From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1XHsNJ-0006uu-5p for mharc-qemu-trivial@gnu.org; Thu, 14 Aug 2014 06:35:17 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46757) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHsNC-0006mD-Jc for qemu-trivial@nongnu.org; Thu, 14 Aug 2014 06:35:15 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XHsN7-000114-Pl for qemu-trivial@nongnu.org; Thu, 14 Aug 2014 06:35:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36741) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XHsMx-0000oV-F5; Thu, 14 Aug 2014 06:34:55 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s7EATb6F013258 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 Aug 2014 06:29:37 -0400 Received: from redhat.com (ovpn-116-117.ams2.redhat.com [10.36.116.117]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id s7EATWRZ005593; Thu, 14 Aug 2014 06:29:33 -0400 Date: Thu, 14 Aug 2014 12:30:10 +0200 From: "Michael S. Tsirkin" To: zhanghailiang Message-ID: <20140814103010.GE31346@redhat.com> References: <1408001361-13580-1-git-send-email-zhang.zhanghailiang@huawei.com> <1408001361-13580-3-git-send-email-zhang.zhanghailiang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1408001361-13580-3-git-send-email-zhang.zhanghailiang@huawei.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: kwolf@redhat.com, lkurusa@redhat.com, qemu-trivial@nongnu.org, jan.kiszka@siemens.com, riku.voipio@iki.fi, mjt@tls.msk.ru, qemu-devel@nongnu.org, lcapitulino@redhat.com, stefanha@redhat.com, luonengjun@huawei.com, pbonzini@redhat.com, peter.huangpeng@huawei.com, alex.bennee@linaro.org, rth@twiddle.net Subject: Re: [Qemu-trivial] [PATCH v6 02/10] monitor: fix access freed memory X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Aug 2014 10:35:15 -0000 On Thu, Aug 14, 2014 at 03:29:13PM +0800, zhanghailiang wrote: > The function monitor_fdset_dup_fd_find_remove() references member of 'mon_fdset' > which may be freed in function monitor_fdset_cleanup() > > Reviewed-by: Gonglei > Signed-off-by: zhanghailiang Id doesn't make sense after fdset is gone. A cleaner way would be return -1 within that remove clause. ---> monitor: fix use after free The function monitor_fdset_dup_fd_find_remove() references member of 'mon_fdset' which - when remove flag is set - may be freed in function monitor_fdset_cleanup(). remove is set by monitor_fdset_dup_fd_remove which in practice does not need the returned value, so make it void, and return -1 from monitor_fdset_dup_fd_find_remove. Signed-off-by: Michael S. Tsirkin --- diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h index 3d6929d..78a5fc8 100644 --- a/include/monitor/monitor.h +++ b/include/monitor/monitor.h @@ -64,7 +64,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id, Error **errp); int monitor_fdset_get_fd(int64_t fdset_id, int flags); int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd); -int monitor_fdset_dup_fd_remove(int dup_fd); +void monitor_fdset_dup_fd_remove(int dup_fd); int monitor_fdset_dup_fd_find(int dup_fd); #endif /* !MONITOR_H */ diff --git a/monitor.c b/monitor.c index 5bc70a6..ef28328 100644 --- a/monitor.c +++ b/monitor.c @@ -2541,8 +2541,10 @@ static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove) if (QLIST_EMPTY(&mon_fdset->dup_fds)) { monitor_fdset_cleanup(mon_fdset); } + return -1; + } else { + return mon_fdset->id; } - return mon_fdset->id; } } } @@ -2554,9 +2556,9 @@ int monitor_fdset_dup_fd_find(int dup_fd) return monitor_fdset_dup_fd_find_remove(dup_fd, false); } -int monitor_fdset_dup_fd_remove(int dup_fd) +void monitor_fdset_dup_fd_remove(int dup_fd) { - return monitor_fdset_dup_fd_find_remove(dup_fd, true); + monitor_fdset_dup_fd_find_remove(dup_fd, true); } int monitor_handle_fd_param(Monitor *mon, const char *fdname) diff --git a/stubs/fdset-remove-fd.c b/stubs/fdset-remove-fd.c index b3886d9..7f6d61e 100644 --- a/stubs/fdset-remove-fd.c +++ b/stubs/fdset-remove-fd.c @@ -1,7 +1,6 @@ #include "qemu-common.h" #include "monitor/monitor.h" -int monitor_fdset_dup_fd_remove(int dupfd) +void monitor_fdset_dup_fd_remove(int dupfd) { - return -1; }