6.12-stable review patch. If anyone has any objections, please let me know.
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From: Qasim Ijaz qasdev00@gmail.com
[ Upstream commit e24c1551059268b37f6f40639883eafb281b8b9c ]
Resolve a UBSAN shift-out-of-bounds issue in iova_bitmap_offset_to_index() where shifting the constant "1" (of type int) by bitmap->mapped.pgshift (an unsigned long value) could result in undefined behavior.
The constant "1" defaults to a 32-bit "int", and when "pgshift" exceeds 31 (e.g., pgshift = 63) the shift operation overflows, as the result cannot be represented in a 32-bit type.
To resolve this, the constant is updated to "1UL", promoting it to an unsigned long type to match the operand's type.
Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support") Link: https://patch.msgid.link/r/20250113223820.10713-1-qasdev00@gmail.com Reported-by: syzbot syzbot+85992ace37d5b7b51635@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=85992ace37d5b7b51635 Signed-off-by: Qasim Ijaz qasdev00@gmail.com Reviewed-by: Joao Martins joao.m.martins@oracle.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommufd/iova_bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/iommu/iommufd/iova_bitmap.c b/drivers/iommu/iommufd/iova_bitmap.c index d90b9e253412f..2cdc4f542df47 100644 --- a/drivers/iommu/iommufd/iova_bitmap.c +++ b/drivers/iommu/iommufd/iova_bitmap.c @@ -130,7 +130,7 @@ struct iova_bitmap { static unsigned long iova_bitmap_offset_to_index(struct iova_bitmap *bitmap, unsigned long iova) { - unsigned long pgsize = 1 << bitmap->mapped.pgshift; + unsigned long pgsize = 1UL << bitmap->mapped.pgshift;
return iova / (BITS_PER_TYPE(*bitmap->bitmap) * pgsize); }