netdev - [PATCH 1/3] net: ftmac100: prepare data path for receiving single segment packets

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-next>] [day] [month] [year] [list]

Date:   Fri, 28 Oct 2022 21:32:18 +0300
From:   Sergei Antonov <saproj@...il.com>
To:     netdev@...r.kernel.org
Cc:     andrew@...n.ch, pabeni@...hat.com, kuba@...nel.org,
        edumazet@...gle.com, davem@...emloft.net,
        Vladimir Oltean <vladimir.oltean@....com>,
        Sergei Antonov <saproj@...il.com>
Subject: [PATCH 1/3] net: ftmac100: prepare data path for receiving single segment packets > 1514

From: Vladimir Oltean <vladimir.oltean@....com>

Eliminate one check in the data path and move it elsewhere, to where our
real limitation is. We'll want to start processing "too long" frames in
the driver (currently there is a hardware MAC setting which drops
theses).

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Signed-off-by: Sergei Antonov <saproj@...il.com>
---
 drivers/net/ethernet/faraday/ftmac100.c | 29 ++++++++++---------------
 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/faraday/ftmac100.c b/drivers/net/ethernet/faraday/ftmac100.c
index d95d78230828..8013f85fc148 100644
--- a/drivers/net/ethernet/faraday/ftmac100.c
+++ b/drivers/net/ethernet/faraday/ftmac100.c
@@ -218,11 +218,6 @@ static bool ftmac100_rxdes_crc_error(struct ftmac100_rxdes *rxdes)
 	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_CRC_ERR);
 }
 
-static bool ftmac100_rxdes_frame_too_long(struct ftmac100_rxdes *rxdes)
-{
-	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_FTL);
-}
-
 static bool ftmac100_rxdes_runt(struct ftmac100_rxdes *rxdes)
 {
 	return rxdes->rxdes0 & cpu_to_le32(FTMAC100_RXDES0_RUNT);
@@ -337,13 +332,7 @@ static bool ftmac100_rx_packet_error(struct ftmac100 *priv,
 		error = true;
 	}
 
-	if (unlikely(ftmac100_rxdes_frame_too_long(rxdes))) {
-		if (net_ratelimit())
-			netdev_info(netdev, "rx frame too long\n");
-
-		netdev->stats.rx_length_errors++;
-		error = true;
-	} else if (unlikely(ftmac100_rxdes_runt(rxdes))) {
+	if (unlikely(ftmac100_rxdes_runt(rxdes))) {
 		if (net_ratelimit())
 			netdev_info(netdev, "rx runt\n");
 
@@ -356,6 +345,11 @@ static bool ftmac100_rx_packet_error(struct ftmac100 *priv,
 		netdev->stats.rx_length_errors++;
 		error = true;
 	}
+	/*
+	 * FTMAC100_RXDES0_FTL is not an error, it just indicates that the
+	 * frame is longer than 1518 octets. Receiving these is possible when
+	 * we told the hardware not to drop them, via FTMAC100_MACCR_RX_FTL.
+	 */
 
 	return error;
 }
@@ -400,12 +394,13 @@ static bool ftmac100_rx_packet(struct ftmac100 *priv, int *processed)
 		return true;
 	}
 
-	/*
-	 * It is impossible to get multi-segment packets
-	 * because we always provide big enough receive buffers.
-	 */
+	/* We don't support multi-segment packets for now, so drop them. */
 	ret = ftmac100_rxdes_last_segment(rxdes);
-	BUG_ON(!ret);
+	if (unlikely(!ret)) {
+		netdev->stats.rx_length_errors++;
+		ftmac100_rx_drop_packet(priv);
+		return true;
+	}
 
 	/* start processing */
 	skb = netdev_alloc_skb_ip_align(netdev, 128);
-- 
2.34.1