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From: Eduard Zingerman <eddyz87@gmail.com>
To: bpf@vger.kernel.org, ast@kernel.org
Cc: andrii@kernel.org, daniel@iogearbox.net, kernel-team@fb.com,
	yhs@fb.com, Eduard Zingerman <eddyz87@gmail.com>
Subject: [RFC bpf-next 1/5] bpf: more precise stack write reasoning for BPF_ST instruction
Date: Sat, 31 Dec 2022 18:31:18 +0200	[thread overview]
Message-ID: <20221231163122.1360813-2-eddyz87@gmail.com> (raw)
In-Reply-To: <20221231163122.1360813-1-eddyz87@gmail.com>

For aligned stack writes using BPF_ST instruction track stored values
in a same way BPF_STX is handled, e.g. make sure that the following
commands produce similar verifier knowledge:

  fp[-8] = 42;             r1 = 42;
                       fp[-8] = r1;

This covers two cases:
 - non-null values written to stack are stored as spill of fake
   registers;
 - null values written to stack are stored as STACK_ZERO marks.

Previously both cases above used STACK_MISC marks instead.

Some verifier test cases relied on the old logic to obtain STACK_MISC
marks for some stack values. These test cases are updated in the same
commit to avoid failures during bisect.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/verifier.c                         |  23 +++-
 .../bpf/verifier/bounds_mix_sign_unsign.c     | 110 ++++++++++--------
 2 files changed, 84 insertions(+), 49 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 4a25375ebb0d..585edea642e1 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3257,6 +3257,11 @@ static void save_register_state(struct bpf_func_state *state,
 		scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
 }
 
+static bool is_bpf_st_mem(struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
+}
+
 /* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
  * stack boundary and alignment are checked in check_mem_access()
  */
@@ -3268,8 +3273,9 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
 {
 	struct bpf_func_state *cur; /* state of the current function */
 	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
-	u32 dst_reg = env->prog->insnsi[insn_idx].dst_reg;
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
 	struct bpf_reg_state *reg = NULL;
+	u32 dst_reg = insn->dst_reg;
 
 	err = grow_stack_state(state, round_up(slot + 1, BPF_REG_SIZE));
 	if (err)
@@ -3316,6 +3322,14 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
 				return err;
 		}
 		save_register_state(state, spi, reg, size);
+	} else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
+		   insn->imm != 0 && env->bpf_capable) {
+		struct bpf_reg_state fake_reg = {};
+
+		__mark_reg_known(&fake_reg, (u32)insn->imm);
+		fake_reg.type = SCALAR_VALUE;
+		fake_reg.parent = state->stack[spi].spilled_ptr.parent;
+		save_register_state(state, spi, &fake_reg, size);
 	} else if (reg && is_spillable_regtype(reg->type)) {
 		/* register containing pointer is being spilled into stack */
 		if (size != BPF_REG_SIZE) {
@@ -3350,7 +3364,8 @@ static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
 			state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
 
 		/* when we zero initialize stack slots mark them as such */
-		if (reg && register_is_null(reg)) {
+		if ((reg && register_is_null(reg)) ||
+		    (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
 			/* backtracking doesn't work for STACK_ZERO yet. */
 			err = mark_chain_precision(env, value_regno);
 			if (err)
@@ -3395,6 +3410,7 @@ static int check_stack_write_var_off(struct bpf_verifier_env *env,
 	int min_off, max_off;
 	int i, err;
 	struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
 	bool writing_zero = false;
 	/* set if the fact that we're writing a zero is used to let any
 	 * stack slots remain STACK_ZERO
@@ -3407,7 +3423,8 @@ static int check_stack_write_var_off(struct bpf_verifier_env *env,
 	max_off = ptr_reg->smax_value + off + size;
 	if (value_regno >= 0)
 		value_reg = &cur->regs[value_regno];
-	if (value_reg && register_is_null(value_reg))
+	if ((value_reg && register_is_null(value_reg)) ||
+	    (!value_reg && is_bpf_st_mem(insn) && insn->imm == 0))
 		writing_zero = true;
 
 	err = grow_stack_state(state, round_up(-min_off, BPF_REG_SIZE));
diff --git a/tools/testing/selftests/bpf/verifier/bounds_mix_sign_unsign.c b/tools/testing/selftests/bpf/verifier/bounds_mix_sign_unsign.c
index c2aa6f26738b..bf82b923c5fe 100644
--- a/tools/testing/selftests/bpf/verifier/bounds_mix_sign_unsign.c
+++ b/tools/testing/selftests/bpf/verifier/bounds_mix_sign_unsign.c
@@ -1,13 +1,14 @@
 {
 	"bounds checks mixing signed and unsigned, positive bounds",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, 2),
 	BPF_JMP_REG(BPF_JGE, BPF_REG_2, BPF_REG_1, 3),
@@ -17,20 +18,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, 3),
@@ -40,20 +42,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 2",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, 5),
@@ -65,20 +68,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 3",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, 4),
@@ -89,20 +93,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 4",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, 1),
 	BPF_ALU64_REG(BPF_AND, BPF_REG_1, BPF_REG_2),
@@ -112,19 +117,20 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.result = ACCEPT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 5",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, 5),
@@ -135,17 +141,20 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 6",
 	.insns = {
+	BPF_MOV64_REG(BPF_REG_9, BPF_REG_1),
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_9),
 	BPF_MOV64_IMM(BPF_REG_2, 0),
 	BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_3, -512),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_6, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_6, 5),
@@ -163,13 +172,14 @@
 {
 	"bounds checks mixing signed and unsigned, variant 7",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, 1024 * 1024 * 1024),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, 3),
@@ -179,19 +189,20 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.result = ACCEPT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 8",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 2),
@@ -203,20 +214,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 9",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_LD_IMM64(BPF_REG_2, -9223372036854775808ULL),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 2),
@@ -228,19 +240,20 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.result = ACCEPT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 10",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, 0),
 	BPF_JMP_REG(BPF_JGT, BPF_REG_2, BPF_REG_1, 2),
@@ -252,20 +265,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 11",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_JMP_REG(BPF_JGE, BPF_REG_2, BPF_REG_1, 2),
@@ -278,20 +292,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 12",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 9),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -6),
 	BPF_JMP_REG(BPF_JGE, BPF_REG_2, BPF_REG_1, 2),
@@ -303,20 +318,21 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 13",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 6),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 5),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, 2),
 	BPF_JMP_REG(BPF_JGE, BPF_REG_2, BPF_REG_1, 2),
@@ -331,7 +347,7 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
@@ -340,13 +356,14 @@
 	.insns = {
 	BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_1,
 		    offsetof(struct __sk_buff, mark)),
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 7),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -1),
 	BPF_MOV64_IMM(BPF_REG_8, 2),
@@ -360,20 +377,21 @@
 	BPF_JMP_REG(BPF_JGT, BPF_REG_1, BPF_REG_2, -3),
 	BPF_JMP_IMM(BPF_JA, 0, 0, -7),
 	},
-	.fixup_map_hash_8b = { 4 },
+	.fixup_map_hash_8b = { 6 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
 {
 	"bounds checks mixing signed and unsigned, variant 15",
 	.insns = {
+	BPF_EMIT_CALL(BPF_FUNC_ktime_get_ns),
+	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
 	BPF_LD_MAP_FD(BPF_REG_1, 0),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
-	BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, -8),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_10, -16),
 	BPF_MOV64_IMM(BPF_REG_2, -6),
 	BPF_JMP_REG(BPF_JGE, BPF_REG_2, BPF_REG_1, 2),
@@ -387,7 +405,7 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_8b = { 3 },
+	.fixup_map_hash_8b = { 5 },
 	.errstr = "unbounded min value",
 	.result = REJECT,
 },
-- 
2.39.0


  reply	other threads:[~2022-12-31 16:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-31 16:31 [RFC bpf-next 0/5] Support for BPF_ST instruction in LLVM C compiler Eduard Zingerman
2022-12-31 16:31 ` Eduard Zingerman [this message]
2022-12-31 16:31 ` [RFC bpf-next 2/5] selftests/bpf: check if verifier tracks constants spilled by BPF_ST_MEM Eduard Zingerman
2022-12-31 16:31 ` [RFC bpf-next 3/5] bpf: allow ctx writes using BPF_ST_MEM instruction Eduard Zingerman
2022-12-31 16:31 ` [RFC bpf-next 4/5] selftests/bpf: test if pointer type is tracked for BPF_ST_MEM Eduard Zingerman
2022-12-31 16:31 ` [RFC bpf-next 5/5] selftests/bpf: don't match exact insn index in expected error message Eduard Zingerman
2023-01-04 22:10 ` [RFC bpf-next 0/5] Support for BPF_ST instruction in LLVM C compiler Andrii Nakryiko
2023-01-05 10:06   ` Jose E. Marchesi
2023-01-05 12:07     ` Eduard Zingerman
2023-01-05 15:07       ` Jose E. Marchesi
2023-01-12 22:27       ` Alexei Starovoitov
2023-01-13  8:02         ` Yonghong Song
2023-01-13  8:53           ` Jose E. Marchesi
2023-01-13 16:47             ` Eduard Zingerman
2023-01-26  5:49               ` Alexei Starovoitov
2023-01-13 19:23             ` Yonghong Song

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