[incubator-nuttx] branch master updated: netdb: fix access within misaligned address error

[xi...@apache.org]

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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 3f94828  netdb: fix access within misaligned address error
3f94828 is described below

commit 3f94828f6b53f641b42e94d48a032cf24aff5b0e
Author: ligd <li...@xiaomi.com>
AuthorDate: Tue Jul 20 14:30:42 2021 +0800

    netdb: fix access within misaligned address error
    
    netdb/lib_dnsquery.c:444:14: runtime error: member access within misaligned address 0xef2f5a1b for type 'struct dns_question_s', which requires 2 byte alignment
    0xef2f5a1b: note: pointer points here
     63  6f 6d 00 00 01 00 01 c0  0c 00 05 00 01 00 00 00  1c 00 1a 05 6d 75 73 69  63 06 6e 74 65 73 35
                  ^
    netdb/lib_dnsquery.c:445:14: runtime error: member access within misaligned address 0xef2f5a1b for type 'struct dns_question_s', which requires 2 byte alignment
    0xef2f5a1b: note: pointer points here
     63  6f 6d 00 00 01 00 01 c0  0c 00 05 00 01 00 00 00  1c 00 1a 05 6d 75 73 69  63 06 6e 74 65 73 35
                  ^
    
    Signed-off-by: ligd <li...@xiaomi.com>
---
 libs/libc/netdb/lib_dnsquery.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libs/libc/netdb/lib_dnsquery.c b/libs/libc/netdb/lib_dnsquery.c
index 45c9843..7b749f7 100644
--- a/libs/libc/netdb/lib_dnsquery.c
+++ b/libs/libc/netdb/lib_dnsquery.c
@@ -334,6 +334,7 @@ static int dns_recv_response(int sd, FAR union dns_addr_u *addr, int naddr,
   FAR struct dns_answer_s *ans;
   FAR struct dns_header_s *hdr;
   FAR struct dns_question_s *que;
+  struct dns_question_s bak;
   uint16_t nquestions;
   uint16_t nanswers;
   uint16_t temp;
@@ -437,12 +438,13 @@ 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;
+  memcpy(&bak, que, sizeof(struct dns_question_s));
 
   /* 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)
+  if (memcmp(&bak.type, &qinfo->rectype, sizeof(uint16_t)) != 0 ||
+      memcmp(&bak.class, &temp, sizeof(uint16_t)) != 0)
     {
       nerr("ERROR: DNS response with wrong question\n");
       return -EBADMSG;