Commit d769ccaf authored by Kal Conley's avatar Kal Conley Committed by Martin KaFai Lau
Browse files

xsk: Fix unaligned descriptor validation 



Make sure unaligned descriptors that straddle the end of the UMEM are
considered invalid. Currently, descriptor validation is broken for
zero-copy mode which only checks descriptors at page granularity.
For example, descriptors in zero-copy mode that overrun the end of the
UMEM but not a page boundary are (incorrectly) considered valid. The
UMEM boundary check needs to happen before the page boundary and
contiguity checks in xp_desc_crosses_non_contig_pg(). Do this check in
xp_unaligned_validate_desc() instead like xp_check_unaligned() already
does.

Fixes: 2b43470a ("xsk: Introduce AF_XDP buffer allocation API")
Signed-off-by: default avatarKal Conley <kal.conley@dectris.com>
Acked-by: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230405235920.7305-2-kal.conley@dectris.com


Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
parent 34bf9347

include/net/xsk_buff_pool.h

+2 −7
Original line number Diff line number Diff line
@@ -180,13 +180,8 @@ static inline bool xp_desc_crosses_non_contig_pg(struct xsk_buff_pool *pool, 
	if (likely(!cross_pg))

		return false;



	if (pool->dma_pages_cnt) {

		return !(pool->dma_pages[addr >> PAGE_SHIFT] &

			 XSK_NEXT_PG_CONTIG_MASK);

	}



	/* skb path */

	return addr + len > pool->addrs_cnt;

	return pool->dma_pages_cnt &&

	       !(pool->dma_pages[addr >> PAGE_SHIFT] & XSK_NEXT_PG_CONTIG_MASK);

}



static inline u64 xp_aligned_extract_addr(struct xsk_buff_pool *pool, u64 addr)

net/xdp/xsk_queue.h

+1 −0
Original line number Diff line number Diff line
@@ -162,6 +162,7 @@ static inline bool xp_unaligned_validate_desc(struct xsk_buff_pool *pool, 
		return false;



	if (base_addr >= pool->addrs_cnt || addr >= pool->addrs_cnt ||

	    addr + desc->len > pool->addrs_cnt ||

	    xp_desc_crosses_non_contig_pg(pool, addr, desc->len))

		return false;