[PATCH 5.19 009/155] xsk: Fix corrupted packets for XDP_SHARED_UMEM

Greg Kroah-Hartman
2022-09-06T14:05:44Z

From: Magnus Karlsson <magnus.karlsson@intel.com>

[ Upstream commit 58ca14ed98c87cfe0d1408cc65a9745d9e9b7a56 ]

Fix an issue in XDP_SHARED_UMEM mode together with aligned mode where
packets are corrupted for the second and any further sockets bound to
the same umem. In other words, this does not affect the first socket
bound to the umem. The culprit for this bug is that the initialization
of the DMA addresses for the pre-populated xsk buffer pool entries was
not performed for any socket but the first one bound to the umem. Only
the linear array of DMA addresses was populated. Fix this by populating
the DMA addresses in the xsk buffer pool for every socket bound to the
same umem.

Fixes: 94033cd8e73b8 ("xsk: Optimize for aligned case")
Reported-by: Alasdair McWilliam <alasdair.mcwilliam@outlook.com>
Reported-by: Intrusion Shield Team <dnevil@intrusion.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Alasdair McWilliam <alasdair.mcwilliam@outlook.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/xdp-newbies/6205E10C-292E-4995-9D10-409649354226@outlook.com/
Link: https://lore.kernel.org/bpf/20220812113259.531-1-magnus.karlsson@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/xdp/xsk_buff_pool.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index f70112176b7c1..a71a8c6edf553 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -379,6 +379,16 @@ static void xp_check_dma_contiguity(struct xsk_dma_map *dma_map)

static int xp_init_dma_info(struct xsk_buff_pool *pool, struct xsk_dma_map *dma_map)
{
+ if (!pool->unaligned) {
+ u32 i;
+
+ for (i = 0; i < pool->heads_cnt; i++) {
+ struct xdp_buff_xsk *xskb = &pool->heads[i];
+
+ xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, xskb->orig_addr);
+ }
+ }
+
pool->dma_pages = kvcalloc(dma_map->dma_pages_cnt, sizeof(*pool->dma_pages), GFP_KERNEL);
if (!pool->dma_pages)
return -ENOMEM;
@@ -428,12 +438,6 @@ int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,

if (pool->unaligned)
xp_check_dma_contiguity(dma_map);
- else
- for (i = 0; i < pool->heads_cnt; i++) {
- struct xdp_buff_xsk *xskb = &pool->heads[i];
-
- xp_init_xskb_dma(xskb, pool, dma_map->dma_pages, xskb->orig_addr);
- }

err = xp_init_dma_info(pool, dma_map);
if (err) {
--
2.35.1