Revert "bpf: Sanity check max value for var_off stack access"

ANBZ: torvalds#342 This reverts commit 443226a. Signed-off-by: Qiao Ma <[email protected]> Acked-by: Mao Wenan <[email protected]> Acked-by: Tony Lu <[email protected]>
gatieme · Apr 20, 2022 · 6647be9 · 6647be9
1 parent 6e79b40
commit 6647be9
Showing 1 changed file with 3 additions and 15 deletions.
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
@@ -1834,28 +1834,16 @@ static int check_stack_boundary(struct bpf_verifier_env *env, int regno,
 		if (meta && meta->raw_mode)
 			meta = NULL;
 
-		if (reg->smax_value >= BPF_MAX_VAR_OFF ||
-		    reg->smax_value <= -BPF_MAX_VAR_OFF) {
-			verbose(env, "R%d unbounded indirect variable offset stack access\n",
-				regno);
-			return -EACCES;
-		}
 		min_off = reg->smin_value + reg->off;
-		max_off = reg->smax_value + reg->off;
+		max_off = reg->umax_value + reg->off;
 		err = __check_stack_boundary(env, regno, min_off, access_size,
 					     zero_size_allowed);
-		if (err) {
-			verbose(env, "R%d min value is outside of stack bound\n",
-				regno);
+		if (err)
 			return err;
-		}
 		err = __check_stack_boundary(env, regno, max_off, access_size,
 					     zero_size_allowed);
-		if (err) {
-			verbose(env, "R%d max value is outside of stack bound\n",
-				regno);
+		if (err)
 			return err;
-		}
 	}
 
 	if (meta && meta->raw_mode) {