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drm/qxl: qxl_release use after free

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commit 933db73351d359f74b14f4af095808260aff11f9 upstream.

qxl_release should not be accesses after qxl_push_*_ring_release() calls:
userspace driver can process submitted command quickly, move qxl_release
into release_ring, generate interrupt and trigger garbage collector.

It can lead to crashes in qxl driver or trigger memory corruption
in some kmalloc-192 slab object

Gerd Hoffmann proposes to swap the qxl_release_fence_buffer_objects() +
qxl_push_{cursor,command}_ring_release() calls to close that race window.

cc: stable@vger.kernel.org
Fixes: f64122c1f6 ("drm: add new QXL driver. (v1.4)")
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Link: http://patchwork.freedesktop.org/patch/msgid/fa17b338-66ae-f299-68fe-8d32419d9071@virtuozzo.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
[backported to v.4.19 stable]
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Vasily Averin 2020-04-29 12:01:24 +03:00 committed by Greg Kroah-Hartman
parent a8d36f64dd
commit 0d28ac49eb
4 changed files with 10 additions and 14 deletions
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5
drivers/gpu/drm/qxl/qxl_cmd.c
View file

@ -501,8 +501,8 @@ int qxl_hw_surface_alloc(struct qxl_device *qdev,
/* no need to add a release to the fence for this surface bo,
since it is only released when we ask to destroy the surface
and it would never signal otherwise */
qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
surf->hw_surf_alloc = true;
spin_lock(&qdev->surf_id_idr_lock);
@ -544,9 +544,8 @@ int qxl_hw_surface_dealloc(struct qxl_device *qdev,
cmd->surface_id = id;
qxl_release_unmap(qdev, release, &cmd->release_info);
qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_SURFACE, false);
return 0;
}

6
drivers/gpu/drm/qxl/qxl_display.c
View file

@ -532,8 +532,8 @@ static int qxl_primary_apply_cursor(struct drm_plane *plane)
cmd->u.set.visible = 1;
qxl_release_unmap(qdev, release, &cmd->release_info);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
qxl_release_fence_buffer_objects(release);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
return ret;
@ -694,8 +694,8 @@ static void qxl_cursor_atomic_update(struct drm_plane *plane,
cmd->u.position.y = plane->state->crtc_y + fb->hot_y;
qxl_release_unmap(qdev, release, &cmd->release_info);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
qxl_release_fence_buffer_objects(release);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
if (old_cursor_bo)
qxl_bo_unref(&old_cursor_bo);
@ -740,8 +740,8 @@ static void qxl_cursor_atomic_disable(struct drm_plane *plane,
cmd->type = QXL_CURSOR_HIDE;
qxl_release_unmap(qdev, release, &cmd->release_info);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
qxl_release_fence_buffer_objects(release);
qxl_push_cursor_ring_release(qdev, release, QXL_CMD_CURSOR, false);
}
static int qxl_plane_prepare_fb(struct drm_plane *plane,

8
drivers/gpu/drm/qxl/qxl_draw.c
View file

@ -241,8 +241,8 @@ void qxl_draw_opaque_fb(const struct qxl_fb_image *qxl_fb_image,
qxl_bo_physical_address(qdev, dimage->bo, 0);
qxl_release_unmap(qdev, release, &drawable->release_info);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_palette:
if (palette_bo)
@ -382,8 +382,8 @@ void qxl_draw_dirty_fb(struct qxl_device *qdev,
}
qxl_bo_kunmap(clips_bo);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_release_backoff:
if (ret)
@ -433,8 +433,8 @@ void qxl_draw_copyarea(struct qxl_device *qdev,
drawable->u.copy_bits.src_pos.y = sy;
qxl_release_unmap(qdev, release, &drawable->release_info);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_release:
if (ret)
@ -477,8 +477,8 @@ void qxl_draw_fill(struct qxl_draw_fill *qxl_draw_fill_rec)
qxl_release_unmap(qdev, release, &drawable->release_info);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
qxl_release_fence_buffer_objects(release);
qxl_push_command_ring_release(qdev, release, QXL_CMD_DRAW, false);
out_free_release:
if (ret)

5
drivers/gpu/drm/qxl/qxl_ioctl.c
View file

@ -257,11 +257,8 @@ static int qxl_process_single_command(struct qxl_device *qdev,
apply_surf_reloc(qdev, &reloc_info[i]);
}
qxl_release_fence_buffer_objects(release);
ret = qxl_push_command_ring_release(qdev, release, cmd->type, true);
if (ret)
qxl_release_backoff_reserve_list(release);
else
qxl_release_fence_buffer_objects(release);
out_free_bos:
out_free_release: