Package: libc6
Version: 2.24-8
Severity: normal
Tags: upstream patch
Hello,
for ease of reproducibility I show my examples in Python, but I verified
that the problem is in glibc and not in Python:
On a machine without network access I get:
>>> import socket
>>> socket.getaddrinfo("0.0.0.0", "http", family=socket.AF_INET,
flags=socket.AI_ADDRCONFIG)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.5/socket.py", line 733, in getaddrinfo
for res in _socket.getaddrinfo(host, port, family, type, proto,
flags):
socket.gaierror: [Errno -2] Name or service not known
as expected. If however I use AF_UNSPEC instead of AF_INET I get:
>>> socket.getaddrinfo("0.0.0.0", "http", family=socket.AF_UNSPEC,
flags=socket.AI_ADDRCONFIG)
[(<AddressFamily.AF_INET: 2>, <SocketKind.SOCK_STREAM: 1>, 6, '',
('0.0.0.0', 80))]
while it should fail in the same way as above instead.
Quoting getaddrinfo(3):
If hints.ai_flags includes the AI_ADDRCONFIG flag, then IPv4
addresses are returned in the list pointed to by res only if the
local system has at least one IPv4 address configured [...].
The following patch should fix this:
--- a/sysdeps/posix/getaddrinfo.c
+++ b/sysdeps/posix/getaddrinfo.c
@@ -2351,7 +2351,8 @@
}
}
else if ((hints->ai_family == PF_INET && ! seen_ipv4)
- || (hints->ai_family == PF_INET6 && ! seen_ipv6))
+ || (hints->ai_family == PF_INET6 && ! seen_ipv6)
+ || (hints->ai_family == PF_UNSPEC))
{
/* We cannot possibly return a valid answer. */
__free_in6ai (in6ai);
Best regards
Uwe
-- System Information:
Debian Release: 9.0
APT prefers testing
APT policy: (800, 'testing'), (600, 'unstable'), (500, 'testing-debug'),
(500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.9.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
