diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-11-01 10:32:19 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-11-01 14:57:52 -0700 |
| commit | a904a0693c189691eeee64f6c6b188bd7dc244e9 (patch) | |
| tree | 393398816e62514323b428a7141d1d1bcecd73fa /net/ipv4/tcp_ipv4.c | |
| parent | c8c2cd8102a7b399873b3d001193a5abef42ffb8 (diff) | |
| download | linux-a904a0693c189691eeee64f6c6b188bd7dc244e9.tar.gz | |
inet: stop leaking jiffies on the wire
Historically linux tried to stick to RFC 791, 1122, 2003
for IPv4 ID field generation.
RFC 6864 made clear that no matter how hard we try,
we can not ensure unicity of IP ID within maximum
lifetime for all datagrams with a given source
address/destination address/protocol tuple.
Linux uses a per socket inet generator (inet_id), initialized
at connection startup with a XOR of 'jiffies' and other
fields that appear clear on the wire.
Thiemo Nagel pointed that this strategy is a privacy
concern as this provides 16 bits of entropy to fingerprint
devices.
Let's switch to a random starting point, this is just as
good as far as RFC 6864 is concerned and does not leak
anything critical.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Thiemo Nagel <tnagel@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index b74192695955..67b2dc7a1727 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -303,7 +303,7 @@ int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len) inet->inet_daddr); } - inet->inet_id = tp->write_seq ^ jiffies; + inet->inet_id = prandom_u32(); if (tcp_fastopen_defer_connect(sk, &err)) return err; @@ -1450,7 +1450,7 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, inet_csk(newsk)->icsk_ext_hdr_len = 0; if (inet_opt) inet_csk(newsk)->icsk_ext_hdr_len = inet_opt->opt.optlen; - newinet->inet_id = newtp->write_seq ^ jiffies; + newinet->inet_id = prandom_u32(); if (!dst) { dst = inet_csk_route_child_sock(sk, newsk, req); |