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pf: Set the pfik_group for userspace

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Userspace relies on this pointer to work out if the kif is a group or
not. It can't use it for anything else, because it's a pointer to a
kernel address. Substitute 0xfeedc0de for 'true', so that we don't leak
kernel memory addresses to userspace.

PR:		255852
Reviewed by:	donner
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D30284
This commit is contained in:
Kristof Provost 2021-05-16 08:50:17 +02:00
parent b2ee069e8c
commit d69cc04014
1 changed files with 8 additions and 0 deletions
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8
sys/netpfil/pf/pf_if.c
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@ -831,6 +831,14 @@ pf_kkif_to_kif(const struct pfi_kkif *kkif, struct pfi_kif *kif)
kif->pfik_flags = kkif->pfik_flags;
kif->pfik_tzero = kkif->pfik_tzero;
kif->pfik_rulerefs = kkif->pfik_rulerefs;
/*
* Userspace relies on this pointer to decide if this is a group or
* not. We don't want to share the actual pointer, because it's
* useless to userspace and leaks kernel memory layout information.
* So instead we provide 0xfeedcode as 'true' and NULL as 'false'.
*/
kif->pfik_group =
kkif->pfik_group ? (struct ifg_group *)0xfeedc0de : NULL;
}
void