Commit 786047dd authored by Andrey Ignatov's avatar Andrey Ignatov Committed by Alexei Starovoitov
Browse files

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: default avatarAndrey Ignatov <rdna@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 11ff34f7

tools/testing/selftests/bpf/test_sysctl.c

+222 −0
Original line number Diff line number Diff line
@@ -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)

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