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bus: fsl-mc-bus: fix KASAN use-after-free in fsl_mc_bus_remove()

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In fsl_mc_bus_remove(), mc->root_mc_bus_dev->mc_io is passed to
fsl_destroy_mc_io(). However, mc->root_mc_bus_dev is already freed in
fsl_mc_device_remove(). Then reference to mc->root_mc_bus_dev->mc_io
triggers KASAN use-after-free. To avoid the use-after-free, keep the
reference to mc->root_mc_bus_dev->mc_io in a local variable and pass to
fsl_destroy_mc_io().

This patch needs rework to apply to kernels older than v5.15.

Fixes: f93627146f ("staging: fsl-mc: fix asymmetry in destroy of mc_io")
Cc: stable@vger.kernel.org # v5.15+
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Link: https://lore.kernel.org/r/20220601105159.87752-1-shinichiro.kawasaki@wdc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shin'ichiro Kawasaki 2022-06-01 19:51:59 +09:00 committed by Greg Kroah-Hartman
parent 3ed8c7d39c
commit 928ea98252
1 changed files with 3 additions and 3 deletions
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6
drivers/bus/fsl-mc/fsl-mc-bus.c
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@ -1239,14 +1239,14 @@ error_cleanup_mc_io:
static int fsl_mc_bus_remove(struct platform_device *pdev) static int fsl_mc_bus_remove(struct platform_device *pdev)
{ {
struct fsl_mc *mc = platform_get_drvdata(pdev); struct fsl_mc *mc = platform_get_drvdata(pdev);
struct fsl_mc_io *mc_io;
if (!fsl_mc_is_root_dprc(&mc->root_mc_bus_dev->dev)) if (!fsl_mc_is_root_dprc(&mc->root_mc_bus_dev->dev))
return -EINVAL; return -EINVAL;
mc_io = mc->root_mc_bus_dev->mc_io;
fsl_mc_device_remove(mc->root_mc_bus_dev); fsl_mc_device_remove(mc->root_mc_bus_dev);
fsl_destroy_mc_io(mc_io);
fsl_destroy_mc_io(mc->root_mc_bus_dev->mc_io);
mc->root_mc_bus_dev->mc_io = NULL;
bus_unregister_notifier(&fsl_mc_bus_type, &fsl_mc_nb); bus_unregister_notifier(&fsl_mc_bus_type, &fsl_mc_nb);