From: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx> commit 2a80c15812372e554474b1dba0b1d8e467af295d upstream. 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+c2a7e5c5211605a90865@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx> Link: https://lore.kernel.org/r/20210202092059.1361381-1-snovitoll@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/qrtr/tun.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/net/qrtr/tun.c +++ b/net/qrtr/tun.c @@ -80,6 +80,12 @@ static ssize_t qrtr_tun_write_iter(struc ssize_t ret; void *kbuf; + if (!len) + return -EINVAL; + + if (len > KMALLOC_MAX_SIZE) + return -ENOMEM; + kbuf = kzalloc(len, GFP_KERNEL); if (!kbuf) return -ENOMEM;
