4.19-stable review patch. If anyone has any objections, please let me know.
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From: Lukasz Pawelczyk l.pawelczyk@samsung.com
[ Upstream commit ea6cc2fd8a2b89ab6dcd096ba6dbc1ecbdf26564 ]
The XT_OWNER_SUPPL_GROUPS flag causes GIDs specified with XT_OWNER_GID to be also checked in the supplementary groups of a process.
f_cred->group_info cannot be modified during its lifetime and f_cred holds a reference to it so it's safe to use.
Signed-off-by: Lukasz Pawelczyk l.pawelczyk@samsung.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Stable-dep-of: 7ae836a3d630 ("netfilter: xt_owner: Fix for unsafe access of sk->sk_socket") Signed-off-by: Sasha Levin sashal@kernel.org --- include/uapi/linux/netfilter/xt_owner.h | 7 ++++--- net/netfilter/xt_owner.c | 23 ++++++++++++++++++++--- 2 files changed, 24 insertions(+), 6 deletions(-)
diff --git a/include/uapi/linux/netfilter/xt_owner.h b/include/uapi/linux/netfilter/xt_owner.h index fa3ad84957d50..9e98c09eda327 100644 --- a/include/uapi/linux/netfilter/xt_owner.h +++ b/include/uapi/linux/netfilter/xt_owner.h @@ -5,9 +5,10 @@ #include <linux/types.h>
enum { - XT_OWNER_UID = 1 << 0, - XT_OWNER_GID = 1 << 1, - XT_OWNER_SOCKET = 1 << 2, + XT_OWNER_UID = 1 << 0, + XT_OWNER_GID = 1 << 1, + XT_OWNER_SOCKET = 1 << 2, + XT_OWNER_SUPPL_GROUPS = 1 << 3, };
struct xt_owner_match_info { diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c index 46686fb73784b..a8784502aca69 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_OWNER_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; }