From c1bf3531aecf4a0ba25bb150dd5fe21edf406c88 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Tue, 23 Feb 2016 19:10:49 +0100 Subject: [PATCH] vhost-user: fix use after free MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit "name" is freed after visiting options, instead use the first NetClientState name. Adds a few assert() for clarifying and checking some impossible states. READ of size 1 at 0x602000000990 thread T0 #0 0x7f6b251c570c (/lib64/libasan.so.2+0x4770c) #1 0x5566dc380600 in qemu_find_net_clients_except net/net.c:824 #2 0x5566dc39bac7 in net_vhost_user_event net/vhost-user.c:193 #3 0x5566dbee862a in qemu_chr_be_event /home/elmarco/src/qemu/qemu-char.c:201 #4 0x5566dbef2890 in tcp_chr_disconnect /home/elmarco/src/qemu/qemu-char.c:2790 #5 0x5566dbef2d0b in tcp_chr_sync_read /home/elmarco/src/qemu/qemu-char.c:2835 #6 0x5566dbee8a99 in qemu_chr_fe_read_all /home/elmarco/src/qemu/qemu-char.c:295 #7 0x5566dc39b964 in net_vhost_user_watch net/vhost-user.c:180 #8 0x5566dc5a06c7 in qio_channel_fd_source_dispatch io/channel-watch.c:70 #9 0x7f6b1aa2ab87 in g_main_dispatch /home/elmarco/src/gnome/glib/glib/gmain.c:3154 #10 0x7f6b1aa2b9cb in g_main_context_dispatch /home/elmarco/src/gnome/glib/glib/gmain.c:3769 #11 0x5566dc475ed4 in glib_pollfds_poll /home/elmarco/src/qemu/main-loop.c:212 #12 0x5566dc476029 in os_host_main_loop_wait /home/elmarco/src/qemu/main-loop.c:257 #13 0x5566dc476165 in main_loop_wait /home/elmarco/src/qemu/main-loop.c:505 #14 0x5566dbf08d31 in main_loop /home/elmarco/src/qemu/vl.c:1932 #15 0x5566dbf16783 in main /home/elmarco/src/qemu/vl.c:4646 #16 0x7f6b180bb57f in __libc_start_main (/lib64/libc.so.6+0x2057f) #17 0x5566dbbf5348 in _start (/home/elmarco/src/qemu/x86_64-softmmu/qemu-system-x86_64+0x3f9348) 0x602000000990 is located 0 bytes inside of 5-byte region [0x602000000990,0x602000000995) freed by thread T0 here: #0 0x7f6b2521666a in __interceptor_free (/lib64/libasan.so.2+0x9866a) #1 0x7f6b1aa332a4 in g_free /home/elmarco/src/gnome/glib/glib/gmem.c:189 #2 0x5566dc5f416f in qapi_dealloc_type_str qapi/qapi-dealloc-visitor.c:134 #3 0x5566dc5f3268 in visit_type_str qapi/qapi-visit-core.c:196 #4 0x5566dc5ced58 in visit_type_Netdev_fields /home/elmarco/src/qemu/qapi-visit.c:5936 #5 0x5566dc5cef71 in visit_type_Netdev /home/elmarco/src/qemu/qapi-visit.c:5960 #6 0x5566dc381a8d in net_visit net/net.c:1049 #7 0x5566dc381c37 in net_client_init net/net.c:1076 #8 0x5566dc3839e2 in net_init_netdev net/net.c:1473 #9 0x5566dc63cc0a in qemu_opts_foreach util/qemu-option.c:1112 #10 0x5566dc383b36 in net_init_clients net/net.c:1499 #11 0x5566dbf15d86 in main /home/elmarco/src/qemu/vl.c:4397 #12 0x7f6b180bb57f in __libc_start_main (/lib64/libc.so.6+0x2057f) Signed-off-by: Marc-André Lureau Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- net/vhost-user.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/vhost-user.c b/net/vhost-user.c index b753b3d800..280341039b 100644 --- a/net/vhost-user.c +++ b/net/vhost-user.c @@ -179,6 +179,8 @@ static void net_vhost_user_event(void *opaque, int event) queues = qemu_find_net_clients_except(name, ncs, NET_CLIENT_OPTIONS_KIND_NIC, MAX_QUEUE_NUM); + assert(queues < MAX_QUEUE_NUM); + s = DO_UPCAST(VhostUserState, nc, ncs[0]); trace_vhost_user_event(s->chr->label, event); switch (event) { @@ -207,6 +209,9 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, VhostUserState *s; int i; + assert(name); + assert(queues > 0); + for (i = 0; i < queues; i++) { nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name); @@ -219,7 +224,7 @@ static int net_vhost_user_init(NetClientState *peer, const char *device, s->chr = chr; } - qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, (void*)name); + qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name); return 0; }