netdev - [PATCH net 4/7] net/mlx5e: kTLS, Fix incorrect page refcounting

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241107183527.676877-5-tariqt@nvidia.com>
Date: Thu, 7 Nov 2024 20:35:24 +0200
From: Tariq Toukan <tariqt@...dia.com>
To: "David S. Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>, Eric Dumazet <edumazet@...gle.com>, "Andrew
 Lunn" <andrew+netdev@...n.ch>
CC: <netdev@...r.kernel.org>, Saeed Mahameed <saeedm@...dia.com>, Gal Pressman
	<gal@...dia.com>, Leon Romanovsky <leonro@...dia.com>, Dragos Tatulea
	<dtatulea@...dia.com>, Tariq Toukan <tariqt@...dia.com>
Subject: [PATCH net 4/7] net/mlx5e: kTLS, Fix incorrect page refcounting

From: Dragos Tatulea <dtatulea@...dia.com>

The kTLS tx handling code is using a mix of get_page() and
page_ref_inc() APIs to increment the page reference. But on the release
path (mlx5e_ktls_tx_handle_resync_dump_comp()), only put_page() is used.

This is an issue when using pages from large folios: the get_page()
references are stored on the folio page while the page_ref_inc()
references are stored directly in the given page. On release the folio
page will be dereferenced too many times.

This was found while doing kTLS testing with sendfile() + ZC when the
served file was read from NFS on a kernel with NFS large folios support
(commit 49b29a573da8 ("nfs: add support for large folios")).

Fixes: 84d1bb2b139e ("net/mlx5e: kTLS, Limit DUMP wqe size")
Signed-off-by: Dragos Tatulea <dtatulea@...dia.com>
Signed-off-by: Tariq Toukan <tariqt@...dia.com>
---
 .../net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c    | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
index d61be26a4df1..3db31cc10719 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
@@ -660,7 +660,7 @@ tx_sync_info_get(struct mlx5e_ktls_offload_context_tx *priv_tx,
 	while (remaining > 0) {
 		skb_frag_t *frag = &record->frags[i];
 
-		get_page(skb_frag_page(frag));
+		page_ref_inc(skb_frag_page(frag));
 		remaining -= skb_frag_size(frag);
 		info->frags[i++] = *frag;
 	}
@@ -763,7 +763,7 @@ void mlx5e_ktls_tx_handle_resync_dump_comp(struct mlx5e_txqsq *sq,
 	stats = sq->stats;
 
 	mlx5e_tx_dma_unmap(sq->pdev, dma);
-	put_page(wi->resync_dump_frag_page);
+	page_ref_dec(wi->resync_dump_frag_page);
 	stats->tls_dump_packets++;
 	stats->tls_dump_bytes += wi->num_bytes;
 }
@@ -816,12 +816,12 @@ mlx5e_ktls_tx_handle_ooo(struct mlx5e_ktls_offload_context_tx *priv_tx,
 
 err_out:
 	for (; i < info.nr_frags; i++)
-		/* The put_page() here undoes the page ref obtained in tx_sync_info_get().
+		/* The page_ref_dec() here undoes the page ref obtained in tx_sync_info_get().
 		 * Page refs obtained for the DUMP WQEs above (by page_ref_add) will be
 		 * released only upon their completions (or in mlx5e_free_txqsq_descs,
 		 * if channel closes).
 		 */
-		put_page(skb_frag_page(&info.frags[i]));
+		page_ref_dec(skb_frag_page(&info.frags[i]));
 
 	return MLX5E_KTLS_SYNC_FAIL;
 }
-- 
2.44.0