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SubjectRe: [Linux-fbdev-devel] [PATCH] viafb: Use sizeof struct rather than pointer
Hi,

Roel Kluin schrieb:
> diff --git a/drivers/video/via/viafbdev.c b/drivers/video/via/viafbdev.c
> index 56ec696..7b181e7 100644
> --- a/drivers/video/via/viafbdev.c
> +++ b/drivers/video/via/viafbdev.c
> @@ -680,7 +680,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
> if (!viafb_gamma_table)
> return -ENOMEM;
> if (copy_from_user(viafb_gamma_table, argp,
> - sizeof(viafb_gamma_table))) {
> + sizeof(*viafb_gamma_table))) {
> kfree(viafb_gamma_table);
> return -EFAULT;
> }
> @@ -694,7 +694,7 @@ static int viafb_ioctl(struct fb_info *info, u_int cmd, u_long arg)
> return -ENOMEM;
> viafb_get_gamma_table(viafb_gamma_table);
> if (copy_to_user(argp, viafb_gamma_table,
> - sizeof(viafb_gamma_table))) {
> + sizeof(*viafb_gamma_table))) {
> kfree(viafb_gamma_table);
> return -EFAULT;
> }

I'm sorry but I fear your fix isn't correct. The reason is a few lines
above:

u32 *viafb_gamma_table;
...
viafb_gamma_table = kmalloc(256 * sizeof(u32), GFP_KERNEL);

so probably the right solution would look like this:

copy_from_user(viafb_gamma_table, argp, 256 * sizeof(u32))
copy_to_user(argp, viafb_gamma_table, 256 * sizeof(u32))

However viafb has way too many private ioctls. I would be curious
whether there exists any program that uses any of them so that they
could be tested. As this ioctl didn't work very well I vote to remove it
at least temporarily.

Thanks for highlighting this problem,


Florian Tobias Schandinat


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