5.10-stable review patch. If anyone has any objections, please let me know.
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From: Christian König christian.koenig@amd.com
commit 35588314e963938dfdcdb792c9170108399377d6 upstream.
The offset is just 32bits here so this can potentially overflow if somebody specifies a large value. Instead reduce the size to calculate the last possible offset.
The error handling path incorrectly drops the reference to the user fence BO resulting in potential reference count underflow.
Signed-off-by: Christian König christian.koenig@amd.com Reviewed-by: Alex Deucher alexander.deucher@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c @@ -45,7 +45,6 @@ static int amdgpu_cs_user_fence_chunk(st struct drm_gem_object *gobj; struct amdgpu_bo *bo; unsigned long size; - int r;
gobj = drm_gem_object_lookup(p->filp, data->handle); if (gobj == NULL) @@ -60,23 +59,14 @@ static int amdgpu_cs_user_fence_chunk(st drm_gem_object_put(gobj);
size = amdgpu_bo_size(bo); - if (size != PAGE_SIZE || (data->offset + 8) > size) { - r = -EINVAL; - goto error_unref; - } - - if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm)) { - r = -EINVAL; - goto error_unref; - } + if (size != PAGE_SIZE || data->offset > (size - 8)) + return -EINVAL;
- *offset = data->offset; + if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm)) + return -EINVAL;
+ *offset = data->offset; return 0; - -error_unref: - amdgpu_bo_unref(&bo); - return r; }
static int amdgpu_cs_bo_handles_chunk(struct amdgpu_cs_parser *p,