diff options
| author | Jason Gunthorpe <jgg@nvidia.com> | 2025-04-25 10:08:37 -0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2025-04-28 13:33:30 +0200 |
| commit | e586e22974d2b7acbef3c6c3e01b2d5ce69efe33 (patch) | |
| tree | 2eeb7c061345c43f1b8eb858157d57e4ecf6e1cd | |
| parent | da33e87bd2bfc63531cf7448a3cd7a3d42182f08 (diff) | |
iommu: Protect against overflow in iommu_pgsize()
On a 32 bit system calling:
iommu_map(0, 0x40000000)
When using the AMD V1 page table type with a domain->pgsize of 0xfffff000
causes iommu_pgsize() to miscalculate a result of:
size=0x40000000 count=2
count should be 1. This completely corrupts the mapping process.
This is because the final test to adjust the pagesize malfunctions when
the addition overflows. Use check_add_overflow() to prevent this.
Fixes: b1d99dc5f983 ("iommu: Hook up '->unmap_pages' driver callback")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/0-v1-3ad28fc2e3a3+163327-iommu_overflow_pgsize_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
| -rw-r--r-- | drivers/iommu/iommu.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 2bd668ae9466..900fb782c3a6 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2413,6 +2413,7 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova, unsigned int pgsize_idx, pgsize_idx_next; unsigned long pgsizes; size_t offset, pgsize, pgsize_next; + size_t offset_end; unsigned long addr_merge = paddr | iova; /* Page sizes supported by the hardware and small enough for @size */ @@ -2453,7 +2454,8 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova, * If size is big enough to accommodate the larger page, reduce * the number of smaller pages. */ - if (offset + pgsize_next <= size) + if (!check_add_overflow(offset, pgsize_next, &offset_end) && + offset_end <= size) size = offset; out_set_count: |