Merge branch 'bpf-jset-verifier'

Jakub Kicinski says:

====================
This is a v2 of the patch set to teach the verifier about BPF_JSET
instruction.  There is also a number of tests include for both
basic functioning of the instruction and the verifier logic.
The NFP JIT handling of JSET is tweaked.  Last patch adds missing
file to gitignore.

Reposting part of previous series without the dead code elimination.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

drivers/net/ethernet/netronome/nfp/bpf/jit.c

@@ -3052,26 +3052,19 @@ static int jset_imm(struct nfp_prog *nfp_prog, struct nfp_insn_meta *meta)
 {
 	const struct bpf_insn *insn = &meta->insn;
 	u64 imm = insn->imm; /* sign extend */
+	u8 dst_gpr = insn->dst_reg * 2;
 	swreg tmp_reg;
 
-	if (!imm) {
-		meta->skip = true;
-		return 0;
-	}
-
-	if (imm & ~0U) {
-		tmp_reg = ur_load_imm_any(nfp_prog, imm & ~0U, imm_b(nfp_prog));
-		emit_alu(nfp_prog, reg_none(),
-			 reg_a(insn->dst_reg * 2), ALU_OP_AND, tmp_reg);
-		emit_br(nfp_prog, BR_BNE, insn->off, 0);
-	}
-
-	if (imm >> 32) {
-		tmp_reg = ur_load_imm_any(nfp_prog, imm >> 32, imm_b(nfp_prog));
+	tmp_reg = ur_load_imm_any(nfp_prog, imm & ~0U, imm_b(nfp_prog));
+	emit_alu(nfp_prog, imm_b(nfp_prog),
+		 reg_a(dst_gpr), ALU_OP_AND, tmp_reg);
+	/* Upper word of the mask can only be 0 or ~0 from sign extension,
+	 * so either ignore it or OR the whole thing in.
+	 */
+	if (imm >> 32)
 		emit_alu(nfp_prog, reg_none(),
-			 reg_a(insn->dst_reg * 2 + 1), ALU_OP_AND, tmp_reg);
-		emit_br(nfp_prog, BR_BNE, insn->off, 0);
-	}
+			 reg_a(dst_gpr + 1), ALU_OP_OR, imm_b(nfp_prog));
+	emit_br(nfp_prog, BR_BNE, insn->off, 0);
 
 	return 0;
 }

kernel/bpf/verifier.c

@@ -3859,6 +3859,12 @@ static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
 		if (tnum_is_const(reg->var_off))
 			return !tnum_equals_const(reg->var_off, val);
 		break;
+	case BPF_JSET:
+		if ((~reg->var_off.mask & reg->var_off.value) & val)
+			return 1;
+		if (!((reg->var_off.mask | reg->var_off.value) & val))
+			return 0;
+		break;
 	case BPF_JGT:
 		if (reg->umin_value > val)
 			return 1;
@@ -3943,6 +3949,13 @@ static void reg_set_min_max(struct bpf_reg_state *true_reg,
 		 */
 		__mark_reg_known(false_reg, val);
 		break;
+	case BPF_JSET:
+		false_reg->var_off = tnum_and(false_reg->var_off,
+					      tnum_const(~val));
+		if (is_power_of_2(val))
+			true_reg->var_off = tnum_or(true_reg->var_off,
+						    tnum_const(val));
+		break;
 	case BPF_JGT:
 		false_reg->umax_value = min(false_reg->umax_value, val);
 		true_reg->umin_value = max(true_reg->umin_value, val + 1);
@@ -4015,6 +4028,13 @@ static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
 		 */
 		__mark_reg_known(false_reg, val);
 		break;
+	case BPF_JSET:
+		false_reg->var_off = tnum_and(false_reg->var_off,
+					      tnum_const(~val));
+		if (is_power_of_2(val))
+			true_reg->var_off = tnum_or(true_reg->var_off,
+						    tnum_const(val));
+		break;
 	case BPF_JGT:
 		true_reg->umax_value = min(true_reg->umax_value, val - 1);
 		false_reg->umin_value = max(false_reg->umin_value, val);
@@ -6963,10 +6983,11 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr,
 	free_states(env);
 
 	if (ret == 0)
-		sanitize_dead_code(env);
+		ret = check_max_stack_depth(env);
 
+	/* instruction rewrites happen after this point */
 	if (ret == 0)
-		ret = check_max_stack_depth(env);
+		sanitize_dead_code(env);
 
 	if (ret == 0)
 		/* program is valid, convert *(u32*)(ctx + off) accesses */

tools/testing/selftests/bpf/.gitignore

@@ -27,3 +27,4 @@ test_flow_dissector
 flow_dissector_load
 test_netcnt
 test_section_names
+test_tcpnotify_user

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 +14170,197 @@ 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, },
+	},
+	{
+		"jset: known const compare",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.retval_unpriv = 1,
+		.result_unpriv = ACCEPT,
+		.retval = 1,
+		.result = ACCEPT,
+	},
+	{
+		"jset: known const compare bad",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.errstr_unpriv = "!read_ok",
+		.result_unpriv = REJECT,
+		.errstr = "!read_ok",
+		.result = REJECT,
+	},
+	{
+		"jset: unknown const compare taken",
+		.insns = {
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_get_prandom_u32),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.errstr_unpriv = "!read_ok",
+		.result_unpriv = REJECT,
+		.errstr = "!read_ok",
+		.result = REJECT,
+	},
+	{
+		"jset: unknown const compare not taken",
+		.insns = {
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_get_prandom_u32),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.errstr_unpriv = "!read_ok",
+		.result_unpriv = REJECT,
+		.errstr = "!read_ok",
+		.result = REJECT,
+	},
+	{
+		"jset: half-known const compare",
+		.insns = {
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_get_prandom_u32),
+			BPF_ALU64_IMM(BPF_OR, BPF_REG_0, 2),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 3, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.result_unpriv = ACCEPT,
+		.result = ACCEPT,
+	},
+	{
+		"jset: range",
+		.insns = {
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_get_prandom_u32),
+			BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_ALU64_IMM(BPF_AND, BPF_REG_1, 0xff),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_1, 0xf0, 3),
+			BPF_JMP_IMM(BPF_JLT, BPF_REG_1, 0x10, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_1, 0x10, 1),
+			BPF_EXIT_INSN(),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 0x10, 1),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_EXIT_INSN(),
+		},
+		.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+		.result_unpriv = ACCEPT,
+		.result = ACCEPT,
+	},
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)
@@ -14443,16 +14643,42 @@ static int set_admin(bool admin)
 	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 +14702,6 @@ 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 +14713,8 @@ 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 +14741,54 @@ 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++)