From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) (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 13AE11DA10D for ; Wed, 4 Sep 2024 13:06:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725455185; cv=none; b=SovfGJst1SVIwgt3j1yCcDUfHvqts3fRWjMk2XJxxMqZ5uzPYsyvb5vstThTLszHHbT4Ga9U8QUhG2IVZ/Ao0a02ejUfzQKXwpwDJZgjCD/cEtppZy2zYWvOclxF1R+H74//xKJDbtqE7cNEPyl94CUjx1H/vwZv151n504qbhE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725455185; c=relaxed/simple; bh=bocrfzcAH59xhLMf/5/46drIM/Q0VMNA+1sVBYNB7lo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Y+I1mn0CqoyuV8dSzb9p47xucShhWdNTr3jdQVRSJE6SszhT4JzGoOIQ7i5G1GqN6KfcpuEBB5pc+I4Tbjbz66pd3OwCBukftYjqkjDgQejSgk/eRSCnc8RQ05nFrOgSv7txcd5kbGFO2nsi5MpmCxJdtqaeOCbcctgnGg1wk7Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=cDeHgAH6; arc=none smtp.client-ip=95.215.58.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="cDeHgAH6" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1725455180; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgYD/ETXr/pJUs1peci6b7joO2Kw9YvzeNs0MfSj3OQ=; b=cDeHgAH655aDNPYPpIzP8Ab6O+Y2dfiWXAIuc+jZDD/lkpzeM7VJoTv4vfzveqLre12NU4 AVRPUtMSS7SksYT1V+pIqnec05wUoTo/RpxJkuekEpEVwBOKylbwyY8qbM4JM8YaashiLF L5TgDb1PzWXjfYFm0DfXBrQx4KQrskE= Date: Wed, 4 Sep 2024 21:06:07 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] nfsd: return -EINVAL when namelen is 0 To: Li Lingfeng , chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, okorniev@redhat.com, Dai.Ngo@oracle.com, tom@talpey.com Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, yukuai1@huaweicloud.com, houtao1@huawei.com, yi.zhang@huawei.com, yangerkun@huawei.com, lilingfeng@huaweicloud.com References: <20240903111446.659884-1-lilingfeng3@huawei.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Guoqing Jiang In-Reply-To: <20240903111446.659884-1-lilingfeng3@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 9/3/24 19:14, Li Lingfeng wrote: > When we have a corrupted main.sqlite in /var/lib/nfs/nfsdcld/, it may > result in namelen being 0, which will cause memdup_user() to return > ZERO_SIZE_PTR. > When we access the name.data that has been assigned the value of > ZERO_SIZE_PTR in nfs4_client_to_reclaim(), null pointer dereference is > triggered. > > [ T1205] ================================================================== > [ T1205] BUG: KASAN: null-ptr-deref in nfs4_client_to_reclaim+0xe9/0x260 > [ T1205] Read of size 1 at addr 0000000000000010 by task nfsdcld/1205 > [ T1205] > [ T1205] CPU: 11 PID: 1205 Comm: nfsdcld Not tainted 5.10.0-00003-g2c1423731b8d #406 > [ T1205] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 > [ T1205] Call Trace: > [ T1205] dump_stack+0x9a/0xd0 > [ T1205] ? nfs4_client_to_reclaim+0xe9/0x260 > [ T1205] __kasan_report.cold+0x34/0x84 > [ T1205] ? nfs4_client_to_reclaim+0xe9/0x260 > [ T1205] kasan_report+0x3a/0x50 > [ T1205] nfs4_client_to_reclaim+0xe9/0x260 > [ T1205] ? nfsd4_release_lockowner+0x410/0x410 > [ T1205] cld_pipe_downcall+0x5ca/0x760 > [ T1205] ? nfsd4_cld_tracking_exit+0x1d0/0x1d0 > [ T1205] ? down_write_killable_nested+0x170/0x170 > [ T1205] ? avc_policy_seqno+0x28/0x40 > [ T1205] ? selinux_file_permission+0x1b4/0x1e0 > [ T1205] rpc_pipe_write+0x84/0xb0 > [ T1205] vfs_write+0x143/0x520 > [ T1205] ksys_write+0xc9/0x170 > [ T1205] ? __ia32_sys_read+0x50/0x50 > [ T1205] ? ktime_get_coarse_real_ts64+0xfe/0x110 > [ T1205] ? ktime_get_coarse_real_ts64+0xa2/0x110 > [ T1205] do_syscall_64+0x33/0x40 > [ T1205] entry_SYSCALL_64_after_hwframe+0x67/0xd1 > [ T1205] RIP: 0033:0x7fdbdb761bc7 > [ T1205] Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 514 > [ T1205] RSP: 002b:00007fff8c4b7248 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > [ T1205] RAX: ffffffffffffffda RBX: 000000000000042b RCX: 00007fdbdb761bc7 > [ T1205] RDX: 000000000000042b RSI: 00007fff8c4b75f0 RDI: 0000000000000008 > [ T1205] RBP: 00007fdbdb761bb0 R08: 0000000000000000 R09: 0000000000000001 > [ T1205] R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000042b > [ T1205] R13: 0000000000000008 R14: 00007fff8c4b75f0 R15: 0000000000000000 > [ T1205] ================================================================== > > Fix it by checking namelen. > > Signed-off-by: Li Lingfeng > --- > fs/nfsd/nfs4recover.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c > index 67d8673a9391..69a3a84e159e 100644 > --- a/fs/nfsd/nfs4recover.c > +++ b/fs/nfsd/nfs4recover.c > @@ -809,6 +809,10 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg, > ci = &cmsg->cm_u.cm_clntinfo; > if (get_user(namelen, &ci->cc_name.cn_len)) > return -EFAULT; If namelen is 0, I think the func should return -EFAULT above per below comment in [1]. Or can get_user return success with x was set to zero?  * Return: zero on success, or -EFAULT on error.  * On error, the variable @x is set to zero.  */ #define get_user(x,ptr) ({ might_fault(); do_get_user_call(get_user,x,ptr); }) [1]. https://elixir.bootlin.com/linux/v6.11-rc6/source/arch/x86/include/asm/uaccess.h#L108 > + if (!namelen) { > + dprintk("%s: namelen should not be zero", __func__); > + return -EINVAL; > + } > name.data = memdup_user(&ci->cc_name.cn_id, namelen); > if (IS_ERR(name.data)) > return PTR_ERR(name.data); > @@ -831,6 +835,10 @@ __cld_pipe_inprogress_downcall(const struct cld_msg_v2 __user *cmsg, > cnm = &cmsg->cm_u.cm_name; > if (get_user(namelen, &cnm->cn_len)) > return -EFAULT; > + if (!namelen) { > + dprintk("%s: namelen should not be zero", __func__); > + return -EINVAL; > + } > name.data = memdup_user(&cnm->cn_id, namelen); > if (IS_ERR(name.data)) > return PTR_ERR(name.data); Thanks, Guoqing