Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:10203 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752878Ab3EPP4z (ORCPT ); Thu, 16 May 2013 11:56:55 -0400 From: Steve Dickson To: Trond Myklebust , "David P. Quigley" Cc: Linux NFS list , Linux FS devel list , Linux Security List , SELinux List Subject: [PATCH 02/13] Security: Add Hook to test if the particular xattr is part of a MAC model. Date: Thu, 16 May 2013 11:56:37 -0400 Message-Id: <1368719808-14584-3-git-send-email-SteveD@redhat.com> In-Reply-To: <1368719808-14584-1-git-send-email-SteveD@redhat.com> References: <1368719808-14584-1-git-send-email-SteveD@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: 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 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. Acked-by: James Morris 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 --- 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 c2af462..cff3e4f 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1323,6 +1323,13 @@ 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 1 if name is a MAC + * attribute otherwise returns 0. + * @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. @@ -1604,6 +1611,7 @@ 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); @@ -1857,6 +1865,7 @@ 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); @@ -2547,6 +2556,11 @@ 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 7aeec66..b3e8b93 100644 --- a/security/capability.c +++ b/security/capability.c @@ -823,6 +823,11 @@ 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; @@ -1042,6 +1047,7 @@ 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 0fe2b2e..c3ceb75 100644 --- a/security/security.c +++ b/security/security.c @@ -1057,6 +1057,12 @@ 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 b1f7bd7..bbf219a 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -5454,6 +5454,11 @@ 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); @@ -5692,6 +5697,7 @@ 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 d52c780..a7f485b 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -3329,6 +3329,16 @@ 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 @@ -3524,6 +3534,7 @@ 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, -- 1.8.1.4