58 lines
1.9 KiB
Diff
58 lines
1.9 KiB
Diff
commit ea9f048761d0b9a2ab6310bffa07351f0b04d8c5
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Author: Olaf Kirch <okir@suse.de>
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Date: Tue Sep 2 12:11:15 2008 -0400
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Always make IPv6 sockets V6ONLY
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Assume you have a netconfig file looking like this:
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udp tpi_clts v inet udp - -
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udp6 tpi_clts v inet6 udp - -
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...
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a call to svc_tli_create(... &someaddr, "udp") will fail to create an
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IPv6 server socket. The problem is that on Linux, passive IPv6 sockets
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will also accept packets/connections from IPv4, and will simply map
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the sender's address to an IPv6 mapped IPv4 address. So if you want to
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bind both a UDPv4 and UDPv6 socket to the same port, this will fail with
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EADDRINUSE.
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The way to avoid this behavior is to change the socket to V6ONLY,
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which tells the kernel to avoid the autmatic mapping.
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The change proposed in the patch below does this. I *think* this is
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a good place to do this, as it will also fix applications that do not
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use svc_tli_create() - such as rpcbind, which creates the sockets on
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its own using __rpc_nconf2fd.
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I think this also improves portability, as BSD code assumes BSD
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behavior, where this mapping does not occur either.
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Signed-off-by: Olaf Kirch <okir@suse.de>
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Signed-off-by: Steve Dickson <steved@redhat.com>
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diff --git a/src/rpc_generic.c b/src/rpc_generic.c
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index 583aff0..ff4ba16 100644
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--- a/src/rpc_generic.c
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+++ b/src/rpc_generic.c
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@@ -525,11 +525,18 @@ int
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__rpc_nconf2fd(const struct netconfig *nconf)
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{
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struct __rpc_sockinfo si;
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+ int fd;
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if (!__rpc_nconf2sockinfo(nconf, &si))
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return 0;
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- return socket(si.si_af, si.si_socktype, si.si_proto);
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+ if ((fd = socket(si.si_af, si.si_socktype, si.si_proto)) >= 0 &&
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+ si.si_af == AF_INET6) {
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+ int val = 1;
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+
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+ setsockopt(fd, SOL_IPV6, IPV6_V6ONLY, &val, sizeof(val));
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+ }
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+ return fd;
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}
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int
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