From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3414C17555; Wed, 25 Mar 2026 12:31:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774441897; cv=none; b=OvwSuwzVUuxSfK810TTjoDb+nM/FODJOGViNgqRSr/2Ja3W8JOGn7K9iWboVvLYImXot4zUge4adUgPu37KoxCrcGZBsrxyy1U1e12fV+DrkpR0OVOTrv+f9JmmmmGZsWfuRzM8Hzp9iuxxj68icmRc/JlaTD06YI/qzoXyeeIE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774441897; c=relaxed/simple; bh=Bhj/syWyI1jpO2YrqX3wR0yX/Q5t22fUviveszri5fg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Gvh9gETNuuqWO3hdri6EMNmCF7h5DRMkOzIkiLe4MeaP1ZKT1claPjggTt68YporrOcejkZV5XO8s7OUgeX6Y6QGoSVs7PDqRRJdXTgcZEBeFUBS+XvmdG8PCb52ANreS4bl2eDLuExR5Dj7Q70kkVcIuf9AzVINPuebfKhfrqc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fjnVPjiG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fjnVPjiG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FF4CC4CEF7; Wed, 25 Mar 2026 12:31:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774441896; bh=Bhj/syWyI1jpO2YrqX3wR0yX/Q5t22fUviveszri5fg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fjnVPjiGm5fxk7WwEWi5IjzajVbZNNVtsZllMt45/dpF9mNfb/qLl33+zd/LmLi/K Q6gAEFJXYSM9saLhRxlITYcyuQE+Khc+9nB6uTOtOZYtYF9dUgZHolS6msX3p9hfri 08vyTVTaELev6lJmTO+0IynslcfwEQWcxBxa0i0cFP0oxhukPu2sJLUyRT5lJRWYPY komOe68CIoUCLejEiTuI7Sp21Pl0KOnjSBxJYrywLSRiMKPLIBGNC54NkaUbBW4Cn1 gewIGVmo1I482miNF+EkJgejy5khrbiREs1b4dqdXg52nsLTaR243Lz223dgYIMrXU ODgMuFOBgNrLg== Date: Wed, 25 Mar 2026 13:31:30 +0100 From: Christian Brauner To: =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= Cc: =?utf-8?Q?G=C3=BCnther?= Noack , Paul Moore , "Serge E . Hallyn" , Justin Suess , Lennart Poettering , Mikhail Ivanov , Nicolas Bouchinet , Shervin Oloumi , Tingmao Wang , kernel-team@cloudflare.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: Re: [RFC PATCH v1 01/11] security: add LSM blob and hooks for namespaces Message-ID: <20260325-filmverleih-auffressen-e897fcf8d3f2@brauner> References: <20260312100444.2609563-1-mic@digikod.net> <20260312100444.2609563-2-mic@digikod.net> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260312100444.2609563-2-mic@digikod.net> On Thu, Mar 12, 2026 at 11:04:34AM +0100, Mickaël Salaün wrote: > From: Christian Brauner > > All namespace types now share the same ns_common infrastructure. Extend > this to include a security blob so LSMs can start managing namespaces > uniformly without having to add one-off hooks or security fields to > every individual namespace type. > > Add a ns_security pointer to ns_common and the corresponding lbs_ns > blob size to lsm_blob_sizes. Allocation and freeing hooks are called > from the common __ns_common_init() and __ns_common_free() paths so > every namespace type gets covered in one go. All information about the > namespace type and the appropriate casting helpers to get at the > containing namespace are available via ns_common making it > straightforward for LSMs to differentiate when they need to. > > A namespace_install hook is called from validate_ns() during setns(2) > giving LSMs a chance to enforce policy on namespace transitions. > > Individual namespace types can still have their own specialized security > hooks when needed. This is just the common baseline that makes it easy > to track and manage namespaces from the security side without requiring > every namespace type to reinvent the wheel. > > Cc: Günther Noack > Cc: Paul Moore > Cc: Serge E. Hallyn > Signed-off-by: Christian Brauner > Link: https://lore.kernel.org/r/20260216-work-security-namespace-v1-1-075c28758e1f@kernel.org > --- > include/linux/lsm_hook_defs.h | 3 ++ > include/linux/lsm_hooks.h | 1 + > include/linux/ns/ns_common_types.h | 3 ++ > include/linux/security.h | 20 ++++++++ > kernel/nscommon.c | 12 +++++ > kernel/nsproxy.c | 8 +++- > security/lsm_init.c | 2 + > security/security.c | 76 ++++++++++++++++++++++++++++++ > 8 files changed, 124 insertions(+), 1 deletion(-) > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index 8c42b4bde09c..fefd3aa6d8f4 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -260,6 +260,9 @@ LSM_HOOK(int, -ENOSYS, task_prctl, int option, unsigned long arg2, > LSM_HOOK(void, LSM_RET_VOID, task_to_inode, struct task_struct *p, > struct inode *inode) > LSM_HOOK(int, 0, userns_create, const struct cred *cred) > +LSM_HOOK(int, 0, namespace_alloc, struct ns_common *ns) > +LSM_HOOK(void, LSM_RET_VOID, namespace_free, struct ns_common *ns) > +LSM_HOOK(int, 0, namespace_install, const struct nsset *nsset, struct ns_common *ns) > LSM_HOOK(int, 0, ipc_permission, struct kern_ipc_perm *ipcp, short flag) > LSM_HOOK(void, LSM_RET_VOID, ipc_getlsmprop, struct kern_ipc_perm *ipcp, > struct lsm_prop *prop) > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index d48bf0ad26f4..3e7afe76e86c 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -111,6 +111,7 @@ struct lsm_blob_sizes { > unsigned int lbs_ipc; > unsigned int lbs_key; > unsigned int lbs_msg_msg; > + unsigned int lbs_ns; > unsigned int lbs_perf_event; > unsigned int lbs_task; > unsigned int lbs_xattr_count; /* num xattr slots in new_xattrs array */ > diff --git a/include/linux/ns/ns_common_types.h b/include/linux/ns/ns_common_types.h > index 0014fbc1c626..170288e2e895 100644 > --- a/include/linux/ns/ns_common_types.h > +++ b/include/linux/ns/ns_common_types.h > @@ -115,6 +115,9 @@ struct ns_common { > struct dentry *stashed; > const struct proc_ns_operations *ops; > unsigned int inum; > +#ifdef CONFIG_SECURITY > + void *ns_security; > +#endif > union { > struct ns_tree; > struct rcu_head ns_rcu; > diff --git a/include/linux/security.h b/include/linux/security.h > index 83a646d72f6f..611b9098367d 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -67,6 +67,7 @@ enum fs_value_type; > struct watch; > struct watch_notification; > struct lsm_ctx; > +struct nsset; > > /* Default (no) options for the capable function */ > #define CAP_OPT_NONE 0x0 > @@ -80,6 +81,7 @@ struct lsm_ctx; > > struct ctl_table; > struct audit_krule; > +struct ns_common; > struct user_namespace; > struct timezone; > > @@ -533,6 +535,9 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, > unsigned long arg4, unsigned long arg5); > void security_task_to_inode(struct task_struct *p, struct inode *inode); > int security_create_user_ns(const struct cred *cred); > +int security_namespace_alloc(struct ns_common *ns); > +void security_namespace_free(struct ns_common *ns); > +int security_namespace_install(const struct nsset *nsset, struct ns_common *ns); > int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag); > void security_ipc_getlsmprop(struct kern_ipc_perm *ipcp, struct lsm_prop *prop); > int security_msg_msg_alloc(struct msg_msg *msg); > @@ -1407,6 +1412,21 @@ static inline int security_create_user_ns(const struct cred *cred) > return 0; > } > > +static inline int security_namespace_alloc(struct ns_common *ns) > +{ > + return 0; > +} > + > +static inline void security_namespace_free(struct ns_common *ns) > +{ > +} > + > +static inline int security_namespace_install(const struct nsset *nsset, > + struct ns_common *ns) > +{ > + return 0; > +} > + > static inline int security_ipc_permission(struct kern_ipc_perm *ipcp, > short flag) > { > diff --git a/kernel/nscommon.c b/kernel/nscommon.c > index bdc3c86231d3..de774e374f9d 100644 > --- a/kernel/nscommon.c > +++ b/kernel/nscommon.c > @@ -4,6 +4,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -59,6 +60,9 @@ int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_ope > > refcount_set(&ns->__ns_ref, 1); > ns->stashed = NULL; > +#ifdef CONFIG_SECURITY > + ns->ns_security = NULL; > +#endif > ns->ops = ops; > ns->ns_id = 0; > ns->ns_type = ns_type; > @@ -77,6 +81,13 @@ int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_ope > ret = proc_alloc_inum(&ns->inum); > if (ret) > return ret; > + > + ret = security_namespace_alloc(ns); > + if (ret) { > + proc_free_inum(ns->inum); ret = security_namespace_alloc(ns); if (ret && !inum) proc_free_inum(ns->inum); return ret; > + return ret; > + } > + > /* > * Tree ref starts at 0. It's incremented when namespace enters > * active use (installed in nsproxy) and decremented when all > @@ -91,6 +102,7 @@ int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_ope > > void __ns_common_free(struct ns_common *ns) > { > + security_namespace_free(ns); > proc_free_inum(ns->inum); > } > > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c > index 259c4b4f1eeb..f0b30d1907e7 100644 > --- a/kernel/nsproxy.c > +++ b/kernel/nsproxy.c > @@ -379,7 +379,13 @@ static int prepare_nsset(unsigned flags, struct nsset *nsset) > > static inline int validate_ns(struct nsset *nsset, struct ns_common *ns) > { > - return ns->ops->install(nsset, ns); > + int ret; > + > + ret = ns->ops->install(nsset, ns); > + if (ret) > + return ret; > + > + return security_namespace_install(nsset, ns); In my local tree I had that moved before the ->install() and I think that's the correct thing to do. So please switch to that. The rest looks good to me, thanks.