From nobody Tue Feb 10 00:00:30 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1576171278; cv=none; d=zohomail.com; s=zohoarc; b=BCzTehOcTKq7N/oCilhpIeUArIKQ4fuHZh3Fc8Sq+iwsrfgpgOSnO5Pi8V52KH31Mxa3Xjn/+SO12OKVWRnCSsfbczKTsgaoHvXCQO6bCFtXkMFyYK/5Ap1NJ3qWeISFKXBbdi8Tum8MWvGdnGv7rRS9UB/aRxCFqIH6qWAl0Mg= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1576171278; h=Content-Type:Content-Transfer-Encoding:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=dDtoPLNQ3V8oD+vwQyOcLXH0VziNW1yt0dVfeNFT2To=; b=Dm1dHHevEKAcvzrSCKSdPRpQmroVXodWI4UGFVZh4bihSJNfoXJxmGg0dBAYZT+bZjFZlrNxelN1gh5bHK7Gx+1lLtofNjytARNEuaq9Az7swh6NAby++n8wHUqGzGL7ya9DtO3/JWQ1nc9MBG2pV0quOSJMcb2xt8zt/QNHxBA= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 157617127853868.43161581349307; Thu, 12 Dec 2019 09:21:18 -0800 (PST) Received: from localhost ([::1]:34580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifS9M-0001T4-VG for importer@patchew.org; Thu, 12 Dec 2019 12:21:16 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:50181) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ifRVg-0005qH-MZ for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ifRVf-0002E1-Ej for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:16 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:60925 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ifRVf-0002BP-52 for qemu-devel@nongnu.org; Thu, 12 Dec 2019 11:40:15 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-36-sdirObqENcmXeZrnGGaZSQ-1; Thu, 12 Dec 2019 11:40:11 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 068881005510 for ; Thu, 12 Dec 2019 16:40:11 +0000 (UTC) Received: from dgilbert-t580.localhost (ovpn-116-226.ams2.redhat.com [10.36.116.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id 25DF460BE1; Thu, 12 Dec 2019 16:40:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576168813; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dDtoPLNQ3V8oD+vwQyOcLXH0VziNW1yt0dVfeNFT2To=; b=FtppkQ6+YxFxamPuWfxgkWVkbbaYC3kPch6jwgjG2zvg80ey0TZFWZTGappCq3P5AxBNZ0 vVB5GdbzjqibLclov/LshpffMD76hCVJsrCIdI4z4Y1VExN/lTEOZcRYVJX6PYhAPIRSeD JFspBE+vUbq+K93zidAvoUDlySX7FU0= From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, stefanha@redhat.com, vgoyal@redhat.com Subject: [PATCH 038/104] virtiofsd: validate path components Date: Thu, 12 Dec 2019 16:37:58 +0000 Message-Id: <20191212163904.159893-39-dgilbert@redhat.com> In-Reply-To: <20191212163904.159893-1-dgilbert@redhat.com> References: <20191212163904.159893-1-dgilbert@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: sdirObqENcmXeZrnGGaZSQ-1 X-Mimecast-Spam-Score: 0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) Content-Type: text/plain; charset="utf-8" From: Stefan Hajnoczi Several FUSE requests contain single path components. A correct FUSE client sends well-formed path components but there is currently no input validation in case something went wrong or the client is malicious. Refuse ".", "..", and paths containing '/' when we expect a path component. Signed-off-by: Stefan Hajnoczi --- tools/virtiofsd/passthrough_ll.c | 59 ++++++++++++++++++++++++++++---- 1 file changed, 53 insertions(+), 6 deletions(-) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough= _ll.c index 1faae2753f..84e9d8916f 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -133,6 +133,21 @@ static void unref_inode(struct lo_data *lo, struct lo_= inode *inode, uint64_t n); =20 static struct lo_inode *lo_find(struct lo_data *lo, struct stat *st); =20 +static int is_dot_or_dotdot(const char *name) +{ + return name[0] =3D=3D '.' && + (name[1] =3D=3D '\0' || (name[1] =3D=3D '.' && name[2] =3D=3D '= \0')); +} + +/* Is `path` a single path component that is not "." or ".."? */ +static int is_safe_path_component(const char *path) +{ + if (strchr(path, '/')) { + return 0; + } + + return !is_dot_or_dotdot(path); +} =20 static struct lo_data *lo_data(fuse_req_t req) { @@ -681,6 +696,15 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t paren= t, const char *name) parent, name); } =20 + /* + * Don't use is_safe_path_component(), allow "." and ".." for NFS expo= rt + * support. + */ + if (strchr(name, '/')) { + fuse_reply_err(req, EINVAL); + return; + } + err =3D lo_do_lookup(req, parent, name, &e); if (err) { fuse_reply_err(req, err); @@ -745,6 +769,11 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_= t parent, struct fuse_entry_param e; struct lo_cred old =3D {}; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + dir =3D lo_inode(req, parent); if (!dir) { fuse_reply_err(req, EBADF); @@ -846,6 +875,11 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fu= se_ino_t parent, struct fuse_entry_param e; int saverr; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + inode =3D lo_inode(req, ino); if (!inode) { fuse_reply_err(req, EBADF); @@ -887,6 +921,10 @@ out_err: static void lo_rmdir(fuse_req_t req, fuse_ino_t parent, const char *name) { int res; + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } =20 res =3D unlinkat(lo_fd(req, parent), name, AT_REMOVEDIR); =20 @@ -899,6 +937,11 @@ static void lo_rename(fuse_req_t req, fuse_ino_t paren= t, const char *name, { int res; =20 + if (!is_safe_path_component(name) || !is_safe_path_component(newname))= { + fuse_reply_err(req, EINVAL); + return; + } + if (flags) { fuse_reply_err(req, EINVAL); return; @@ -913,6 +956,11 @@ static void lo_unlink(fuse_req_t req, fuse_ino_t paren= t, const char *name) { int res; =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + res =3D unlinkat(lo_fd(req, parent), name, 0); =20 fuse_reply_err(req, res =3D=3D -1 ? errno : 0); @@ -1076,12 +1124,6 @@ out_err: fuse_reply_err(req, error); } =20 -static int is_dot_or_dotdot(const char *name) -{ - return name[0] =3D=3D '.' && - (name[1] =3D=3D '\0' || (name[1] =3D=3D '.' && name[2] =3D=3D '= \0')); -} - static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size, off_t offset, struct fuse_file_info *fi, int plu= s) { @@ -1231,6 +1273,11 @@ static void lo_create(fuse_req_t req, fuse_ino_t par= ent, const char *name, parent, name); } =20 + if (!is_safe_path_component(name)) { + fuse_reply_err(req, EINVAL); + return; + } + err =3D lo_change_cred(req, &old); if (err) { goto out; --=20 2.23.0