Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:47858 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731Ab2KLMP3 (ORCPT ); Mon, 12 Nov 2012 07:15:29 -0500 Date: Mon, 12 Nov 2012 07:15:25 -0500 From: "J. Bruce Fields" To: David Quigley Cc: trond.myklebust@netapp.com, sds@tycho.nsa.gov, linux-nfs@vger.kernel.org, selinux@tycho.nsa.gov, linux-security-module@vger.kernel.org, "Matthew N. Dodd" , Miguel Rodel Felipe , Phua Eu Gene , Khin Mi Mi Aung Subject: Re: [PATCH 02/13] Security: Add Hook to test if the particular xattr is part of a MAC model. Message-ID: <20121112121525.GD30713@fieldses.org> References: <1352700947-3915-1-git-send-email-dpquigl@davequigley.com> <1352700947-3915-3-git-send-email-dpquigl@davequigley.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1352700947-3915-3-git-send-email-dpquigl@davequigley.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 12, 2012 at 01:15:36AM -0500, David Quigley wrote: > From: David Quigley > > The interface to request security labels from user space is the xattr > interface. When requesting the security label from an NFS server it is > important to make sure the requested xattr I'm confused--clients can't request xattrs from NFS servers. I must be reading this wrong, but I'm not sure what you meant. --b. > actually is a MAC label. This allows > us to make sure that we get the desired semantics from the attribute instead of > something else such as capabilities or a time based LSM. > > Signed-off-by: Matthew N. Dodd > Signed-off-by: Miguel Rodel Felipe > Signed-off-by: Phua Eu Gene > Signed-off-by: Khin Mi Mi Aung > Signed-off-by: David Quigley > --- > include/linux/security.h | 14 ++++++++++++++ > security/capability.c | 6 ++++++ > security/security.c | 6 ++++++ > security/selinux/hooks.c | 6 ++++++ > security/smack/smack_lsm.c | 11 +++++++++++ > 5 files changed, 43 insertions(+) > > diff --git a/include/linux/security.h b/include/linux/security.h > index c9f5eec..167bdd5 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -1301,6 +1301,13 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) > * @pages contains the number of pages. > * Return 0 if permission is granted. > * > + * @ismaclabel: > + * Check if the extended attribute specified by @name > + * represents a MAC label. Returns 0 if name is a MAC > + * attribute otherwise returns non-zero. > + * @name full extended attribute name to check against > + * LSM as a MAC label. > + * > * @secid_to_secctx: > * Convert secid to security context. If secdata is NULL the length of > * the result will be returned in seclen, but no secdata will be returned. > @@ -1581,6 +1588,7 @@ struct security_operations { > > int (*getprocattr) (struct task_struct *p, char *name, char **value); > int (*setprocattr) (struct task_struct *p, char *name, void *value, size_t size); > + int (*ismaclabel) (const char *name); > int (*secid_to_secctx) (u32 secid, char **secdata, u32 *seclen); > int (*secctx_to_secid) (const char *secdata, u32 seclen, u32 *secid); > void (*release_secctx) (char *secdata, u32 seclen); > @@ -1829,6 +1837,7 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode); > int security_getprocattr(struct task_struct *p, char *name, char **value); > int security_setprocattr(struct task_struct *p, char *name, void *value, size_t size); > int security_netlink_send(struct sock *sk, struct sk_buff *skb); > +int security_ismaclabel(const char *name); > int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); > int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid); > void security_release_secctx(char *secdata, u32 seclen); > @@ -2512,6 +2521,11 @@ static inline int security_netlink_send(struct sock *sk, struct sk_buff *skb) > return cap_netlink_send(sk, skb); > } > > +static inline int security_ismaclabel(const char *name) > +{ > + return 0; > +} > + > static inline int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) > { > return -EOPNOTSUPP; > diff --git a/security/capability.c b/security/capability.c > index f1eb284..9071447 100644 > --- a/security/capability.c > +++ b/security/capability.c > @@ -797,6 +797,11 @@ static int cap_setprocattr(struct task_struct *p, char *name, void *value, > return -EINVAL; > } > > +static int cap_ismaclabel(const char *name) > +{ > + return 0; > +} > + > static int cap_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) > { > return -EOPNOTSUPP; > @@ -1015,6 +1020,7 @@ void __init security_fixup_ops(struct security_operations *ops) > set_to_cap_if_null(ops, d_instantiate); > set_to_cap_if_null(ops, getprocattr); > set_to_cap_if_null(ops, setprocattr); > + set_to_cap_if_null(ops, ismaclabel); > set_to_cap_if_null(ops, secid_to_secctx); > set_to_cap_if_null(ops, secctx_to_secid); > set_to_cap_if_null(ops, release_secctx); > diff --git a/security/security.c b/security/security.c > index b4b2017..a7bee7b 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -1047,6 +1047,12 @@ int security_netlink_send(struct sock *sk, struct sk_buff *skb) > return security_ops->netlink_send(sk, skb); > } > > +int security_ismaclabel(const char *name) > +{ > + return security_ops->ismaclabel(name); > +} > +EXPORT_SYMBOL(security_ismaclabel); > + > int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) > { > return security_ops->secid_to_secctx(secid, secdata, seclen); > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 22d9adf..f7c4899 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -5401,6 +5401,11 @@ abort_change: > return error; > } > > +static int selinux_ismaclabel(const char *name) > +{ > + return (strcmp(name, XATTR_SELINUX_SUFFIX) == 0); > +} > + > static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) > { > return security_sid_to_context(secid, secdata, seclen); > @@ -5639,6 +5644,7 @@ static struct security_operations selinux_ops = { > .getprocattr = selinux_getprocattr, > .setprocattr = selinux_setprocattr, > > + .ismaclabel = selinux_ismaclabel, > .secid_to_secctx = selinux_secid_to_secctx, > .secctx_to_secid = selinux_secctx_to_secid, > .release_secctx = selinux_release_secctx, > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index 38be92c..82c3c72 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -3335,6 +3335,16 @@ static void smack_audit_rule_free(void *vrule) > #endif /* CONFIG_AUDIT */ > > /** > + * smack_ismaclabel - check if xattr @name references a smack MAC label > + * @name: Full xattr name to check. > + */ > +static int smack_ismaclabel(const char *name) > +{ > + return (strcmp(name, XATTR_SMACK_SUFFIX) == 0); > +} > + > + > +/** > * smack_secid_to_secctx - return the smack label for a secid > * @secid: incoming integer > * @secdata: destination > @@ -3530,6 +3540,7 @@ struct security_operations smack_ops = { > .audit_rule_free = smack_audit_rule_free, > #endif /* CONFIG_AUDIT */ > > + .ismaclabel = smack_ismaclabel, > .secid_to_secctx = smack_secid_to_secctx, > .secctx_to_secid = smack_secctx_to_secid, > .release_secctx = smack_release_secctx, > -- > 1.7.11.7 >