6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Qasim Ijaz <qasdev00@xxxxxxxxx>
[ 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@xxxxxxxxx
Reported-by: syzbot <syzbot+85992ace37d5b7b51635@xxxxxxxxxxxxxxxxxxxxxxxxx>
Closes: https://syzkaller.appspot.com/bug?extid=85992ace37d5b7b51635
Signed-off-by: Qasim Ijaz <qasdev00@xxxxxxxxx>
Reviewed-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/vfio/iova_bitmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vfio/iova_bitmap.c b/drivers/vfio/iova_bitmap.c
index 7af5b204990bb..38b51613ecca9 100644
--- a/drivers/vfio/iova_bitmap.c
+++ b/drivers/vfio/iova_bitmap.c
@@ -127,7 +127,7 @@ 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);
}
--
2.39.5
