Merge branch 'bpf-precision-tracking-tests'

Alexei Starovoitov says:

====================
Add few additional tests for precision tracking in the verifier.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

include/linux/bpf_verifier.h

@@ -355,6 +355,7 @@ struct bpf_verifier_env {
 	struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
 	int stack_size;			/* number of states to be processed */
 	bool strict_alignment;		/* perform strict pointer alignment checks */
+	bool test_state_freq;		/* test verifier with different pruning frequency */
 	struct bpf_verifier_state *cur_state; /* current verifier state */
 	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
 	struct bpf_verifier_state_list *free_list;

include/uapi/linux/bpf.h

@@ -285,6 +285,9 @@ enum bpf_attach_type {
  */
 #define BPF_F_TEST_RND_HI32	(1U << 2)
 
+/* The verifier internal test flag. Behavior is undefined */
+#define BPF_F_TEST_STATE_FREQ	(1U << 3)
+
 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
  * two extensions:
  *

kernel/bpf/syscall.c

@@ -1629,6 +1629,7 @@ static int bpf_prog_load(union bpf_attr *attr, union bpf_attr __user *uattr)
 
 	if (attr->prog_flags & ~(BPF_F_STRICT_ALIGNMENT |
 				 BPF_F_ANY_ALIGNMENT |
+				 BPF_F_TEST_STATE_FREQ |
 				 BPF_F_TEST_RND_HI32))
 		return -EINVAL;
 

kernel/bpf/verifier.c

@@ -7222,7 +7222,7 @@ static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
 	struct bpf_verifier_state_list *sl, **pprev;
 	struct bpf_verifier_state *cur = env->cur_state, *new;
 	int i, j, err, states_cnt = 0;
-	bool add_new_state = false;
+	bool add_new_state = env->test_state_freq ? true : false;
 
 	cur->last_insn_idx = env->prev_insn_idx;
 	if (!env->insn_aux_data[insn_idx].prune_point)
@@ -9262,6 +9262,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 
 	env->allow_ptr_leaks = is_priv;
 
+	if (is_priv)
+		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+
 	ret = replace_map_fd_with_map_ptr(env);
 	if (ret < 0)
 		goto skip_full_check;

tools/include/uapi/linux/bpf.h

@@ -285,6 +285,9 @@ enum bpf_attach_type {
  */
 #define BPF_F_TEST_RND_HI32	(1U << 2)
 
+/* The verifier internal test flag. Behavior is undefined */
+#define BPF_F_TEST_STATE_FREQ	(1U << 3)
+
 /* When BPF ldimm64's insn[0].src_reg != 0 then this can have
  * two extensions:
  *

tools/testing/selftests/bpf/test_verifier.c

@@ -61,6 +61,7 @@
 #define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
 static bool unpriv_disabled = false;
 static int skips;
+static bool verbose = false;
 
 struct bpf_test {
 	const char *descr;
@@ -92,7 +93,8 @@ struct bpf_test {
 	enum {
 		UNDEF,
 		ACCEPT,
-		REJECT
+		REJECT,
+		VERBOSE_ACCEPT,
 	} result, result_unpriv;
 	enum bpf_prog_type prog_type;
 	uint8_t flags;
@@ -859,6 +861,36 @@ static int do_prog_test_run(int fd_prog, bool unpriv, uint32_t expected_val,
 	return 0;
 }
 
+static bool cmp_str_seq(const char *log, const char *exp)
+{
+	char needle[80];
+	const char *p, *q;
+	int len;
+
+	do {
+		p = strchr(exp, '\t');
+		if (!p)
+			p = exp + strlen(exp);
+
+		len = p - exp;
+		if (len >= sizeof(needle) || !len) {
+			printf("FAIL\nTestcase bug\n");
+			return false;
+		}
+		strncpy(needle, exp, len);
+		needle[len] = 0;
+		q = strstr(log, needle);
+		if (!q) {
+			printf("FAIL\nUnexpected verifier log in successful load!\n"
+			       "EXP: %s\nRES:\n", needle);
+			return false;
+		}
+		log = q + len;
+		exp = p + 1;
+	} while (*p);
+	return true;
+}
+
 static void do_test_single(struct bpf_test *test, bool unpriv,
 			   int *passes, int *errors)
 {
@@ -897,14 +929,20 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		pflags |= BPF_F_STRICT_ALIGNMENT;
 	if (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS)
 		pflags |= BPF_F_ANY_ALIGNMENT;
+	if (test->flags & ~3)
+		pflags |= test->flags;
 
+	expected_ret = unpriv && test->result_unpriv != UNDEF ?
+		       test->result_unpriv : test->result;
+	expected_err = unpriv && test->errstr_unpriv ?
+		       test->errstr_unpriv : test->errstr;
 	memset(&attr, 0, sizeof(attr));
 	attr.prog_type = prog_type;
 	attr.expected_attach_type = test->expected_attach_type;
 	attr.insns = prog;
 	attr.insns_cnt = prog_len;
 	attr.license = "GPL";
-	attr.log_level = 4;
+	attr.log_level = verbose || expected_ret == VERBOSE_ACCEPT ? 1 : 4;
 	attr.prog_flags = pflags;
 
 	fd_prog = bpf_load_program_xattr(&attr, bpf_vlog, sizeof(bpf_vlog));
@@ -914,14 +952,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		goto close_fds;
 	}
 
-	expected_ret = unpriv && test->result_unpriv != UNDEF ?
-		       test->result_unpriv : test->result;
-	expected_err = unpriv && test->errstr_unpriv ?
-		       test->errstr_unpriv : test->errstr;
-
 	alignment_prevented_execution = 0;
 
-	if (expected_ret == ACCEPT) {
+	if (expected_ret == ACCEPT || expected_ret == VERBOSE_ACCEPT) {
 		if (fd_prog < 0) {
 			printf("FAIL\nFailed to load prog '%s'!\n",
 			       strerror(errno));
@@ -932,6 +965,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		    (test->flags & F_NEEDS_EFFICIENT_UNALIGNED_ACCESS))
 			alignment_prevented_execution = 1;
 #endif
+		if (expected_ret == VERBOSE_ACCEPT && !cmp_str_seq(bpf_vlog, expected_err)) {
+			goto fail_log;
+		}
 	} else {
 		if (fd_prog >= 0) {
 			printf("FAIL\nUnexpected success to load!\n");
@@ -957,6 +993,9 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 		}
 	}
 
+	if (verbose)
+		printf(", verifier log:\n%s", bpf_vlog);
+
 	run_errs = 0;
 	run_successes = 0;
 	if (!alignment_prevented_execution && fd_prog >= 0) {
@@ -1097,17 +1136,24 @@ int main(int argc, char **argv)
 {
 	unsigned int from = 0, to = ARRAY_SIZE(tests);
 	bool unpriv = !is_admin();
+	int arg = 1;
+
+	if (argc > 1 && strcmp(argv[1], "-v") == 0) {
+		arg++;
+		verbose = true;
+		argc--;
+	}
 
 	if (argc == 3) {
-		unsigned int l = atoi(argv[argc - 2]);
-		unsigned int u = atoi(argv[argc - 1]);
+		unsigned int l = atoi(argv[arg]);
+		unsigned int u = atoi(argv[arg + 1]);
 
 		if (l < to && u < to) {
 			from = l;
 			to   = u + 1;
 		}
 	} else if (argc == 2) {
-		unsigned int t = atoi(argv[argc - 1]);
+		unsigned int t = atoi(argv[arg]);
 
 		if (t < to) {
 			from = t;

tools/testing/selftests/bpf/verifier/precise.c

+{
+	"precise: test 1",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_LD_MAP_FD(BPF_REG_6, 0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
+
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+
+	BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_EMIT_CALL(BPF_FUNC_probe_read),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.fixup_map_array_48b = { 1 },
+	.result = VERBOSE_ACCEPT,
+	.errstr =
+	"26: (85) call bpf_probe_read#4\
+	last_idx 26 first_idx 20\
+	regs=4 stack=0 before 25\
+	regs=4 stack=0 before 24\
+	regs=4 stack=0 before 23\
+	regs=4 stack=0 before 22\
+	regs=4 stack=0 before 20\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 19 first_idx 10\
+	regs=4 stack=0 before 19\
+	regs=200 stack=0 before 18\
+	regs=300 stack=0 before 17\
+	regs=201 stack=0 before 15\
+	regs=201 stack=0 before 14\
+	regs=200 stack=0 before 13\
+	regs=200 stack=0 before 12\
+	regs=200 stack=0 before 11\
+	regs=200 stack=0 before 10\
+	parent already had regs=0 stack=0 marks",
+},
+{
+	"precise: test 2",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 1),
+	BPF_LD_MAP_FD(BPF_REG_6, 0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_ST_MEM(BPF_DW, BPF_REG_FP, -8, 0),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_9, BPF_REG_0),
+
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_MOV64_REG(BPF_REG_8, BPF_REG_0),
+
+	BPF_ALU64_REG(BPF_SUB, BPF_REG_9, BPF_REG_8), /* map_value_ptr -= map_value_ptr */
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_2, 8, 1),
+	BPF_EXIT_INSN(),
+
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1), /* R2=inv(umin=1, umax=8) */
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_FP),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_EMIT_CALL(BPF_FUNC_probe_read),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.fixup_map_array_48b = { 1 },
+	.result = VERBOSE_ACCEPT,
+	.flags = BPF_F_TEST_STATE_FREQ,
+	.errstr =
+	"26: (85) call bpf_probe_read#4\
+	last_idx 26 first_idx 22\
+	regs=4 stack=0 before 25\
+	regs=4 stack=0 before 24\
+	regs=4 stack=0 before 23\
+	regs=4 stack=0 before 22\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 20 first_idx 20\
+	regs=4 stack=0 before 20\
+	parent didn't have regs=4 stack=0 marks\
+	last_idx 19 first_idx 17\
+	regs=4 stack=0 before 19\
+	regs=200 stack=0 before 18\
+	regs=300 stack=0 before 17\
+	parent already had regs=0 stack=0 marks",
+},
+{
+	"precise: cross frame pruning",
+	.insns = {
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	BPF_MOV64_IMM(BPF_REG_8, 0),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_MOV64_IMM(BPF_REG_8, 1),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	BPF_MOV64_IMM(BPF_REG_9, 0),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_MOV64_IMM(BPF_REG_9, 1),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
+	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.flags = BPF_F_TEST_STATE_FREQ,
+	.errstr = "!read_ok",
+	.result = REJECT,
+},