[PATCH bpf-next v3 1/6] bpf: Refactor reg_bounds_sanity_check

Paul Chaignon
2026-04-02T15:08:23Z

From: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>

This commit refactors reg_bounds_sanity_check to factor out the logic
that performs the sanity check from the logic that does the reporting.

Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
kernel/bpf/verifier.c | 64 +++++++++++++++++++++++++++----------------
1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8c1cf2eb6cbb..760cd137bf3f 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2804,39 +2804,55 @@ static void reg_bounds_sync(struct bpf_reg_state *reg)
__update_reg_bounds(reg);
}

+static bool range_bounds_violation(struct bpf_reg_state *reg)
+{
+ return (reg->umin_value > reg->umax_value || reg->smin_value > reg->smax_value ||
+ reg->u32_min_value > reg->u32_max_value ||
+ reg->s32_min_value > reg->s32_max_value);
+}
+
+static bool const_tnum_range_mismatch(struct bpf_reg_state *reg)
+{
+ u64 uval = reg->var_off.value;
+ s64 sval = (s64)uval;
+
+ if (!tnum_is_const(reg->var_off))
+ return false;
+
+ return reg->umin_value != uval || reg->umax_value != uval ||
+ reg->smin_value != sval || reg->smax_value != sval;
+}
+
+static bool const_tnum_range_mismatch_32(struct bpf_reg_state *reg)
+{
+ u32 uval32 = tnum_subreg(reg->var_off).value;
+ s32 sval32 = (s32)uval32;
+
+ if (!tnum_subreg_is_const(reg->var_off))
+ return false;
+
+ return reg->u32_min_value != uval32 || reg->u32_max_value != uval32 ||
+ reg->s32_min_value != sval32 || reg->s32_max_value != sval32;
+}
+
static int reg_bounds_sanity_check(struct bpf_verifier_env *env,
struct bpf_reg_state *reg, const char *ctx)
{
const char *msg;

- if (reg->umin_value > reg->umax_value ||
- reg->smin_value > reg->smax_value ||
- reg->u32_min_value > reg->u32_max_value ||
- reg->s32_min_value > reg->s32_max_value) {
- msg = "range bounds violation";
- goto out;
+ if (range_bounds_violation(reg)) {
+ msg = "range bounds violation";
+ goto out;
}

- if (tnum_is_const(reg->var_off)) {
- u64 uval = reg->var_off.value;
- s64 sval = (s64)uval;
-
- if (reg->umin_value != uval || reg->umax_value != uval ||
- reg->smin_value != sval || reg->smax_value != sval) {
- msg = "const tnum out of sync with range bounds";
- goto out;
- }
+ if (const_tnum_range_mismatch(reg)) {
+ msg = "const tnum out of sync with range bounds";
+ goto out;
}

- if (tnum_subreg_is_const(reg->var_off)) {
- u32 uval32 = tnum_subreg(reg->var_off).value;
- s32 sval32 = (s32)uval32;
-
- if (reg->u32_min_value != uval32 || reg->u32_max_value != uval32 ||
- reg->s32_min_value != sval32 || reg->s32_max_value != sval32) {
- msg = "const subreg tnum out of sync with range bounds";
- goto out;
- }
+ if (const_tnum_range_mismatch_32(reg)) {
+ msg = "const subreg tnum out of sync with range bounds";
+ goto out;
}

return 0;
--
2.43.0