From 3e604a6f49fde97ef003cfffe7f62a382bb669bb Mon Sep 17 00:00:00 2001
From: Luis Gerhorst <gerhorst@cs.fau.de>
Date: Thu, 21 Dec 2023 16:34:56 +0100
Subject: [PATCH] [DRAFT] bpf: Raise stack/other sanitization errors up
push_stack() may fail:
- to limit complexity (when called for speculative path)
-> do_check() will insert nospec
- because of resource limits
-> we are too close already, do not try to cover these errors up
---
kernel/bpf/verifier.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8edf87e92a0e..14f783a190c7 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11546,7 +11546,6 @@ enum {
REASON_TYPE = -2,
REASON_PATHS = -3,
REASON_LIMIT = -4,
- REASON_STACK = -5,
};
static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
@@ -11742,7 +11741,7 @@ static int sanitize_ptr_alu(struct bpf_verifier_env *env,
env->insn_idx);
if (!ptr_is_dst_reg && !err)
*dst_reg = tmp;
- return (err == -ENOMEM || err == -EFAULT) ? REASON_STACK : err;
+ return err;
}
static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
@@ -11792,17 +11791,12 @@ static int sanitize_err(struct bpf_verifier_env *env,
aux->nospec_v1_result = true;
aux->alu_state = 0;
return 0;
- case REASON_STACK:
- verbose(env, "R%d could not be pushed for speculative verification, %s\n",
- dst, err);
- break;
default:
- verbose(env, "verifier internal error: unknown reason (%d)\n",
- reason);
break;
}
- return -EACCES;
+ WARN_ON_ONCE(reason >= 0);
+ return reason;
}
/* check that stack access falls within stack limits and that 'reg' doesn't
--
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