bpf: Refactor reg_bounds_sanity_check

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>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/198ec3e69343e2c46dc9cbe2b1bc9be9ae2df5bd.1775142354.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8c1cf2eb6cbbdd38a79014d903f880a94b526504..760cd137bf3fc4993af4a6efa95db267cb04b34a 100644 (file)
--- 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;