From 5a8d5209ac0228c9cf8f335dfdfffa71c54b3201 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 19 Dec 2018 22:13:03 -0800 Subject: [PATCH] selftests: bpf: add trivial JSET tests We seem to have no JSET instruction test, and LLVM does not generate it at all, so let's add a simple hand-coded test to make sure JIT implementations are correct. v2: - extend test_verifier to handle multiple inputs and add the sample there (Daniel) - add a sign extension case Signed-off-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_verifier.c | 209 +++++++++++++++++++++++----- 1 file changed, 178 insertions(+), 31 deletions(-) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 7865b94..580fc94 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -49,6 +49,7 @@ #define MAX_INSNS BPF_MAXINSNS #define MAX_FIXUPS 8 #define MAX_NR_MAPS 13 +#define MAX_TEST_RUNS 8 #define POINTER_VALUE 0xcafe4all #define TEST_DATA_LEN 64 @@ -86,6 +87,14 @@ struct bpf_test { uint8_t flags; __u8 data[TEST_DATA_LEN]; void (*fill_helper)(struct bpf_test *self); + uint8_t runs; + struct { + uint32_t retval, retval_unpriv; + union { + __u8 data[TEST_DATA_LEN]; + __u64 data64[TEST_DATA_LEN / 8]; + }; + } retvals[MAX_TEST_RUNS]; }; /* Note we want this to be 64 bit aligned so that the end of our array is @@ -14161,6 +14170,101 @@ static struct bpf_test tests[] = { .errstr_unpriv = "R1 leaks addr", .result = REJECT, }, + { + "jset: functional", + .insns = { + /* r0 = 0 */ + BPF_MOV64_IMM(BPF_REG_0, 0), + /* prep for direct packet access via r2 */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct __sk_buff, data)), + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, + offsetof(struct __sk_buff, data_end)), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8), + BPF_JMP_REG(BPF_JLE, BPF_REG_4, BPF_REG_3, 1), + BPF_EXIT_INSN(), + + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_2, 0), + + /* reg, bit 63 or bit 0 set, taken */ + BPF_LD_IMM64(BPF_REG_8, 0x8000000000000001), + BPF_JMP_REG(BPF_JSET, BPF_REG_7, BPF_REG_8, 1), + BPF_EXIT_INSN(), + + /* reg, bit 62, not taken */ + BPF_LD_IMM64(BPF_REG_8, 0x4000000000000000), + BPF_JMP_REG(BPF_JSET, BPF_REG_7, BPF_REG_8, 1), + BPF_JMP_IMM(BPF_JA, 0, 0, 1), + BPF_EXIT_INSN(), + + /* imm, any bit set, taken */ + BPF_JMP_IMM(BPF_JSET, BPF_REG_7, -1, 1), + BPF_EXIT_INSN(), + + /* imm, bit 31 set, taken */ + BPF_JMP_IMM(BPF_JSET, BPF_REG_7, 0x80000000, 1), + BPF_EXIT_INSN(), + + /* all good - return r0 == 2 */ + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + .runs = 7, + .retvals = { + { .retval = 2, + .data64 = { (1ULL << 63) | (1U << 31) | (1U << 0), } + }, + { .retval = 2, + .data64 = { (1ULL << 63) | (1U << 31), } + }, + { .retval = 2, + .data64 = { (1ULL << 31) | (1U << 0), } + }, + { .retval = 2, + .data64 = { (__u32)-1, } + }, + { .retval = 2, + .data64 = { ~0x4000000000000000ULL, } + }, + { .retval = 0, + .data64 = { 0, } + }, + { .retval = 0, + .data64 = { ~0ULL, } + }, + }, + }, + { + "jset: sign-extend", + .insns = { + /* r0 = 0 */ + BPF_MOV64_IMM(BPF_REG_0, 0), + /* prep for direct packet access via r2 */ + BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, + offsetof(struct __sk_buff, data)), + BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1, + offsetof(struct __sk_buff, data_end)), + BPF_MOV64_REG(BPF_REG_4, BPF_REG_2), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_4, 8), + BPF_JMP_REG(BPF_JLE, BPF_REG_4, BPF_REG_3, 1), + BPF_EXIT_INSN(), + + BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_2, 0), + + BPF_JMP_IMM(BPF_JSET, BPF_REG_7, 0x80000000, 1), + BPF_EXIT_INSN(), + + BPF_MOV64_IMM(BPF_REG_0, 2), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, + .retval = 2, + .data = { 1, 0, 0, 0, 0, 0, 0, 1, }, + }, }; static int probe_filter_length(const struct bpf_insn *fp) @@ -14443,16 +14547,42 @@ out: return ret; } +static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val, + void *data, size_t size_data) +{ + __u8 tmp[TEST_DATA_LEN << 2]; + __u32 size_tmp = sizeof(tmp); + uint32_t retval; + int err; + + if (unpriv) + set_admin(true); + err = bpf_prog_test_run(fd_prog, 1, data, size_data, + tmp, &size_tmp, &retval, NULL); + if (unpriv) + set_admin(false); + if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) { + printf("Unexpected bpf_prog_test_run error "); + return err; + } + if (!err && retval != expected_val && + expected_val != POINTER_VALUE) { + printf("FAIL retval %d != %d ", retval, expected_val); + return 1; + } + + return 0; +} + static void do_test_single(struct bpf_test *test, bool unpriv, int *passes, int *errors) { int fd_prog, expected_ret, alignment_prevented_execution; int prog_len, prog_type = test->prog_type; struct bpf_insn *prog = test->insns; + int run_errs, run_successes; int map_fds[MAX_NR_MAPS]; const char *expected_err; - uint32_t expected_val; - uint32_t retval; __u32 pflags; int i, err; @@ -14476,8 +14606,6 @@ static void do_test_single(struct bpf_test *test, bool unpriv, test->result_unpriv : test->result; expected_err = unpriv && test->errstr_unpriv ? test->errstr_unpriv : test->errstr; - expected_val = unpriv && test->retval_unpriv ? - test->retval_unpriv : test->retval; alignment_prevented_execution = 0; @@ -14489,10 +14617,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv, } #ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS if (fd_prog >= 0 && - (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)) { + (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)) alignment_prevented_execution = 1; - goto test_ok; - } #endif } else { if (fd_prog >= 0) { @@ -14519,33 +14645,54 @@ static void do_test_single(struct bpf_test *test, bool unpriv, } } - if (fd_prog >= 0) { - __u8 tmp[TEST_DATA_LEN << 2]; - __u32 size_tmp = sizeof(tmp); - - if (unpriv) - set_admin(true); - err = bpf_prog_test_run(fd_prog, 1, test->data, - sizeof(test->data), tmp, &size_tmp, - &retval, NULL); - if (unpriv) - set_admin(false); - if (err && errno != 524/*ENOTSUPP*/ && errno != EPERM) { - printf("Unexpected bpf_prog_test_run error\n"); - goto fail_log; + run_errs = 0; + run_successes = 0; + if (!alignment_prevented_execution && fd_prog >= 0) { + uint32_t expected_val; + int i; + + if (!test->runs) { + expected_val = unpriv && test->retval_unpriv ? + test->retval_unpriv : test->retval; + + err = do_prog_test_run(fd_prog, unpriv, expected_val, + test->data, sizeof(test->data)); + if (err) + run_errs++; + else + run_successes++; } - if (!err && retval != expected_val && - expected_val != POINTER_VALUE) { - printf("FAIL retval %d != %d\n", retval, expected_val); - goto fail_log; + + for (i = 0; i < test->runs; i++) { + if (unpriv && test->retvals[i].retval_unpriv) + expected_val = test->retvals[i].retval_unpriv; + else + expected_val = test->retvals[i].retval; + + err = do_prog_test_run(fd_prog, unpriv, expected_val, + test->retvals[i].data, + sizeof(test->retvals[i].data)); + if (err) { + printf("(run %d/%d) ", i + 1, test->runs); + run_errs++; + } else { + run_successes++; + } } } -#ifndef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS -test_ok: -#endif - (*passes)++; - printf("OK%s\n", alignment_prevented_execution ? - " (NOTE: not executed due to unknown alignment)" : ""); + + if (!run_errs) { + (*passes)++; + if (run_successes > 1) + printf("%d cases ", run_successes); + printf("OK"); + if (alignment_prevented_execution) + printf(" (NOTE: not executed due to unknown alignment)"); + printf("\n"); + } else { + printf("\n"); + goto fail_log; + } close_fds: close(fd_prog); for (i = 0; i < MAX_NR_MAPS; i++) -- 2.7.4