diff options
| author | Nicolin Chen <nicolinc@nvidia.com> | 2026-05-21 17:36:34 -0700 |
|---|---|---|
| committer | Jason Gunthorpe <jgg@nvidia.com> | 2026-06-01 14:54:19 -0300 |
| commit | 6ebf2eb46fbd5b40393ff8fbb847ba96925beaff (patch) | |
| tree | cbe632fd06694a78ea20797ed502f72469dad31f | |
| parent | 47443565d10c51366c9382dbc8597cd6c460b8a2 (diff) | |
iommufd: Set veventq_depth upper bound
iommufd_veventq_alloc() accepts any !0 veventq_depth from userspace, with
an upper bound at U32_MAX.
This leaves a vulnerability where userspace can allocate excessively large
queues to exhaust kernel memory reserves.
Cap the veventq_depth (maximum number of entries) to 1 << 19, matching the
maximum number of entries in the SMMUv3 EVTQ (the largest use case today).
Fixes: e36ba5ab808e ("iommufd: Add IOMMUFD_OBJ_VEVENTQ and IOMMUFD_CMD_VEVENTQ_ALLOC")
Link: https://patch.msgid.link/r/8426cbaa5e8294472ec7f076ef427cc473be5985.1779408671.git.nicolinc@nvidia.com
Cc: stable@vger.kernel.org
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
| -rw-r--r-- | drivers/iommu/iommufd/eventq.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/iommu/iommufd/eventq.c b/drivers/iommu/iommufd/eventq.c index 78689fb52d24..1f1e415285b1 100644 --- a/drivers/iommu/iommufd/eventq.c +++ b/drivers/iommu/iommufd/eventq.c @@ -473,6 +473,9 @@ int iommufd_fault_iopf_handler(struct iopf_group *group) static const struct file_operations iommufd_veventq_fops = INIT_EVENTQ_FOPS(iommufd_veventq_fops_read, NULL); +/* An arbitrary upper bound for veventq_depth that fits all existing HWs */ +#define VEVENTQ_MAX_DEPTH (1U << 19) + int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd) { struct iommu_veventq_alloc *cmd = ucmd->cmd; @@ -484,7 +487,7 @@ int iommufd_veventq_alloc(struct iommufd_ucmd *ucmd) if (cmd->flags || cmd->__reserved || cmd->type == IOMMU_VEVENTQ_TYPE_DEFAULT) return -EOPNOTSUPP; - if (!cmd->veventq_depth) + if (!cmd->veventq_depth || cmd->veventq_depth > VEVENTQ_MAX_DEPTH) return -EINVAL; viommu = iommufd_get_viommu(ucmd, cmd->viommu_id); |