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| author |   Andrey Ignatov <rdna@fb.com> | 2019-01-04 01:07:07 -0800 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2019-01-04 20:23:33 -0800 |
| commit | e8e36984080b55ac5e57bdb09a5b570f2fc8e963 (patch) | |
| tree | d7a0a1a4a052f8cbf7ea95b05e6383c28028fe81 /net/ipv6 | |
| parent | ipv6: Consider sk_bound_dev_if when binding a socket to a v4 mapped address (diff) | |
| download | linux-dev-e8e36984080b55ac5e57bdb09a5b570f2fc8e963.tar.xz linux-dev-e8e36984080b55ac5e57bdb09a5b570f2fc8e963.zip | |
bpf: Fix [::] -> [::1] rewrite in sys_sendmsg
sys_sendmsg has supported unspecified destination IPv6 (wildcard) for
unconnected UDP sockets since 876c7f41. When [::] is passed by user as
destination, sys_sendmsg rewrites it with [::1] to be consistent with
BSD (see "BSD'ism" comment in the code).
This didn't work when cgroup-bpf was enabled though since the rewrite
[::] -> [::1] happened before passing control to cgroup-bpf block where
fl6.daddr was updated with passed by user sockaddr_in6.sin6_addr (that
might or might not be changed by BPF program). That way if user passed
[::] as dst IPv6 it was first rewritten with [::1] by original code from
876c7f41, but then rewritten back with [::] by cgroup-bpf block.
It happened even when BPF_CGROUP_UDP6_SENDMSG program was not present
(CONFIG_CGROUP_BPF=y was enough).
The fix is to apply BSD'ism after cgroup-bpf block so that [::] is
replaced with [::1] no matter where it came from: passed by user to
sys_sendmsg or set by BPF_CGROUP_UDP6_SENDMSG program.
Fixes: 1cedee13d25a ("bpf: Hooks for sys_sendmsg")
Reported-by: Nitin Rawat <nitin.rawat@intel.com>
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/udp.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 9cbf363172bd..7c3505006f8e 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1390,10 +1390,7 @@ do_udp_sendmsg: ipc6.opt = opt; fl6.flowi6_proto = sk->sk_protocol; - if (!ipv6_addr_any(daddr)) - fl6.daddr = *daddr; - else - fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ + fl6.daddr = *daddr; if (ipv6_addr_any(&fl6.saddr) && !ipv6_addr_any(&np->saddr)) fl6.saddr = np->saddr; fl6.fl6_sport = inet->inet_sport; @@ -1421,6 +1418,9 @@ do_udp_sendmsg: } } + if (ipv6_addr_any(&fl6.daddr)) + fl6.daddr.s6_addr[15] = 0x1; /* :: means loopback (BSD'ism) */ + final_p = fl6_update_dst(&fl6, opt, &final); if (final_p) connected = false; |