From 515129ccccf53d05c4fe397b4e90f8e14b264d73 Mon Sep 17 00:00:00 2001
From: Lurker00 <Lurker00@users.noreply.github.com>
Date: Tue, 17 Sep 2024 22:29:47 +0300
Subject: [PATCH] Bug fix: uninitialized padding eliminated (#137)

---
 extend.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/extend.c b/extend.c
index 5f6db8b..5b592ee 100644
--- a/extend.c
+++ b/extend.c
@@ -49,18 +49,24 @@ int mode_add_get(struct sockaddr_ina *dst, int m)
 {
     // m < 0: get, m > 0: set, m == 0: delete
     assert(m >= -1 && m < params.dp_count);
-    struct {
+    #pragma pack(push,4)
+    struct key_struct {
         uint16_t port;
+        uint16_t pad0; // fill with 0 before use!
         union {
             struct in_addr i4;
             struct in6_addr i6;
         };
-    } key = { .port = dst->in.sin_port };
-    
+    } key = { .port = dst->in.sin_port, .pad0 = 0 };
+    #pragma pack(pop)
+    #if defined(__GNUC__)
+    _Static_assert(offsetof(struct key_struct, i4) == sizeof(key.port)+sizeof(key.pad0), "key_struct");
+    #endif
+
     time_t t = 0;
     struct elem *val = 0;
-    int len = sizeof(dst->in.sin_port);
-    
+    int len = offsetof(struct key_struct, i4);
+
     if (dst->sa.sa_family == AF_INET) {
         len += sizeof(dst->in.sin_addr);
         key.i4 = dst->in.sin_addr;
@@ -69,7 +75,7 @@ int mode_add_get(struct sockaddr_ina *dst, int m)
         len += sizeof(dst->in6.sin6_addr);
         key.i6 = dst->in6.sin6_addr;
     }
-    
+
     if (m < 0) {
         val = mem_get(params.mempool, (char *)&key, len);
         if (!val) {
@@ -83,7 +89,7 @@ int mode_add_get(struct sockaddr_ina *dst, int m)
         return val->m;
     }
     INIT_ADDR_STR((*dst));
-    
+
     if (m == 0) {
         LOG(LOG_S, "delete ip: %s\n", ADDR_STR);
         mem_delete(params.mempool, (char *)&key, len);
@@ -101,7 +107,6 @@ int mode_add_get(struct sockaddr_ina *dst, int m)
         val->time = t;
         return 0;
     }
-    
 }