On Tue, Dec 07, 2021 at 01:46:14PM +0300, Dan Carpenter wrote:
> The "config.offset" comes from the user. There needs to a check to
> prevent it being out of bounds. The "config.offset" and
> "dev->config_size" variables are both type u32. So if the offset if
> out of bounds then the "dev->config_size - config.offset" subtraction
> results in a very high u32 value.
>
> Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index c9204c62f339..2f789dca0c0b 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -975,7 +975,8 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
> break;
>
> ret = -EINVAL;
> - if (config.length == 0 ||
> + if (config.offset < dev->config_size ||
This is reversed. Sorry. Will send a fix. I was over excited about
this patch.
Also I need to write a Smatch test for this so both the original and my
patched version generate a warning.
regards,
dan carpenter
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