| Message ID | 20200524180002.148619-1-edumazet@google.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] tcp: allow traceroute -Mtcp for unpriv users | expand |
On Sun, May 24, 2020 at 11:00 AM Eric Dumazet <edumazet@google.com> wrote: > > Unpriv users can use traceroute over plain UDP sockets, but not TCP ones. > > $ traceroute -Mtcp 8.8.8.8 > You do not have enough privileges to use this traceroute method. > > $ traceroute -n -Mudp 8.8.8.8 > traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets > 1 192.168.86.1 3.631 ms 3.512 ms 3.405 ms > 2 10.1.10.1 4.183 ms 4.125 ms 4.072 ms > 3 96.120.88.125 20.621 ms 19.462 ms 20.553 ms > 4 96.110.177.65 24.271 ms 25.351 ms 25.250 ms > 5 69.139.199.197 44.492 ms 43.075 ms 44.346 ms > 6 68.86.143.93 27.969 ms 25.184 ms 25.092 ms > 7 96.112.146.18 25.323 ms 96.112.146.22 25.583 ms 96.112.146.26 24.502 ms > 8 72.14.239.204 24.405 ms 74.125.37.224 16.326 ms 17.194 ms > 9 209.85.251.9 18.154 ms 209.85.247.55 14.449 ms 209.85.251.9 26.296 ms^C > > We can easily support traceroute over TCP, by queueing an error message > into socket error queue. > > Note that applications need to set IP_RECVERR/IPV6_RECVERR option to > enable this feature, and that the error message is only queued > while in SYN_SNT state. > > socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 > setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0 > setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0 > setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0 > connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), > inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host) > recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), > inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, > msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}], > msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}}, > {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}], > msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144 > > Suggested-by: Maciej Żenczykowski <maze@google.com > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Willem de Bruijn <willemb@google.com> > --- > net/ipv4/tcp_ipv4.c | 2 ++ > net/ipv6/tcp_ipv6.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c > index 6c05f1ceb538cbb9981835440163485de2ccf716..900c6d154cbcf04fb09d71f1445d0723bcf3c409 100644 > --- a/net/ipv4/tcp_ipv4.c > +++ b/net/ipv4/tcp_ipv4.c > @@ -573,6 +573,8 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info) > if (fastopen && !fastopen->sk) > break; > > + ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th); > + > if (!sock_owned_by_user(sk)) { > sk->sk_err = err; > > diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c > index 413b3425ac66bd758bb83562efa955f277da90a5..01a6f5111a77b4397038bf4d40cc09a94e57408c 100644 > --- a/net/ipv6/tcp_ipv6.c > +++ b/net/ipv6/tcp_ipv6.c > @@ -463,6 +463,8 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, > if (fastopen && !fastopen->sk) > break; > > + ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th); > + > if (!sock_owned_by_user(sk)) { > sk->sk_err = err; > sk->sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */ > -- > 2.27.0.rc0.183.gde8f92d652-goog Thanks! I was not expecting it to be this easy... Reviewed-by: Maciej Żenczykowski <maze@google.com>
From: Eric Dumazet <edumazet@google.com> Date: Sun, 24 May 2020 11:00:02 -0700 > Unpriv users can use traceroute over plain UDP sockets, but not TCP ones. > > $ traceroute -Mtcp 8.8.8.8 > You do not have enough privileges to use this traceroute method. > > $ traceroute -n -Mudp 8.8.8.8 > traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets > 1 192.168.86.1 3.631 ms 3.512 ms 3.405 ms > 2 10.1.10.1 4.183 ms 4.125 ms 4.072 ms > 3 96.120.88.125 20.621 ms 19.462 ms 20.553 ms > 4 96.110.177.65 24.271 ms 25.351 ms 25.250 ms > 5 69.139.199.197 44.492 ms 43.075 ms 44.346 ms > 6 68.86.143.93 27.969 ms 25.184 ms 25.092 ms > 7 96.112.146.18 25.323 ms 96.112.146.22 25.583 ms 96.112.146.26 24.502 ms > 8 72.14.239.204 24.405 ms 74.125.37.224 16.326 ms 17.194 ms > 9 209.85.251.9 18.154 ms 209.85.247.55 14.449 ms 209.85.251.9 26.296 ms^C > > We can easily support traceroute over TCP, by queueing an error message > into socket error queue. > > Note that applications need to set IP_RECVERR/IPV6_RECVERR option to > enable this feature, and that the error message is only queued > while in SYN_SNT state. > > socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 > setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0 > setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0 > setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0 > connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), > inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host) > recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), > inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, > msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}], > msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}}, > {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}], > msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144 > > Suggested-by: Maciej Żenczykowski <maze@google.com > Signed-off-by: Eric Dumazet <edumazet@google.com> Applied, thanks Eric.
On 5/25/20 5:54 PM, David Miller wrote: > From: Eric Dumazet <edumazet@google.com> > Date: Sun, 24 May 2020 11:00:02 -0700 > >> Unpriv users can use traceroute over plain UDP sockets, but not TCP ones. >> >> $ traceroute -Mtcp 8.8.8.8 >> You do not have enough privileges to use this traceroute method. >> >> $ traceroute -n -Mudp 8.8.8.8 >> traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets >> 1 192.168.86.1 3.631 ms 3.512 ms 3.405 ms >> 2 10.1.10.1 4.183 ms 4.125 ms 4.072 ms >> 3 96.120.88.125 20.621 ms 19.462 ms 20.553 ms >> 4 96.110.177.65 24.271 ms 25.351 ms 25.250 ms >> 5 69.139.199.197 44.492 ms 43.075 ms 44.346 ms >> 6 68.86.143.93 27.969 ms 25.184 ms 25.092 ms >> 7 96.112.146.18 25.323 ms 96.112.146.22 25.583 ms 96.112.146.26 24.502 ms >> 8 72.14.239.204 24.405 ms 74.125.37.224 16.326 ms 17.194 ms >> 9 209.85.251.9 18.154 ms 209.85.247.55 14.449 ms 209.85.251.9 26.296 ms^C >> >> We can easily support traceroute over TCP, by queueing an error message >> into socket error queue. >> >> Note that applications need to set IP_RECVERR/IPV6_RECVERR option to >> enable this feature, and that the error message is only queued >> while in SYN_SNT state. >> >> socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 >> setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0 >> setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0 >> setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0 >> connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), >> inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host) >> recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), >> inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, >> msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}], >> msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}}, >> {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}], >> msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144 >> >> Suggested-by: Maciej Żenczykowski <maze@google.com >> Signed-off-by: Eric Dumazet <edumazet@google.com> > > Applied, thanks Eric. > I will send a fix, it appears tcp_v4_err() has two sk_buff variables, one named icmp_skb, and another one :/
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 6c05f1ceb538cbb9981835440163485de2ccf716..900c6d154cbcf04fb09d71f1445d0723bcf3c409 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -573,6 +573,8 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info) if (fastopen && !fastopen->sk) break; + ip_icmp_error(sk, skb, err, th->dest, info, (u8 *)th); + if (!sock_owned_by_user(sk)) { sk->sk_err = err; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 413b3425ac66bd758bb83562efa955f277da90a5..01a6f5111a77b4397038bf4d40cc09a94e57408c 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -463,6 +463,8 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, if (fastopen && !fastopen->sk) break; + ipv6_icmp_error(sk, skb, err, th->dest, ntohl(info), (u8 *)th); + if (!sock_owned_by_user(sk)) { sk->sk_err = err; sk->sk_error_report(sk); /* Wake people up to see the error (see connect in sock.c) */
Unpriv users can use traceroute over plain UDP sockets, but not TCP ones. $ traceroute -Mtcp 8.8.8.8 You do not have enough privileges to use this traceroute method. $ traceroute -n -Mudp 8.8.8.8 traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets 1 192.168.86.1 3.631 ms 3.512 ms 3.405 ms 2 10.1.10.1 4.183 ms 4.125 ms 4.072 ms 3 96.120.88.125 20.621 ms 19.462 ms 20.553 ms 4 96.110.177.65 24.271 ms 25.351 ms 25.250 ms 5 69.139.199.197 44.492 ms 43.075 ms 44.346 ms 6 68.86.143.93 27.969 ms 25.184 ms 25.092 ms 7 96.112.146.18 25.323 ms 96.112.146.22 25.583 ms 96.112.146.26 24.502 ms 8 72.14.239.204 24.405 ms 74.125.37.224 16.326 ms 17.194 ms 9 209.85.251.9 18.154 ms 209.85.247.55 14.449 ms 209.85.251.9 26.296 ms^C We can easily support traceroute over TCP, by queueing an error message into socket error queue. Note that applications need to set IP_RECVERR/IPV6_RECVERR option to enable this feature, and that the error message is only queued while in SYN_SNT state. socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3 setsockopt(3, SOL_IPV6, IPV6_RECVERR, [1], 4) = 0 setsockopt(3, SOL_SOCKET, SO_TIMESTAMP_OLD, [1], 4) = 0 setsockopt(3, SOL_IPV6, IPV6_UNICAST_HOPS, [5], 4) = 0 connect(3, {sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, 28) = -1 EHOSTUNREACH (No route to host) recvmsg(3, {msg_name={sa_family=AF_INET6, sin6_port=htons(8787), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "2002:a05:6608:297::", &sin6_addr), sin6_scope_id=0}, msg_namelen=1024->28, msg_iov=[{iov_base="`\r\337\320\0004\6\1&\7\370\260\200\231\16\27\0\0\0\0\0\0\0\0 \2\n\5f\10\2\227"..., iov_len=1024}], msg_iovlen=1, msg_control=[{cmsg_len=32, cmsg_level=SOL_SOCKET, cmsg_type=SO_TIMESTAMP_OLD, cmsg_data={tv_sec=1590340680, tv_usec=272424}}, {cmsg_len=60, cmsg_level=SOL_IPV6, cmsg_type=IPV6_RECVERR}], msg_controllen=96, msg_flags=MSG_ERRQUEUE}, MSG_ERRQUEUE) = 144 Suggested-by: Maciej Żenczykowski <maze@google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> --- net/ipv4/tcp_ipv4.c | 2 ++ net/ipv6/tcp_ipv6.c | 2 ++ 2 files changed, 4 insertions(+)