selftests/bpf: Test bpf_sysctl_{get,set}_new_value helpers

Test that new value provided by user space on sysctl write can be read
by bpf_sysctl_get_new_value and overridden by bpf_sysctl_set_new_value.

  # ./test_sysctl
  ...
  Test case: sysctl_get_new_value sysctl:read EINVAL .. [PASS]
  Test case: sysctl_get_new_value sysctl:write ok .. [PASS]
  Test case: sysctl_get_new_value sysctl:write ok long .. [PASS]
  Test case: sysctl_get_new_value sysctl:write E2BIG .. [PASS]
  Test case: sysctl_set_new_value sysctl:read EINVAL .. [PASS]
  Test case: sysctl_set_new_value sysctl:write ok .. [PASS]
  Summary: 22 PASSED, 0 FAILED

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrey Ignatov 2019-03-08 15:22:03 -08:00 committed by Alexei Starovoitov
parent 11ff34f74e
commit 786047dd08

View File

@ -536,6 +536,228 @@ static struct sysctl_test tests[] = {
.newval = "600", /* same as default, should fail anyway */
.result = OP_EPERM,
},
{
.descr = "sysctl_get_new_value sysctl:read EINVAL",
.insns = {
/* sysctl_get_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_get_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 8),
/* sysctl_get_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),
/* if (ret == expected) */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),
/* return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_A(1),
/* else return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/tcp_mem",
.open_flags = O_RDONLY,
.result = SUCCESS,
},
{
.descr = "sysctl_get_new_value sysctl:write ok",
.insns = {
/* sysctl_get_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_get_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 4),
/* sysctl_get_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),
/* if (ret == expected && */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 3, 4),
/* buf[0:4] == "606\0") */
BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_7, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0x00363036, 2),
/* return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_A(1),
/* else return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/route/mtu_expires",
.open_flags = O_WRONLY,
.newval = "606",
.result = OP_EPERM,
},
{
.descr = "sysctl_get_new_value sysctl:write ok long",
.insns = {
/* sysctl_get_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_get_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 24),
/* sysctl_get_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),
/* if (ret == expected && */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 23, 14),
/* buf[0:8] == "3000000 " && */
BPF_LD_IMM64(BPF_REG_8, 0x2030303030303033ULL),
BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),
BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 10),
/* buf[8:16] == "4000000 " && */
BPF_LD_IMM64(BPF_REG_8, 0x2030303030303034ULL),
BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 8),
BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 6),
/* buf[16:24] == "6000000\0") */
BPF_LD_IMM64(BPF_REG_8, 0x0030303030303036ULL),
BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 16),
BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 2),
/* return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_A(1),
/* else return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/tcp_mem",
.open_flags = O_WRONLY,
.newval = "3000000 4000000 6000000",
.result = OP_EPERM,
},
{
.descr = "sysctl_get_new_value sysctl:write E2BIG",
.insns = {
/* sysctl_get_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_STX_MEM(BPF_B, BPF_REG_7, BPF_REG_0, 3),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_get_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 3),
/* sysctl_get_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_get_new_value),
/* if (ret == expected && */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 4),
/* buf[0:3] == "60\0") */
BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_7, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_9, 0x003036, 2),
/* return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_JMP_A(1),
/* else return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/route/mtu_expires",
.open_flags = O_WRONLY,
.newval = "606",
.result = OP_EPERM,
},
{
.descr = "sysctl_set_new_value sysctl:read EINVAL",
.insns = {
/* sysctl_set_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
BPF_MOV64_IMM(BPF_REG_0, 0x00303036),
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_set_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 3),
/* sysctl_set_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_set_new_value),
/* if (ret == expected) */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -EINVAL, 2),
/* return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_A(1),
/* else return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/route/mtu_expires",
.open_flags = O_RDONLY,
.result = SUCCESS,
},
{
.descr = "sysctl_set_new_value sysctl:write ok",
.fixup_value_insn = 2,
.insns = {
/* sysctl_set_new_value arg2 (buf) */
BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -8),
BPF_MOV64_IMM(BPF_REG_0, FIXUP_SYSCTL_VALUE),
BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),
BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),
/* sysctl_set_new_value arg3 (buf_len) */
BPF_MOV64_IMM(BPF_REG_3, 3),
/* sysctl_set_new_value(ctx, buf, buf_len) */
BPF_EMIT_CALL(BPF_FUNC_sysctl_set_new_value),
/* if (ret == expected) */
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 2),
/* return ALLOW; */
BPF_MOV64_IMM(BPF_REG_0, 1),
BPF_JMP_A(1),
/* else return DENY; */
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
},
.attach_type = BPF_CGROUP_SYSCTL,
.sysctl = "net/ipv4/route/mtu_expires",
.open_flags = O_WRONLY,
.newval = "606",
.result = SUCCESS,
},
};
static size_t probe_prog_length(const struct bpf_insn *fp)