From 1c2eb5b2853c9f513690ba6b71072d8eb65da16a Mon Sep 17 00:00:00 2001 From: Vishnu DASA Date: Fri, 24 May 2019 15:13:10 +0000 Subject: VMCI: Fix integer overflow in VMCI handle arrays The VMCI handle array has an integer overflow in vmci_handle_arr_append_entry when it tries to expand the array. This can be triggered from a guest, since the doorbell link hypercall doesn't impose a limit on the number of doorbell handles that a VM can create in the hypervisor, and these handles are stored in a handle array. In this change, we introduce a mandatory max capacity for handle arrays/lists to avoid excessive memory usage. Signed-off-by: Vishnu Dasa Reviewed-by: Adit Ranadive Reviewed-by: Jorgen Hansen Cc: stable Signed-off-by: Greg Kroah-Hartman --- include/linux/vmw_vmci_defs.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'include/linux/vmw_vmci_defs.h') diff --git a/include/linux/vmw_vmci_defs.h b/include/linux/vmw_vmci_defs.h index 606504bf376a..fefb5292403b 100644 --- a/include/linux/vmw_vmci_defs.h +++ b/include/linux/vmw_vmci_defs.h @@ -62,9 +62,18 @@ enum { /* * A single VMCI device has an upper limit of 128MB on the amount of - * memory that can be used for queue pairs. + * memory that can be used for queue pairs. Since each queue pair + * consists of at least two pages, the memory limit also dictates the + * number of queue pairs a guest can create. */ #define VMCI_MAX_GUEST_QP_MEMORY (128 * 1024 * 1024) +#define VMCI_MAX_GUEST_QP_COUNT (VMCI_MAX_GUEST_QP_MEMORY / PAGE_SIZE / 2) + +/* + * There can be at most PAGE_SIZE doorbells since there is one doorbell + * per byte in the doorbell bitmap page. + */ +#define VMCI_MAX_GUEST_DOORBELL_COUNT PAGE_SIZE /* * Queues with pre-mapped data pages must be small, so that we don't pin -- cgit