Commit ffe0402d authored by Nicolin Chen's avatar Nicolin Chen Committed by Jason Zeng
Browse files

iommufd: Fix iopt_access_list_id overwrite bug 

mainline inclusion
from mainline-v6.8-rc7
commit aeb004c0cd6958e910123a1607634401009c9539
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I938E2
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=aeb004c0cd6958e910123a1607634401009c9539

--------------------------------

Syzkaller reported the following WARN_ON:
  WARNING: CPU: 1 PID: 4738 at drivers/iommu/iommufd/io_pagetable.c:1360

  Call Trace:
   iommufd_access_change_ioas+0x2fe/0x4e0
   iommufd_access_destroy_object+0x50/0xb0
   iommufd_object_remove+0x2a3/0x490
   iommufd_object_destroy_user
   iommufd_access_destroy+0x71/0xb0
   iommufd_test_staccess_release+0x89/0xd0
   __fput+0x272/0xb50
   __fput_sync+0x4b/0x60
   __do_sys_close
   __se_sys_close
   __x64_sys_close+0x8b/0x110
   do_syscall_x64

The mismatch between the access pointer in the list and the passed-in
pointer is resulting from an overwrite of access->iopt_access_list_id, in
iopt_add_access(). Called from iommufd_access_change_ioas() when
xa_alloc() succeeds but iopt_calculate_iova_alignment() fails.

Add a new_id in iopt_add_access() and only update iopt_access_list_id when
returning successfully.

Cc: stable@vger.kernel.org
Fixes: 9227da78 ("iommufd: Add iommufd_access_change_ioas(_id) helpers")
Link: https://lore.kernel.org/r/2dda7acb25b8562ec5f1310de828ef5da9ef509c.1708636627.git.nicolinc@nvidia.com


Reported-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Suggested-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarJason Zeng <jason.zeng@intel.com>
parent 40c1ca07

drivers/iommu/iommufd/io_pagetable.c

+6 −3
Original line number Diff line number Diff line
@@ -1330,20 +1330,23 @@ int iopt_disable_large_pages(struct io_pagetable *iopt) 


int iopt_add_access(struct io_pagetable *iopt, struct iommufd_access *access)

{

	u32 new_id;

	int rc;



	down_write(&iopt->domains_rwsem);

	down_write(&iopt->iova_rwsem);

	rc = xa_alloc(&iopt->access_list, &access->iopt_access_list_id, access,

		      xa_limit_16b, GFP_KERNEL_ACCOUNT);

	rc = xa_alloc(&iopt->access_list, &new_id, access, xa_limit_16b,

		      GFP_KERNEL_ACCOUNT);



	if (rc)

		goto out_unlock;



	rc = iopt_calculate_iova_alignment(iopt);

	if (rc) {

		xa_erase(&iopt->access_list, access->iopt_access_list_id);

		xa_erase(&iopt->access_list, new_id);

		goto out_unlock;

	}

	access->iopt_access_list_id = new_id;



out_unlock:

	up_write(&iopt->iova_rwsem);