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 4A67ACCA47F for ; Mon, 13 Jun 2022 11:40:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355174AbiFMLkH (ORCPT ); Mon, 13 Jun 2022 07:40:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355630AbiFMLjV (ORCPT ); Mon, 13 Jun 2022 07:39:21 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 93B2A20F56; Mon, 13 Jun 2022 03:49:26 -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 ams.source.kernel.org (Postfix) with ESMTPS id 4D42BB80E59; Mon, 13 Jun 2022 10:49:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9FDC1C34114; Mon, 13 Jun 2022 10:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655117364; bh=zDNe4IoNLyVziODlgX+z2yo998cNoUKH66zbKZgwCW4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NhKuWKyce5g/djBMWF5y4YIFaUUaFXCqd/Vfr2Jl/NG1OEY3CZ4ovr3U/5oKm9sE7 SVdmYlrMEpks/I7xpb35o57tdPPVoUtIDAsNZiOVILCtbRxQBlUvWljOcZUdOcghnG eIpTUF0oQ/EyIPXGHo/zGrbVA+Vz9bvuzTY1JIZ8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Eric Dumazet , Daniel Borkmann , Song Liu , Alexei Starovoitov , Sasha Levin Subject: [PATCH 5.4 353/411] bpf, arm64: Clear prog->jited_len along prog->jited Date: Mon, 13 Jun 2022 12:10:26 +0200 Message-Id: <20220613094939.286776045@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094928.482772422@linuxfoundation.org> References: <20220613094928.482772422@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 10f3b29c65bb2fe0d47c2945cd0b4087be1c5218 ] syzbot reported an illegal copy_to_user() attempt from bpf_prog_get_info_by_fd() [1] There was no repro yet on this bug, but I think that commit 0aef499f3172 ("mm/usercopy: Detect vmalloc overruns") is exposing a prior bug in bpf arm64. bpf_prog_get_info_by_fd() looks at prog->jited_len to determine if the JIT image can be copied out to user space. My theory is that syzbot managed to get a prog where prog->jited_len has been set to 43, while prog->bpf_func has ben cleared. It is not clear why copy_to_user(uinsns, NULL, ulen) is triggering this particular warning. I thought find_vma_area(NULL) would not find a vm_struct. As we do not hold vmap_area_lock spinlock, it might be possible that the found vm_struct was garbage. [1] usercopy: Kernel memory exposure attempt detected from vmalloc (offset 792633534417210172, size 43)! kernel BUG at mm/usercopy.c:101! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 25002 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-10139-g8291eaafed36 #0 Hardware name: linux,dummy-virt (DT) pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : usercopy_abort+0x90/0x94 mm/usercopy.c:101 lr : usercopy_abort+0x90/0x94 mm/usercopy.c:89 sp : ffff80000b773a20 x29: ffff80000b773a30 x28: faff80000b745000 x27: ffff80000b773b48 x26: 0000000000000000 x25: 000000000000002b x24: 0000000000000000 x23: 00000000000000e0 x22: ffff80000b75db67 x21: 0000000000000001 x20: 000000000000002b x19: ffff80000b75db3c x18: 00000000fffffffd x17: 2820636f6c6c616d x16: 76206d6f72662064 x15: 6574636574656420 x14: 74706d6574746120 x13: 2129333420657a69 x12: 73202c3237313031 x11: 3237313434333533 x10: 3336323937207465 x9 : 657275736f707865 x8 : ffff80000a30c550 x7 : ffff80000b773830 x6 : ffff80000b773830 x5 : 0000000000000000 x4 : ffff00007fbbaa10 x3 : 0000000000000000 x2 : 0000000000000000 x1 : f7ff000028fc0000 x0 : 0000000000000064 Call trace: usercopy_abort+0x90/0x94 mm/usercopy.c:89 check_heap_object mm/usercopy.c:186 [inline] __check_object_size mm/usercopy.c:252 [inline] __check_object_size+0x198/0x36c mm/usercopy.c:214 check_object_size include/linux/thread_info.h:199 [inline] check_copy_size include/linux/thread_info.h:235 [inline] copy_to_user include/linux/uaccess.h:159 [inline] bpf_prog_get_info_by_fd.isra.0+0xf14/0xfdc kernel/bpf/syscall.c:3993 bpf_obj_get_info_by_fd+0x12c/0x510 kernel/bpf/syscall.c:4253 __sys_bpf+0x900/0x2150 kernel/bpf/syscall.c:4956 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline] __se_sys_bpf kernel/bpf/syscall.c:5019 [inline] __arm64_sys_bpf+0x28/0x40 kernel/bpf/syscall.c:5019 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142 do_el0_svc+0xa0/0xc0 arch/arm64/kernel/syscall.c:206 el0_svc+0x44/0xb0 arch/arm64/kernel/entry-common.c:624 el0t_64_sync_handler+0x1ac/0x1b0 arch/arm64/kernel/entry-common.c:642 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581 Code: aa0003e3 d00038c0 91248000 97fff65f (d4210000) Fixes: db496944fdaa ("bpf: arm64: add JIT support for multi-function programs") Reported-by: syzbot Signed-off-by: Eric Dumazet Signed-off-by: Daniel Borkmann Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20220531215113.1100754-1-eric.dumazet@gmail.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- arch/arm64/net/bpf_jit_comp.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 17a8d1484f9b..9f71ca441482 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -973,6 +973,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bpf_jit_binary_free(header); prog->bpf_func = NULL; prog->jited = 0; + prog->jited_len = 0; goto out_off; } bpf_jit_binary_lock_ro(header); -- 2.35.1