From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 89D4631986E; Thu, 14 Aug 2025 20:07:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755202034; cv=none; b=ihVxSlPu3fWR3li8rXgiot0D+DN0GvUwzBsiEgzxpNXFVzSXFWstFsTAWnRpnbGlfwErpEruJLIy54Ljf1JdAuj3XtyPtwLbv6LVTS2OmMyE8yp+IRH8pS6yGVoIWh4lHXk/Egm72Fc1LLB3wKZBIXHKcoszhZSe/wsUA68qEds= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755202034; c=relaxed/simple; bh=2owaul9A+dGf0QynrL5Uey/mmFkKxTm9pfu4odz6WOM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=UQIwNbN9k8Ap4foMvsDHFf+iXM2w+FYreGfwG5kUaLNIGaID3ZQ6GngnqHAGE8A1BdWqCNYdvw6tOCXtPeV8TjAwbcI+O9lOiXJDFnNGa9YgkrLhg8wUXYOc5ec8ROMXuvVMWjOBHRC0ld7/joJb4DNpKCJMESaaWk5YVVHiQhs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bPyHj37S; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bPyHj37S" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1FD3C4CEED; Thu, 14 Aug 2025 20:07:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755202034; bh=2owaul9A+dGf0QynrL5Uey/mmFkKxTm9pfu4odz6WOM=; h=From:To:Cc:Subject:Date:From; b=bPyHj37SnbrR3nIDx/xq0t4zhvLZT9kqcnEYK3dOXx7tsscuNIbRBcJPv1XQdS97F hIn0BQUN57TT5oBOWY8VcBRFNTwkqzB/6g6l6lYgwAEEktGTabNecUELY5hEkgAc4q XvA0seAtol90Kz5bB70BFNZGw6t09rKs2OjedApqpR4VlswR9+RXygWb9QobP25wMr 6UAAzFbBbMvI4YN2cKxIEPAuhsWz5VZlkqdcDxsNcfZneKVmA/c+u6GjgQQZm4pZPA CQYgnnNSzpSKvgAo9mYyA9oT/4pcmrvQeW8QBrE6xo3RxTb4D/Shbupvrs6mFqefkj l9f3T66z7Li6g== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: kernel test robot , Paul Chaignon , bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , Hao Luo Subject: [PATCHv3 bpf] bpf: Check the helper function is valid in get_helper_proto Date: Thu, 14 Aug 2025 22:06:55 +0200 Message-ID: <20250814200655.945632-1-jolsa@kernel.org> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jiri Olsa kernel test robot reported verifier bug [1] where the helper func pointer could be NULL due to disabled config option. As Alexei suggested we could check on that in get_helper_proto directly. Marking tail_call helper func with BPF_PTR_POISON, because it is unused by design. [1] https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202507160818.68358831-lkp@intel.com Suggested-by: Alexei Starovoitov Acked-by: Paul Chaignon Signed-off-by: Jiri Olsa --- v3 changes: - use BPF_PTR_POISON instead of number 1 [Andrii] - fixed reported info and ack [Paul] kernel/bpf/core.c | 5 ++++- kernel/bpf/verifier.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 5d1650af899d..f8ac77d08ca7 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -3024,7 +3024,10 @@ EXPORT_SYMBOL_GPL(bpf_event_output); /* Always built-in helper functions. */ const struct bpf_func_proto bpf_tail_call_proto = { - .func = NULL, + /* func is unused for tail_call, we set it to pass the + * get_helper_proto check + */ + .func = BPF_PTR_POISON, .gpl_only = false, .ret_type = RET_VOID, .arg1_type = ARG_PTR_TO_CTX, diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index c4f69a9e9af6..c89e2b1bc644 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11354,7 +11354,7 @@ static int get_helper_proto(struct bpf_verifier_env *env, int func_id, return -EINVAL; *ptr = env->ops->get_func_proto(func_id, env->prog); - return *ptr ? 0 : -EINVAL; + return *ptr && (*ptr)->func ? 0 : -EINVAL; } static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn, -- 2.50.1