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| author | Weiming Shi <bestswngs@gmail.com> | 2026-08-18 23:45:15 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-08-22 13:10:48 -0700 |
| commit | 71283aaa6c65b3cec84caf1dc78560985737641f (patch) | |
| tree | 23e19a663952ac51fb5835852df484ddcd3d516b | |
| parent | 7c3a1a34810d9570d65701200f23d6a9e7e6c874 (diff) | |
| download | linux-71283aaa6c65b3cec84caf1dc78560985737641f.tar.gz linux-71283aaa6c65b3cec84caf1dc78560985737641f.zip | |
xdp: fix zero-copy frame layout
xdp_convert_zc_to_xdp_frame() clones an XSK packet into an order-0 page
and advertises PAGE_SIZE as its frame size. It allows the copied frame
to occupy the page tail needed by skb_shared_info and records zero
headroom even when metadata separates the frame header from packet data.
An AF_XDP zero-copy packet redirected through cpumap can therefore make
the skb overlap skb_shared_info or place it beyond the allocated page.
Limit the copied layout to SKB_WITH_OVERHEAD(PAGE_SIZE) and include the
metadata length in frame headroom. Redirect callers already handle a
NULL conversion result.
BUG: KASAN: slab-out-of-bounds in skb_gro_receive
Write of size 4 at addr ffff88800cf37004 by task cpumap/1/map:1/146
Call Trace:
skb_gro_receive (net/core/gro.c:174)
udp_gro_receive (net/ipv4/udp_offload.c:812)
inet_gro_receive (net/ipv4/af_inet.c:1539)
dev_gro_receive (net/core/gro.c:515)
gro_receive_skb (net/core/gro.c:633)
cpu_map_kthread_run (kernel/bpf/cpumap.c:395)
kthread (kernel/kthread.c:436)
ret_from_fork (arch/x86/kernel/process.c:164)
ret_from_fork_asm (arch/x86/entry/entry_64.S:255)
Kernel panic - not syncing: KASAN: panic_on_warn set ...
Fixes: b0d1beeff2a9 ("xdp: implement convert_to_xdp_frame for MEM_TYPE_ZERO_COPY")
Cc: stable@vger.kernel.org
Reported-by: Xiang Mei <xmei5@asu.edu>
Signed-off-by: Weiming Shi <bestswngs@gmail.com>
Link: https://patch.msgid.link/20260818154516.793517-1-bestswngs@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/core/xdp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/xdp.c b/net/core/xdp.c index 0194e69da339..1d679e8fd649 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -585,7 +585,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) xdp->data - xdp->data_meta; totsize = xdp->data_end - xdp->data + metasize; - if (sizeof(*xdpf) + totsize > PAGE_SIZE) + if (sizeof(*xdpf) + totsize > SKB_WITH_OVERHEAD(PAGE_SIZE)) return NULL; page = dev_alloc_page(); @@ -602,7 +602,7 @@ struct xdp_frame *xdp_convert_zc_to_xdp_frame(struct xdp_buff *xdp) xdpf->data = addr + metasize; xdpf->len = totsize - metasize; - xdpf->headroom = 0; + xdpf->headroom = metasize; xdpf->metasize = metasize; xdpf->frame_sz = PAGE_SIZE; xdpf->mem_type = MEM_TYPE_PAGE_ORDER0; |