dirmngr: Fix aliasing problem in dns.c.

* dirmngr/dns.c (dns_ai_setent): Care about aliasing.

--

Co-authored-by: Tomas Mraz
GnuPG-bug-id: 3105
Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
(cherry picked from commit 247932f367f856e7ce91528e14f0aaf838150857)

Gbp-Pq: Name 0075-dirmngr-Fix-aliasing-problem-in-dns.c.patch

diff --git a/dirmngr/dns.c b/dirmngr/dns.c
index ebfd4c31f75782a35f5fa9847d974584127f3858..866f69dd5ff3addae2f04dbd8fce9fc72570129e 100644 (file)
--- a/dirmngr/dns.c
+++ b/dirmngr/dns.c
@@ -9440,29 +9440,31 @@ void dns_ai_close(struct dns_addrinfo *ai) {
 
 
 static int dns_ai_setent(struct addrinfo **ent, union dns_any *any, enum dns_type type, struct dns_addrinfo *ai) {
-       struct sockaddr *saddr;
-       struct sockaddr_in sin;
-       struct sockaddr_in6 sin6;
+       union u {
+               struct sockaddr_in sin;
+               struct sockaddr_in6 sin6;
+               struct sockaddr_storage ss;
+       } addr;
        const char *cname;
        size_t clen;
 
        switch (type) {
        case DNS_T_A:
-               saddr   = memset(&sin, '\0', sizeof sin);
+               memset(&addr.sin, '\0', sizeof addr.sin);
 
-               sin.sin_family  = AF_INET;
-               sin.sin_port    = htons(ai->port);
+               addr.sin.sin_family     = AF_INET;
+               addr.sin.sin_port       = htons(ai->port);
 
-               memcpy(&sin.sin_addr, any, sizeof sin.sin_addr);
+               memcpy(&addr.sin.sin_addr, any, sizeof addr.sin.sin_addr);
 
                break;
        case DNS_T_AAAA:
-               saddr   = memset(&sin6, '\0', sizeof sin6);
+               memset(&addr.sin6, '\0', sizeof addr.sin6);
 
-               sin6.sin6_family        = AF_INET6;
-               sin6.sin6_port          = htons(ai->port);
+               addr.sin6.sin6_family   = AF_INET6;
+               addr.sin6.sin6_port     = htons(ai->port);
 
-               memcpy(&sin6.sin6_addr, any, sizeof sin6.sin6_addr);
+               memcpy(&addr.sin6.sin6_addr, any, sizeof addr.sin6.sin6_addr);
 
                break;
        default:
@@ -9477,20 +9479,20 @@ static int dns_ai_setent(struct addrinfo **ent, union dns_any *any, enum dns_typ
                clen    = 0;
        }
 
-       if (!(*ent = malloc(sizeof **ent + dns_sa_len(saddr) + ((ai->hints.ai_flags & AI_CANONNAME)? clen + 1 : 0))))
+       if (!(*ent = malloc(sizeof **ent + dns_sa_len(&addr) + ((ai->hints.ai_flags & AI_CANONNAME)? clen + 1 : 0))))
                return dns_syerr();
 
        memset(*ent, '\0', sizeof **ent);
 
-       (*ent)->ai_family       = saddr->sa_family;
+       (*ent)->ai_family       = addr.ss.ss_family;
        (*ent)->ai_socktype     = ai->hints.ai_socktype;
        (*ent)->ai_protocol     = ai->hints.ai_protocol;
 
-       (*ent)->ai_addr         = memcpy((unsigned char *)*ent + sizeof **ent, saddr, dns_sa_len(saddr));
-       (*ent)->ai_addrlen      = dns_sa_len(saddr);
+       (*ent)->ai_addr         = memcpy((unsigned char *)*ent + sizeof **ent, &addr, dns_sa_len(&addr));
+       (*ent)->ai_addrlen      = dns_sa_len(&addr);
 
        if (ai->hints.ai_flags & AI_CANONNAME)
-               (*ent)->ai_canonname    = memcpy((unsigned char *)*ent + sizeof **ent + dns_sa_len(saddr), cname, clen + 1);
+               (*ent)->ai_canonname    = memcpy((unsigned char *)*ent + sizeof **ent + dns_sa_len(&addr), cname, clen + 1);
 
        ai->found++;