Re: [PATCH] iommu: apple-dart: fix potential null pointer deref
From: Alyssa Rosenzweig
Date: Fri Mar 14 2025 - 19:52:01 EST
Reviewed-by: Alyssa Rosenzweig <alyssa@xxxxxxxxxxxxx>
Le Fri , Mar 14, 2025 at 11:01:02PM +0000, Qasim Ijaz a écrit :
> If kzalloc() fails, accessing cfg->supports_bypass causes a null pointer dereference.
>
> Fix by checking for NULL immediately after allocation and returning -ENOMEM.
>
> Fixes: 3bc0102835f6 ("iommu: apple-dart: Allow mismatched bypass support")
> Signed-off-by: Qasim Ijaz <qasdev00@xxxxxxxxx>
> ---
> drivers/iommu/apple-dart.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
> index 13ccb801f52a..e13501541fdd 100644
> --- a/drivers/iommu/apple-dart.c
> +++ b/drivers/iommu/apple-dart.c
> @@ -797,12 +797,11 @@ static int apple_dart_of_xlate(struct device *dev,
>
> if (!cfg) {
> cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
> -
> + if (!cfg)
> + return -ENOMEM;
> /* Will be ANDed with DART capabilities */
> cfg->supports_bypass = true;
> }
> - if (!cfg)
> - return -ENOMEM;
> dev_iommu_priv_set(dev, cfg);
>
> cfg_dart = cfg->stream_maps[0].dart;
> --
> 2.39.5
>