From bcf1b70ac6eb0ed8286c66e6bf37cb747cbaa04c Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Thu, 5 Apr 2012 12:07:45 +0000 Subject: phonet: Check input from user before allocating 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 --- net/phonet/pep.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/phonet') diff --git a/net/phonet/pep.c b/net/phonet/pep.c index 9f60008740e3..9726fe684ab8 100644 --- a/net/phonet/pep.c +++ b/net/phonet/pep.c @@ -1130,6 +1130,9 @@ static int pep_sendmsg(struct kiocb *iocb, struct sock *sk, int flags = msg->msg_flags; int err, done; + if (len > USHRT_MAX) + return -EMSGSIZE; + if ((msg->msg_flags & ~(MSG_DONTWAIT|MSG_EOR|MSG_NOSIGNAL| MSG_CMSG_COMPAT)) || !(msg->msg_flags & MSG_EOR)) -- cgit v1.2.3