From 00d23e71b7712ea744b6cd3117a75b96bfc27a82 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Thu, 5 Apr 2012 12:07:45 +0000 Subject: [PATCH] phonet: Check input from user before allocating MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit bcf1b70ac6eb0ed8286c66e6bf37cb747cbaa04c upstream. A phonet packet is limited to USHRT_MAX bytes, this is never checked during tx which means that the user can specify any size he wishes, and the kernel will attempt to allocate that size. In the good case, it'll lead to the following warning, but it may also cause the kernel to kick in the OOM and kill a random task on the server. [ 8921.744094] WARNING: at mm/page_alloc.c:2255 __alloc_pages_slowpath+0x65/0x730() [ 8921.749770] Pid: 5081, comm: trinity Tainted: G W 3.4.0-rc1-next-20120402-sasha #46 [ 8921.756672] Call Trace: [ 8921.758185] [] warn_slowpath_common+0x87/0xb0 [ 8921.762868] [] warn_slowpath_null+0x15/0x20 [ 8921.765399] [] __alloc_pages_slowpath+0x65/0x730 [ 8921.769226] [] ? zone_watermark_ok+0x1a/0x20 [ 8921.771686] [] ? get_page_from_freelist+0x625/0x660 [ 8921.773919] [] __alloc_pages_nodemask+0x1f8/0x240 [ 8921.776248] [] kmalloc_large_node+0x70/0xc0 [ 8921.778294] [] __kmalloc_node_track_caller+0x34/0x1c0 [ 8921.780847] [] ? sock_alloc_send_pskb+0xbc/0x260 [ 8921.783179] [] __alloc_skb+0x75/0x170 [ 8921.784971] [] sock_alloc_send_pskb+0xbc/0x260 [ 8921.787111] [] ? release_sock+0x7e/0x90 [ 8921.788973] [] sock_alloc_send_skb+0x10/0x20 [ 8921.791052] [] pep_sendmsg+0x60/0x380 [ 8921.792931] [] ? pn_socket_bind+0x156/0x180 [ 8921.794917] [] ? pn_socket_autobind+0x3f/0x90 [ 8921.797053] [] pn_socket_sendmsg+0x4f/0x70 [ 8921.798992] [] sock_aio_write+0x187/0x1b0 [ 8921.801395] [] ? sub_preempt_count+0xae/0xf0 [ 8921.803501] [] ? __lock_acquire+0x42c/0x4b0 [ 8921.805505] [] ? __sock_recv_ts_and_drops+0x140/0x140 [ 8921.807860] [] do_sync_readv_writev+0xbc/0x110 [ 8921.809986] [] ? might_fault+0x97/0xa0 [ 8921.811998] [] ? security_file_permission+0x1e/0x90 [ 8921.814595] [] do_readv_writev+0xe2/0x1e0 [ 8921.816702] [] ? do_setitimer+0x1ac/0x200 [ 8921.818819] [] ? get_parent_ip+0x11/0x50 [ 8921.820863] [] ? sub_preempt_count+0xae/0xf0 [ 8921.823318] [] vfs_writev+0x46/0x60 [ 8921.825219] [] sys_writev+0x4f/0xb0 [ 8921.827127] [] system_call_fastpath+0x16/0x1b [ 8921.829384] ---[ end trace dffe390f30db9eb7 ]--- Signed-off-by: Sasha Levin Acked-by: Rémi Denis-Courmont Signed-off-by: David S. Miller Signed-off-by: Paul Gortmaker --- net/phonet/pep.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/phonet/pep.c b/net/phonet/pep.c index dc1e8ae817810..ca21189392fee 100644 --- a/net/phonet/pep.c +++ b/net/phonet/pep.c @@ -862,6 +862,9 @@ static int pep_sendmsg(struct kiocb *iocb, struct sock *sk, int flags = msg->msg_flags; int err, done; + if (len > USHORT_MAX) + return -EMSGSIZE; + if ((msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL| MSG_CMSG_COMPAT)) || !(msg->msg_flags & MSG_EOR)) -- 2.47.2