From nobody Sun Dec 14 06:17:14 2025 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 B574FC00140 for ; Mon, 15 Aug 2022 19:32:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243954AbiHOTcw (ORCPT ); Mon, 15 Aug 2022 15:32:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344850AbiHOT1S (ORCPT ); Mon, 15 Aug 2022 15:27:18 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 225185A8BC; Mon, 15 Aug 2022 11:43:09 -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 BC0C0B81081; Mon, 15 Aug 2022 18:43:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AE0CC433C1; Mon, 15 Aug 2022 18:43:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660588986; bh=GOfBK2gscdwO9OyW57PLbtTXBjoNAVxft36u86R8bUQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0dIC9TjrSnssIIp2F6yXwYAoPRQwmnvA/GE/K4dfSn3ijWV2Jaeas2msGX2KJ+Onz H9YIhM4Oj6QaSqoeAJwL3apqIwkrQIfrToMxASeu5EoyeW+r90CDxUMvOGfWOk75Sf 63luD0DyWZmUwJuocjsGIMoTQOGOuE0Vo2jVVuQc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chen Zhongjin , Andrew Morton , Sasha Levin Subject: [PATCH 5.15 577/779] profiling: fix shift too large makes kernel panic Date: Mon, 15 Aug 2022 20:03:41 +0200 Message-Id: <20220815180401.999342942@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Chen Zhongjin [ Upstream commit 0fe6ee8f123a4dfb529a5aff07536bb481f34043 ] 2d186afd04d6 ("profiling: fix shift-out-of-bounds bugs") limits shift value by [0, BITS_PER_LONG -1], which means [0, 63]. However, syzbot found that the max shift value should be the bit number of (_etext - _stext). If shift is outside of this, the "buffer_bytes" will be zero and will cause kzalloc(0). Then the kernel panics due to dereferencing the returned pointer 16. This can be easily reproduced by passing a large number like 60 to enable profiling and then run readprofile. LOGS: BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 6148067 P4D 6148067 PUD 6142067 PMD 0 PREEMPT SMP CPU: 4 PID: 184 Comm: readprofile Not tainted 5.18.0+ #162 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g= 2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:read_profile+0x104/0x220 RSP: 0018:ffffc900006fbe80 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff888006150000 RSI: 0000000000000001 RDI: ffffffff82aba4a0 RBP: 000000000188bb60 R08: 0000000000000010 R09: ffff888006151000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff82aba4a0 R13: 0000000000000000 R14: ffffc900006fbf08 R15: 0000000000020c30 FS: 000000000188a8c0(0000) GS:ffff88803ed00000(0000) knlGS:00000000000000= 00 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 0000000006144000 CR4: 00000000000006e0 Call Trace: proc_reg_read+0x56/0x70 vfs_read+0x9a/0x1b0 ksys_read+0xa1/0xe0 ? fpregs_assert_state_consistent+0x1e/0x40 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x4d4b4e RSP: 002b:00007ffebb668d58 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 000000000188a8a0 RCX: 00000000004d4b4e RDX: 0000000000000400 RSI: 000000000188bb60 RDI: 0000000000000003 RBP: 0000000000000003 R08: 000000000000006e R09: 0000000000000000 R10: 0000000000000041 R11: 0000000000000246 R12: 000000000188bb60 R13: 0000000000000400 R14: 0000000000000000 R15: 000000000188bb60 Modules linked in: CR2: 0000000000000010 Killed ---[ end trace 0000000000000000 ]--- Check prof_len in profile_init() to prevent it be zero. Link: https://lkml.kernel.org/r/20220531012854.229439-1-chenzhongjin@huawei= .com Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Chen Zhongjin Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- kernel/profile.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/profile.c b/kernel/profile.c index eb9c7f0f5ac5..0db1122855c0 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -109,6 +109,13 @@ int __ref profile_init(void) =20 /* only text is profiled */ prof_len =3D (_etext - _stext) >> prof_shift; + + if (!prof_len) { + pr_warn("profiling shift: %u too large\n", prof_shift); + prof_on =3D 0; + return -EINVAL; + } + buffer_bytes =3D prof_len*sizeof(atomic_t); =20 if (!alloc_cpumask_var(&prof_cpu_mask, GFP_KERNEL)) --=20 2.35.1