linux-kernel - [PATCH] vdpa_sim: avoid putting an uninitialized iova

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20211122122221.56-1-longpeng2@huawei.com>
Date:   Mon, 22 Nov 2021 20:22:21 +0800
From:   "Longpeng(Mike)" <longpeng2@...wei.com>
To:     <mst@...hat.com>, <jasowang@...hat.com>
CC:     <sgarzare@...hat.com>, <mgurtovoy@...dia.com>, <parav@...dia.com>,
        <virtualization@...ts.linux-foundation.org>,
        <linux-kernel@...r.kernel.org>, <arei.gonglei@...wei.com>,
        Longpeng <longpeng2@...wei.com>
Subject: [PATCH] vdpa_sim: avoid putting an uninitialized iova_domain

From: Longpeng <longpeng2@...wei.com>

The system will crash if we put an uninitialized iova_domain, this
could happen when an error occurs before initializing the iova_domain
in vdpasim_create().

BUG: kernel NULL pointer dereference, address: 0000000000000000
...
RIP: 0010:__cpuhp_state_remove_instance+0x96/0x1c0
...
Call Trace:
 <TASK>
 put_iova_domain+0x29/0x220
 vdpasim_free+0xd1/0x120 [vdpa_sim]
 vdpa_release_dev+0x21/0x40 [vdpa]
 device_release+0x33/0x90
 kobject_release+0x63/0x160
 vdpasim_create+0x127/0x2a0 [vdpa_sim]
 vdpasim_net_dev_add+0x7d/0xfe [vdpa_sim_net]
 vdpa_nl_cmd_dev_add_set_doit+0xe1/0x1a0 [vdpa]
 genl_family_rcv_msg_doit+0x112/0x140
 genl_rcv_msg+0xdf/0x1d0
 ...

So we must make sure the iova_domain is already initialized before
put it.

In addition, we may get the following warning in this case:
WARNING: ... drivers/iommu/iova.c:344 iova_cache_put+0x58/0x70

So we must make sure the iova_cache_put() is invoked only if the
iova_cache_get() is already invoked. Let's fix it together.

Signed-off-by: Longpeng <longpeng2@...wei.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index 5f484fff8dbe..41b0cd17fcba 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -591,8 +591,11 @@ static void vdpasim_free(struct vdpa_device *vdpa)
 		vringh_kiov_cleanup(&vdpasim->vqs[i].in_iov);
 	}

-	put_iova_domain(&vdpasim->iova);
-	iova_cache_put();
+	if (vdpa_get_dma_dev(vdpa)) {
+		put_iova_domain(&vdpasim->iova);
+		iova_cache_put();
+	}
+
 	kvfree(vdpasim->buffer);
 	if (vdpasim->iommu)
 		vhost_iotlb_free(vdpasim->iommu);
-- 
2.27.0