From 7c0c6095d48dcd0e67c917aa73cdbb2715aafc36 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Tue, 21 May 2019 20:14:20 -0700 Subject: [PATCH] selftests/bpf: adjust verifier scale test Adjust scale tests to check for new jmp sequence limit. BPF_JGT had to be changed to BPF_JEQ because the verifier was too smart. It tracked the known safe range of R0 values and pruned the search earlier before hitting exact 8192 limit. bpf_semi_rand_get() was too (un)?lucky. k = 0; was missing in bpf_fill_scale2. It was testing a bit shorter sequence of jumps than intended. Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_verifier.c | 31 +++++++++++---------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index ccd896b98cac..6e2fec84c929 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -210,33 +210,35 @@ static void bpf_fill_rand_ld_dw(struct bpf_test *self) self->retval = (uint32_t)res; } -/* test the sequence of 1k jumps */ +#define MAX_JMP_SEQ 8192 + +/* test the sequence of 8k jumps */ static void bpf_fill_scale1(struct bpf_test *self) { struct bpf_insn *insn = self->fill_insns; int i = 0, k = 0; insn[i++] = BPF_MOV64_REG(BPF_REG_6, BPF_REG_1); - /* test to check that the sequence of 1024 jumps is acceptable */ - while (k++ < 1024) { + /* test to check that the long sequence of jumps is acceptable */ + while (k++ < MAX_JMP_SEQ) { insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32); - insn[i++] = BPF_JMP_IMM(BPF_JGT, BPF_REG_0, bpf_semi_rand_get(), 2); + insn[i++] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, bpf_semi_rand_get(), 2); insn[i++] = BPF_MOV64_REG(BPF_REG_1, BPF_REG_10); insn[i++] = BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, -8 * (k % 64 + 1)); } - /* every jump adds 1024 steps to insn_processed, so to stay exactly - * within 1m limit add MAX_TEST_INSNS - 1025 MOVs and 1 EXIT + /* every jump adds 1 step to insn_processed, so to stay exactly + * within 1m limit add MAX_TEST_INSNS - MAX_JMP_SEQ - 1 MOVs and 1 EXIT */ - while (i < MAX_TEST_INSNS - 1025) + while (i < MAX_TEST_INSNS - MAX_JMP_SEQ - 1) insn[i++] = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, 42); insn[i] = BPF_EXIT_INSN(); self->prog_len = i + 1; self->retval = 42; } -/* test the sequence of 1k jumps in inner most function (function depth 8)*/ +/* test the sequence of 8k jumps in inner most function (function depth 8)*/ static void bpf_fill_scale2(struct bpf_test *self) { struct bpf_insn *insn = self->fill_insns; @@ -248,19 +250,20 @@ static void bpf_fill_scale2(struct bpf_test *self) insn[i++] = BPF_EXIT_INSN(); } insn[i++] = BPF_MOV64_REG(BPF_REG_6, BPF_REG_1); - /* test to check that the sequence of 1024 jumps is acceptable */ - while (k++ < 1024) { + /* test to check that the long sequence of jumps is acceptable */ + k = 0; + while (k++ < MAX_JMP_SEQ) { insn[i++] = BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32); - insn[i++] = BPF_JMP_IMM(BPF_JGT, BPF_REG_0, bpf_semi_rand_get(), 2); + insn[i++] = BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, bpf_semi_rand_get(), 2); insn[i++] = BPF_MOV64_REG(BPF_REG_1, BPF_REG_10); insn[i++] = BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, -8 * (k % (64 - 4 * FUNC_NEST) + 1)); } - /* every jump adds 1024 steps to insn_processed, so to stay exactly - * within 1m limit add MAX_TEST_INSNS - 1025 MOVs and 1 EXIT + /* every jump adds 1 step to insn_processed, so to stay exactly + * within 1m limit add MAX_TEST_INSNS - MAX_JMP_SEQ - 1 MOVs and 1 EXIT */ - while (i < MAX_TEST_INSNS - 1025) + while (i < MAX_TEST_INSNS - MAX_JMP_SEQ - 1) insn[i++] = BPF_ALU32_IMM(BPF_MOV, BPF_REG_0, 42); insn[i] = BPF_EXIT_INSN(); self->prog_len = i + 1; -- 2.30.2