On Wed, 2019-05-08 at 07:58 -0700, Eric Dumazet wrote: > > On 5/8/19 10:12 AM, Lukasz Pawelczyk wrote: > > The XT_SUPPL_GROUPS flag causes GIDs specified with XT_OWNER_GID to > > be also checked in the supplementary groups of a process. > > > > Signed-off-by: Lukasz Pawelczyk <[email protected]> > > --- > > include/uapi/linux/netfilter/xt_owner.h | 1 + > > net/netfilter/xt_owner.c | 23 ++++++++++++++++++++- > > -- > > 2 files changed, 21 insertions(+), 3 deletions(-) > > > > diff --git a/include/uapi/linux/netfilter/xt_owner.h > > b/include/uapi/linux/netfilter/xt_owner.h > > index fa3ad84957d5..d646f0dc3466 100644 > > --- a/include/uapi/linux/netfilter/xt_owner.h > > +++ b/include/uapi/linux/netfilter/xt_owner.h > > @@ -8,6 +8,7 @@ enum { > > XT_OWNER_UID = 1 << 0, > > XT_OWNER_GID = 1 << 1, > > XT_OWNER_SOCKET = 1 << 2, > > + XT_SUPPL_GROUPS = 1 << 3, > > }; > > > > struct xt_owner_match_info { > > diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c > > index 46686fb73784..283a1fb5cc52 100644 > > --- a/net/netfilter/xt_owner.c > > +++ b/net/netfilter/xt_owner.c > > @@ -91,11 +91,28 @@ owner_mt(const struct sk_buff *skb, struct > > xt_action_param *par) > > } > > > > if (info->match & XT_OWNER_GID) { > > + unsigned int i, match = false; > > kgid_t gid_min = make_kgid(net->user_ns, info- > > >gid_min); > > kgid_t gid_max = make_kgid(net->user_ns, info- > > >gid_max); > > - if ((gid_gte(filp->f_cred->fsgid, gid_min) && > > - gid_lte(filp->f_cred->fsgid, gid_max)) ^ > > - !(info->invert & XT_OWNER_GID)) > > + struct group_info *gi = filp->f_cred->group_info; > > + > > + if (gid_gte(filp->f_cred->fsgid, gid_min) && > > + gid_lte(filp->f_cred->fsgid, gid_max)) > > + match = true; > > + > > + if (!match && (info->match & XT_SUPPL_GROUPS) && gi) { > > + for (i = 0; i < gi->ngroups; ++i) { > > + kgid_t group = gi->gid[i]; > > + > > + if (gid_gte(group, gid_min) && > > + gid_lte(group, gid_max)) { > > + match = true; > > + break; > > + } > > + } > > + } > > + > > + if (match ^ !(info->invert & XT_OWNER_GID)) > > return false; > > } > > > > > > How can this be safe on SMP ? >
>From what I see after the group_info rework some time ago this struct is never modified. It's replaced. Would get_group_info/put_group_info around the code be enough? -- Lukasz Pawelczyk Samsung R&D Institute Poland Samsung Electronics
