From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout09.his.huawei.com (canpmsgout09.his.huawei.com [113.46.200.224]) (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 71E7033B6D7; Wed, 17 Dec 2025 09:33:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.224 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765963996; cv=none; b=URjIIlEWJMSkALIijK4HWdLXxUUnH1hWkNpgpEX/875UGwqyBbx2fiuV/hUWdLbRF4/HSwQ4zx365dqivPj8q2dk0nEqKZBIzXALUkX06v+3mUXDQ74eim6E002741ZoOYidx/O29v32AL9vOYZZYEBGX+57a9XOyg7FsJ7ekEM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765963996; c=relaxed/simple; bh=ZGRs2pcLuixLt5s7rTmxagUvSzbPPvpp1VsSAXcuED0=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=Q8YjyT6awVzq5E9sM/BX/60hL5nVhAoLpZI/QqTC5Ep8uaFazcJR6K889IVB+c13Z2u+kTxkm0u1iRZ7bmXya5OzTUKdmTcRDNsXPoiENmv2iebi3Z8yq0BtWmZKHbUIULy/zxFkAO9ZSr7+v1h9mWXCbIfEdHSJIbWNkf2DwU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=uwuE4hxu; arc=none smtp.client-ip=113.46.200.224 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="uwuE4hxu" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=0gdo0wfOTVQDq1jL/5AEFLdrE4ZMkHZAdq3trl2BrkA=; b=uwuE4hxuxRXoBHXHhYNUJH7R2C2iFzBC/RVIUiovldJYNkJIoMrZk9T7AfYwkalpDROcsUZY8 8xIX3rtwdUPM37kKbadSaDeTLEHGbzgTxkLGvPuApoqMyWSBTuys/hnITvzpoJH1b7vtVqE+ytC eliTPEzwBGgJJCbdl6aaPc8= Received: from mail.maildlp.com (unknown [172.19.88.234]) by canpmsgout09.his.huawei.com (SkyGuard) with ESMTPS id 4dWT6S4J78z1cyPb; Wed, 17 Dec 2025 17:30:08 +0800 (CST) Received: from kwepemr500012.china.huawei.com (unknown [7.202.195.23]) by mail.maildlp.com (Postfix) with ESMTPS id C12F3140157; Wed, 17 Dec 2025 17:33:10 +0800 (CST) Received: from [100.103.109.72] (100.103.109.72) by kwepemr500012.china.huawei.com (7.202.195.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Wed, 17 Dec 2025 17:33:10 +0800 Message-ID: Date: Wed, 17 Dec 2025 17:33:09 +0800 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] PCI: Prevent overflow in proc_bus_pci_write() To: =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= CC: , , LKML , , , , References: <20251216083912.758219-1-duziming2@huawei.com> <20251216083912.758219-4-duziming2@huawei.com> <47ccdb75-7134-b86a-e8bb-eebb9f1e0b47@linux.intel.com> From: duziming In-Reply-To: <47ccdb75-7134-b86a-e8bb-eebb9f1e0b47@linux.intel.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems100001.china.huawei.com (7.221.188.238) To kwepemr500012.china.huawei.com (7.202.195.23) 在 2025/12/16 18:57, Ilpo Järvinen 写道: > On Tue, 16 Dec 2025, Ziming Du wrote: > >> When the value of ppos over the INT_MAX, the pos will be > is over > >> set a negtive value which will be pass to get_user() or > set to a negative value which will be passed > >> pci_user_write_config_dword(). And unexpected behavior > Please start the sentence with something else than And. > > Hmm, the lines look rather short too, can you please reflow the changelog > paragraphs to 75 characters. Thanks for the review. I'll reflow the changelog to 75-character lines and avoid starting sentences with 'And' in the next revision. >> such as a softlock happens: >> >> watchdog: BUG: soft lockup - CPU#0 stuck for 130s! [syz.3.109:3444] >> Modules linked in: >> CPU: 0 PID: 3444 Comm: syz.3.109 Not tainted 6.6.0+ #33 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 >> RIP: 0010:_raw_spin_unlock_irq+0x17/0x30 >> Code: cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 e8 52 12 00 00 90 fb 65 ff 0d b1 a1 86 6d <74> 05 e9 42 52 00 00 0f 1f 44 00 00 c3 cc cc cc cc 0f 1f 84 00 00 >> RSP: 0018:ffff88816851fb50 EFLAGS: 00000246 >> RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff927daf9b >> RDX: 0000000000000cfc RSI: 0000000000000046 RDI: ffffffff9a7c7400 >> RBP: 00000000818bb9dc R08: 0000000000000001 R09: ffffed102d0a3f59 >> R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000 >> R13: ffff888102220000 R14: ffffffff926d3b10 R15: 00000000210bbb5f >> FS: 00007ff2d4e56640(0000) GS:ffff8881f5c00000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00000000210bbb5b CR3: 0000000147374002 CR4: 0000000000772ef0 >> PKRU: 00000000 >> Call Trace: >> >> pci_user_write_config_dword+0x126/0x1f0 >> ? __get_user_nocheck_8+0x20/0x20 >> proc_bus_pci_write+0x273/0x470 >> proc_reg_write+0x1b6/0x280 >> do_iter_write+0x48e/0x790 >> ? import_iovec+0x47/0x90 >> vfs_writev+0x125/0x4a0 >> ? futex_wake+0xed/0x500 >> ? __pfx_vfs_writev+0x10/0x10 >> ? userfaultfd_ioctl+0x131/0x1ae0 >> ? userfaultfd_ioctl+0x131/0x1ae0 >> ? do_futex+0x17e/0x220 >> ? __pfx_do_futex+0x10/0x10 >> ? __fget_files+0x193/0x2b0 >> __x64_sys_pwritev+0x1e2/0x2a0 >> ? __pfx___x64_sys_pwritev+0x10/0x10 >> do_syscall_64+0x59/0x110 >> entry_SYSCALL_64_after_hwframe+0x78/0xe2 > Could you please trim the dump so it only contains things relevant to this > issue () (also check trimming in the other patches). Thanks for pointing that out, we'll make sure to only keep the relevant stacks in future patches. >> Fix this by use unsigned int for the pos. >> >> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") >> Signed-off-by: Yongqiang Liu >> Signed-off-by: Ziming Du >> --- >> drivers/pci/proc.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c >> index 9348a0fb8084..dbec1d4209c9 100644 >> --- a/drivers/pci/proc.c >> +++ b/drivers/pci/proc.c >> @@ -113,7 +113,7 @@ static ssize_t proc_bus_pci_write(struct file *file, const char __user *buf, >> { >> struct inode *ino = file_inode(file); >> struct pci_dev *dev = pde_data(ino); >> - int pos = *ppos; >> + unsigned int pos = *ppos; >> int size = dev->cfg_size; >> int cnt, ret; > So this still throws away some bits compared with the original ppos ? The current approach may lose some precision compared to the original ppos, but a later check ensures  pos remains valid—so any potential information loss is handled safely. >