From c9e7c76d70fa50582ca96759829c93d0dd024662 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 21 Sep 2020 15:36:51 +0100 Subject: xfrm: Provide API to register translator module Add a skeleton for xfrm_compat module and provide API to register it in xfrm_state.ko. struct xfrm_translator will have function pointers to translate messages received from 32-bit userspace or to be sent to it from 64-bit kernel. module_get()/module_put() are used instead of rcu_read_lock() as the module will vmalloc() memory for translation. The new API is registered with xfrm_state module, not with xfrm_user as the former needs translator for user_policy set by setsockopt() and xfrm_user already uses functions from xfrm_state. Signed-off-by: Dmitry Safonov Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) (limited to 'net/xfrm/xfrm_state.c') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index 69520ad3d83b..cc206ca3df78 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2264,6 +2264,66 @@ static bool km_is_alive(const struct km_event *c) return is_alive; } +#if IS_ENABLED(CONFIG_XFRM_USER_COMPAT) +static DEFINE_SPINLOCK(xfrm_translator_lock); +static struct xfrm_translator __rcu *xfrm_translator; + +struct xfrm_translator *xfrm_get_translator(void) +{ + struct xfrm_translator *xtr; + + rcu_read_lock(); + xtr = rcu_dereference(xfrm_translator); + if (unlikely(!xtr)) + goto out; + if (!try_module_get(xtr->owner)) + xtr = NULL; +out: + rcu_read_unlock(); + return xtr; +} +EXPORT_SYMBOL_GPL(xfrm_get_translator); + +void xfrm_put_translator(struct xfrm_translator *xtr) +{ + module_put(xtr->owner); +} +EXPORT_SYMBOL_GPL(xfrm_put_translator); + +int xfrm_register_translator(struct xfrm_translator *xtr) +{ + int err = 0; + + spin_lock_bh(&xfrm_translator_lock); + if (unlikely(xfrm_translator != NULL)) + err = -EEXIST; + else + rcu_assign_pointer(xfrm_translator, xtr); + spin_unlock_bh(&xfrm_translator_lock); + + return err; +} +EXPORT_SYMBOL_GPL(xfrm_register_translator); + +int xfrm_unregister_translator(struct xfrm_translator *xtr) +{ + int err = 0; + + spin_lock_bh(&xfrm_translator_lock); + if (likely(xfrm_translator != NULL)) { + if (rcu_access_pointer(xfrm_translator) != xtr) + err = -EINVAL; + else + RCU_INIT_POINTER(xfrm_translator, NULL); + } + spin_unlock_bh(&xfrm_translator_lock); + synchronize_rcu(); + + return err; +} +EXPORT_SYMBOL_GPL(xfrm_unregister_translator); +#endif + int xfrm_user_policy(struct sock *sk, int optname, sockptr_t optval, int optlen) { int err; -- cgit v1.2.3 From 96392ee5a13b992563cfe07d23ee30d333b89126 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 21 Sep 2020 15:36:56 +0100 Subject: xfrm/compat: Translate 32-bit user_policy from sockptr Provide compat_xfrm_userpolicy_info translation for xfrm setsocketopt(). Reallocate buffer and put the missing padding for 64-bit message. Signed-off-by: Dmitry Safonov Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'net/xfrm/xfrm_state.c') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index cc206ca3df78..f9961884500b 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -2331,9 +2331,6 @@ int xfrm_user_policy(struct sock *sk, int optname, sockptr_t optval, int optlen) struct xfrm_mgr *km; struct xfrm_policy *pol = NULL; - if (in_compat_syscall()) - return -EOPNOTSUPP; - if (sockptr_is_null(optval) && !optlen) { xfrm_sk_policy_insert(sk, XFRM_POLICY_IN, NULL); xfrm_sk_policy_insert(sk, XFRM_POLICY_OUT, NULL); @@ -2348,6 +2345,20 @@ int xfrm_user_policy(struct sock *sk, int optname, sockptr_t optval, int optlen) if (IS_ERR(data)) return PTR_ERR(data); + if (in_compat_syscall()) { + struct xfrm_translator *xtr = xfrm_get_translator(); + + if (!xtr) + return -EOPNOTSUPP; + + err = xtr->xlate_user_policy_sockptr(&data, optlen); + xfrm_put_translator(xtr); + if (err) { + kfree(data); + return err; + } + } + err = -EINVAL; rcu_read_lock(); list_for_each_entry_rcu(km, &xfrm_km_list, list) { -- cgit v1.2.3