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Message-ID: <78b2d756-d69c-866a-e52f-fe0c94051c9f@lab.ntt.co.jp>
Date: Fri, 5 Oct 2018 11:07:27 +0900
From: Prashant Bhole <bhole_prashant_q7@....ntt.co.jp>
To: Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Jakub Kicinski <jakub.kicinski@...ronome.com>,
"David S . Miller" <davem@...emloft.net>,
Quentin Monnet <quentin.monnet@...ronome.com>,
netdev@...r.kernel.org
Subject: Re: [RFC v2 bpf-next 5/5] selftests/bpf: verifier, check
bpf_map_lookup_elem access in bpf prog
On 10/5/2018 10:51 AM, Alexei Starovoitov wrote:
> On Tue, Oct 02, 2018 at 02:35:19PM +0900, Prashant Bhole wrote:
>> map_lookup_elem isn't supported by certain map types like:
>> - BPF_MAP_TYPE_PROG_ARRAY
>> - BPF_MAP_TYPE_STACK_TRACE
>> - BPF_MAP_TYPE_XSKMAP
>> - BPF_MAP_TYPE_SOCKMAP/BPF_MAP_TYPE_SOCKHASH
>> Let's add verfier tests to check whether verifier prevents
>> bpf_map_lookup_elem call on above programs from bpf program.
>>
>> Signed-off-by: Prashant Bhole <bhole_prashant_q7@....ntt.co.jp>
>> ---
>> tools/testing/selftests/bpf/test_verifier.c | 121 +++++++++++++++++++-
>> 1 file changed, 120 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
>> index c7d25f23baf9..afa7e67f66e4 100644
>> --- a/tools/testing/selftests/bpf/test_verifier.c
>> +++ b/tools/testing/selftests/bpf/test_verifier.c
>> @@ -47,7 +47,7 @@
>>
>> #define MAX_INSNS BPF_MAXINSNS
>> #define MAX_FIXUPS 8
>> -#define MAX_NR_MAPS 8
>> +#define MAX_NR_MAPS 13
>> #define POINTER_VALUE 0xcafe4all
>> #define TEST_DATA_LEN 64
>>
>> @@ -64,6 +64,10 @@ struct bpf_test {
>> int fixup_map2[MAX_FIXUPS];
>> int fixup_map3[MAX_FIXUPS];
>> int fixup_map4[MAX_FIXUPS];
>> + int fixup_map5[MAX_FIXUPS];
>> + int fixup_map6[MAX_FIXUPS];
>> + int fixup_map7[MAX_FIXUPS];
>> + int fixup_map8[MAX_FIXUPS];
>> int fixup_prog1[MAX_FIXUPS];
>> int fixup_prog2[MAX_FIXUPS];
>> int fixup_map_in_map[MAX_FIXUPS];
>> @@ -4391,6 +4395,85 @@ static struct bpf_test tests[] = {
>> .errstr = "invalid access to packet",
>> .prog_type = BPF_PROG_TYPE_SCHED_CLS,
>> },
>> + {
>> + "prevent map lookup in sockmap",
>> + .insns = {
>> + 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_LD_MAP_FD(BPF_REG_1, 0),
>> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
>> + BPF_FUNC_map_lookup_elem),
>> + BPF_EXIT_INSN(),
>> + },
>> + .fixup_map5 = { 3 },
>> + .result = REJECT,
>> + .errstr = "cannot pass map_type 15 into func bpf_map_lookup_elem",
>> + .prog_type = BPF_PROG_TYPE_SOCK_OPS,
>> + },
>> + {
>> + "prevent map lookup in sockhash",
>> + .insns = {
>> + 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_LD_MAP_FD(BPF_REG_1, 0),
>> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
>> + BPF_FUNC_map_lookup_elem),
>> + BPF_EXIT_INSN(),
>> + },
>> + .fixup_map6 = { 3 },
>> + .result = REJECT,
>> + .errstr = "cannot pass map_type 18 into func bpf_map_lookup_elem",
>> + .prog_type = BPF_PROG_TYPE_SOCK_OPS,
>> + },
>> + {
>> + "prevent map lookup in xskmap",
>> + .insns = {
>> + 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_LD_MAP_FD(BPF_REG_1, 0),
>> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
>> + BPF_FUNC_map_lookup_elem),
>> + BPF_EXIT_INSN(),
>> + },
>> + .fixup_map7 = { 3 },
>> + .result = REJECT,
>> + .errstr = "cannot pass map_type 17 into func bpf_map_lookup_elem",
>> + .prog_type = BPF_PROG_TYPE_XDP,
>> + },
>> + {
>> + "prevent map lookup in stack trace",
>> + .insns = {
>> + 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_LD_MAP_FD(BPF_REG_1, 0),
>> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
>> + BPF_FUNC_map_lookup_elem),
>> + BPF_EXIT_INSN(),
>> + },
>> + .fixup_map8 = { 3 },
>> + .result = REJECT,
>> + .errstr = "cannot pass map_type 7 into func bpf_map_lookup_elem",
>> + .prog_type = BPF_PROG_TYPE_PERF_EVENT,
>> + },
>> + {
>> + "prevent map lookup in prog array",
>> + .insns = {
>> + 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_LD_MAP_FD(BPF_REG_1, 0),
>> + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
>> + BPF_FUNC_map_lookup_elem),
>> + BPF_EXIT_INSN(),
>> + },
>> + .fixup_prog2 = { 3 },
>> + .result = REJECT,
>> + .errstr = "cannot pass map_type 3 into func bpf_map_lookup_elem",
>
> excellent tests. exactly what I was hoping to see.
>
>> + },
>> {
>> "valid map access into an array with a constant",
>> .insns = {
>> @@ -12755,6 +12838,10 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
>> int *fixup_map2 = test->fixup_map2;
>> int *fixup_map3 = test->fixup_map3;
>> int *fixup_map4 = test->fixup_map4;
>> + int *fixup_map5 = test->fixup_map5;
>> + int *fixup_map6 = test->fixup_map6;
>> + int *fixup_map7 = test->fixup_map7;
>> + int *fixup_map8 = test->fixup_map8;
>> int *fixup_prog1 = test->fixup_prog1;
>> int *fixup_prog2 = test->fixup_prog2;
>> int *fixup_map_in_map = test->fixup_map_in_map;
>> @@ -12843,6 +12930,38 @@ static void do_test_fixup(struct bpf_test *test, struct bpf_insn *prog,
>> fixup_percpu_cgroup_storage++;
>> } while (*fixup_percpu_cgroup_storage);
>> }
>> + if (*fixup_map5) {
>> + map_fds[9] = create_map(BPF_MAP_TYPE_SOCKMAP, sizeof(int),
>> + sizeof(int), 1);
>> + do {
>> + prog[*fixup_map5].imm = map_fds[9];
>> + fixup_map5++;
>> + } while (*fixup_map5);
>> + }
>> + if (*fixup_map6) {
>> + map_fds[10] = create_map(BPF_MAP_TYPE_SOCKHASH, sizeof(int),
>> + sizeof(int), 1);
>> + do {
>> + prog[*fixup_map6].imm = map_fds[10];
>> + fixup_map6++;
>> + } while (*fixup_map6);
>> + }
>> + if (*fixup_map7) {
>> + map_fds[11] = create_map(BPF_MAP_TYPE_XSKMAP, sizeof(int),
>> + sizeof(int), 1);
>> + do {
>> + prog[*fixup_map7].imm = map_fds[11];
>> + fixup_map7++;
>> + } while (*fixup_map7);
>> + }
>> + if (*fixup_map8) {
>> + map_fds[12] = create_map(BPF_MAP_TYPE_STACK_TRACE, sizeof(u32),
>> + sizeof(u64), 1);
>> + do {
>> + prog[*fixup_map8].imm = map_fds[12];
>> + fixup_map8++;
>> + } while (fixup_map8);
>
> I understand that you're following the existing naming convention
> with fixup_mapN, but it was ugly before and these 4 additions
> make it completely unreadable.
>
> Could you please refactor the old names:
> fixup_map1 -> fixup_map_hash_8b
> fixup_map2 -> fixup_map_hash_48b (pls double check my math)
> fixup_map3 -> fixup_map_hash_16b
> fixup_map4 -> fixup_map_array_48b
>
> then your new diff will use
> fixup_map5 -> fixup_map_sockmap
> fixup_map6 -> fixup_map_sockhash
> ...
>
> and please drop rfc tag from the next respin.
> Thanks!
>
Thanks for reviewing. I will fix the naming convention in the next patch
series.
-Prashant
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