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| author | Andrey Ignatov <rdna@fb.com> | 2019-01-04 12:07:07 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-27 12:08:52 +0300 |
| commit | 8b0d641e6152fabf740b39f5765a0185e941c281 (patch) | |
| tree | bd016020da287531ba411086e4c936324754d810 /net/ipv6 | |
| parent | 6bcf4e0703b1f5f1b20466be8730c34b79633c81 (diff) | |
| download | linux-8b0d641e6152fabf740b39f5765a0185e941c281.tar.xz | |
bpf: Fix [::] -> [::1] rewrite in sys_sendmsg
[ Upstream commit e8e36984080b55ac5e57bdb09a5b570f2fc8e963 ]
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>
Signed-off-by: Sasha Levin <sashal@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 76ba2f34ef6b..cab8b2b647f9 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -1322,10 +1322,7 @@ 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; @@ -1353,6 +1350,9 @@ 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; |