On Tue, Jan 12, 2021 at 4:56 PM KP Singh <kpsingh@xxxxxxxxxx> wrote: > > On Tue, Jan 12, 2021 at 10:16 AM Gilad Reti <gilad.reti@xxxxxxxxx> wrote: > > > > Add test to check that the verifier is able to recognize spilling of > > PTR_TO_MEM registers. > > > > It would be nice to have some explanation of what the test does to > recognize the spilling of the PTR_TO_MEM registers in the commit > log as well. > > Would it be possible to augment an existing test_progs > program like tools/testing/selftests/bpf/progs/test_ringbuf.c to test > this functionality? > It may be possible, but from what I understood from Daniel's comment here https://lore.kernel.org/bpf/17629073-4fab-a922-ecc3-25b019960f44@xxxxxxxxxxxxx/ the test should be a part of the verifier tests (which is reasonable to me since it is a verifier bugfix) > > > > The patch was partially contibuted by CyberArk Software, Inc. > > > > Signed-off-by: Gilad Reti <gilad.reti@xxxxxxxxx> > > --- > > tools/testing/selftests/bpf/test_verifier.c | 12 +++++++- > > .../selftests/bpf/verifier/spill_fill.c | 30 +++++++++++++++++++ > > 2 files changed, 41 insertions(+), 1 deletion(-) > > > > diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c > > index 777a81404fdb..f8569f04064b 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_TEST_INSNS 1000000 > > #define MAX_FIXUPS 8 > > -#define MAX_NR_MAPS 20 > > +#define MAX_NR_MAPS 21 > > #define MAX_TEST_RUNS 8 > > #define POINTER_VALUE 0xcafe4all > > #define TEST_DATA_LEN 64 > > @@ -87,6 +87,7 @@ struct bpf_test { > > int fixup_sk_storage_map[MAX_FIXUPS]; > > int fixup_map_event_output[MAX_FIXUPS]; > > int fixup_map_reuseport_array[MAX_FIXUPS]; > > + int fixup_map_ringbuf[MAX_FIXUPS]; > > const char *errstr; > > const char *errstr_unpriv; > > uint32_t insn_processed; > > @@ -640,6 +641,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type, > > int *fixup_sk_storage_map = test->fixup_sk_storage_map; > > int *fixup_map_event_output = test->fixup_map_event_output; > > int *fixup_map_reuseport_array = test->fixup_map_reuseport_array; > > + int *fixup_map_ringbuf = test->fixup_map_ringbuf; > > > > if (test->fill_helper) { > > test->fill_insns = calloc(MAX_TEST_INSNS, sizeof(struct bpf_insn)); > > @@ -817,6 +819,14 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type, > > fixup_map_reuseport_array++; > > } while (*fixup_map_reuseport_array); > > } > > + if (*fixup_map_ringbuf) { > > + map_fds[20] = create_map(BPF_MAP_TYPE_RINGBUF, 0, > > + 0, 4096); > > + do { > > + prog[*fixup_map_ringbuf].imm = map_fds[20]; > > + fixup_map_ringbuf++; > > + } while (*fixup_map_ringbuf); > > + } > > } > > > > struct libcap { > > diff --git a/tools/testing/selftests/bpf/verifier/spill_fill.c b/tools/testing/selftests/bpf/verifier/spill_fill.c > > index 45d43bf82f26..1833b6c730dd 100644 > > --- a/tools/testing/selftests/bpf/verifier/spill_fill.c > > +++ b/tools/testing/selftests/bpf/verifier/spill_fill.c > > @@ -28,6 +28,36 @@ > > .result = ACCEPT, > > .result_unpriv = ACCEPT, > > }, > > +{ > > + "check valid spill/fill, ptr to mem", > > + .insns = { > > + /* reserve 8 byte ringbuf memory */ > > + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), > > + BPF_LD_MAP_FD(BPF_REG_1, 0), > > + BPF_MOV64_IMM(BPF_REG_2, 8), > > + BPF_MOV64_IMM(BPF_REG_3, 0), > > + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve), > > + /* store a pointer to the reserved memory in R6 */ > > + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), > > + /* check whether the reservation was successful */ > > + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6), > > + /* spill R6(mem) into the stack */ > > + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, -8), > > + /* fill it back in R7 */ > > + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, -8), > > + /* should be able to access *(R7) = 0 */ > > + BPF_ST_MEM(BPF_DW, BPF_REG_7, 0, 0), > > + /* submit the reserved rungbuf memory */ > > + BPF_MOV64_REG(BPF_REG_1, BPF_REG_7), > > + BPF_MOV64_IMM(BPF_REG_2, 0), > > + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_submit), > > + BPF_MOV64_IMM(BPF_REG_0, 0), > > + BPF_EXIT_INSN(), > > + }, > > + .fixup_map_ringbuf = { 1 }, > > + .result = ACCEPT, > > + .result_unpriv = ACCEPT, > > +}, > > { > > "check corrupted spill/fill", > > .insns = { > > -- > > 2.27.0 > >
