On Friday, January 08, 2016 09:52:50 AM Huw Davies wrote:
> In some cases, the lsm needs to add the label to the skbuff directly.
> A NF_INET_LOCAL_OUT IPv6 hook is added to selinux to match the IPv4
> behaviour. This allows selinux to label the skbuffs that it requires.
>
> Signed-off-by: Huw Davies <huw@xxxxxxxxxxxxxxx>
...
> diff --git a/include/net/ipv6.h b/include/net/ipv6.h
> index 5f9c252..71b5045 100644
> --- a/include/net/ipv6.h
> +++ b/include/net/ipv6.h
> @@ -920,7 +920,7 @@ enum {
> int ipv6_find_hdr(const struct sk_buff *skb, unsigned int *offset, int
> target, unsigned short *fragoff, int *fragflg);
>
> -int ipv6_find_tlv(struct sk_buff *skb, int offset, int type);
> +int ipv6_find_tlv(const struct sk_buff *skb, int offset, int type);
It probably does make sense to constify the skb argument, but you should do
that in a separate patch.
> struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
> const struct ipv6_txoptions *opt,
> diff --git a/include/net/netlabel.h b/include/net/netlabel.h
> index a2408c3..0697ba2 100644
> --- a/include/net/netlabel.h
> +++ b/include/net/netlabel.h
> @@ -231,6 +231,10 @@ struct netlbl_lsm_secattr {
> * @sock_delattr: remove the socket's attr
> * @req_setattr: set the req socket's attr
> * @req_delattr: remove the req socket's attr
> + * @optptr: find option in packet
How about "skbuff_optptr" instead?
> + * @getattr: retrieve attr from memory block
How about "opt_getattr"?
> + * @skbuff_setattr: set the skbuff's attr
> + * @skbuff_delattr: remove the skbuff's attr
...
> +/**
> + * calipso_skbuff_setattr - Set the CALIPSO option on a packet
> + * @skb: the packet
> + * @doi_def: the CALIPSO DOI to use
> + * @secattr: the security attributes
> + *
> + * Description:
> + * Set the CALIPSO option on the given packet based on the security
> attributes. + * Returns a pointer to the IP header on success and NULL on
> failure. + *
> + */
> +static int calipso_skbuff_setattr(struct sk_buff *skb,
> + const struct calipso_doi *doi_def,
> + const struct netlbl_lsm_secattr *secattr)
> +{
> + int ret_val;
> + struct ipv6hdr *ip6_hdr;
> + struct ipv6_opt_hdr *hop;
> + unsigned char buf[CALIPSO_MAX_BUFFER];
> + int len_delta;
> + unsigned int start, end, next_opt, pad;
> +
> + ip6_hdr = ipv6_hdr(skb);
> + if (ip6_hdr->nexthdr == NEXTHDR_HOP) {
> + hop = (struct ipv6_opt_hdr *)(ip6_hdr + 1);
> + ret_val = calipso_opt_find(hop, &start, &end);
> + if (ret_val && ret_val != -ENOENT)
> + return ret_val;
> + if (end != ipv6_optlen(hop))
> + next_opt = end;
> + else
> + next_opt = 0;
> + len_delta = -(int)end;
> + } else {
> + start = 0;
> + next_opt = 0;
> + len_delta = 0;
> + }
> +
> + memset(buf, 0, sizeof(buf));
> + ret_val = calipso_genopt(buf, start & 3, sizeof(buf), doi_def, secattr);
> + if (ret_val < 0)
> + return ret_val;
> +
> + end = start + ret_val;
> +
> + if (WARN_ON_ONCE(end & 3))
> + return -EINVAL;
See my earlier comments about the use of WARN_ON_ONCE().
> + pad = ((end & 7) + (next_opt & 7)) & 7;
> + len_delta += end + pad;
> +
> + if (WARN_ON_ONCE(len_delta & 7))
> + return -EINVAL;
Same.
> + ret_val = skb_cow(skb, skb_headroom(skb) + len_delta);
> + if (ret_val < 0)
> + return ret_val;
> +
> + if (len_delta) {
> + if (len_delta > 0)
> + skb_push(skb, len_delta);
> + else
> + skb_pull(skb, -len_delta);
> + memmove((char *)ip6_hdr - len_delta, ip6_hdr,
> + sizeof(*ip6_hdr) + start);
> + skb_reset_network_header(skb);
> + ip6_hdr = ipv6_hdr(skb);
> + }
--
paul moore
security @ redhat
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