Thread (3 messages) 3 messages, 3 authors, 2021-04-28
STALE1907d

[PATCH bpf] xsk: fix for xp_aligned_validate_desc() when len == chunk_size

From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: 2021-04-27 12:19:08
Also in: bpf
Subsystem: networking [general], the rest, xdp sockets (af_xdp) · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski

When desc->len is equal to chunk_size, it is legal. But
xp_aligned_validate_desc() got "chunk_end" by desc->addr + desc->len
pointing to the next chunk during the check, which caused the check to
fail.

Fixes: 35fcde7f8deb ("xsk: support for Tx")
Fixes: bbff2f321a86 ("xsk: new descriptor addressing scheme")
Fixes: 2b43470add8c ("xsk: Introduce AF_XDP buffer allocation API")
Fixes: 26062b185eee ("xsk: Explicitly inline functions and move definitions")
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 net/xdp/xsk_queue.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 2823b7c3302d..40f359bf2044 100644
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -128,13 +128,12 @@ static inline bool xskq_cons_read_addr_unchecked(struct xsk_queue *q, u64 *addr)
 static inline bool xp_aligned_validate_desc(struct xsk_buff_pool *pool,
 					    struct xdp_desc *desc)
 {
-	u64 chunk, chunk_end;
+	u64 chunk;
 
-	chunk = xp_aligned_extract_addr(pool, desc->addr);
-	chunk_end = xp_aligned_extract_addr(pool, desc->addr + desc->len);
-	if (chunk != chunk_end)
+	if (desc->len > pool->chunk_size)
 		return false;
 
+	chunk = xp_aligned_extract_addr(pool, desc->addr);
 	if (chunk >= pool->addrs_cnt)
 		return false;
 
-- 
2.31.0
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