Commit 6041c67f authored by Andrey Ignatov's avatar Andrey Ignatov Committed by Alexei Starovoitov
Browse files

selftests/bpf: Test bpf_sysctl_get_name helper 



Test w/ and w/o BPF_F_SYSCTL_BASE_NAME, buffers with enough space and
too small buffers to get E2BIG and truncated result, etc.

  # ./test_sysctl
  ...
  Test case: sysctl_get_name sysctl_value:base ok .. [PASS]
  Test case: sysctl_get_name sysctl_value:base E2BIG truncated .. [PASS]
  Test case: sysctl_get_name sysctl:full ok .. [PASS]
  Test case: sysctl_get_name sysctl:full E2BIG truncated .. [PASS]
  Test case: sysctl_get_name sysctl:full E2BIG truncated small .. [PASS]
  Summary: 11 PASSED, 0 FAILED

Signed-off-by: default avatarAndrey Ignatov <rdna@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 1f5fa9ab

tools/testing/selftests/bpf/test_sysctl.c

+222 −0
Original line number Diff line number Diff line
@@ -128,6 +128,228 @@ static struct sysctl_test tests[] = { 
		.open_flags = O_RDONLY,

		.result = LOAD_REJECT,

	},

	{

		.descr = "sysctl_get_name sysctl_value:base ok",

		.insns = {

			/* sysctl_get_name 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_name arg3 (buf_len) */

			BPF_MOV64_IMM(BPF_REG_3, 8),



			/* sysctl_get_name arg4 (flags) */

			BPF_MOV64_IMM(BPF_REG_4, BPF_F_SYSCTL_BASE_NAME),



			/* sysctl_get_name(ctx, buf, buf_len, flags) */

			BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),



			/* if (ret == expected && */

			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, sizeof("tcp_mem") - 1, 6),

			/*     buf == "tcp_mem\0") */

			BPF_LD_IMM64(BPF_REG_8, 0x006d656d5f706374ULL),

			BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),

			BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 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_name sysctl_value:base E2BIG truncated",

		.insns = {

			/* sysctl_get_name 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_name arg3 (buf_len) too small */

			BPF_MOV64_IMM(BPF_REG_3, 7),



			/* sysctl_get_name arg4 (flags) */

			BPF_MOV64_IMM(BPF_REG_4, BPF_F_SYSCTL_BASE_NAME),



			/* sysctl_get_name(ctx, buf, buf_len, flags) */

			BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),



			/* if (ret == expected && */

			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 6),



			/*     buf[0:7] == "tcp_me\0") */

			BPF_LD_IMM64(BPF_REG_8, 0x00656d5f706374ULL),

			BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),

			BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 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_name sysctl:full ok",

		.insns = {

			/* sysctl_get_name arg2 (buf) */

			BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -24),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

			BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),

			BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 16),



			BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),



			/* sysctl_get_name arg3 (buf_len) */

			BPF_MOV64_IMM(BPF_REG_3, 17),



			/* sysctl_get_name arg4 (flags) */

			BPF_MOV64_IMM(BPF_REG_4, 0),



			/* sysctl_get_name(ctx, buf, buf_len, flags) */

			BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),



			/* if (ret == expected && */

			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 16, 14),



			/*     buf[0:8] == "net/ipv4" && */

			BPF_LD_IMM64(BPF_REG_8, 0x347670692f74656eULL),

			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] == "/tcp_mem" && */

			BPF_LD_IMM64(BPF_REG_8, 0x6d656d5f7063742fULL),

			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] == "\0") */

			BPF_LD_IMM64(BPF_REG_8, 0x0ULL),

			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 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_name sysctl:full E2BIG truncated",

		.insns = {

			/* sysctl_get_name arg2 (buf) */

			BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),

			BPF_ALU64_IMM(BPF_ADD, BPF_REG_7, -16),

			BPF_MOV64_IMM(BPF_REG_0, 0),

			BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 0),

			BPF_STX_MEM(BPF_DW, BPF_REG_7, BPF_REG_0, 8),



			BPF_MOV64_REG(BPF_REG_2, BPF_REG_7),



			/* sysctl_get_name arg3 (buf_len) */

			BPF_MOV64_IMM(BPF_REG_3, 16),



			/* sysctl_get_name arg4 (flags) */

			BPF_MOV64_IMM(BPF_REG_4, 0),



			/* sysctl_get_name(ctx, buf, buf_len, flags) */

			BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),



			/* if (ret == expected && */

			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 10),



			/*     buf[0:8] == "net/ipv4" && */

			BPF_LD_IMM64(BPF_REG_8, 0x347670692f74656eULL),

			BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),

			BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 6),



			/*     buf[8:16] == "/tcp_me\0") */

			BPF_LD_IMM64(BPF_REG_8, 0x00656d5f7063742fULL),

			BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 8),

			BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 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_name sysctl:full E2BIG truncated small",

		.insns = {

			/* sysctl_get_name 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_name arg3 (buf_len) */

			BPF_MOV64_IMM(BPF_REG_3, 7),



			/* sysctl_get_name arg4 (flags) */

			BPF_MOV64_IMM(BPF_REG_4, 0),



			/* sysctl_get_name(ctx, buf, buf_len, flags) */

			BPF_EMIT_CALL(BPF_FUNC_sysctl_get_name),



			/* if (ret == expected && */

			BPF_JMP_IMM(BPF_JNE, BPF_REG_0, -E2BIG, 6),



			/*     buf[0:8] == "net/ip\0") */

			BPF_LD_IMM64(BPF_REG_8, 0x000070692f74656eULL),

			BPF_LDX_MEM(BPF_DW, BPF_REG_9, BPF_REG_7, 0),

			BPF_JMP_REG(BPF_JNE, BPF_REG_8, BPF_REG_9, 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,

	},

};



static size_t probe_prog_length(const struct bpf_insn *fp)

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