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: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrey Ignatov 2019-03-08 15:13:43 -08:00 committed by Alexei Starovoitov
parent 1f5fa9ab6e
commit 6041c67f28

View File

@ -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)