6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jason Gunthorpe jgg@nvidia.com
[ Upstream commit e586e22974d2b7acbef3c6c3e01b2d5ce69efe33 ]
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... Signed-off-by: Joerg Roedel jroedel@suse.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 5bc2fc969494f..e4628d9621610 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2399,6 +2399,7 @@ 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 */ @@ -2439,7 +2440,8 @@ 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: