[PATCH AUTOSEL 4.14 05/19] rxe: correctly calculate iCRC for unaligned payloads

[Sasha Levin]

From: Steve Wise <larrystevenwise@xxxxxxxxx>

[ Upstream commit 2030abddec6884aaf5892f5724c48fc340e6826f ]

If RoCE PDUs being sent or received contain pad bytes, then the iCRC
is miscalculated, resulting in PDUs being emitted by RXE with an incorrect
iCRC, as well as ingress PDUs being dropped due to erroneously detecting
a bad iCRC in the PDU.  The fix is to include the pad bytes, if any,
in iCRC computations.

Note: This bug has caused broken on-the-wire compatibility with actual
hardware RoCE devices since the soft-RoCE driver was first put into the
mainstream kernel.  Fixing it will create an incompatibility with the
original soft-RoCE devices, but is necessary to be compatible with real
hardware devices.

Fixes: 8700e3e7c485 ("Soft RoCE driver")
Signed-off-by: Steve Wise <larrystevenwise@xxxxxxxxx>
Link: https://lore.kernel.org/r/20191203020319.15036-2-larrystevenwise@xxxxxxxxx
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_recv.c | 2 +-
 drivers/infiniband/sw/rxe/rxe_req.c  | 6 ++++++
 drivers/infiniband/sw/rxe/rxe_resp.c | 7 +++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rxe/rxe_recv.c b/drivers/infiniband/sw/rxe/rxe_recv.c
index 83412df726a51..b7098f7bb30e5 100644
--- a/drivers/infiniband/sw/rxe/rxe_recv.c
+++ b/drivers/infiniband/sw/rxe/rxe_recv.c
@@ -393,7 +393,7 @@ int rxe_rcv(struct sk_buff *skb)
 
 	calc_icrc = rxe_icrc_hdr(pkt, skb);
 	calc_icrc = rxe_crc32(rxe, calc_icrc, (u8 *)payload_addr(pkt),
-			      payload_size(pkt));
+			      payload_size(pkt) + bth_pad(pkt));
 	calc_icrc = (__force u32)cpu_to_be32(~calc_icrc);
 	if (unlikely(calc_icrc != pack_icrc)) {
 		if (skb->protocol == htons(ETH_P_IPV6))
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
index 9fd4f04df3b33..e6785b1ea85fc 100644
--- a/drivers/infiniband/sw/rxe/rxe_req.c
+++ b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -500,6 +500,12 @@ static int fill_packet(struct rxe_qp *qp, struct rxe_send_wqe *wqe,
 			if (err)
 				return err;
 		}
+		if (bth_pad(pkt)) {
+			u8 *pad = payload_addr(pkt) + paylen;
+
+			memset(pad, 0, bth_pad(pkt));
+			crc = rxe_crc32(rxe, crc, pad, bth_pad(pkt));
+		}
 	}
 	p = payload_addr(pkt) + paylen + bth_pad(pkt);
 
diff --git a/drivers/infiniband/sw/rxe/rxe_resp.c b/drivers/infiniband/sw/rxe/rxe_resp.c
index 9207682b7a2ee..a07a29b488632 100644
--- a/drivers/infiniband/sw/rxe/rxe_resp.c
+++ b/drivers/infiniband/sw/rxe/rxe_resp.c
@@ -738,6 +738,13 @@ static enum resp_states read_reply(struct rxe_qp *qp,
 	if (err)
 		pr_err("Failed copying memory\n");
 
+	if (bth_pad(&ack_pkt)) {
+		struct rxe_dev *rxe = to_rdev(qp->ibqp.device);
+		u8 *pad = payload_addr(&ack_pkt) + payload;
+
+		memset(pad, 0, bth_pad(&ack_pkt));
+		icrc = rxe_crc32(rxe, icrc, pad, bth_pad(&ack_pkt));
+	}
 	p = payload_addr(&ack_pkt) + payload + bth_pad(&ack_pkt);
 	*p = ~icrc;
 
-- 
2.20.1