linux-kernel - [PATCH 5.10 080/121] net/ncsi : Add payload to be 32-bit aligned to fix dropped packets

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Message-Id: <20211129181714.355382572@linuxfoundation.org>
Date:   Mon, 29 Nov 2021 19:18:31 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kumar Thangavel <thangavel.k@....com>,
        Samuel Mendoza-Jonas <sam@...dozajonas.com>,
        Paul Menzel <pmenzel@...gen.mpg.de>,
        "David S. Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 080/121] net/ncsi : Add payload to be 32-bit aligned to fix dropped packets

From: Kumar Thangavel <kumarthangavel.hcl@...il.com>

[ Upstream commit ac132852147ad303a938dda318970dd1bbdfda4e ]

Update NC-SI command handler (both standard and OEM) to take into
account of payload paddings in allocating skb (in case of payload
size is not 32-bit aligned).

The checksum field follows payload field, without taking payload
padding into account can cause checksum being truncated, leading to
dropped packets.

Fixes: fb4ee67529ff ("net/ncsi: Add NCSI OEM command support")
Signed-off-by: Kumar Thangavel <thangavel.k@....com>
Acked-by: Samuel Mendoza-Jonas <sam@...dozajonas.com>
Reviewed-by: Paul Menzel <pmenzel@...gen.mpg.de>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ncsi/ncsi-cmd.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c
index ba9ae482141b0..dda8b76b77988 100644
--- a/net/ncsi/ncsi-cmd.c
+++ b/net/ncsi/ncsi-cmd.c
@@ -18,6 +18,8 @@
 #include "internal.h"
 #include "ncsi-pkt.h"
 
+static const int padding_bytes = 26;
+
 u32 ncsi_calculate_checksum(unsigned char *data, int len)
 {
 	u32 checksum = 0;
@@ -213,12 +215,17 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
 {
 	struct ncsi_cmd_oem_pkt *cmd;
 	unsigned int len;
+	int payload;
+	/* NC-SI spec DSP_0222_1.2.0, section 8.2.2.2
+	 * requires payload to be padded with 0 to
+	 * 32-bit boundary before the checksum field.
+	 * Ensure the padding bytes are accounted for in
+	 * skb allocation
+	 */
 
+	payload = ALIGN(nca->payload, 4);
 	len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;
-	if (nca->payload < 26)
-		len += 26;
-	else
-		len += nca->payload;
+	len += max(payload, padding_bytes);
 
 	cmd = skb_put_zero(skb, len);
 	memcpy(&cmd->mfr_id, nca->data, nca->payload);
@@ -272,6 +279,7 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
 	struct net_device *dev = nd->dev;
 	int hlen = LL_RESERVED_SPACE(dev);
 	int tlen = dev->needed_tailroom;
+	int payload;
 	int len = hlen + tlen;
 	struct sk_buff *skb;
 	struct ncsi_request *nr;
@@ -281,14 +289,14 @@ static struct ncsi_request *ncsi_alloc_command(struct ncsi_cmd_arg *nca)
 		return NULL;
 
 	/* NCSI command packet has 16-bytes header, payload, 4 bytes checksum.
+	 * Payload needs padding so that the checksum field following payload is
+	 * aligned to 32-bit boundary.
 	 * The packet needs padding if its payload is less than 26 bytes to
 	 * meet 64 bytes minimal ethernet frame length.
 	 */
 	len += sizeof(struct ncsi_cmd_pkt_hdr) + 4;
-	if (nca->payload < 26)
-		len += 26;
-	else
-		len += nca->payload;
+	payload = ALIGN(nca->payload, 4);
+	len += max(payload, padding_bytes);
 
 	/* Allocate skb */
 	skb = alloc_skb(len, GFP_ATOMIC);
-- 
2.33.0