diff -urN vsftpd-3.0.5-orig/postlogin.c vsftpd-3.0.5/postlogin.c

--- vsftpd-3.0.5-orig/postlogin.c	2015-07-22 21:03:22.000000000 +0200

+++ vsftpd-3.0.5/postlogin.c	2023-02-13 16:34:05.244467476 +0100

@@ -27,4 +27,6 @@

 #include "ssl.h"

 #include "vsftpver.h"

+#include <netdb.h>

+#include <arpa/inet.h>

 #include "opts.h"

@@ -628,9 +629,10 @@

   else

   {

     const void* p_v4addr = vsf_sysutil_sockaddr_ipv6_v4(s_p_sockaddr);

+    static char result[INET_ADDRSTRLEN];

     if (p_v4addr)

     {

-      str_append_text(&s_pasv_res_str, vsf_sysutil_inet_ntoa(p_v4addr));

+      str_append_text(&s_pasv_res_str, inet_ntop(AF_INET, p_v4addr, result, INET_ADDRSTRLEN));

     }

     else

     {

diff -urN vsftpd-3.0.5-orig/sysutil.c vsftpd-3.0.5/sysutil.c

--- vsftpd-3.0.5-orig/sysutil.c	2012-09-16 09:07:38.000000000 +0200

+++ vsftpd-3.0.5/sysutil.c	2023-02-13 16:08:58.557153109 +0100

@@ -2205,20 +2205,13 @@

   const struct sockaddr* p_sockaddr = &p_sockptr->u.u_sockaddr;

   if (p_sockaddr->sa_family == AF_INET)

   {

-    return inet_ntoa(p_sockptr->u.u_sockaddr_in.sin_addr);

+    static char result[INET_ADDRSTRLEN];

+    return inet_ntop(AF_INET, &p_sockptr->u.u_sockaddr_in.sin_addr, result, INET_ADDRSTRLEN);

   }

   else if (p_sockaddr->sa_family == AF_INET6)

   {

-    static char inaddr_buf[64];

-    const char* p_ret = inet_ntop(AF_INET6,

-                                  &p_sockptr->u.u_sockaddr_in6.sin6_addr,

-                                  inaddr_buf, sizeof(inaddr_buf));

-    inaddr_buf[sizeof(inaddr_buf) - 1] = '\0';

-    if (p_ret == NULL)

-    {

-      inaddr_buf[0] = '\0';

-    }

-    return inaddr_buf;

+    static char result[INET6_ADDRSTRLEN];

+    return inet_ntop(AF_INET6, &p_sockptr->u.u_sockaddr_in6.sin6_addr, result, INET6_ADDRSTRLEN);

   }

   else

   {

@@ -2227,12 +2220,6 @@

   }

 }

-const char*

-vsf_sysutil_inet_ntoa(const void* p_raw_addr)

-{

-  return inet_ntoa(*((struct in_addr*)p_raw_addr));

-}

-

 int

 vsf_sysutil_inet_aton(const char* p_text, struct vsf_sysutil_sockaddr* p_addr)

 {

@@ -2241,7 +2228,7 @@

   {

     bug("bad family");

   }

-  if (inet_aton(p_text, &sin_addr))

+  if (inet_pton(AF_INET, p_text, &sin_addr))

   {

     vsf_sysutil_memcpy(&p_addr->u.u_sockaddr_in.sin_addr,

                        &sin_addr, sizeof(p_addr->u.u_sockaddr_in.sin_addr));

@@ -2257,37 +2244,46 @@

 vsf_sysutil_dns_resolve(struct vsf_sysutil_sockaddr** p_sockptr,

                         const char* p_name)

 {

-  struct hostent* hent = gethostbyname(p_name);

-  if (hent == NULL)

+  struct addrinfo *result;

+  struct addrinfo hints;

+  int ret;

+

+  memset(&hints, 0, sizeof(struct addrinfo));

+  hints.ai_family = AF_UNSPEC;

+

+  if ((ret = getaddrinfo(p_name, NULL, &hints, &result)) != 0)

   {

+    fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(ret));

     die2("cannot resolve host:", p_name);

   }

   vsf_sysutil_sockaddr_clear(p_sockptr);

-  if (hent->h_addrtype == AF_INET)

+  if (result->ai_family == AF_INET)

   {

-    unsigned int len = hent->h_length;

+    unsigned int len = result->ai_addrlen;

     if (len > sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr))

     {

       len = sizeof((*p_sockptr)->u.u_sockaddr_in.sin_addr);

     }

     vsf_sysutil_sockaddr_alloc_ipv4(p_sockptr);

     vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in.sin_addr,

-                       hent->h_addr_list[0], len);

+                       &result->ai_addrlen, len);

   }

-  else if (hent->h_addrtype == AF_INET6)

+  else if (result->ai_family == AF_INET6)

   {

-    unsigned int len = hent->h_length;

+    unsigned int len = result->ai_addrlen;

     if (len > sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr))

     {

       len = sizeof((*p_sockptr)->u.u_sockaddr_in6.sin6_addr);

     }

     vsf_sysutil_sockaddr_alloc_ipv6(p_sockptr);

     vsf_sysutil_memcpy(&(*p_sockptr)->u.u_sockaddr_in6.sin6_addr,

-                       hent->h_addr_list[0], len);

+                       &result->ai_addrlen, len);

   }

   else

   {

-    die("gethostbyname(): neither IPv4 nor IPv6");

+    freeaddrinfo(result);

+    die("getaddrinfo(): neither IPv4 nor IPv6");

   }

+  freeaddrinfo(result);

 }

diff -urN vsftpd-3.0.5-orig/sysutil.h vsftpd-3.0.5/sysutil.h

--- vsftpd-3.0.5-orig/sysutil.h	2021-05-18 08:50:21.000000000 +0200

+++ vsftpd-3.0.5/sysutil.h	2023-02-13 15:59:22.088331075 +0100

@@ -277,7 +277,6 @@

 const char* vsf_sysutil_inet_ntop(

   const struct vsf_sysutil_sockaddr* p_sockptr);

-const char* vsf_sysutil_inet_ntoa(const void* p_raw_addr);

 int vsf_sysutil_inet_aton(

   const char* p_text, struct vsf_sysutil_sockaddr* p_addr);