Re: [PATCH] net/qrtr: restrict user-controlled length in qrtr_tun_write_iter()
From: Eric Dumazet <hidden>
Date: 2021-02-12 11:52:14
Also in:
lkml
On 2/2/21 10:20 AM, Sabyrzhan Tasbolatov wrote:
quoted hunk ↗ jump to hunk
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@syzkaller.appspotmail.com Signed-off-by: Sabyrzhan Tasbolatov <redacted> --- 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;
Probably not enough. qrtr_endpoint_post() will later attempt a netdev_alloc_skb() which will need some extra space (for struct skb_shared_info) Do we really expect to accept huge lengths here ?
quoted hunk ↗ jump to hunk
+ kbuf = kzalloc(len, GFP_KERNEL); if (!kbuf) return -ENOMEM;