On 22.12.2015 12:46, Huw Davies wrote:
> The functionality is equivalent to ipv6_renew_options() except
> that the newopt pointer is in kernel, not user, memory
>
> The kernel memory implementation will be used by the CALIPSO network
> labelling engine, which needs to be able to set IPv6 hop-by-hop
> options.
>
> Signed-off-by: Huw Davies <h...@codeweavers.com>
> ---
> include/net/ipv6.h | 6 +++
> net/ipv6/exthdrs.c | 131
> ++++++++++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 125 insertions(+), 12 deletions(-)
>
> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
> index 9a5c9f0..5a72ffd 100644
> --- a/include/net/ipv6.h
> +++ b/include/net/ipv6.h
> @@ -304,6 +304,12 @@ struct ipv6_txoptions *ipv6_renew_options(struct sock
> *sk,
> int newtype,
> struct ipv6_opt_hdr __user *newopt,
> int newoptlen);
> +struct ipv6_txoptions *
> +ipv6_renew_options_kern(struct sock *sk,
> + struct ipv6_txoptions *opt,
> + int newtype,
> + struct ipv6_opt_hdr *newopt,
> + int newoptlen);
> struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
> struct ipv6_txoptions *opt);
>
> diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
> index ea7c4d6..9426b26 100644
> --- a/net/ipv6/exthdrs.c
> +++ b/net/ipv6/exthdrs.c
> @@ -734,11 +734,16 @@ ipv6_dup_options(struct sock *sk, struct ipv6_txoptions
> *opt)
> EXPORT_SYMBOL_GPL(ipv6_dup_options);
>
> static int ipv6_renew_option(void *ohdr,
> - struct ipv6_opt_hdr __user *newopt, int newoptlen,
> + struct ipv6_opt_hdr __user *newopt_user,
> + struct ipv6_opt_hdr *newopt,
> + int newoptlen,
> int inherit,
> struct ipv6_opt_hdr **hdr,
> char **p)
This looks quite ugly to me.
Wouldn't it be possible to do something like this:
ipv6_renew_option_kern(...)
{
int ret;
const mm_segment_t old_fs = get_fs();
set_fs(KERNEL_DS);
ret = ipv6_renew_option(...); // maybe you need to forcefully cast the
user away here
set_fs(old_fs);
return ret;
}
Bye,
Hannes
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