From: Ido Schimmel <idosch@nvidia.com> stable inclusion from stable-v6.6.143 commit e19eff331240bd45e43b3a4a9422505b02e3bda2 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16416 CVE: CVE-2026-64137 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit cd4d7263d58ab98fd4dee876776e4da6c328faa3 ] As explained in commit e03781879a0d ("drop_monitor: Require 'CAP_SYS_ADMIN' when joining "events" group"), the "flags" field in the multicast group structure reuses uAPI flags despite the field not being exposed to user space. This makes it impossible to extend its use without adding new uAPI flags, which is inappropriate for internal kernel checks. Solve this by adding internal flags (i.e., "GENL_MCAST_*") and convert the existing users to use them instead of the uAPI flags. Tested using the reproducers in commit 44ec98ea5ea9 ("psample: Require 'CAP_NET_ADMIN' when joining "packets" group") and commit e03781879a0d ("drop_monitor: Require 'CAP_SYS_ADMIN' when joining "events" group"). No functional changes intended. Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Mat Martineau <martineau@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net> Stable-dep-of: d1ebfce2c1d1 ("smb: client: require net admin for CIFS SWN netlink") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Conflicts: include/net/genetlink.h net/mptcp/pm_netlink.c [commit 5d35419049ac from hulk kabi and commit d2afb9d6d1e8 has been backport lead to conflict] Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- include/net/genetlink.h | 8 ++++++-- net/core/drop_monitor.c | 2 +- net/mptcp/pm_netlink.c | 2 +- net/netlink/genetlink.c | 4 ++-- net/psample/psample.c | 2 +- 5 files changed, 11 insertions(+), 7 deletions(-) diff --git a/include/net/genetlink.h b/include/net/genetlink.h index 49d9be598c2b..4a1cf31a459a 100644 --- a/include/net/genetlink.h +++ b/include/net/genetlink.h @@ -9,11 +9,15 @@ #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN) +/* Binding to multicast group requires %CAP_NET_ADMIN */ +#define GENL_MCAST_CAP_NET_ADMIN BIT(0) +/* Binding to multicast group requires %CAP_SYS_ADMIN */ +#define GENL_MCAST_CAP_SYS_ADMIN BIT(1) + /** * struct genl_multicast_group - generic netlink multicast group * @name: name of the multicast group, names are per-family - * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM) - * @cap_sys_admin: whether %CAP_SYS_ADMIN is required for binding + * @flags: GENL_MCAST_* flags */ struct genl_multicast_group { char name[GENL_NAMSIZ]; diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index fccda85ce8fe..a3f73588fb6c 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -183,7 +183,7 @@ static struct sk_buff *reset_per_cpu_data(struct per_cpu_dm_data *data) } static const struct genl_multicast_group dropmon_mcgrps[] = { - { .name = "events", .cap_sys_admin = 1 }, + { .name = "events", .flags = GENL_MCAST_CAP_SYS_ADMIN, }, }; static void send_dm_alert(struct work_struct *work) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index eafe3a71290c..ed989c610adc 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1282,7 +1282,7 @@ bool mptcp_pm_nl_is_backup(struct mptcp_sock *msk, struct mptcp_addr_info *skc) static const struct genl_multicast_group mptcp_pm_mcgrps[] = { [MPTCP_PM_CMD_GRP_OFFSET] = { .name = MPTCP_PM_CMD_GRP_NAME, }, [MPTCP_PM_EV_GRP_OFFSET] = { .name = MPTCP_PM_EV_GRP_NAME, - .flags = GENL_UNS_ADMIN_PERM, + .flags = GENL_MCAST_CAP_NET_ADMIN, }, }; diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index d6eee5140c8b..982536950566 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -1683,10 +1683,10 @@ static int genl_bind(struct net *net, int group) continue; grp = &family->mcgrps[i]; - if ((grp->flags & GENL_UNS_ADMIN_PERM) && + if ((grp->flags & GENL_MCAST_CAP_NET_ADMIN) && !ns_capable(net->user_ns, CAP_NET_ADMIN)) ret = -EPERM; - if (grp->cap_sys_admin && + if ((grp->flags & GENL_MCAST_CAP_SYS_ADMIN) && !ns_capable(net->user_ns, CAP_SYS_ADMIN)) ret = -EPERM; diff --git a/net/psample/psample.c b/net/psample/psample.c index 5d9532555d4a..a4d094377955 100644 --- a/net/psample/psample.c +++ b/net/psample/psample.c @@ -32,7 +32,7 @@ enum psample_nl_multicast_groups { static const struct genl_multicast_group psample_nl_mcgrps[] = { [PSAMPLE_NL_MCGRP_CONFIG] = { .name = PSAMPLE_NL_MCGRP_CONFIG_NAME }, [PSAMPLE_NL_MCGRP_SAMPLE] = { .name = PSAMPLE_NL_MCGRP_SAMPLE_NAME, - .flags = GENL_UNS_ADMIN_PERM }, + .flags = GENL_MCAST_CAP_NET_ADMIN, }, }; static struct genl_family psample_nl_family __ro_after_init; -- 2.52.0