Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:47851 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751691Ab2KLMOE (ORCPT ); Mon, 12 Nov 2012 07:14:04 -0500 Date: Mon, 12 Nov 2012 07:13:56 -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 01/13] Security: Add hook to calculate context based on a negative dentry. Message-ID: <20121112121356.GC30713@fieldses.org> References: <1352700947-3915-1-git-send-email-dpquigl@davequigley.com> <1352700947-3915-2-git-send-email-dpquigl@davequigley.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1352700947-3915-2-git-send-email-dpquigl@davequigley.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, Nov 12, 2012 at 01:15:35AM -0500, David Quigley wrote: > From: David Quigley > > There is a time where we need to calculate a context without the > inode having been created yet. To do this we take the negative dentry and > calculate a context based on the process and the parent directory contexts. > > 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 | 27 +++++++++++++++++++++++++++ > security/capability.c | 8 ++++++++ > security/security.c | 10 ++++++++++ > security/selinux/hooks.c | 35 +++++++++++++++++++++++++++++++++++ > 4 files changed, 80 insertions(+) > > diff --git a/include/linux/security.h b/include/linux/security.h > index 05e88bd..c9f5eec 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -26,6 +26,7 @@ > #include > #include > #include > +#include > > struct linux_binprm; > struct cred; > @@ -306,6 +307,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) > * Parse a string of security data filling in the opts structure > * @options string containing all mount options known by the LSM > * @opts binary data structure usable by the LSM > + * @dentry_init_security: > + * Compute a context for a dentry as the inode is not yet available > + * since NFSv4 has no label backed by an EA anyway. I don't understand this comment. Why exactly is NFSv4 the first user that needs this? --b. > + * @dentry dentry to use in calculating the context. > + * @mode mode used to determine resource type. > + * @name name of the last path component used to create file > + * @ctx pointer to place the pointer to the resulting context in. > + * @ctxlen point to place the length of the resulting context. > + * > * > * Security hooks for inode operations. > * > @@ -1421,6 +1431,10 @@ struct security_operations { > void (*sb_clone_mnt_opts) (const struct super_block *oldsb, > struct super_block *newsb); > int (*sb_parse_opts_str) (char *options, struct security_mnt_opts *opts); > + int (*dentry_init_security) (struct dentry *dentry, int mode, > + struct qstr *name, void **ctx, > + u32 *ctxlen); > + > > #ifdef CONFIG_SECURITY_PATH > int (*path_unlink) (struct path *dir, struct dentry *dentry); > @@ -1702,6 +1716,9 @@ int security_sb_set_mnt_opts(struct super_block *sb, struct security_mnt_opts *o > void security_sb_clone_mnt_opts(const struct super_block *oldsb, > struct super_block *newsb); > int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts); > +int security_dentry_init_security(struct dentry *dentry, int mode, > + struct qstr *name, void **ctx, > + u32 *ctxlen); > > int security_inode_alloc(struct inode *inode); > void security_inode_free(struct inode *inode); > @@ -2005,6 +2022,16 @@ static inline int security_inode_alloc(struct inode *inode) > static inline void security_inode_free(struct inode *inode) > { } > > +static inline int security_dentry_init_security(struct dentry *dentry, > + int mode, > + struct qstr *name, > + void **ctx, > + u32 *ctxlen) > +{ > + return -EOPNOTSUPP; > +} > + > + > static inline int security_inode_init_security(struct inode *inode, > struct inode *dir, > const struct qstr *qstr, > diff --git a/security/capability.c b/security/capability.c > index b14a30c..f1eb284 100644 > --- a/security/capability.c > +++ b/security/capability.c > @@ -108,6 +108,13 @@ static int cap_sb_parse_opts_str(char *options, struct security_mnt_opts *opts) > return 0; > } > > +static int cap_dentry_init_security(struct dentry *dentry, int mode, > + struct qstr *name, void **ctx, > + u32 *ctxlen) > +{ > + return 0; > +} > + > static int cap_inode_alloc_security(struct inode *inode) > { > return 0; > @@ -905,6 +912,7 @@ void __init security_fixup_ops(struct security_operations *ops) > set_to_cap_if_null(ops, sb_set_mnt_opts); > set_to_cap_if_null(ops, sb_clone_mnt_opts); > set_to_cap_if_null(ops, sb_parse_opts_str); > + set_to_cap_if_null(ops, dentry_init_security); > set_to_cap_if_null(ops, inode_alloc_security); > set_to_cap_if_null(ops, inode_free_security); > set_to_cap_if_null(ops, inode_init_security); > diff --git a/security/security.c b/security/security.c > index 8dcd4ae..b4b2017 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -12,6 +12,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -324,6 +325,15 @@ void security_inode_free(struct inode *inode) > security_ops->inode_free_security(inode); > } > > +int security_dentry_init_security(struct dentry *dentry, int mode, > + struct qstr *name, void **ctx, > + u32 *ctxlen) > +{ > + return security_ops->dentry_init_security(dentry, mode, name, > + ctx, ctxlen); > +} > +EXPORT_SYMBOL(security_dentry_init_security); > + > int security_inode_init_security(struct inode *inode, struct inode *dir, > const struct qstr *qstr, > const initxattrs initxattrs, void *fs_data) > diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c > index 61a5336..22d9adf 100644 > --- a/security/selinux/hooks.c > +++ b/security/selinux/hooks.c > @@ -2483,6 +2483,40 @@ static void selinux_inode_free_security(struct inode *inode) > inode_free_security(inode); > } > > +static int selinux_dentry_init_security(struct dentry *dentry, int mode, > + struct qstr *name, void **ctx, > + u32 *ctxlen) > +{ > + struct cred *cred = current_cred(); > + struct task_security_struct *tsec; > + struct inode_security_struct *dsec; > + struct superblock_security_struct *sbsec; > + struct inode *dir = dentry->d_parent->d_inode; > + u32 newsid; > + int rc; > + > + tsec = cred->security; > + dsec = dir->i_security; > + sbsec = dir->i_sb->s_security; > + > + if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) { > + newsid = tsec->create_sid; > + } else { > + rc = security_transition_sid(tsec->sid, dsec->sid, > + inode_mode_to_security_class(mode), > + name, > + &newsid); > + if (rc) { > + printk(KERN_WARNING > + "%s: security_transition_sid failed, rc=%d\n", > + __func__, -rc); > + return rc; > + } > + } > + > + return security_sid_to_context(newsid, (char **)ctx, ctxlen); > +} > + > static int selinux_inode_init_security(struct inode *inode, struct inode *dir, > const struct qstr *qstr, char **name, > void **value, size_t *len) > @@ -5509,6 +5543,7 @@ static struct security_operations selinux_ops = { > .sb_clone_mnt_opts = selinux_sb_clone_mnt_opts, > .sb_parse_opts_str = selinux_parse_opts_str, > > + .dentry_init_security = selinux_dentry_init_security, > > .inode_alloc_security = selinux_inode_alloc_security, > .inode_free_security = selinux_inode_free_security, > -- > 1.7.11.7 >