From 6e7e40f18fa8dfbded48e56684cb156cd6cbdd30 Mon Sep 17 00:00:00 2001 From: Jason Gunthorpe Date: Thu, 22 Aug 2024 11:45:54 -0300 Subject: [PATCH] iommufd: Do not allow creating areas without READ or WRITE BugLink: https://bugs.launchpad.net/bugs/2084225 commit 996dc53ac289b81957aa70d62ccadc6986d26a87 upstream. This results in passing 0 or just IOMMU_CACHE to iommu_map(). Most of the page table formats don't like this: amdv1 - -EINVAL armv7s - returns 0, doesn't update mapped arm-lpae - returns 0 doesn't update mapped dart - returns 0, doesn't update mapped VT-D - returns -EINVAL Unfortunately the three formats that return 0 cause serious problems: - Returning ret = but not uppdating mapped from domain->map_pages() causes an infinite loop in __iommu_map() - Not writing ioptes means that VFIO/iommufd have no way to recover them and we will have memory leaks and worse during unmap Since almost nothing can support this, and it is a useless thing to do, block it early in iommufd. Cc: stable@kernel.org Fixes: aad37e71d5c4 ("iommufd: IOCTLs for the io_pagetable") Signed-off-by: Jason Gunthorpe Reviewed-by: Nicolin Chen Reviewed-by: Kevin Tian Link: https://lore.kernel.org/r/1-v1-1211e1294c27+4b1-iommu_no_prot_jgg@nvidia.com Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/iommu/iommufd/ioas.c | 8 ++++++++ tools/testing/selftests/iommu/iommufd.c | 6 +++--- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/iommufd/ioas.c b/drivers/iommu/iommufd/ioas.c index 742248276548..157a89b993e4 100644 --- a/drivers/iommu/iommufd/ioas.c +++ b/drivers/iommu/iommufd/ioas.c @@ -213,6 +213,10 @@ int iommufd_ioas_map(struct iommufd_ucmd *ucmd) if (cmd->iova >= ULONG_MAX || cmd->length >= ULONG_MAX) return -EOVERFLOW; + if (!(cmd->flags & + (IOMMU_IOAS_MAP_WRITEABLE | IOMMU_IOAS_MAP_READABLE))) + return -EINVAL; + ioas = iommufd_get_ioas(ucmd->ictx, cmd->ioas_id); if (IS_ERR(ioas)) return PTR_ERR(ioas); @@ -253,6 +257,10 @@ int iommufd_ioas_copy(struct iommufd_ucmd *ucmd) cmd->dst_iova >= ULONG_MAX) return -EOVERFLOW; + if (!(cmd->flags & + (IOMMU_IOAS_MAP_WRITEABLE | IOMMU_IOAS_MAP_READABLE))) + return -EINVAL; + src_ioas = iommufd_get_ioas(ucmd->ictx, cmd->src_ioas_id); if (IS_ERR(src_ioas)) return PTR_ERR(src_ioas); diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c index 5f7d5a5ba89b..d79bd5fc08db 100644 --- a/tools/testing/selftests/iommu/iommufd.c +++ b/tools/testing/selftests/iommu/iommufd.c @@ -803,7 +803,7 @@ TEST_F(iommufd_ioas, copy_area) { struct iommu_ioas_copy copy_cmd = { .size = sizeof(copy_cmd), - .flags = IOMMU_IOAS_MAP_FIXED_IOVA, + .flags = IOMMU_IOAS_MAP_FIXED_IOVA | IOMMU_IOAS_MAP_WRITEABLE, .dst_ioas_id = self->ioas_id, .src_ioas_id = self->ioas_id, .length = PAGE_SIZE, @@ -1296,7 +1296,7 @@ TEST_F(iommufd_ioas, copy_sweep) { struct iommu_ioas_copy copy_cmd = { .size = sizeof(copy_cmd), - .flags = IOMMU_IOAS_MAP_FIXED_IOVA, + .flags = IOMMU_IOAS_MAP_FIXED_IOVA | IOMMU_IOAS_MAP_WRITEABLE, .src_ioas_id = self->ioas_id, .dst_iova = MOCK_APERTURE_START, .length = MOCK_PAGE_SIZE, @@ -1586,7 +1586,7 @@ TEST_F(iommufd_mock_domain, user_copy) }; struct iommu_ioas_copy copy_cmd = { .size = sizeof(copy_cmd), - .flags = IOMMU_IOAS_MAP_FIXED_IOVA, + .flags = IOMMU_IOAS_MAP_FIXED_IOVA | IOMMU_IOAS_MAP_WRITEABLE, .dst_ioas_id = self->ioas_id, .dst_iova = MOCK_APERTURE_START, .length = BUFFER_SIZE,