On Tue, 2 Feb 2021 15:20:59 +0600 Sabyrzhan Tasbolatov wrote: > syzbot found WARNING in qrtr_tun_write_iter [1] when write_iter length > exceeds KMALLOC_MAX_SIZE causing order >= MAX_ORDER condition. > > Additionally, there is no check for 0 length write. > > [1] > WARNING: mm/page_alloc.c:5011 > [..] > Call Trace: > alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2267 > alloc_pages include/linux/gfp.h:547 [inline] > kmalloc_order+0x2e/0xb0 mm/slab_common.c:837 > kmalloc_order_trace+0x14/0x120 mm/slab_common.c:853 > kmalloc include/linux/slab.h:557 [inline] > kzalloc include/linux/slab.h:682 [inline] > qrtr_tun_write_iter+0x8a/0x180 net/qrtr/tun.c:83 > call_write_iter include/linux/fs.h:1901 [inline] > > Reported-by: syzbot+c2a7e5c5211605a90...@syzkaller.appspotmail.com > Signed-off-by: Sabyrzhan Tasbolatov <snovit...@gmail.com> > --- > net/qrtr/tun.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/qrtr/tun.c b/net/qrtr/tun.c > index 15ce9b642b25..b238c40a9984 100644 > --- a/net/qrtr/tun.c > +++ b/net/qrtr/tun.c > @@ -80,6 +80,12 @@ static ssize_t qrtr_tun_write_iter(struct kiocb *iocb, > struct iov_iter *from) > ssize_t ret; > void *kbuf; > > + if (!len) > + return -EINVAL; > + > + if (len > KMALLOC_MAX_SIZE) > + return -ENOMEM; > + > kbuf = kzalloc(len, GFP_KERNEL);
For potential, separate clean up - this is followed by copy_from_iter_full(len) kzalloc() can probably be replaced by kmalloc()? > if (!kbuf) > return -ENOMEM;
