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Message-ID: <CAPhsuW6Oo804YHfformbyNEV=CgFa5sSC0kOOarcHcHG9ysDXw@mail.gmail.com>
Date: Tue, 29 May 2018 11:01:44 -0700
From: Song Liu <liu.song.a23@...il.com>
To: Daniel Borkmann <daniel@...earbox.net>
Cc: Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org
Subject: Re: [PATCH bpf-next 01/11] bpf: test case for map pointer poison with calls/branches
On Sun, May 27, 2018 at 5:43 PM, Daniel Borkmann <daniel@...earbox.net> wrote:
> Add several test cases where the same or different map pointers
> originate from different paths in the program and execute a map
> lookup or tail call at a common location.
>
> Signed-off-by: Daniel Borkmann <daniel@...earbox.net>
> Acked-by: Alexei Starovoitov <ast@...nel.org>
Acked-by: Song Liu <songliubraving@...com>
> ---
> include/linux/filter.h | 10 ++
> tools/include/linux/filter.h | 10 ++
> tools/testing/selftests/bpf/test_verifier.c | 185 ++++++++++++++++++++++++----
> 3 files changed, 178 insertions(+), 27 deletions(-)
>
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index d358d18..b443f70 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -289,6 +289,16 @@ struct xdp_buff;
> .off = OFF, \
> .imm = 0 })
>
> +/* Relative call */
> +
> +#define BPF_CALL_REL(TGT) \
> + ((struct bpf_insn) { \
> + .code = BPF_JMP | BPF_CALL, \
> + .dst_reg = 0, \
> + .src_reg = BPF_PSEUDO_CALL, \
> + .off = 0, \
> + .imm = TGT })
> +
> /* Function call */
>
> #define BPF_EMIT_CALL(FUNC) \
> diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h
> index c5e512d..af55acf 100644
> --- a/tools/include/linux/filter.h
> +++ b/tools/include/linux/filter.h
> @@ -263,6 +263,16 @@
> #define BPF_LD_MAP_FD(DST, MAP_FD) \
> BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
>
> +/* Relative call */
> +
> +#define BPF_CALL_REL(TGT) \
> + ((struct bpf_insn) { \
> + .code = BPF_JMP | BPF_CALL, \
> + .dst_reg = 0, \
> + .src_reg = BPF_PSEUDO_CALL, \
> + .off = 0, \
> + .imm = TGT })
> +
> /* Program exit */
>
> #define BPF_EXIT_INSN() \
> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
> index 4b4f015..7cb1d74 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -50,7 +50,7 @@
>
> #define MAX_INSNS BPF_MAXINSNS
> #define MAX_FIXUPS 8
> -#define MAX_NR_MAPS 4
> +#define MAX_NR_MAPS 7
> #define POINTER_VALUE 0xcafe4all
> #define TEST_DATA_LEN 64
>
> @@ -66,7 +66,9 @@ struct bpf_test {
> int fixup_map1[MAX_FIXUPS];
> int fixup_map2[MAX_FIXUPS];
> int fixup_map3[MAX_FIXUPS];
> - int fixup_prog[MAX_FIXUPS];
> + int fixup_map4[MAX_FIXUPS];
> + int fixup_prog1[MAX_FIXUPS];
> + int fixup_prog2[MAX_FIXUPS];
> int fixup_map_in_map[MAX_FIXUPS];
> const char *errstr;
> const char *errstr_unpriv;
> @@ -2769,7 +2771,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 0),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .errstr_unpriv = "R3 leaks addr into helper",
> .result_unpriv = REJECT,
> .result = ACCEPT,
> @@ -2856,7 +2858,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 1),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .result = ACCEPT,
> .retval = 42,
> },
> @@ -2870,7 +2872,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 1),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .result = ACCEPT,
> .retval = 41,
> },
> @@ -2884,7 +2886,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 1),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .result = ACCEPT,
> .retval = 1,
> },
> @@ -2898,7 +2900,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 2),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .result = ACCEPT,
> .retval = 2,
> },
> @@ -2912,7 +2914,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 2),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 1 },
> + .fixup_prog1 = { 1 },
> .result = ACCEPT,
> .retval = 2,
> },
> @@ -2926,7 +2928,7 @@ static struct bpf_test tests[] = {
> BPF_MOV64_IMM(BPF_REG_0, 2),
> BPF_EXIT_INSN(),
> },
> - .fixup_prog = { 2 },
> + .fixup_prog1 = { 2 },
> .result = ACCEPT,
> .retval = 42,
> },
> @@ -11682,6 +11684,112 @@ static struct bpf_test tests[] = {
> .prog_type = BPF_PROG_TYPE_XDP,
> },
> {
> + "calls: two calls returning different map pointers for lookup (hash, array)",
> + .insns = {
> + /* main prog */
> + BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
> + BPF_CALL_REL(11),
> + BPF_JMP_IMM(BPF_JA, 0, 0, 1),
> + BPF_CALL_REL(12),
> + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
> + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
> + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
> + BPF_FUNC_map_lookup_elem),
> + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
> + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0,
> + offsetof(struct test_val, foo)),
> + BPF_MOV64_IMM(BPF_REG_0, 1),
> + BPF_EXIT_INSN(),
> + /* subprog 1 */
> + BPF_LD_MAP_FD(BPF_REG_0, 0),
> + BPF_EXIT_INSN(),
> + /* subprog 2 */
> + BPF_LD_MAP_FD(BPF_REG_0, 0),
> + BPF_EXIT_INSN(),
> + },
> + .prog_type = BPF_PROG_TYPE_SCHED_CLS,
> + .fixup_map2 = { 13 },
> + .fixup_map4 = { 16 },
> + .result = ACCEPT,
> + .retval = 1,
> + },
> + {
> + "calls: two calls returning different map pointers for lookup (hash, map in map)",
> + .insns = {
> + /* main prog */
> + BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, 2),
> + BPF_CALL_REL(11),
> + BPF_JMP_IMM(BPF_JA, 0, 0, 1),
> + BPF_CALL_REL(12),
> + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
> + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
> + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
> + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
> + BPF_FUNC_map_lookup_elem),
> + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
> + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0,
> + offsetof(struct test_val, foo)),
> + BPF_MOV64_IMM(BPF_REG_0, 1),
> + BPF_EXIT_INSN(),
> + /* subprog 1 */
> + BPF_LD_MAP_FD(BPF_REG_0, 0),
> + BPF_EXIT_INSN(),
> + /* subprog 2 */
> + BPF_LD_MAP_FD(BPF_REG_0, 0),
> + BPF_EXIT_INSN(),
> + },
> + .prog_type = BPF_PROG_TYPE_SCHED_CLS,
> + .fixup_map_in_map = { 16 },
> + .fixup_map4 = { 13 },
> + .result = REJECT,
> + .errstr = "R0 invalid mem access 'map_ptr'",
> + },
> + {
> + "cond: two branches returning different map pointers for lookup (tail, tail)",
> + .insns = {
> + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
> + offsetof(struct __sk_buff, mark)),
> + BPF_JMP_IMM(BPF_JNE, BPF_REG_6, 0, 3),
> + BPF_LD_MAP_FD(BPF_REG_2, 0),
> + BPF_JMP_IMM(BPF_JA, 0, 0, 2),
> + BPF_LD_MAP_FD(BPF_REG_2, 0),
> + BPF_MOV64_IMM(BPF_REG_3, 7),
> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
> + BPF_FUNC_tail_call),
> + BPF_MOV64_IMM(BPF_REG_0, 1),
> + BPF_EXIT_INSN(),
> + },
> + .fixup_prog1 = { 5 },
> + .fixup_prog2 = { 2 },
> + .result_unpriv = REJECT,
> + .errstr_unpriv = "tail_call abusing map_ptr",
> + .result = ACCEPT,
> + .retval = 42,
> + },
> + {
> + "cond: two branches returning same map pointers for lookup (tail, tail)",
> + .insns = {
> + BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
> + offsetof(struct __sk_buff, mark)),
> + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 3),
> + BPF_LD_MAP_FD(BPF_REG_2, 0),
> + BPF_JMP_IMM(BPF_JA, 0, 0, 2),
> + BPF_LD_MAP_FD(BPF_REG_2, 0),
> + BPF_MOV64_IMM(BPF_REG_3, 7),
> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
> + BPF_FUNC_tail_call),
> + BPF_MOV64_IMM(BPF_REG_0, 1),
> + BPF_EXIT_INSN(),
> + },
> + .fixup_prog2 = { 2, 5 },
> + .result_unpriv = ACCEPT,
> + .result = ACCEPT,
> + .retval = 42,
> + },
> + {
> "search pruning: all branches should be verified (nop operation)",
> .insns = {
> BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
> @@ -12162,12 +12270,13 @@ static int probe_filter_length(const struct bpf_insn *fp)
> return len + 1;
> }
>
> -static int create_map(uint32_t size_value, uint32_t max_elem)
> +static int create_map(uint32_t type, uint32_t size_key,
> + uint32_t size_value, uint32_t max_elem)
> {
> int fd;
>
> - fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(long long),
> - size_value, max_elem, BPF_F_NO_PREALLOC);
> + fd = bpf_create_map(type, size_key, size_value, max_elem,
> + type == BPF_MAP_TYPE_HASH ? BPF_F_NO_PREALLOC : 0);
> if (fd < 0)
> printf("Failed to create hash map '%s'!\n", strerror(errno));
>
> @@ -12200,13 +12309,13 @@ static int create_prog_dummy2(int mfd, int idx)
> ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
> }
>
> -static int create_prog_array(void)
> +static int create_prog_array(uint32_t max_elem, int p1key)
> {
> - int p1key = 0, p2key = 1;
> + int p2key = 1;
> int mfd, p1fd, p2fd;
>
> mfd = bpf_create_map(BPF_MAP_TYPE_PROG_ARRAY, sizeof(int),
> - sizeof(int), 4, 0);
> + sizeof(int), max_elem, 0);
> if (mfd < 0) {
> printf("Failed to create prog array '%s'!\n", strerror(errno));
> return -1;
> @@ -12261,7 +12370,9 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
> int *fixup_map1 = test->fixup_map1;
> int *fixup_map2 = test->fixup_map2;
> int *fixup_map3 = test->fixup_map3;
> - int *fixup_prog = test->fixup_prog;
> + int *fixup_map4 = test->fixup_map4;
> + int *fixup_prog1 = test->fixup_prog1;
> + int *fixup_prog2 = test->fixup_prog2;
> int *fixup_map_in_map = test->fixup_map_in_map;
>
> if (test->fill_helper)
> @@ -12272,7 +12383,8 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
> * that really matters is value size in this case.
> */
> if (*fixup_map1) {
> - map_fds[0] = create_map(sizeof(long long), 1);
> + map_fds[0] = create_map(BPF_MAP_TYPE_HASH, sizeof(long long),
> + sizeof(long long), 1);
> do {
> prog[*fixup_map1].imm = map_fds[0];
> fixup_map1++;
> @@ -12280,7 +12392,8 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
> }
>
> if (*fixup_map2) {
> - map_fds[1] = create_map(sizeof(struct test_val), 1);
> + map_fds[1] = create_map(BPF_MAP_TYPE_HASH, sizeof(long long),
> + sizeof(struct test_val), 1);
> do {
> prog[*fixup_map2].imm = map_fds[1];
> fixup_map2++;
> @@ -12288,25 +12401,43 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
> }
>
> if (*fixup_map3) {
> - map_fds[1] = create_map(sizeof(struct other_val), 1);
> + map_fds[2] = create_map(BPF_MAP_TYPE_HASH, sizeof(long long),
> + sizeof(struct other_val), 1);
> do {
> - prog[*fixup_map3].imm = map_fds[1];
> + prog[*fixup_map3].imm = map_fds[2];
> fixup_map3++;
> } while (*fixup_map3);
> }
>
> - if (*fixup_prog) {
> - map_fds[2] = create_prog_array();
> + if (*fixup_map4) {
> + map_fds[3] = create_map(BPF_MAP_TYPE_ARRAY, sizeof(int),
> + sizeof(struct test_val), 1);
> + do {
> + prog[*fixup_map4].imm = map_fds[3];
> + fixup_map4++;
> + } while (*fixup_map4);
> + }
> +
> + if (*fixup_prog1) {
> + map_fds[4] = create_prog_array(4, 0);
> + do {
> + prog[*fixup_prog1].imm = map_fds[4];
> + fixup_prog1++;
> + } while (*fixup_prog1);
> + }
> +
> + if (*fixup_prog2) {
> + map_fds[5] = create_prog_array(8, 7);
> do {
> - prog[*fixup_prog].imm = map_fds[2];
> - fixup_prog++;
> - } while (*fixup_prog);
> + prog[*fixup_prog2].imm = map_fds[5];
> + fixup_prog2++;
> + } while (*fixup_prog2);
> }
>
> if (*fixup_map_in_map) {
> - map_fds[3] = create_map_in_map();
> + map_fds[6] = create_map_in_map();
> do {
> - prog[*fixup_map_in_map].imm = map_fds[3];
> + prog[*fixup_map_in_map].imm = map_fds[6];
> fixup_map_in_map++;
> } while (*fixup_map_in_map);
> }
> --
> 2.9.5
>
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