Commit Graph

4 Commits

Author SHA1 Message Date
Jason Gunthorpe
fd8c1a4aee iommufd/selftest: Catch overflow of uptr and length
syzkaller hits a WARN_ON when trying to have a uptr close to UINTPTR_MAX:

  WARNING: CPU: 1 PID: 393 at drivers/iommu/iommufd/selftest.c:403 iommufd_test+0xb19/0x16f0
  Modules linked in:
  CPU: 1 PID: 393 Comm: repro Not tainted 6.2.0-c9c3395d5e3d #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
  RIP: 0010:iommufd_test+0xb19/0x16f0
  Code: 94 c4 31 ff 44 89 e6 e8 a5 54 17 ff 45 84 e4 0f 85 bb 0b 00 00 41 be fb ff ff ff e8 31 53 17 ff e9 a0 f7 ff ff e8 27 53 17 ff <0f> 0b 41 be 8
  RSP: 0018:ffffc90000eabdc0 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8214c487
  RDX: 0000000000000000 RSI: ffff88800f5c8000 RDI: 0000000000000002
  RBP: ffffc90000eabe48 R08: 0000000000000000 R09: 0000000000000001
  R10: 0000000000000001 R11: 0000000000000000 R12: 00000000cd2b0000
  R13: 00000000cd2af000 R14: 0000000000000000 R15: ffffc90000eabe68
  FS:  00007f94d76d5740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000020000043 CR3: 0000000006880006 CR4: 0000000000770ee0
  PKRU: 55555554
  Call Trace:
   <TASK>
   ? write_comp_data+0x2f/0x90
   iommufd_fops_ioctl+0x1ef/0x310
   __x64_sys_ioctl+0x10e/0x160
   ? __pfx_iommufd_fops_ioctl+0x10/0x10
   do_syscall_64+0x3b/0x90
   entry_SYSCALL_64_after_hwframe+0x72/0xdc

Check that the user memory range doesn't overflow.

Fixes: f4b20bb34c ("iommufd: Add kernel support for testing iommufd")
Link: https://lore.kernel.org/r/0-v1-95390ed1df8d+8f-iommufd_mock_overflow_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Link: https://lore.kernel.org/r/Y/hOiilV1wJvu/Hv@xpf.sh.intel.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-03-10 15:29:59 -04:00
Jason Gunthorpe
65c619ae06 iommufd/selftest: Make selftest create a more complete mock device
iommufd wants to use more infrastructure, like the iommu_group, that the
mock device does not support. Create a more complete mock device that can
go through the whole cycle of ownership, blocking domain, and has an
iommu_group.

This requires creating a real struct device on a real bus to be able to
connect it to a iommu_group. Unfortunately we cannot formally attach the
mock iommu driver as an actual driver as the iommu core does not allow
more than one driver or provide a general way for busses to link to
iommus. This can be solved with a little hack to open code the dev_iommus
struct.

With this infrastructure things work exactly the same as the normal domain
path, including the auto domains mechanism and direct attach of hwpts.  As
the created hwpt is now an autodomain it is no longer required to destroy
it and trying to do so will trigger a failure.

Link: https://lore.kernel.org/r/11-v3-ae9c2975a131+2e1e8-iommufd_hwpt_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-03-06 13:06:11 -04:00
Jason Gunthorpe
2cfdeaa07b iommufd/selftest: Rename the sefltest 'device_id' to 'stdev_id'
It is too confusing now that we have the 'dev_id' as part of the main
interface. Make it clear this is the special selftest device object. This
object is analogous to the VFIO device FD.

Link: https://lore.kernel.org/r/7-v3-ae9c2975a131+2e1e8-iommufd_hwpt_jgg@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2023-03-06 10:51:58 -04:00
Jason Gunthorpe
f4b20bb34c iommufd: Add kernel support for testing iommufd
Provide a mock kernel module for the iommu_domain that allows it to run
without any HW and the mocking provides a way to directly validate that
the PFNs loaded into the iommu_domain are correct. This exposes the access
kAPI toward userspace to allow userspace to explore the functionality of
pages.c and io_pagetable.c

The mock also simulates the rare case of PAGE_SIZE > iommu page size as
the mock will operate at a 2K iommu page size. This allows exercising all
of the calculations to support this mismatch.

This is also intended to support syzkaller exploring the same space.

However, it is an unusually invasive config option to enable all of
this. The config option should not be enabled in a production kernel.

Link: https://lore.kernel.org/r/16-v6-a196d26f289e+11787-iommufd_jgg@nvidia.com
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com> # s390
Tested-by: Eric Auger <eric.auger@redhat.com> # aarch64
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
2022-11-30 20:16:49 -04:00