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drm/xe/vm: move xa_alloc to prevent UAF

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BugLink: https://bugs.launchpad.net/bugs/2097301

[ Upstream commit 74231870cf4976f69e83aa24f48edb16619f652f ]

Evil user can guess the next id of the vm before the ioctl completes and
then call vm destroy ioctl to trigger UAF since create ioctl is still
referencing the same vm. Move the xa_alloc all the way to the end to
prevent this.

v2:
 - Rebase

Fixes: dd08ebf6c3 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: <stable@vger.kernel.org> # v6.8+
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240925071426.144015-3-matthew.auld@intel.com
(cherry picked from commit dcfd3971327f3ee92765154baebbaece833d3ca9)
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
CVE-2024-49865
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Koichiro Den <koichiro.den@canonical.com>
This commit is contained in:
Matthew Auld
2024-09-25 08:14:27 +01:00
committed by Mehmet Basaran
parent 77168e1011
commit 03621719fe
1 changed files with 10 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/gpu/drm/xe/xe_vm.c
+10 -12
View File
@@ -1934,12 +1934,6 @@ int xe_vm_create_ioctl(struct drm_device *dev, void *data,
if (IS_ERR(vm))
return PTR_ERR(vm);
mutex_lock(&xef->vm.lock);
err = xa_alloc(&xef->vm.xa, &id, vm, xa_limit_32b, GFP_KERNEL);
mutex_unlock(&xef->vm.lock);
if (err)
goto err_close_and_put;
if (xe->info.has_asid) {
mutex_lock(&xe->usm.lock);
err = xa_alloc_cyclic(&xe->usm.asid_to_vm, &asid, vm,
@@ -1947,12 +1941,11 @@ int xe_vm_create_ioctl(struct drm_device *dev, void *data,
&xe->usm.next_asid, GFP_KERNEL);
mutex_unlock(&xe->usm.lock);
if (err < 0)
goto err_free_id;
goto err_close_and_put;
vm->usm.asid = asid;
}
args->vm_id = id;
vm->xef = xef;
/* Record BO memory for VM pagetable created against client */
@@ -1965,12 +1958,17 @@ int xe_vm_create_ioctl(struct drm_device *dev, void *data,
args->reserved[0] = xe_bo_main_addr(vm->pt_root[0]->bo, XE_PAGE_SIZE);
#endif
/* user id alloc must always be last in ioctl to prevent UAF */
mutex_lock(&xef->vm.lock);
err = xa_alloc(&xef->vm.xa, &id, vm, xa_limit_32b, GFP_KERNEL);
mutex_unlock(&xef->vm.lock);
if (err)
goto err_close_and_put;
args->vm_id = id;
return 0;
err_free_id:
mutex_lock(&xef->vm.lock);
xa_erase(&xef->vm.xa, id);
mutex_unlock(&xef->vm.lock);
err_close_and_put:
xe_vm_close_and_put(vm);