From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 049E6C433F5 for ; Mon, 11 Apr 2022 15:35:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245017AbiDKPiD (ORCPT ); Mon, 11 Apr 2022 11:38:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348021AbiDKPh5 (ORCPT ); Mon, 11 Apr 2022 11:37:57 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 774513818C for ; Mon, 11 Apr 2022 08:35:42 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E8EDE615B8 for ; Mon, 11 Apr 2022 15:35:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00F71C385A4; Mon, 11 Apr 2022 15:35:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649691341; bh=r72YOipZqBp8ihjx0dMQ3iH6PRLt6qQwefHtSwteauU=; h=Subject:To:Cc:From:Date:From; b=RQKlhVLvB+dcdzVaup+yts+/SdNOJnk08CRz+tm58DN5jGmoGInIyQOFyi2QnxVEg xJloiBp4Bt7sK+ZHJ3Nut3KfWEJZn8fTpNeQC6LZkWtPtG4dvBzx1yoInJr5U7oEmA 4tkWSuG2mCsGjH9eXVZybT5AdUfEXcYgRDt7/ZMk= Subject: FAILED: patch "[PATCH] bpf: Resolve to prog->aux->dst_prog->type only for" failed to apply to 5.17-stable tree To: kafai@fb.com, ast@kernel.org, yhs@fb.com Cc: From: Date: Mon, 11 Apr 2022 17:35:33 +0200 Message-ID: <1649691333104119@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 4a9c7bbe2ed4d2b240674b1fb606c41d3940c412 Mon Sep 17 00:00:00 2001 From: Martin KaFai Lau Date: Tue, 29 Mar 2022 18:14:56 -0700 Subject: [PATCH] bpf: Resolve to prog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT The commit 7e40781cc8b7 ("bpf: verifier: Use target program's type for access verifications") fixes the verifier checking for BPF_PROG_TYPE_EXT (extension) prog such that the verifier looks for things based on the target prog type that it is extending instead of the BPF_PROG_TYPE_EXT itself. The current resolve_prog_type() returns the target prog type. It checks for nullness on prog->aux->dst_prog. However, when loading a BPF_PROG_TYPE_TRACING prog and it is tracing another bpf prog instead of a kernel function, prog->aux->dst_prog is not NULL also. In this case, the verifier should still verify as the BPF_PROG_TYPE_TRACING type instead of the traced prog type in prog->aux->dst_prog->type. An oops has been reported when tracing a struct_ops prog. A NULL dereference happened in check_return_code() when accessing the prog->aux->attach_func_proto->type and prog->aux->attach_func_proto is NULL here because the traced struct_ops prog has the "unreliable" set. This patch is to change the resolve_prog_type() to only return the target prog type if the prog being verified is BPF_PROG_TYPE_EXT. Fixes: 7e40781cc8b7 ("bpf: verifier: Use target program's type for access verifications") Signed-off-by: Martin KaFai Lau Signed-off-by: Alexei Starovoitov Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20220330011456.2984509-1-kafai@fb.com diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index c1fc4af47f69..3a9d2d7cc6b7 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -570,9 +570,11 @@ static inline u32 type_flag(u32 type) return type & ~BPF_BASE_TYPE_MASK; } +/* only use after check_attach_btf_id() */ static inline enum bpf_prog_type resolve_prog_type(struct bpf_prog *prog) { - return prog->aux->dst_prog ? prog->aux->dst_prog->type : prog->type; + return prog->type == BPF_PROG_TYPE_EXT ? + prog->aux->dst_prog->type : prog->type; } #endif /* _LINUX_BPF_VERIFIER_H */