VMCI: Resource wildcard match fixed

When adding a VMCI resource, the check for an existing entry would ignore that the new entry could be a wildcard. This could result in multiple resource entries that would match a given handle. One disastrous outcome of this is that the refcounting used to ensure that delayed callbacks for VMCI datagrams have run before the datagram is destroyed can be wrong, since the refcount could be increased on the duplicate entry. This in turn leads to a use after free bug. This issue was discovered by Hangbin Liu using KASAN and syzkaller. Fixes: bc63ded ("VMCI: resource object implementation") Reported-by: Hangbin Liu <[email protected]> Reviewed-by: Adit Ranadive <[email protected]> Reviewed-by: Vishnu Dasa <[email protected]> Signed-off-by: Jorgen Hansen <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
Freescale · Oct 2, 2018 · 11924ba · 11924ba
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commit 11924ba
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Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/drivers/misc/vmw_vmci/vmci_driver.c b/drivers/misc/vmw_vmci/vmci_driver.c
@@ -113,5 +113,5 @@ module_exit(vmci_drv_exit);
 
 MODULE_AUTHOR("VMware, Inc.");
 MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
-MODULE_VERSION("1.1.5.0-k");
+MODULE_VERSION("1.1.6.0-k");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/misc/vmw_vmci/vmci_resource.c b/drivers/misc/vmw_vmci/vmci_resource.c
@@ -57,7 +57,8 @@ static struct vmci_resource *vmci_resource_lookup(struct vmci_handle handle,
 
 		if (r->type == type &&
 		    rid == handle.resource &&
-		    (cid == handle.context || cid == VMCI_INVALID_ID)) {
+		    (cid == handle.context || cid == VMCI_INVALID_ID ||
+		     handle.context == VMCI_INVALID_ID)) {
 			resource = r;
 			break;
 		}