On Wed, 19 Aug 2020 15:13:49 +0200
Lorenzo Bianconi [off-list ref] wrote:
quoted hunk ↗ jump to hunk
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 884f140fc3be..006b24b5d276 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -370,19 +370,55 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct)
void xdp_return_frame(struct xdp_frame *xdpf)
{
+ struct skb_shared_info *sinfo;
+ int i;
+
__xdp_return(xdpf->data, &xdpf->mem, false);
There is a use-after-free race here. The xdpf->data contains the
shared_info (xdp_get_shared_info_from_frame(xdpf)). Thus you cannot
free/return the page and use this data area below.
quoted hunk ↗ jump to hunk
+ if (!xdpf->mb)
+ return;
+
+ sinfo = xdp_get_shared_info_from_frame(xdpf);
+ for (i = 0; i < sinfo->nr_frags; i++) {
+ struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+ __xdp_return(page_address(page), &xdpf->mem, false);
+ }
}
EXPORT_SYMBOL_GPL(xdp_return_frame);
void xdp_return_frame_rx_napi(struct xdp_frame *xdpf)
{
+ struct skb_shared_info *sinfo;
+ int i;
+
__xdp_return(xdpf->data, &xdpf->mem, true);
Same issue.
quoted hunk ↗ jump to hunk
+ if (!xdpf->mb)
+ return;
+
+ sinfo = xdp_get_shared_info_from_frame(xdpf);
+ for (i = 0; i < sinfo->nr_frags; i++) {
+ struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+ __xdp_return(page_address(page), &xdpf->mem, true);
+ }
}
EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
void xdp_return_buff(struct xdp_buff *xdp)
{
+ struct skb_shared_info *sinfo;
+ int i;
+
__xdp_return(xdp->data, &xdp->rxq->mem, true);
Same issue.
quoted hunk ↗ jump to hunk
+ if (!xdp->mb)
+ return;
+
+ sinfo = xdp_get_shared_info_from_buff(xdp);
+ for (i = 0; i < sinfo->nr_frags; i++) {
+ struct page *page = skb_frag_page(&sinfo->frags[i]);
+
+ __xdp_return(page_address(page), &xdp->rxq->mem, true);
+ }
}
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer