Re: [PATCH 1/2] block: reject dma-bufs larger than 4GiB

[Pavel Begunkov <asml.silence@gmail.com>]

On 10/21/26 19:46, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
> 
> The dma-buf offset is set in the 32-bit bvec_iter bi_offset. Reject
> buffers that can carry an offset that would wrap.
> 
> Fixes: 839231d19393 ("block: add dma-buf support for raw bdev")
> Signed-off-by: Keith Busch <kbusch@kernel.org>
> ---
>   block/fops.c | 3 ++++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/block/fops.c b/block/fops.c
> index 46cb86dd36d23..a974b423869eb 100644
> --- a/block/fops.c
> +++ b/block/fops.c
> @@ -19,6 +19,7 @@
>   #include <linux/iomap.h>
>   #include <linux/module.h>
>   #include <linux/io_uring/cmd.h>
> +#include <linux/dma-buf-io.h>
>   #include "blk.h"
>   
>   static inline struct inode *bdev_file_inode(struct file *file)
> @@ -1009,6 +1010,9 @@ static int blkdev_init_dma_buf_io_ctx(struct file *file,
>   
>   	if (!(file->f_flags & O_DIRECT))
>   		return -EINVAL;
> +	if (ctx->dmabuf->size > UINT_MAX)
> +		return -EINVAL;

Sounds good, should be reasonable for now. It'd also be good to
move it to dma-buf-io* as it's not a block problem.

Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>


>   	if (!disk->fops->init_dma_buf_io_ctx)
>   		return -EOPNOTSUPP;
>   	if (bdev_has_integrity_csum(bdev))

-- 
Pavel Begunkov