daemon: fix IPv6 address corruption in lookup_hostname()
getaddrinfo() is called with AF_UNSPEC hints, so it may return IPv6 results. However, the code unconditionally casts ai_addr to sockaddr_in and passes AF_INET to inet_ntop(). On IPv6-only hosts, this reads from the wrong struct offset, producing garbage IP addresses. Fix this by checking ai_family and extracting the address pointer into a local variable before calling inet_ntop() once with the correct family. Die on unexpected address families. Signed-off-by: Sebastien Tardif <sebtardif@ncf.ca> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Sebastien Tardif committed
May 28, 2026 at 02:56 UTC
b8cda126b4e0fbfd514b26dec4ee8a1c6849abe9
1 file changed
+13
-2
daemon.c
+13
-2
@@ -674,9 +674,20 @@ static void lookup_hostname(struct hostinfo *hi)
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gai = getaddrinfo(hi->hostname.buf, NULL, &hints, &ai);
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if (!gai) {
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- struct sockaddr_in *sin_addr = (void *)ai->ai_addr;
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+ void *addr;
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+
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+ if (ai->ai_family == AF_INET) {
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+ struct sockaddr_in *sa = (void *)ai->ai_addr;
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+ addr = &sa->sin_addr;
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+ } else if (ai->ai_family == AF_INET6) {
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+ struct sockaddr_in6 *sa6 = (void *)ai->ai_addr;
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+ addr = &sa6->sin6_addr;
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+ } else {
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+ die("unexpected address family: %d",
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+ ai->ai_family);
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+ }
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- inet_ntop(AF_INET, &sin_addr->sin_addr,
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+ inet_ntop(ai->ai_family, addr,
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addrbuf, sizeof(addrbuf));
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strbuf_addstr(&hi->ip_address, addrbuf);
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