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Subject[PATCH] net: ncsi: Adding padding bytes in the payload
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.

Signed-off-by: Kumar Thangavel <thangavel.k@hcl.com>

---
net/ncsi/ncsi-cmd.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/net/ncsi/ncsi-cmd.c b/net/ncsi/ncsi-cmd.c
index ba9ae482141b..4625fc935603 100644
--- a/net/ncsi/ncsi-cmd.c
+++ b/net/ncsi/ncsi-cmd.c
@@ -214,11 +214,19 @@ static int ncsi_cmd_handler_oem(struct sk_buff *skb,
struct ncsi_cmd_oem_pkt *cmd;
unsigned int len;

+ /* NC-SI spec 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
+ */
+
+ unsigned short payload = ALIGN(nca->payload, 4);
+
len = sizeof(struct ncsi_cmd_pkt_hdr) + 4;
- if (nca->payload < 26)
+ if (payload < 26)
len += 26;
else
- len += nca->payload;
+ len += payload;

cmd = skb_put_zero(skb, len);
memcpy(&cmd->mfr_id, nca->data, nca->payload);
@@ -272,6 +280,7 @@ 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 +290,18 @@ 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 follwoing payload is
+ * aligned to 32bit 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)
+
+ payload = ALIGN(nca->payload, 4);
+ if (payload < 26)
len += 26;
else
- len += nca->payload;
+ len += payload;

/* Allocate skb */
skb = alloc_skb(len, GFP_ATOMIC);
--
2.17.1
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