From: Xiaolong Ye <[email protected]>

A malicious container which has direct access to the vhost-user socket
can keep sending VHOST_USER_GET_INFLIGHT_FD messages which may cause
leaking resources until resulting a DOS. Fix it by unmapping the
dev->inflight_info->addr before assigning new mapped addr to it.

CVE-2020-10726
Fixes: d87f1a1cb7b6 ("vhost: support inflight info sharing")
Cc: [email protected]

Signed-off-by: Xiaolong Ye <[email protected]>
Reviewed-by: Maxime Coquelin <[email protected]>
---
 lib/librte_vhost/vhost_user.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index e51a8a6b77..0424e49cb8 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -1433,6 +1433,11 @@ vhost_user_get_inflight_fd(struct virtio_net **pdev,
        }
        memset(addr, 0, mmap_size);
 
+       if (dev->inflight_info->addr) {
+               munmap(dev->inflight_info->addr, dev->inflight_info->size);
+               dev->inflight_info->addr = NULL;
+       }
+
        dev->inflight_info->addr = addr;
        dev->inflight_info->size = msg->payload.inflight.mmap_size = mmap_size;
        dev->inflight_info->fd = msg->fds[0] = fd;
@@ -1517,8 +1522,10 @@ vhost_user_set_inflight_fd(struct virtio_net **pdev, 
VhostUserMsg *msg,
                }
        }
 
-       if (dev->inflight_info->addr)
+       if (dev->inflight_info->addr) {
                munmap(dev->inflight_info->addr, dev->inflight_info->size);
+               dev->inflight_info->addr = NULL;
+       }
 
        addr = mmap(0, mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED,
                    fd, mmap_offset);
-- 
2.25.2

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