From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37219) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buBAp-0001vd-AF for qemu-devel@nongnu.org; Wed, 12 Oct 2016 00:29:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1buBAm-0003IE-41 for qemu-devel@nongnu.org; Wed, 12 Oct 2016 00:29:47 -0400 Received: from mail-it0-x243.google.com ([2607:f8b0:4001:c0b::243]:34140) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1buBAl-0003Ho-VW for qemu-devel@nongnu.org; Wed, 12 Oct 2016 00:29:44 -0400 Received: by mail-it0-x243.google.com with SMTP id e203so3245003itc.1 for ; Tue, 11 Oct 2016 21:29:43 -0700 (PDT) Message-ID: <57fdbc36.486b240a.941a3.ac8a@mx.google.com> From: Li Qiang Date: Tue, 11 Oct 2016 21:29:19 -0700 Subject: [Qemu-devel] [PATCH] 9pfs: fix integer overflow issue in xattr read/write List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: groug@kaod.org, qemu-devel@nongnu.org Cc: Li Qiang From: Li Qiang In 9pfs xattr read/write function, it mix to use unsigned/signed ,32/64 bits integers. This will causes oob read/write issues. This patch fix this. Signed-off-by: Li Qiang --- hw/9pfs/9p.c | 29 +++++++++++++---------------- 1 file changed, 13 insertions(+), 16 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index e4040dc..8b50bfb 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1642,21 +1642,21 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp, { ssize_t err; size_t offset = 7; - int read_count; - int64_t xattr_len; + uint64_t read_count; + uint64_t xattr_len; V9fsVirtioState *v = container_of(s, V9fsVirtioState, state); VirtQueueElement *elem = v->elems[pdu->idx]; xattr_len = fidp->fs.xattr.len; + if (xattr_len < off) { + read_count = 0; + goto over_read_count; + } read_count = xattr_len - off; if (read_count > max_count) { read_count = max_count; - } else if (read_count < 0) { - /* - * read beyond XATTR value - */ - read_count = 0; } +over_read_count: err = pdu_marshal(pdu, offset, "d", read_count); if (err < 0) { return err; @@ -1982,22 +1982,19 @@ static int v9fs_xattr_write(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp, { int i, to_copy; ssize_t err = 0; - int write_count; - int64_t xattr_len; + uint64_t write_count; + uint64_t xattr_len; size_t offset = 7; xattr_len = fidp->fs.xattr.len; + if (xattr_len < off) { + err = -ENOSPC; + goto out; + } write_count = xattr_len - off; if (write_count > count) { write_count = count; - } else if (write_count < 0) { - /* - * write beyond XATTR value len specified in - * xattrcreate - */ - err = -ENOSPC; - goto out; } err = pdu_marshal(pdu, offset, "d", write_count); if (err < 0) { -- 1.8.3.1