On 12/02/2016 01:43 PM, Andrey Konovalov wrote: > Hi! > > I've got the following error report while running the syzkaller fuzzer. > > A reproducer is attached. > > On commit d8e435f3ab6fea2ea324dce72b51dd7761747523 (Nov 26). > > ------------[ cut here ]------------ > WARNING: CPU: 0 PID: 4009 at mm/page_alloc.c:3511 > __alloc_pages_slowpath+0x3d4/0x1bf0 > Modules linked in: > CPU: 0 PID: 4009 Comm: a.out Not tainted 4.9.0-rc6+ #54 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > ffff88006832f8a8 ffffffff81c73b14 0000000000000000 0000000000000000 > ffffffff842c6320 0000000000000000 ffff88006832f8f0 ffffffff8123dc57 > ffff880067d86000 ffffffff00000db7 ffffffff842c6320 0000000000000db7 > Call Trace: > [< inline >] __dump_stack lib/dump_stack.c:15 > [<ffffffff81c73b14>] dump_stack+0xb3/0x10f lib/dump_stack.c:51 > [<ffffffff8123dc57>] __warn+0x1a7/0x1f0 kernel/panic.c:550 > [<ffffffff8123de6c>] warn_slowpath_null+0x2c/0x40 kernel/panic.c:585 > [<ffffffff81559b04>] __alloc_pages_slowpath+0x3d4/0x1bf0 mm/page_alloc.c:3511 > [<ffffffff8155b8e2>] __alloc_pages_nodemask+0x5c2/0x710 mm/page_alloc.c:3781 > [<ffffffff816236a4>] alloc_pages_current+0xf4/0x400 mm/mempolicy.c:2072 > [< inline >] alloc_pages ./include/linux/gfp.h:469 > [<ffffffff815a834f>] kmalloc_order+0x1f/0x70 mm/slab_common.c:1015 > [<ffffffff815a83bf>] kmalloc_order_trace+0x1f/0x160 mm/slab_common.c:1026 > [< inline >] kmalloc_large ./include/linux/slab.h:422 > [<ffffffff81635e67>] __kmalloc_track_caller+0x227/0x2a0 mm/slub.c:4233 > [<ffffffff8159932c>] memdup_user+0x2c/0xa0 mm/util.c:137 > [<ffffffff8369e0de>] raw_setsockopt+0x1be/0x9f0 net/can/raw.c:506
We should add a check for a sensible optlen....
> static int raw_setsockopt(struct socket *sock, int level, int optname,
> char __user *optval, unsigned int optlen)
> {
> struct sock *sk = sock->sk;
> struct raw_sock *ro = raw_sk(sk);
> struct can_filter *filter = NULL; /* dyn. alloc'ed filters */
> struct can_filter sfilter; /* single filter */
> struct net_device *dev = NULL;
> can_err_mask_t err_mask = 0;
> int count = 0;
> int err = 0;
>
> if (level != SOL_CAN_RAW)
> return -EINVAL;
>
> switch (optname) {
>
> case CAN_RAW_FILTER:
> if (optlen % sizeof(struct can_filter) != 0)
> return -EINVAL;
here...
if (optlen > 64 * sizeof(struct can_filter))
return -EINVAL;
>
> count = optlen / sizeof(struct can_filter);
>
> if (count > 1) {
> /* filter does not fit into dfilter => alloc space */
> filter = memdup_user(optval, optlen);
> if (IS_ERR(filter))
> return PTR_ERR(filter);
> } else if (count == 1) {
> if (copy_from_user(&sfilter, optval, sizeof(sfilter)))
> return -EFAULT;
> }
>
> lock_sock(sk);
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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