From patchwork Tue Oct 4 14:38:14 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Juan Quintela X-Patchwork-Id: 117632 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 5AF901007D1 for ; Wed, 5 Oct 2011 01:38:58 +1100 (EST) Received: from localhost ([::1]:45203 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RB691-0001dA-Fd for incoming@patchwork.ozlabs.org; Tue, 04 Oct 2011 10:38:55 -0400 Received: from eggs.gnu.org ([140.186.70.92]:35925) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RB68c-0000yj-B7 for qemu-devel@nongnu.org; Tue, 04 Oct 2011 10:38:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RB68a-000193-MB for qemu-devel@nongnu.org; Tue, 04 Oct 2011 10:38:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:4777) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RB68a-00018w-F5 for qemu-devel@nongnu.org; Tue, 04 Oct 2011 10:38:28 -0400 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p94EcR3a005966 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 4 Oct 2011 10:38:27 -0400 Received: from trasno.mitica (ovpn-116-22.ams2.redhat.com [10.36.116.22]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id p94EcLER017233; Tue, 4 Oct 2011 10:38:26 -0400 From: Juan Quintela To: qemu-devel@nongnu.org Date: Tue, 4 Oct 2011 16:38:14 +0200 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 3) X-Received-From: 209.132.183.28 Cc: pbonzini@redhat.com Subject: [Qemu-devel] [PATCH 3/4] savevm: improve subsections detection on load X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org We add qemu_peek_buffer, that is identical to qemu_get_buffer, just that it don't update f->buf_index. We add a paramenter to qemu_peek_byte() to be able to peek more than one byte. Once this is done, to see if we have a subsection we look: - 1st byte is QEMU_VM_SUBSECTION - 2nd byte is a length, and is bigger than section name - 3rd element is a string that starts with section_name So, we shouldn't have false positives (yes, content could still get us wrong but probabilities are really low). Signed-off-by: Juan Quintela --- savevm.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 files changed, 60 insertions(+), 11 deletions(-) diff --git a/savevm.c b/savevm.c index 5fee4e2..db6ea12 100644 --- a/savevm.c +++ b/savevm.c @@ -532,6 +532,37 @@ void qemu_put_byte(QEMUFile *f, int v) qemu_fflush(f); } +static int qemu_peek_buffer(QEMUFile *f, uint8_t *buf, int size1, int offset) +{ + int size, l; + int index = f->buf_index + offset; + + if (f->is_write) { + abort(); + } + + size = size1; + while (size > 0) { + l = f->buf_size - index; + if (l == 0) { + qemu_fill_buffer(f); + index = f->buf_index + offset; + l = f->buf_size - index; + if (l == 0) { + break; + } + } + if (l > size) { + l = size; + } + memcpy(buf, f->buf + index, l); + index += l; + buf += l; + size -= l; + } + return size1 - size; +} + int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size1) { int size, l; @@ -561,19 +592,22 @@ int qemu_get_buffer(QEMUFile *f, uint8_t *buf, int size1) return size1 - size; } -static int qemu_peek_byte(QEMUFile *f) +static int qemu_peek_byte(QEMUFile *f, int offset) { + int index = f->buf_index + offset; + if (f->is_write) { abort(); } - if (f->buf_index >= f->buf_size) { + if (index >= f->buf_size) { qemu_fill_buffer(f); - if (f->buf_index >= f->buf_size) { + index = f->buf_index + offset; + if (index >= f->buf_size) { return 0; } } - return f->buf[f->buf_index]; + return f->buf[index]; } int qemu_get_byte(QEMUFile *f) @@ -1687,22 +1721,37 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd, return 0; } - while (qemu_peek_byte(f) == QEMU_VM_SUBSECTION) { + while (qemu_peek_byte(f, 0) == QEMU_VM_SUBSECTION) { char idstr[256]; int ret; - uint8_t version_id, len; + uint8_t version_id, len, size; const VMStateDescription *sub_vmsd; - qemu_get_byte(f); /* subsection */ - len = qemu_get_byte(f); - qemu_get_buffer(f, (uint8_t *)idstr, len); - idstr[len] = 0; - version_id = qemu_get_be32(f); + len = qemu_peek_byte(f, 1); + if (len < strlen(vmsd->name) + 1) { + /* subsection name has be be "section_name/a" */ + return 0; + } + size = qemu_peek_buffer(f, (uint8_t *)idstr, len, 2); + if (size != len) { + return 0; + } + idstr[size] = 0; + if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) { + /* it don't have a valid subsection name */ + return 0; + } sub_vmsd = vmstate_get_subsection(sub, idstr); if (sub_vmsd == NULL) { return -ENOENT; } + qemu_get_byte(f); /* subsection */ + qemu_get_byte(f); /* len */ + qemu_get_buffer(f, (uint8_t *)idstr, len); + idstr[len] = 0; + version_id = qemu_get_be32(f); + assert(!sub_vmsd->subsections); ret = vmstate_load_state(f, sub_vmsd, opaque, version_id); if (ret) {