From: Nicolin Chen Date: Mon, 1 Jun 2026 20:42:35 +0000 (-0700) Subject: iommufd: Reject invalid read count in iommufd_fault_fops_read() X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=47916a54eeb2a9e654512ee609f71bd5b29db702;p=thirdparty%2Flinux.git iommufd: Reject invalid read count in iommufd_fault_fops_read() The read count must be large enough to hold one fault or a group's faults. iommufd_fault_fops_read() does not validate the count, but returns 0 as if the read had succeeded while leaving the pending fault in the queue. Return -EINVAL in the undersize cases. Fixes: 07838f7fd529 ("iommufd: Add iommufd fault object") Link: https://patch.msgid.link/r/85c118a606fbedc5c132a1f5ec223a5ba23b92d2.1780343944.git.nicolinc@nvidia.com Cc: stable@vger.kernel.org Signed-off-by: Nicolin Chen Reviewed-by: Pranjal Shrivastava Reviewed-by: Kevin Tian Signed-off-by: Jason Gunthorpe --- diff --git a/drivers/iommu/iommufd/eventq.c b/drivers/iommu/iommufd/eventq.c index f55d173c59f6..613024ca8f1f 100644 --- a/drivers/iommu/iommufd/eventq.c +++ b/drivers/iommu/iommufd/eventq.c @@ -142,6 +142,9 @@ static ssize_t iommufd_fault_fops_read(struct file *filep, char __user *buf, if (done >= count || group->fault_count * fault_size > count - done) { iommufd_fault_deliver_restore(fault, group); + /* Read count doesn't fit the first fault group */ + if (done == 0) + rc = -EINVAL; break; }