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bpf: Invoke cgroup/connect{4,6} programs for unprivileged ICMP ping

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Usually when a TCP/UDP connection is initiated, we can bind the socket
to a specific IP attached to an interface in a cgroup/connect hook.
But for pings, this is impossible, as the hook is not being called.

This adds the hook invocation to unprivileged ICMP ping (i.e. ping
sockets created with SOCK_DGRAM IPPROTO_ICMP(V6) as opposed to
SOCK_RAW. Logic is mirrored from UDP sockets where the hook is invoked
during pre_connect, after a check for suficiently sized addr_len.

Signed-off-by: YiFei Zhu <zhuyifei@google.com>
Link: https://lore.kernel.org/r/5764914c252fad4cd134fb6664c6ede95f409412.1662682323.git.zhuyifei@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
This commit is contained in:
YiFei Zhu 2022-09-09 00:49:39 +00:00 committed by Martin KaFai Lau
parent 665f5d3577
commit 0ffe241253
2 changed files with 31 additions and 0 deletions
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15
net/ipv4/ping.c
View File

@ -33,6 +33,7 @@
#include <linux/skbuff.h> #include <linux/skbuff.h>
#include <linux/proc_fs.h> #include <linux/proc_fs.h>
#include <linux/export.h> #include <linux/export.h>
#include <linux/bpf-cgroup.h>
#include <net/sock.h> #include <net/sock.h>
#include <net/ping.h> #include <net/ping.h>
#include <net/udp.h> #include <net/udp.h>
@ -295,6 +296,19 @@ void ping_close(struct sock *sk, long timeout)
} }
EXPORT_SYMBOL_GPL(ping_close); EXPORT_SYMBOL_GPL(ping_close);
static int ping_pre_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len)
{
/* This check is replicated from __ip4_datagram_connect() and
* intended to prevent BPF program called below from accessing bytes
* that are out of the bound specified by user in addr_len.
*/
if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
}
/* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */ /* Checks the bind address and possibly modifies sk->sk_bound_dev_if. */
static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk, static int ping_check_bind_addr(struct sock *sk, struct inet_sock *isk,
struct sockaddr *uaddr, int addr_len) struct sockaddr *uaddr, int addr_len)
@ -1009,6 +1023,7 @@ struct proto ping_prot = {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.init = ping_init_sock, .init = ping_init_sock,
.close = ping_close, .close = ping_close,
.pre_connect = ping_pre_connect,
.connect = ip4_datagram_connect, .connect = ip4_datagram_connect,
.disconnect = __udp_disconnect, .disconnect = __udp_disconnect,
.setsockopt = ip_setsockopt, .setsockopt = ip_setsockopt,

16
net/ipv6/ping.c
View File

@ -20,6 +20,7 @@
#include <net/udp.h> #include <net/udp.h>
#include <net/transp_v6.h> #include <net/transp_v6.h>
#include <linux/proc_fs.h> #include <linux/proc_fs.h>
#include <linux/bpf-cgroup.h>
#include <net/ping.h> #include <net/ping.h>
static void ping_v6_destroy(struct sock *sk) static void ping_v6_destroy(struct sock *sk)
@ -49,6 +50,20 @@ static int dummy_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
return 0; return 0;
} }
static int ping_v6_pre_connect(struct sock *sk, struct sockaddr *uaddr,
int addr_len)
{
/* This check is replicated from __ip6_datagram_connect() and
* intended to prevent BPF program called below from accessing
* bytes that are out of the bound specified by user in addr_len.
*/
if (addr_len < SIN6_LEN_RFC2133)
return -EINVAL;
return BPF_CGROUP_RUN_PROG_INET6_CONNECT_LOCK(sk, uaddr);
}
static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{ {
struct inet_sock *inet = inet_sk(sk); struct inet_sock *inet = inet_sk(sk);
@ -191,6 +206,7 @@ struct proto pingv6_prot = {
.init = ping_init_sock, .init = ping_init_sock,
.close = ping_close, .close = ping_close,
.destroy = ping_v6_destroy, .destroy = ping_v6_destroy,
.pre_connect = ping_v6_pre_connect,
.connect = ip6_datagram_connect_v6_only, .connect = ip6_datagram_connect_v6_only,
.disconnect = __udp_disconnect, .disconnect = __udp_disconnect,
.setsockopt = ipv6_setsockopt, .setsockopt = ipv6_setsockopt,