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| author | Joao Martins <joao.m.martins@oracle.com> | 2023-10-30 11:34:46 +0000 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2023-10-30 12:03:20 -0300 |
| commit | 2e22aac3ea9cfc0ec3209c96644f60c1806a8117 (patch) | |
| tree | 6eaa4e3592fe393e08d2b2f184e2616f6fc1858e /drivers/iommu | |
| parent | 361d744ddd61de065fbeb042aaed590d32dd92ec (diff) | |
| download | lwn-2e22aac3ea9cfc0ec3209c96644f60c1806a8117.tar.gz lwn-2e22aac3ea9cfc0ec3209c96644f60c1806a8117.zip | |
iommufd/selftest: Fix page-size check in iommufd_test_dirty()
iommufd_test_dirty()/IOMMU_TEST_OP_DIRTY sets the dirty bits in the mock
domain implementation that the userspace side validates against what it
obtains via the UAPI.
However in introducing iommufd_test_dirty() it forgot to validate page_size
being 0 leading to two possible divide-by-zero problems: one at the
beginning when calculating @max and while calculating the IOVA in the
XArray PFN tracking list.
While at it, validate the length to require non-zero value as well, as we
can't be allocating a 0-sized bitmap.
Link: https://lore.kernel.org/r/20231030113446.7056-1-joao.m.martins@oracle.com
Reported-by: syzbot+25dc7383c30ecdc83c38@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-iommu/00000000000005f6aa0608b9220f@google.com/
Fixes: a9af47e382a4 ("iommufd/selftest: Test IOMMU_HWPT_GET_DIRTY_BITMAP")
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'drivers/iommu')
| -rw-r--r-- | drivers/iommu/iommufd/selftest.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index 6684ab4cdc7a..a11d29f368ff 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -1195,14 +1195,15 @@ static int iommufd_test_dirty(struct iommufd_ucmd *ucmd, unsigned int mockpt_id, unsigned long page_size, void __user *uptr, u32 flags) { - unsigned long bitmap_size, i, max = length / page_size; + unsigned long bitmap_size, i, max; struct iommu_test_cmd *cmd = ucmd->cmd; struct iommufd_hw_pagetable *hwpt; struct mock_iommu_domain *mock; int rc, count = 0; void *tmp; - if (iova % page_size || length % page_size || !uptr) + if (!page_size || !length || iova % page_size || length % page_size || + !uptr) return -EINVAL; hwpt = get_md_pagetable(ucmd, mockpt_id, &mock); @@ -1214,6 +1215,7 @@ static int iommufd_test_dirty(struct iommufd_ucmd *ucmd, unsigned int mockpt_id, goto out_put; } + max = length / page_size; bitmap_size = max / BITS_PER_BYTE; tmp = kvzalloc(bitmap_size, GFP_KERNEL_ACCOUNT); |