RDMA/cma: Allow UD qp_type to join multicast only

BugLink: https://bugs.launchpad.net/bugs/2017219
[ Upstream commit 58e84f6b3e84e46524b7e5a916b53c1ad798bc8f ]

As for multicast:
- The SIDR is the only mode that makes sense;
- Besides PS_UDP, other port spaces like PS_IB is also allowed, as it is
  UD compatible. In this case qkey also needs to be set [1].

This patch allows only UD qp_type to join multicast, and set qkey to
default if it's not set, to fix an uninit-value error: the ib->rec.qkey
field is accessed without being initialized.

=====================================================
BUG: KMSAN: uninit-value in cma_set_qkey drivers/infiniband/core/cma.c:510 [inline]
BUG: KMSAN: uninit-value in cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570
 cma_set_qkey drivers/infiniband/core/cma.c:510 [inline]
 cma_make_mc_event+0xb73/0xe00 drivers/infiniband/core/cma.c:4570
 cma_iboe_join_multicast drivers/infiniband/core/cma.c:4782 [inline]
 rdma_join_multicast+0x2b83/0x30a0 drivers/infiniband/core/cma.c:4814
 ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479
 ucma_join_multicast+0x1e3/0x250 drivers/infiniband/core/ucma.c:1546
 ucma_write+0x639/0x6d0 drivers/infiniband/core/ucma.c:1732
 vfs_write+0x8ce/0x2030 fs/read_write.c:588
 ksys_write+0x28c/0x520 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __ia32_sys_write+0xdb/0x120 fs/read_write.c:652
 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
 __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable ib.i created at:
cma_iboe_join_multicast drivers/infiniband/core/cma.c:4737 [inline]
rdma_join_multicast+0x586/0x30a0 drivers/infiniband/core/cma.c:4814
ucma_process_join+0xa76/0xf60 drivers/infiniband/core/ucma.c:1479

CPU: 0 PID: 29874 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================

[1] https://lore.kernel.org/linux-rdma/20220117183832.GD84788@nvidia.com/

Fixes: b5de0c60cc30 ("RDMA/cma: Fix use after free race in roce multicast join")
Reported-by: syzbot+8fcbb77276d43cc8b693@syzkaller.appspotmail.com
Signed-off-by: Mark Zhang <markzhang@nvidia.com>
Link: https://lore.kernel.org/r/58a4a98323b5e6b1282e83f6b76960d06e43b9fa.1679309909.git.leon@kernel.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>

diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index 7e508b15e7761b9241a23a547c74997f45234eca..00c9529c3143fb5e2bf2bae79ae18936cef75455 100644 (file)
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -624,22 +624,11 @@ static inline unsigned short cma_family(struct rdma_id_private *id_priv)
        return id_priv->id.route.addr.src_addr.ss_family;
 }
 
-static int cma_set_qkey(struct rdma_id_private *id_priv, u32 qkey)
+static int cma_set_default_qkey(struct rdma_id_private *id_priv)
 {
        struct ib_sa_mcmember_rec rec;
        int ret = 0;
 
-       if (id_priv->qkey) {
-               if (qkey && id_priv->qkey != qkey)
-                       return -EINVAL;
-               return 0;
-       }
-
-       if (qkey) {
-               id_priv->qkey = qkey;
-               return 0;
-       }
-
        switch (id_priv->id.ps) {
        case RDMA_PS_UDP:
        case RDMA_PS_IB:
@@ -659,6 +648,16 @@ static int cma_set_qkey(struct rdma_id_private *id_priv, u32 qkey)
        return ret;
 }
 
+static int cma_set_qkey(struct rdma_id_private *id_priv, u32 qkey)
+{
+       if (!qkey ||
+           (id_priv->qkey && (id_priv->qkey != qkey)))
+               return -EINVAL;
+
+       id_priv->qkey = qkey;
+       return 0;
+}
+
 static void cma_translate_ib(struct sockaddr_ib *sib, struct rdma_dev_addr *dev_addr)
 {
        dev_addr->dev_type = ARPHRD_INFINIBAND;
@@ -1229,7 +1228,7 @@ static int cma_ib_init_qp_attr(struct rdma_id_private *id_priv,
        *qp_attr_mask = IB_QP_STATE | IB_QP_PKEY_INDEX | IB_QP_PORT;
 
        if (id_priv->id.qp_type == IB_QPT_UD) {
-               ret = cma_set_qkey(id_priv, 0);
+               ret = cma_set_default_qkey(id_priv);
                if (ret)
                        return ret;
 
@@ -4558,7 +4557,10 @@ static int cma_send_sidr_rep(struct rdma_id_private *id_priv,
        memset(&rep, 0, sizeof rep);
        rep.status = status;
        if (status == IB_SIDR_SUCCESS) {
-               ret = cma_set_qkey(id_priv, qkey);
+               if (qkey)
+                       ret = cma_set_qkey(id_priv, qkey);
+               else
+                       ret = cma_set_default_qkey(id_priv);
                if (ret)
                        return ret;
                rep.qp_num = id_priv->qp_num;
@@ -4763,9 +4765,7 @@ static void cma_make_mc_event(int status, struct rdma_id_private *id_priv,
        enum ib_gid_type gid_type;
        struct net_device *ndev;
 
-       if (!status)
-               status = cma_set_qkey(id_priv, be32_to_cpu(multicast->rec.qkey));
-       else
+       if (status)
                pr_debug_ratelimited("RDMA CM: MULTICAST_ERROR: failed to join multicast. status %d\n",
                                     status);
 
@@ -4793,7 +4793,7 @@ static void cma_make_mc_event(int status, struct rdma_id_private *id_priv,
        }
 
        event->param.ud.qp_num = 0xFFFFFF;
-       event->param.ud.qkey = be32_to_cpu(multicast->rec.qkey);
+       event->param.ud.qkey = id_priv->qkey;
 
 out:
        if (ndev)
@@ -4812,8 +4812,11 @@ static int cma_ib_mc_handler(int status, struct ib_sa_multicast *multicast)
            READ_ONCE(id_priv->state) == RDMA_CM_DESTROYING)
                goto out;
 
-       cma_make_mc_event(status, id_priv, multicast, &event, mc);
-       ret = cma_cm_event_handler(id_priv, &event);
+       ret = cma_set_qkey(id_priv, be32_to_cpu(multicast->rec.qkey));
+       if (!ret) {
+               cma_make_mc_event(status, id_priv, multicast, &event, mc);
+               ret = cma_cm_event_handler(id_priv, &event);
+       }
        rdma_destroy_ah_attr(&event.param.ud.ah_attr);
        WARN_ON(ret);
 
@@ -4866,9 +4869,11 @@ static int cma_join_ib_multicast(struct rdma_id_private *id_priv,
        if (ret)
                return ret;
 
-       ret = cma_set_qkey(id_priv, 0);
-       if (ret)
-               return ret;
+       if (!id_priv->qkey) {
+               ret = cma_set_default_qkey(id_priv);
+               if (ret)
+                       return ret;
+       }
 
        cma_set_mgid(id_priv, (struct sockaddr *) &mc->addr, &rec.mgid);
        rec.qkey = cpu_to_be32(id_priv->qkey);
@@ -4945,9 +4950,6 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
        cma_iboe_set_mgid(addr, &ib.rec.mgid, gid_type);
 
        ib.rec.pkey = cpu_to_be16(0xffff);
-       if (id_priv->id.ps == RDMA_PS_UDP)
-               ib.rec.qkey = cpu_to_be32(RDMA_UDP_QKEY);
-
        if (dev_addr->bound_dev_if)
                ndev = dev_get_by_index(dev_addr->net, dev_addr->bound_dev_if);
        if (!ndev)
@@ -4973,6 +4975,9 @@ static int cma_iboe_join_multicast(struct rdma_id_private *id_priv,
        if (err || !ib.rec.mtu)
                return err ?: -EINVAL;
 
+       if (!id_priv->qkey)
+               cma_set_default_qkey(id_priv);
+
        rdma_ip2gid((struct sockaddr *)&id_priv->id.route.addr.src_addr,
                    &ib.rec.port_gid);
        INIT_WORK(&mc->iboe_join.work, cma_iboe_join_work_handler);
@@ -4998,6 +5003,9 @@ int rdma_join_multicast(struct rdma_cm_id *id, struct sockaddr *addr,
                            READ_ONCE(id_priv->state) != RDMA_CM_ADDR_RESOLVED))
                return -EINVAL;
 
+       if (id_priv->id.qp_type != IB_QPT_UD)
+               return -EINVAL;
+
        mc = kzalloc(sizeof(*mc), GFP_KERNEL);
        if (!mc)
                return -ENOMEM;