From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58451) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dtNZ4-0002v1-8w for qemu-devel@nongnu.org; Sat, 16 Sep 2017 20:36:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dtNZ1-0006vK-6W for qemu-devel@nongnu.org; Sat, 16 Sep 2017 20:36:02 -0400 Received: from mail-lf0-x241.google.com ([2a00:1450:4010:c07::241]:33672) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dtNZ0-0006u7-UL for qemu-devel@nongnu.org; Sat, 16 Sep 2017 20:35:59 -0400 Received: by mail-lf0-x241.google.com with SMTP id y15so2883432lfd.0 for ; Sat, 16 Sep 2017 17:35:58 -0700 (PDT) From: Jan Dakinevich Date: Sun, 17 Sep 2017 03:38:11 +0300 Message-Id: <1505608691-11975-1-git-send-email-jan.dakinevich@gmail.com> Subject: [Qemu-devel] [PATCH v2] 9pfs: check the size of transport buffer before marshaling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Greg Kurz , qemu-devel@nongnu.org Cc: "Aneesh Kumar K.V" , Jan Dakinevich v9fs_do_readdir_with_stat() should check for a maximum buffer size before an attempt to marshal gathered data. Otherwise, buffers assumed as misconfigured and the transport would be broken. The patch brings v9fs_do_readdir_with_stat() in conformity with v9fs_do_readdir() behavior. Signed-off-by: Jan Dakinevich --- hw/9pfs/9p.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index 144c330..4d4ed85 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1754,17 +1754,26 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu, if (err < 0) { break; } + if ((count + v9stat.size + 2) > max_count) { + v9fs_readdir_unlock(&fidp->fs.dir); + + /* Ran out of buffer. Set dir back to old position and return */ + v9fs_co_seekdir(pdu, fidp, saved_dir_pos); + v9fs_stat_free(&v9stat); + v9fs_path_free(&path); + return count; + } + /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */ len = pdu_marshal(pdu, 11 + count, "S", &v9stat); v9fs_readdir_unlock(&fidp->fs.dir); - if ((len != (v9stat.size + 2)) || ((count + len) > max_count)) { - /* Ran out of buffer. Set dir back to old position and return */ + if (len < 0) { v9fs_co_seekdir(pdu, fidp, saved_dir_pos); v9fs_stat_free(&v9stat); v9fs_path_free(&path); - return count; + return len; } count += len; v9fs_stat_free(&v9stat); -- 2.1.4