From: Maxim Mikityanskiy <maxim@xxxxxxxxxxxxx>
Extract the common code that generates a register ID for src_reg before
MOV if needed into a new function. This function will also be used in
a following commit.
Signed-off-by: Maxim Mikityanskiy <maxim@xxxxxxxxxxxxx>
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
---
kernel/bpf/verifier.c | 33 +++++++++++++++++++--------------
1 file changed, 19 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index bc565f445410..e3eff2becd64 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4403,6 +4403,18 @@ static bool __is_pointer_value(bool allow_ptr_leaks,
return reg->type != SCALAR_VALUE;
}
+static void assign_scalar_id_before_mov(struct bpf_verifier_env *env,
+ struct bpf_reg_state *src_reg)
+{
+ if (src_reg->type == SCALAR_VALUE && !src_reg->id &&
+ !tnum_is_const(src_reg->var_off))
+ /* Ensure that src_reg has a valid ID that will be copied to
+ * dst_reg and then will be used by find_equal_scalars() to
+ * propagate min/max range.
+ */
+ src_reg->id = ++env->id_gen;
+}
+
/* Copy src state preserving dst->parent and dst->live fields */
static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
{
@@ -13901,20 +13913,13 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (BPF_SRC(insn->code) == BPF_X) {
struct bpf_reg_state *src_reg = regs + insn->src_reg;
struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
- bool need_id = src_reg->type == SCALAR_VALUE && !src_reg->id &&
- !tnum_is_const(src_reg->var_off);
if (BPF_CLASS(insn->code) == BPF_ALU64) {
if (insn->off == 0) {
/* case: R1 = R2
* copy register state to dest reg
*/
- if (need_id)
- /* Assign src and dst registers the same ID
- * that will be used by find_equal_scalars()
- * to propagate min/max range.
- */
- src_reg->id = ++env->id_gen;
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
dst_reg->live |= REG_LIVE_WRITTEN;
dst_reg->subreg_def = DEF_NOT_SUBREG;
@@ -13929,8 +13934,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
bool no_sext;
no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
- if (no_sext && need_id)
- src_reg->id = ++env->id_gen;
+ if (no_sext)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
if (!no_sext)
dst_reg->id = 0;
@@ -13952,8 +13957,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
if (insn->off == 0) {
bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
- if (is_src_reg_u32 && need_id)
- src_reg->id = ++env->id_gen;
+ if (is_src_reg_u32)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
/* Make sure ID is cleared if src_reg is not in u32
* range otherwise dst_reg min/max could be incorrectly
@@ -13967,8 +13972,8 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
/* case: W1 = (s8, s16)W2 */
bool no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
- if (no_sext && need_id)
- src_reg->id = ++env->id_gen;
+ if (no_sext)
+ assign_scalar_id_before_mov(env, src_reg);
copy_register_state(dst_reg, src_reg);
if (!no_sext)
dst_reg->id = 0;
--
2.43.0
