From 0adc3dd90050538ac543c6c0bea8e8527a9e2e2c Mon Sep 17 00:00:00 2001 From: David Ahern Date: Thu, 31 Aug 2017 15:05:50 -0700 Subject: [PATCH] samples/bpf: Update cgroup socket examples to use uid gid helper Signed-off-by: David Ahern Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/sock_flags_kern.c | 5 +++++ samples/bpf/test_cgrp2_sock.c | 12 +++++++++++- 2 files changed, 16 insertions(+), 1 deletion(-) diff --git a/samples/bpf/sock_flags_kern.c b/samples/bpf/sock_flags_kern.c index 533dd11a6baa..05dcdf8a4baa 100644 --- a/samples/bpf/sock_flags_kern.c +++ b/samples/bpf/sock_flags_kern.c @@ -9,8 +9,13 @@ SEC("cgroup/sock1") int bpf_prog1(struct bpf_sock *sk) { char fmt[] = "socket: family %d type %d protocol %d\n"; + char fmt2[] = "socket: uid %u gid %u\n"; + __u64 gid_uid = bpf_get_current_uid_gid(); + __u32 uid = gid_uid & 0xffffffff; + __u32 gid = gid_uid >> 32; bpf_trace_printk(fmt, sizeof(fmt), sk->family, sk->type, sk->protocol); + bpf_trace_printk(fmt2, sizeof(fmt2), uid, gid); /* block PF_INET6, SOCK_RAW, IPPROTO_ICMPV6 sockets * ie., make ping6 fail diff --git a/samples/bpf/test_cgrp2_sock.c b/samples/bpf/test_cgrp2_sock.c index 5a688837720c..e79594dd629b 100644 --- a/samples/bpf/test_cgrp2_sock.c +++ b/samples/bpf/test_cgrp2_sock.c @@ -46,8 +46,18 @@ static int prog_load(__u32 idx, __u32 mark, __u32 prio) /* set mark on socket */ struct bpf_insn prog_mark[] = { - BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + /* get uid of process */ + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_get_current_uid_gid), + BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xffffffff), + + /* if uid is 0, use given mark, else use the uid as the mark */ + BPF_MOV64_REG(BPF_REG_3, BPF_REG_0), + BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1), BPF_MOV64_IMM(BPF_REG_3, mark), + + /* set the mark on the new socket */ + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), BPF_MOV64_IMM(BPF_REG_2, offsetof(struct bpf_sock, mark)), BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_3, offsetof(struct bpf_sock, mark)), }; -- 2.20.1