Re: [patch] isdn/kcapi: return -EFAULT on copy_from_user errors

Jan Kiszka
2010-06-03T10:26:42Z

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Dan Carpenter wrote:
> copy_from_user() returns the number of bytes remaining but we should
> return -EFAULT here. The error code gets returned to the user. Both
> old_capi_manufacturer() and capi20_manufacturer() had other places
> that already returned -EFAULT so this won't break anything.
>

Good point.

> Signed-off-by: Dan Carpenter <error27@gmail.com>
>
> diff --git a/drivers/isdn/capi/kcapi.c b/drivers/isdn/capi/kcapi.c
> index bde3c88..b054494 100644
> --- a/drivers/isdn/capi/kcapi.c
> +++ b/drivers/isdn/capi/kcapi.c
> @@ -1020,12 +1020,12 @@ static int old_capi_manufacturer(unsigned int cmd, void __user *data)
> if (cmd == AVMB1_ADDCARD) {
> if ((retval = copy_from_user(&cdef, data,
> sizeof(avmb1_carddef))))
> - return retval;
> + return -EFAULT;
> cdef.cardtype = AVM_CARDTYPE_B1;
> } else {
> if ((retval = copy_from_user(&cdef, data,
> sizeof(avmb1_extcarddef))))
> - return retval;
> + return -EFAULT;
> }
> cparams.port = cdef.port;
> cparams.irq = cdef.irq;
> @@ -1218,7 +1218,7 @@ int capi20_manufacturer(unsigned int cmd, void __user *data)
> kcapi_carddef cdef;
>
> if ((retval = copy_from_user(&cdef, data, sizeof(cdef))))
> - return retval;
> + return -EFAULT;
>
> cparams.port = cdef.port;
> cparams.irq = cdef.irq;

No need to assign retval anymore, it is overwritten in all non-error cases.

Jan

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