From 0ec8ce07394442d722806fe61b901a5b2b17249d Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Fri, 14 Oct 2022 15:25:41 -0700 Subject: dmaengine: idxd: Do not enable user type Work Queue without Shared Virtual Addressing When the idxd_user_drv driver is bound to a Work Queue (WQ) device without IOMMU or with IOMMU Passthrough without Shared Virtual Addressing (SVA), the application gains direct access to physical memory via the device by programming physical address to a submitted descriptor. This allows direct userspace read and write access to arbitrary physical memory. This is inconsistent with the security goals of a good kernel API. Unlike vfio_pci driver, the IDXD char device driver does not provide any ways to pin user pages and translate the address from user VA to IOVA or PA without IOMMU SVA. Therefore the application has no way to instruct the device to perform DMA function. This makes the char device not usable for normal application usage. Since user type WQ without SVA cannot be used for normal application usage and presents the security issue, bind idxd_user_drv driver and enable user type WQ only when SVA is enabled (i.e. user PASID is enabled). Fixes: 448c3de8ac83 ("dmaengine: idxd: create user driver for wq 'device'") Cc: stable@vger.kernel.org Suggested-by: Arjan Van De Ven Signed-off-by: Fenghua Yu Reviewed-by: Dave Jiang Reviewed-by: Jerry Snitselaar Link: https://lore.kernel.org/r/20221014222541.3912195-1-fenghua.yu@intel.com Signed-off-by: Vinod Koul --- include/uapi/linux/idxd.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/idxd.h b/include/uapi/linux/idxd.h index 095299c75828..2b9e7feba3f3 100644 --- a/include/uapi/linux/idxd.h +++ b/include/uapi/linux/idxd.h @@ -29,6 +29,7 @@ enum idxd_scmd_stat { IDXD_SCMD_WQ_NO_SIZE = 0x800e0000, IDXD_SCMD_WQ_NO_PRIV = 0x800f0000, IDXD_SCMD_WQ_IRQ_ERR = 0x80100000, + IDXD_SCMD_WQ_USER_NO_IOMMU = 0x80110000, }; #define IDXD_SCMD_SOFTERR_MASK 0x80000000 -- cgit v1.2.3