xsk: Fix out of boundary write in __xsk_rcv_memcpy

commit db5c97f02373917efe2c218ebf8e3d8b19e343b6 upstream.

first_len is the remainder of the first page we're copying.
If this size is larger, then out of page boundary write will
otherwise happen.

Fixes: c05cd36458 ("xsk: add support to allow unaligned chunk placement")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Link: https://lore.kernel.org/bpf/1585813930-19712-1-git-send-email-lirongqing@baidu.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Li RongQing 2020-04-02 15:52:10 +08:00 committed by Greg Kroah-Hartman
parent 9a9eae7852
commit e7f6c25baf

View File

@ -129,8 +129,9 @@ static void __xsk_rcv_memcpy(struct xdp_umem *umem, u64 addr, void *from_buf,
u64 page_start = addr & ~(PAGE_SIZE - 1);
u64 first_len = PAGE_SIZE - (addr - page_start);
memcpy(to_buf, from_buf, first_len + metalen);
memcpy(next_pg_addr, from_buf + first_len, len - first_len);
memcpy(to_buf, from_buf, first_len);
memcpy(next_pg_addr, from_buf + first_len,
len + metalen - first_len);
return;
}