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Commit d47be3df authored by David Quigley's avatar David Quigley Committed by Trond Myklebust
Browse files

Security: Add hook to calculate context based on a negative dentry. 



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.

Acked-by: default avatarEric Paris <eparis@redhat.com>
Acked-by: default avatarJames Morris <james.l.morris@oracle.com>
Signed-off-by: default avatarMatthew N. Dodd <Matthew.Dodd@sparta.com>
Signed-off-by: default avatarMiguel Rodel Felipe <Rodel_FM@dsi.a-star.edu.sg>
Signed-off-by: default avatarPhua Eu Gene <PHUA_Eu_Gene@dsi.a-star.edu.sg>
Signed-off-by: default avatarKhin Mi Mi Aung <Mi_Mi_AUNG@dsi.a-star.edu.sg>
Signed-off-by: default avatarSteve Dickson <steved@redhat.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 4488cc96

include/linux/security.h

+27 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ 
#include <linux/capability.h>

#include <linux/slab.h>

#include <linux/err.h>

#include <linux/string.h>



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.

 *	@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.

 *
@@ -1443,6 +1453,10 @@ struct security_operations { 
	int (*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);
@@ -1729,6 +1743,9 @@ int security_sb_set_mnt_opts(struct super_block *sb, struct security_mnt_opts *o 
int 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);
@@ -2035,6 +2052,16 @@ 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,

security/capability.c

+8 −0
Original line number Diff line number Diff line
@@ -109,6 +109,13 @@ 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;
@@ -931,6 +938,7 @@ 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);

security/security.c

+10 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
 */



#include <linux/capability.h>

#include <linux/dcache.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/kernel.h>
@@ -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)

security/selinux/hooks.c

+35 −0
Original line number Diff line number Diff line
@@ -2515,6 +2515,40 @@ 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)

{

	const 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)
@@ -5562,6 +5596,7 @@ 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,