From 62476cc1bf24b34d9442c7ba76e5eb6bf242f911 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Wed, 27 Jan 2021 15:28:50 -0800 Subject: [PATCH] bpf: Enable bpf_{g,s}etsockopt in BPF_CGROUP_UDP{4,6}_SENDMSG Can be used to query/modify socket state for unconnected UDP sendmsg. Those hooks run as BPF_CGROUP_RUN_SA_PROG_LOCK and operate on a locked socket. Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20210127232853.3753823-2-sdf@google.com --- net/core/filter.c | 4 ++++ tools/testing/selftests/bpf/bpf_sockopt_helpers.h | 21 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/sendmsg4_prog.c | 7 +++++++ tools/testing/selftests/bpf/progs/sendmsg6_prog.c | 5 +++++ 4 files changed, 37 insertions(+) create mode 100644 tools/testing/selftests/bpf/bpf_sockopt_helpers.h diff --git a/net/core/filter.c b/net/core/filter.c index 9ab94e9..3d7f78a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -7023,6 +7023,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_CGROUP_INET6_BIND: case BPF_CGROUP_INET4_CONNECT: case BPF_CGROUP_INET6_CONNECT: + case BPF_CGROUP_UDP4_SENDMSG: + case BPF_CGROUP_UDP6_SENDMSG: return &bpf_sock_addr_setsockopt_proto; default: return NULL; @@ -7033,6 +7035,8 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_CGROUP_INET6_BIND: case BPF_CGROUP_INET4_CONNECT: case BPF_CGROUP_INET6_CONNECT: + case BPF_CGROUP_UDP4_SENDMSG: + case BPF_CGROUP_UDP6_SENDMSG: return &bpf_sock_addr_getsockopt_proto; default: return NULL; diff --git a/tools/testing/selftests/bpf/bpf_sockopt_helpers.h b/tools/testing/selftests/bpf/bpf_sockopt_helpers.h new file mode 100644 index 0000000..11f3a09 --- /dev/null +++ b/tools/testing/selftests/bpf/bpf_sockopt_helpers.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include + +int get_set_sk_priority(void *ctx) +{ + int prio; + + /* Verify that context allows calling bpf_getsockopt and + * bpf_setsockopt by reading and writing back socket + * priority. + */ + + if (bpf_getsockopt(ctx, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio))) + return 0; + if (bpf_setsockopt(ctx, SOL_SOCKET, SO_PRIORITY, &prio, sizeof(prio))) + return 0; + + return 1; +} diff --git a/tools/testing/selftests/bpf/progs/sendmsg4_prog.c b/tools/testing/selftests/bpf/progs/sendmsg4_prog.c index 092d9da..ac5abc3 100644 --- a/tools/testing/selftests/bpf/progs/sendmsg4_prog.c +++ b/tools/testing/selftests/bpf/progs/sendmsg4_prog.c @@ -8,6 +8,8 @@ #include #include +#include + #define SRC1_IP4 0xAC100001U /* 172.16.0.1 */ #define SRC2_IP4 0x00000000U #define SRC_REWRITE_IP4 0x7f000004U @@ -21,9 +23,14 @@ int _version SEC("version") = 1; SEC("cgroup/sendmsg4") int sendmsg_v4_prog(struct bpf_sock_addr *ctx) { + int prio; + if (ctx->type != SOCK_DGRAM) return 0; + if (!get_set_sk_priority(ctx)) + return 0; + /* Rewrite source. */ if (ctx->msg_src_ip4 == bpf_htonl(SRC1_IP4) || ctx->msg_src_ip4 == bpf_htonl(SRC2_IP4)) { diff --git a/tools/testing/selftests/bpf/progs/sendmsg6_prog.c b/tools/testing/selftests/bpf/progs/sendmsg6_prog.c index 255a432b..24694b1 100644 --- a/tools/testing/selftests/bpf/progs/sendmsg6_prog.c +++ b/tools/testing/selftests/bpf/progs/sendmsg6_prog.c @@ -8,6 +8,8 @@ #include #include +#include + #define SRC_REWRITE_IP6_0 0 #define SRC_REWRITE_IP6_1 0 #define SRC_REWRITE_IP6_2 0 @@ -28,6 +30,9 @@ int sendmsg_v6_prog(struct bpf_sock_addr *ctx) if (ctx->type != SOCK_DGRAM) return 0; + if (!get_set_sk_priority(ctx)) + return 0; + /* Rewrite source. */ if (ctx->msg_src_ip6[3] == bpf_htonl(1) || ctx->msg_src_ip6[3] == bpf_htonl(0)) { -- 2.7.4