2ea532c8c7108b7947e8179
Author: Virus.V <vir...@live.com>
AuthorDate: Thu Jun 10 10:02:03 2021 +0800

    net/dns:fix unaligned access in dns query
---
 libs/libc/netdb/lib_dnsquery.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/libs/libc/netdb/lib_dnsquery.c b/libs/libc/netdb/lib_dnsquery.c
index b24d4a1..97d9b3f 100644
--- a/libs/libc/netdb/lib_dnsquery.c
+++ b/libs/libc/netdb/lib_dnsquery.c
@@ -336,6 +336,7 @@ static int dns_recv_response(int sd, FAR union dns_addr_u 
*addr, int naddr,
   FAR struct dns_question_s *que;
   uint16_t nquestions;
   uint16_t nanswers;
+  uint16_t temp;
   int naddr_read;
   int ret;
 
@@ -436,11 +437,12 @@ static int dns_recv_response(int sd, FAR union dns_addr_u 
*addr, int naddr,
   /* Validate query type and class */
 
   que = (FAR struct dns_question_s *)nameptr;
-  ninfo("Question: type=%04x, class=%04x\n",
-        ntohs(que->type), ntohs(que->class));
 
-  if (que->type  != qinfo->rectype ||
-      que->class != HTONS(DNS_CLASS_IN))
+  /* N.B. Unaligned access may occur here */
+
+  temp = HTONS(DNS_CLASS_IN);
+  if (memcmp(&que->type, &qinfo->rectype, sizeof(uint16_t)) != 0 ||
+      memcmp(&que->class, &temp, sizeof(uint16_t)) != 0)
     {
       nerr("ERROR: DNS response with wrong question\n");
       return -EBADMSG;