[GitHub] [incubator-nuttx] normanr commented on a change in pull request #4890: [SECURITY]net/udp/icmp: correct the unreadchable handling

[GitBox <gi...@apache.org>]

normanr commented on a change in pull request #4890:
URL: https://github.com/apache/incubator-nuttx/pull/4890#discussion_r775740083



##########
File path: include/nuttx/net/icmp.h
##########
@@ -113,8 +133,16 @@ struct icmp_hdr_s
 
   /* ICMP_ECHO_REQUEST and ICMP_ECHO_REPLY data */
 
-  uint16_t id;               /* Used to match requests with replies */
-  uint16_t seqno;            /* "  " "" "   " "      " "  " "     " */
+  union
+    {
+      struct
+        {
+          uint16_t id;      /* Used to match requests with replies */
+          uint16_t seqno;   /* "  " "" "   " "      " "  " "     " */
+        };
+
+      uint32_t data;

Review comment:
       This causes unaligned stores, because icmp is not guaranteed to be aligned to 4-bytes. None of the other parts of the icmp or ip headers use `unit32_t` anywhere, (rather they use `uint16_t[2]`).




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