From nobody Sat Nov 23 22:38:42 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; 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 Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1731147899865762.8547577424029; Sat, 9 Nov 2024 02:24:59 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t9ido-0004AG-DM; Sat, 09 Nov 2024 05:24:29 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t9iYk-0002fv-Qe; Sat, 09 Nov 2024 05:19:15 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1t9iYj-0008F1-3I; Sat, 09 Nov 2024 05:19:14 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id EBF64A1416; Sat, 9 Nov 2024 13:13:51 +0300 (MSK) Received: from think4mjt.tls.msk.ru (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id 990AA167F01; Sat, 9 Nov 2024 13:14:46 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Christian Schoenebeck , Akihiro Suda , Greg Kurz , Michael Tokarev Subject: [Stable-8.2.8 49/49] 9pfs: fix crash on 'Treaddir' request Date: Sat, 9 Nov 2024 13:14:40 +0300 Message-Id: <20241109101443.312701-49-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable 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; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 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-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1731147900806116600 Content-Type: text/plain; charset="utf-8" From: Christian Schoenebeck A bad (broken or malicious) 9p client (guest) could cause QEMU host to crash by sending a 9p 'Treaddir' request with a numeric file ID (FID) that was previously opened for a file instead of an expected directory: #0 0x0000762aff8f4919 in __GI___rewinddir (dirp=3D0xf) at ../sysdeps/unix/sysv/linux/rewinddir.c:29 #1 0x0000557b7625fb40 in do_readdir_many (pdu=3D0x557bb67d2eb0, fidp=3D0x557bb67955b0, entries=3D0x762afe9fff58, offset=3D0, maxsize=3D= 131072, dostat=3D) at ../hw/9pfs/codir.c:101 #2 v9fs_co_readdir_many (pdu=3Dpdu@entry=3D0x557bb67d2eb0, fidp=3Dfidp@entry=3D0x557bb67955b0, entries=3Dentries@entry=3D0x762afe9= fff58, offset=3D0, maxsize=3D131072, dostat=3Dfalse) at ../hw/9pfs/codir.c:226 #3 0x0000557b7625c1f9 in v9fs_do_readdir (pdu=3D0x557bb67d2eb0, fidp=3D0x557bb67955b0, offset=3D, max_count=3D) at ../hw/9pfs/9p.c:2488 #4 v9fs_readdir (opaque=3D0x557bb67d2eb0) at ../hw/9pfs/9p.c:2602 That's because V9fsFidOpenState was declared as union type. So the same memory region is used for either an open POSIX file handle (int), or a POSIX DIR* pointer, etc., so 9p server incorrectly used the previously opened (valid) POSIX file handle (0xf) as DIR* pointer, eventually causing a crash in glibc's rewinddir() function. Root cause was therefore a missing check in 9p server's 'Treaddir' request handler, which must ensure that the client supplied FID was really opened as directory stream before trying to access the aforementioned union and its DIR* member. Cc: qemu-stable@nongnu.org Fixes: d62dbb51f7 ("virtio-9p: Add fidtype so that we can do type ...") Reported-by: Akihiro Suda Tested-by: Akihiro Suda Signed-off-by: Christian Schoenebeck Reviewed-by: Greg Kurz Message-Id: (cherry picked from commit 042b4ebfd2298ae01553844124f27d651cdb1071) Signed-off-by: Michael Tokarev diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index af636cfb2d..9a291d1b51 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -2587,6 +2587,11 @@ static void coroutine_fn v9fs_readdir(void *opaque) retval =3D -EINVAL; goto out_nofid; } + if (fidp->fid_type !=3D P9_FID_DIR) { + warn_report_once("9p: bad client: T_readdir on non-directory strea= m"); + retval =3D -ENOTDIR; + goto out; + } if (!fidp->fs.dir.stream) { retval =3D -EINVAL; goto out; --=20 2.39.5