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| author | Andrey Ignatov <rdna@fb.com> | 2018-03-30 15:08:07 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2018-03-31 02:16:26 +0200 |
| commit | aac3fc320d9404f2665a8b1249dc3170d5fa3caf (patch) | |
| tree | 1893d29bcde432c8d807a645a4dbbd2f9ca9fa9a /include/linux | |
| parent | 622adafb2a12cac6042d4d0d7eb735b7621bf28c (diff) | |
| download | linux-aac3fc320d9404f2665a8b1249dc3170d5fa3caf.tar.gz linux-aac3fc320d9404f2665a8b1249dc3170d5fa3caf.tar.bz2 linux-aac3fc320d9404f2665a8b1249dc3170d5fa3caf.zip | |
bpf: Post-hooks for sys_bind
"Post-hooks" are hooks that are called right before returning from
sys_bind. At this time IP and port are already allocated and no further
changes to `struct sock` can happen before returning from sys_bind but
BPF program has a chance to inspect the socket and change sys_bind
result.
Specifically it can e.g. inspect what port was allocated and if it
doesn't satisfy some policy, BPF program can force sys_bind to fail and
return EPERM to user.
Another example of usage is recording the IP:port pair to some map to
use it in later calls to sys_connect. E.g. if some TCP server inside
cgroup was bound to some IP:port_n, it can be recorded to a map. And
later when some TCP client inside same cgroup is trying to connect to
127.0.0.1:port_n, BPF hook for sys_connect can override the destination
and connect application to IP:port_n instead of 127.0.0.1:port_n. That
helps forcing all applications inside a cgroup to use desired IP and not
break those applications if they e.g. use localhost to communicate
between each other.
== Implementation details ==
Post-hooks are implemented as two new attach types
`BPF_CGROUP_INET4_POST_BIND` and `BPF_CGROUP_INET6_POST_BIND` for
existing prog type `BPF_PROG_TYPE_CGROUP_SOCK`.
Separate attach types for IPv4 and IPv6 are introduced to avoid access
to IPv6 field in `struct sock` from `inet_bind()` and to IPv4 field from
`inet6_bind()` since those fields might not make sense in such cases.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/bpf-cgroup.h | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index c6ab295e6dcb..30d15e64b993 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -98,16 +98,24 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, __ret; \ }) -#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \ +#define BPF_CGROUP_RUN_SK_PROG(sk, type) \ ({ \ int __ret = 0; \ if (cgroup_bpf_enabled) { \ - __ret = __cgroup_bpf_run_filter_sk(sk, \ - BPF_CGROUP_INET_SOCK_CREATE); \ + __ret = __cgroup_bpf_run_filter_sk(sk, type); \ } \ __ret; \ }) +#define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_CREATE) + +#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET4_POST_BIND) + +#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET6_POST_BIND) + #define BPF_CGROUP_RUN_SA_PROG(sk, uaddr, type) \ ({ \ int __ret = 0; \ @@ -183,6 +191,8 @@ static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; } #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_BIND(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET6_BIND(sk, uaddr) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) ({ 0; }) +#define BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_CONNECT(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr) ({ 0; }) #define BPF_CGROUP_RUN_PROG_INET6_CONNECT(sk, uaddr) ({ 0; }) |