smc: switch to usage of IB_PD_UNSAFE_GLOBAL_RKEY

Currently, SMC enables remote access to physical memory when a user
has successfully configured and established an SMC-connection until ten
minutes after the last SMC connection is closed. Because this is considered
a security risk, drivers are supposed to use IB_PD_UNSAFE_GLOBAL_RKEY in
such a case.

This patch changes the current SMC code to use IB_PD_UNSAFE_GLOBAL_RKEY.
This improves user awareness, but does not remove the security risk itself.

Signed-off-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/smc/smc_clc.c

@@ -204,7 +204,7 @@ int smc_clc_send_confirm(struct smc_sock *smc)
 	memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(cclc.qpn, link->roce_qp->qp_num);
 	cclc.rmb_rkey =
-		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
+		htonl(conn->rmb_desc->rkey[SMC_SINGLE_LINK]);
 	cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
 	cclc.rmbe_alert_token = htonl(conn->alert_token_local);
 	cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
@@ -256,7 +256,7 @@ int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
 	memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(aclc.qpn, link->roce_qp->qp_num);
 	aclc.rmb_rkey =
-		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
+		htonl(conn->rmb_desc->rkey[SMC_SINGLE_LINK]);
 	aclc.conn_idx = 1;			/* as long as 1 RMB = 1 RMBE */
 	aclc.rmbe_alert_token = htonl(conn->alert_token_local);
 	aclc.qp_mtu = link->path_mtu;

net/smc/smc_core.c

@@ -613,19 +613,8 @@ int smc_rmb_create(struct smc_sock *smc)
 			rmb_desc = NULL;
 			continue; /* if mapping failed, try smaller one */
 		}
-		rc = smc_ib_get_memory_region(lgr->lnk[SMC_SINGLE_LINK].roce_pd,
-					      IB_ACCESS_REMOTE_WRITE |
-					      IB_ACCESS_LOCAL_WRITE,
-					     &rmb_desc->mr_rx[SMC_SINGLE_LINK]);
-		if (rc) {
-			smc_ib_buf_unmap(lgr->lnk[SMC_SINGLE_LINK].smcibdev,
-					 tmp_bufsize, rmb_desc,
-					 DMA_FROM_DEVICE);
-			kfree(rmb_desc->cpu_addr);
-			kfree(rmb_desc);
-			rmb_desc = NULL;
-			continue;
-		}
+		rmb_desc->rkey[SMC_SINGLE_LINK] =
+			lgr->lnk[SMC_SINGLE_LINK].roce_pd->unsafe_global_rkey;
 		rmb_desc->used = 1;
 		write_lock_bh(&lgr->rmbs_lock);
 		list_add(&rmb_desc->list,
@@ -668,6 +657,7 @@ int smc_rmb_rtoken_handling(struct smc_connection *conn,
 
 	for (i = 0; i < SMC_RMBS_PER_LGR_MAX; i++) {
 		if ((lgr->rtokens[i][SMC_SINGLE_LINK].rkey == rkey) &&
+		    (lgr->rtokens[i][SMC_SINGLE_LINK].dma_addr == dma_addr) &&
 		    test_bit(i, lgr->rtokens_used_mask)) {
 			conn->rtoken_idx = i;
 			return 0;

net/smc/smc_core.h

@@ -93,7 +93,7 @@ struct smc_buf_desc {
 	u64			dma_addr[SMC_LINKS_PER_LGR_MAX];
 						/* mapped address of buffer */
 	void			*cpu_addr;	/* virtual address of buffer */
-	struct ib_mr		*mr_rx[SMC_LINKS_PER_LGR_MAX];
+	u32			rkey[SMC_LINKS_PER_LGR_MAX];
 						/* for rmb only:
 						 * rkey provided to peer
 						 */

net/smc/smc_ib.c

@@ -37,24 +37,6 @@ u8 local_systemid[SMC_SYSTEMID_LEN] = SMC_LOCAL_SYSTEMID_RESET;	/* unique system
 								 * identifier
 								 */
 
-int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
-			     struct ib_mr **mr)
-{
-	int rc;
-
-	if (*mr)
-		return 0; /* already done */
-
-	/* obtain unique key -
-	 * next invocation of get_dma_mr returns a different key!
-	 */
-	*mr = pd->device->get_dma_mr(pd, access_flags);
-	rc = PTR_ERR_OR_ZERO(*mr);
-	if (IS_ERR(*mr))
-		*mr = NULL;
-	return rc;
-}
-
 static int smc_ib_modify_qp_init(struct smc_link *lnk)
 {
 	struct ib_qp_attr qp_attr;
@@ -210,7 +192,8 @@ int smc_ib_create_protection_domain(struct smc_link *lnk)
 {
 	int rc;
 
-	lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev, 0);
+	lnk->roce_pd = ib_alloc_pd(lnk->smcibdev->ibdev,
+				   IB_PD_UNSAFE_GLOBAL_RKEY);
 	rc = PTR_ERR_OR_ZERO(lnk->roce_pd);
 	if (IS_ERR(lnk->roce_pd))
 		lnk->roce_pd = NULL;

net/smc/smc_ib.h

@@ -61,8 +61,6 @@ void smc_ib_dealloc_protection_domain(struct smc_link *lnk);
 int smc_ib_create_protection_domain(struct smc_link *lnk);
 void smc_ib_destroy_queue_pair(struct smc_link *lnk);
 int smc_ib_create_queue_pair(struct smc_link *lnk);
-int smc_ib_get_memory_region(struct ib_pd *pd, int access_flags,
-			     struct ib_mr **mr);
 int smc_ib_ready_link(struct smc_link *lnk);
 int smc_ib_modify_qp_rts(struct smc_link *lnk);
 int smc_ib_modify_qp_reset(struct smc_link *lnk);