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 X-Spam-Level: X-Spam-Status: No, score=-12.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03245C07E9B for ; Tue, 20 Jul 2021 00:13:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00E166113E for ; Tue, 20 Jul 2021 00:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356651AbhGSXcQ (ORCPT ); Mon, 19 Jul 2021 19:32:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376744AbhGSWc6 (ORCPT ); Mon, 19 Jul 2021 18:32:58 -0400 Received: from mail-il1-x12b.google.com (mail-il1-x12b.google.com [IPv6:2607:f8b0:4864:20::12b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A138CC061797; Mon, 19 Jul 2021 16:11:52 -0700 (PDT) Received: by mail-il1-x12b.google.com with SMTP id b6so17530865iln.12; Mon, 19 Jul 2021 16:11:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:content-transfer-encoding; bh=UInFx3lsKkpvv0erIEUaDzneQf280BDgbwg4LuWK5Zk=; b=lLB9Yldmy7KbqPY/COpnRBeMcw8tAx6dntzKr4rMQyki3XQqqliZfaxahyFe6FQYS+ 1pRh67/oyxfO64Wjq04bKaCky3pwuBE1xX5P6Iqd3EM52oCq+RYS7WNMBfH0zrno+IYt ee1xFS9333Hgfw4AbbzR4VPd8wrClUoIt4gblyxWuVBmFWF1XGrOvI7OM7cAX1D745lD pUkaYzStWyYbXbVNVkgZH7gUeUhLucp/iK8KZTP1wnrzRI5UMYBTcSeQAfCkypA3UGtV 6F1yABRTN5GLbzZI1k1Gl7aFHTMk2o/y+j8f/98U3j4wjtHrJH9xD1OVQvzck+e07Ilu /WgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:content-transfer-encoding; bh=UInFx3lsKkpvv0erIEUaDzneQf280BDgbwg4LuWK5Zk=; b=jfLCpXmrXhLOQOFLesHI0ah4Zur+9Xzn2YJMCIyWgltIvop0S+tVpx+ge1R/d3jpl9 H+GoTzT+A0fMbps+8cczSJMr7OhnINFcJ/ZDTmnt20mUgfVkMChUbuAAStJKX7lpxi7z e/JkwCA49n0KXvCfIf4rzZSn7zk/lvevDkC8QKce6nMEnDTKM4L2MhUHQoxHBbkloDu5 TAj4/2OmnXTwop8+HvPw6Quc05CfMVzekHrRIEPpknBMrxbVFq5KACo772BdoHnsCLpS cyGJ0MwZowlQyyBX3iXe4GuTwGG/4sEgKmv7tGfK0wvgmQwkTx0ERtGlaNjPnsehuY77 flZg== X-Gm-Message-State: AOAM532LkLhgIewbuhPjHgyLJJCO9esC9gUxZmkVxhkWrIv7SrJNMBwe qISffuGKfqE87d0E8e4ZPOE= X-Google-Smtp-Source: ABdhPJxrqPifbHMteNN1GWXSaMfoXWJFNG8A9DR2VfDqX6Db+Mw2ZI+nLOb3+2gwOqSmvZDNizwNRg== X-Received: by 2002:a05:6e02:c73:: with SMTP id f19mr18055464ilj.291.1626736312070; Mon, 19 Jul 2021 16:11:52 -0700 (PDT) Received: from localhost ([172.243.157.240]) by smtp.gmail.com with ESMTPSA id l5sm11245729ion.44.2021.07.19.16.11.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 19 Jul 2021 16:11:51 -0700 (PDT) Date: Mon, 19 Jul 2021 16:11:43 -0700 From: John Fastabend To: Lorenz Bauer , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , "David S. Miller" , Jakub Kicinski , Jesper Dangaard Brouer , John Fastabend Cc: kernel-team@cloudflare.com, Lorenz Bauer , Andrii Nakryiko , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <60f606afc66a1_1e832208e7@john-XPS-13-9370.notmuch> In-Reply-To: <20210719085134.43325-2-lmb@cloudflare.com> References: <20210719085134.43325-1-lmb@cloudflare.com> <20210719085134.43325-2-lmb@cloudflare.com> Subject: RE: [PATCH bpf v2 1/1] bpf: fix OOB read when printing XDP link fdinfo Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Lorenz Bauer wrote: > We got the following UBSAN report on one of our testing machines: > > ================================================================================ > UBSAN: array-index-out-of-bounds in kernel/bpf/syscall.c:2389:24 > index 6 is out of range for type 'char *[6]' > CPU: 43 PID: 930921 Comm: systemd-coredum Tainted: G O 5.10.48-cloudflare-kasan-2021.7.0 #1 > Hardware name: > Call Trace: > dump_stack+0x7d/0xa3 > ubsan_epilogue+0x5/0x40 > __ubsan_handle_out_of_bounds.cold+0x43/0x48 > ? seq_printf+0x17d/0x250 > bpf_link_show_fdinfo+0x329/0x380 > ? bpf_map_value_size+0xe0/0xe0 > ? put_files_struct+0x20/0x2d0 > ? __kasan_kmalloc.constprop.0+0xc2/0xd0 > seq_show+0x3f7/0x540 > seq_read_iter+0x3f8/0x1040 > seq_read+0x329/0x500 > ? seq_read_iter+0x1040/0x1040 > ? __fsnotify_parent+0x80/0x820 > ? __fsnotify_update_child_dentry_flags+0x380/0x380 > vfs_read+0x123/0x460 > ksys_read+0xed/0x1c0 > ? __x64_sys_pwrite64+0x1f0/0x1f0 > do_syscall_64+0x33/0x40 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > ================================================================================ > ================================================================================ > UBSAN: object-size-mismatch in kernel/bpf/syscall.c:2384:2 > > From the report, we can infer that some array access in bpf_link_show_fdinfo at index 6 > is out of bounds. The obvious candidate is bpf_link_type_strs[BPF_LINK_TYPE_XDP] with > BPF_LINK_TYPE_XDP == 6. It turns out that BPF_LINK_TYPE_XDP is missing from bpf_types.h > and therefore doesn't have an entry in bpf_link_type_strs: > > pos: 0 > flags: 02000000 > mnt_id: 13 > link_type: (null) > link_id: 4 > prog_tag: bcf7977d3b93787c > prog_id: 4 > ifindex: 1 > > Fixes: aa8d3a716b59 ("bpf, xdp: Add bpf_link-based XDP attachment API") > Signed-off-by: Lorenz Bauer > --- > include/linux/bpf_types.h | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h > index a9db1eae6796..ae3ac3a2018c 100644 > --- a/include/linux/bpf_types.h > +++ b/include/linux/bpf_types.h > @@ -134,4 +134,5 @@ BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup) > BPF_LINK_TYPE(BPF_LINK_TYPE_ITER, iter) > #ifdef CONFIG_NET > BPF_LINK_TYPE(BPF_LINK_TYPE_NETNS, netns) > +BPF_LINK_TYPE(BPF_LINK_TYPE_XDP, xdp) > #endif > -- > 2.30.2 > Still lgtm. Acked-by; John Fastabend