[PATCH 1/3] sunrpc: check that domain table is empty at module unload.
From: NeilBrown <neilb@suse.de> hulk inclusion category: bugfix bugzilla: NA CVE: CVE-2020-12656 --------------------------- The domain table should be empty at module unload. If it isn't there is a bug somewhere. So check and report. Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651 Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Wenan Mao <maowenan@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/sunrpc/sunrpc.h | 1 + net/sunrpc/sunrpc_syms.c | 2 ++ net/sunrpc/svcauth.c | 27 +++++++++++++++++++++++++++ 3 files changed, 30 insertions(+) diff --git a/net/sunrpc/sunrpc.h b/net/sunrpc/sunrpc.h index c9bacb3..82035fa 100644 --- a/net/sunrpc/sunrpc.h +++ b/net/sunrpc/sunrpc.h @@ -56,4 +56,5 @@ int svc_send_common(struct socket *sock, struct xdr_buf *xdr, int rpc_clients_notifier_register(void); void rpc_clients_notifier_unregister(void); +void auth_domain_cleanup(void); #endif /* _NET_SUNRPC_SUNRPC_H */ diff --git a/net/sunrpc/sunrpc_syms.c b/net/sunrpc/sunrpc_syms.c index 56f9eff..7b4c6ee 100644 --- a/net/sunrpc/sunrpc_syms.c +++ b/net/sunrpc/sunrpc_syms.c @@ -22,6 +22,7 @@ #include <linux/sunrpc/rpc_pipe_fs.h> #include <linux/sunrpc/xprtsock.h> +#include "sunrpc.h" #include "netns.h" unsigned int sunrpc_net_id; @@ -130,6 +131,7 @@ static __net_exit void sunrpc_exit_net(struct net *net) unregister_rpc_pipefs(); rpc_destroy_mempool(); unregister_pernet_subsys(&sunrpc_net_ops); + auth_domain_cleanup(); #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) rpc_unregister_sysctl(); #endif diff --git a/net/sunrpc/svcauth.c b/net/sunrpc/svcauth.c index bb8db3c..0107350 100644 --- a/net/sunrpc/svcauth.c +++ b/net/sunrpc/svcauth.c @@ -18,6 +18,10 @@ #include <linux/err.h> #include <linux/hash.h> +#include <trace/events/sunrpc.h> + +#include "sunrpc.h" + #define RPCDBG_FACILITY RPCDBG_AUTH @@ -170,3 +174,26 @@ struct auth_domain *auth_domain_find(char *name) return auth_domain_lookup(name, NULL); } EXPORT_SYMBOL_GPL(auth_domain_find); + +/** + * auth_domain_cleanup - check that the auth_domain table is empty + * + * On module unload the auth_domain_table must be empty. To make it + * easier to catch bugs which don't clean up domains properly, we + * warn if anything remains in the table at cleanup time. + * + * Note that we cannot proactively remove the domains at this stage. + * The ->release() function might be in a module that has already been + * unloaded. + */ + +void auth_domain_cleanup(void) +{ + int h; + struct auth_domain *hp; + + for (h = 0; h < DN_HASHMAX; h++) + hlist_for_each_entry(hp, &auth_domain_table[h], hash) + pr_warn("svc: domain %s still present at module unload.\n", + hp->name); +} -- 1.8.3
From: NeilBrown <neilb@suse.de> hulk inclusion category: bugfix bugzilla: NA CVE: CVE-2020-12656 --------------------------- There is no valid case for supporting duplicate pseudoflavor registrations. Currently the silent acceptance of such registrations is hiding a bug. The rpcsec_gss_krb5 module registers 2 flavours but does not unregister them, so if you load, unload, reload the module, it will happily continue to use the old registration which now has pointers to the memory were the module was originally loaded. This could lead to unexpected results. So disallow duplicate registrations. Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651 Cc: stable@vger.kernel.org (v2.6.12+) Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Wenan Mao <maowenan@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- net/sunrpc/auth_gss/svcauth_gss.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 68830e8..92da153 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -796,9 +796,11 @@ u32 svcauth_gss_flavor(struct auth_domain *dom) new->h.flavour = &svcauthops_gss; new->pseudoflavor = pseudoflavor; - stat = 0; test = auth_domain_lookup(name, &new->h); - if (test != &new->h) { /* Duplicate registration */ + if (test != &new->h) { + pr_warn("svc: duplicate registration of gss pseudo flavour %s.\n", + name); + stat = -EADDRINUSE; auth_domain_put(test); kfree(new->h.name); goto out_free_dom; -- 1.8.3
From: NeilBrown <neilb@suse.de> hulk inclusion category: bugfix bugzilla: NA CVE: CVE-2020-12656 --------------------------- gss_mech_register() calls svcauth_gss_register_pseudoflavor() for each flavour, but gss_mech_unregister() does not call auth_domain_put(). This is unbalanced and makes it impossible to reload the module. Change svcauth_gss_register_pseudoflavor() to return the registered auth_domain, and save it for later release. Cc: stable@vger.kernel.org (v2.6.12+) Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651 Signed-off-by: NeilBrown <neilb@suse.de> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Wenan Mao <maowenan@huawei.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- include/linux/sunrpc/gss_api.h | 1 + include/linux/sunrpc/svcauth_gss.h | 3 ++- net/sunrpc/auth_gss/gss_mech_switch.c | 12 +++++++++--- net/sunrpc/auth_gss/svcauth_gss.c | 12 ++++++------ 4 files changed, 18 insertions(+), 10 deletions(-) diff --git a/include/linux/sunrpc/gss_api.h b/include/linux/sunrpc/gss_api.h index 5ac5db4..566d5f5 100644 --- a/include/linux/sunrpc/gss_api.h +++ b/include/linux/sunrpc/gss_api.h @@ -83,6 +83,7 @@ struct pf_desc { u32 service; char *name; char *auth_domain_name; + struct auth_domain *domain; bool datatouch; }; diff --git a/include/linux/sunrpc/svcauth_gss.h b/include/linux/sunrpc/svcauth_gss.h index a4528b2..d229d27 100644 --- a/include/linux/sunrpc/svcauth_gss.h +++ b/include/linux/sunrpc/svcauth_gss.h @@ -21,7 +21,8 @@ void gss_svc_shutdown(void); int gss_svc_init_net(struct net *net); void gss_svc_shutdown_net(struct net *net); -int svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name); +struct auth_domain *svcauth_gss_register_pseudoflavor(u32 pseudoflavor, + char *name); u32 svcauth_gss_flavor(struct auth_domain *dom); #endif /* __KERNEL__ */ diff --git a/net/sunrpc/auth_gss/gss_mech_switch.c b/net/sunrpc/auth_gss/gss_mech_switch.c index 5fec3ab..c7d88f9 100644 --- a/net/sunrpc/auth_gss/gss_mech_switch.c +++ b/net/sunrpc/auth_gss/gss_mech_switch.c @@ -61,6 +61,8 @@ for (i = 0; i < gm->gm_pf_num; i++) { pf = &gm->gm_pfs[i]; + if (pf->domain) + auth_domain_put(pf->domain); kfree(pf->auth_domain_name); pf->auth_domain_name = NULL; } @@ -83,6 +85,7 @@ static int gss_mech_svc_setup(struct gss_api_mech *gm) { + struct auth_domain *dom; struct pf_desc *pf; int i, status; @@ -92,10 +95,13 @@ status = -ENOMEM; if (pf->auth_domain_name == NULL) goto out; - status = svcauth_gss_register_pseudoflavor(pf->pseudoflavor, - pf->auth_domain_name); - if (status) + dom = svcauth_gss_register_pseudoflavor( + pf->pseudoflavor, pf->auth_domain_name); + if (IS_ERR(dom)) { + status = PTR_ERR(dom); goto out; + } + pf->domain = dom; } return 0; out: diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c index 92da153..68259ee 100644 --- a/net/sunrpc/auth_gss/svcauth_gss.c +++ b/net/sunrpc/auth_gss/svcauth_gss.c @@ -779,7 +779,7 @@ u32 svcauth_gss_flavor(struct auth_domain *dom) EXPORT_SYMBOL_GPL(svcauth_gss_flavor); -int +struct auth_domain * svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name) { struct gss_domain *new; @@ -802,17 +802,17 @@ u32 svcauth_gss_flavor(struct auth_domain *dom) name); stat = -EADDRINUSE; auth_domain_put(test); - kfree(new->h.name); - goto out_free_dom; + goto out_free_name; } - return 0; + return test; +out_free_name: + kfree(new->h.name); out_free_dom: kfree(new); out: - return stat; + return ERR_PTR(stat); } - EXPORT_SYMBOL_GPL(svcauth_gss_register_pseudoflavor); static inline int -- 1.8.3
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Yang Yingliang