| From ffdd748dd09307b817e40f24a128c084e9366e6d Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <levinsasha928@gmail.com> |
| 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=UTF-8 |
| 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] [<ffffffff810b2ba7>] warn_slowpath_common+0x87/0xb0 |
| [ 8921.762868] [<ffffffff810b2be5>] warn_slowpath_null+0x15/0x20 |
| [ 8921.765399] [<ffffffff8117eae5>] __alloc_pages_slowpath+0x65/0x730 |
| [ 8921.769226] [<ffffffff81179c8a>] ? zone_watermark_ok+0x1a/0x20 |
| [ 8921.771686] [<ffffffff8117d045>] ? get_page_from_freelist+0x625/0x660 |
| [ 8921.773919] [<ffffffff8117f3a8>] __alloc_pages_nodemask+0x1f8/0x240 |
| [ 8921.776248] [<ffffffff811c03e0>] kmalloc_large_node+0x70/0xc0 |
| [ 8921.778294] [<ffffffff811c4bd4>] __kmalloc_node_track_caller+0x34/0x1c0 |
| [ 8921.780847] [<ffffffff821b0e3c>] ? sock_alloc_send_pskb+0xbc/0x260 |
| [ 8921.783179] [<ffffffff821b3c65>] __alloc_skb+0x75/0x170 |
| [ 8921.784971] [<ffffffff821b0e3c>] sock_alloc_send_pskb+0xbc/0x260 |
| [ 8921.787111] [<ffffffff821b002e>] ? release_sock+0x7e/0x90 |
| [ 8921.788973] [<ffffffff821b0ff0>] sock_alloc_send_skb+0x10/0x20 |
| [ 8921.791052] [<ffffffff824cfc20>] pep_sendmsg+0x60/0x380 |
| [ 8921.792931] [<ffffffff824cb4a6>] ? pn_socket_bind+0x156/0x180 |
| [ 8921.794917] [<ffffffff824cb50f>] ? pn_socket_autobind+0x3f/0x90 |
| [ 8921.797053] [<ffffffff824cb63f>] pn_socket_sendmsg+0x4f/0x70 |
| [ 8921.798992] [<ffffffff821ab8e7>] sock_aio_write+0x187/0x1b0 |
| [ 8921.801395] [<ffffffff810e325e>] ? sub_preempt_count+0xae/0xf0 |
| [ 8921.803501] [<ffffffff8111842c>] ? __lock_acquire+0x42c/0x4b0 |
| [ 8921.805505] [<ffffffff821ab760>] ? __sock_recv_ts_and_drops+0x140/0x140 |
| [ 8921.807860] [<ffffffff811e07cc>] do_sync_readv_writev+0xbc/0x110 |
| [ 8921.809986] [<ffffffff811958e7>] ? might_fault+0x97/0xa0 |
| [ 8921.811998] [<ffffffff817bd99e>] ? security_file_permission+0x1e/0x90 |
| [ 8921.814595] [<ffffffff811e17e2>] do_readv_writev+0xe2/0x1e0 |
| [ 8921.816702] [<ffffffff810b8dac>] ? do_setitimer+0x1ac/0x200 |
| [ 8921.818819] [<ffffffff810e2ec1>] ? get_parent_ip+0x11/0x50 |
| [ 8921.820863] [<ffffffff810e325e>] ? sub_preempt_count+0xae/0xf0 |
| [ 8921.823318] [<ffffffff811e1926>] vfs_writev+0x46/0x60 |
| [ 8921.825219] [<ffffffff811e1a3f>] sys_writev+0x4f/0xb0 |
| [ 8921.827127] [<ffffffff82658039>] system_call_fastpath+0x16/0x1b |
| [ 8921.829384] ---[ end trace dffe390f30db9eb7 ]--- |
| |
| Signed-off-by: Sasha Levin <levinsasha928@gmail.com> |
| Acked-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| --- |
| net/phonet/pep.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| diff --git a/net/phonet/pep.c b/net/phonet/pep.c |
| index dc1e8ae81781..ca21189392fe 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)) |
| -- |
| 1.8.5.2 |
| |
