fs/vfs/security: pass last path component to LSM on inode creation

SELinux would like to implement a new labeling behavior of newly created
inodes.  We currently label new inodes based on the parent and the creating
process.  This new behavior would also take into account the name of the
new object when deciding the new label.  This is not the (supposed) full path,
just the last component of the path.

This is very useful because creating /etc/shadow is different than creating
/etc/passwd but the kernel hooks are unable to differentiate these
operations.  We currently require that userspace realize it is doing some
difficult operation like that and than userspace jumps through SELinux hoops
to get things set up correctly.  This patch does not implement new
behavior, that is obviously contained in a seperate SELinux patch, but it
does pass the needed name down to the correct LSM hook.  If no such name
exists it is fine to pass NULL.

Signed-off-by: Eric Paris <eparis@redhat.com>

4 files changed, 13 insertions, 6 deletions

diff --git a/security/capability.c b/security/capability.c
index 2a5df2b7da83..383d14dc12ef 100644
--- a/security/capability.c
+++ b/security/capability.c
@@ -118,7 +118,8 @@ static void cap_inode_free_security(struct inode *inode)
 }
 
 static int cap_inode_init_security(struct inode *inode, struct inode *dir,
-                                   char **name, void **value, size_t *len)
+                                   const struct qstr *qstr, char **name,
+                                   void **value, size_t *len)
 {
         return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index b84a89dd59c6..4830f36e1ab5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -336,11 +336,13 @@ void security_inode_free(struct inode *inode)
 }
 
 int security_inode_init_security(struct inode *inode, struct inode *dir,
-                                  char **name, void **value, size_t *len)
+                                 const struct qstr *qstr, char **name,
+                                 void **value, size_t *len)
 {
         if (unlikely(IS_PRIVATE(inode)))
                 return -EOPNOTSUPP;
-        return security_ops->inode_init_security(inode, dir, name, value, len);
+        return security_ops->inode_init_security(inode, dir, qstr, name, value,
+                                                 len);
 }
 EXPORT_SYMBOL(security_inode_init_security);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e276eb468536..099bbd07732f 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -39,6 +39,7 @@
 #include <linux/swap.h>
 #include <linux/spinlock.h>
 #include <linux/syscalls.h>
+#include <linux/dcache.h>
 #include <linux/file.h>
 #include <linux/fdtable.h>
 #include <linux/namei.h>
@@ -2509,8 +2510,8 @@ static void selinux_inode_free_security(struct inode *inode)
 }
 
 static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
-                                       char **name, void **value,
-                                       size_t *len)
+                                       const struct qstr *qstr, char **name,
+                                       void **value, size_t *len)
 {
         const struct task_security_struct *tsec = current_security();
         struct inode_security_struct *dsec;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 123a499ded37..0c91a906b3f4 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -33,6 +33,7 @@
 #include <net/cipso_ipv4.h>
 #include <linux/audit.h>
 #include <linux/magic.h>
+#include <linux/dcache.h>
 #include "smack.h"
 
 #define task_security(task)     (task_cred_xxx((task), security))
@@ -501,6 +502,7 @@ static void smack_inode_free_security(struct inode *inode)
  * smack_inode_init_security - copy out the smack from an inode
  * @inode: the inode
  * @dir: unused
+ * @qstr: unused
  * @name: where to put the attribute name
  * @value: where to put the attribute value
  * @len: where to put the length of the attribute
@@ -508,7 +510,8 @@ static void smack_inode_free_security(struct inode *inode)
  * Returns 0 if it all works out, -ENOMEM if there's no memory
  */
 static int smack_inode_init_security(struct inode *inode, struct inode *dir,
-                                     char **name, void **value, size_t *len)
+                                     const struct qstr *qstr, char **name,
+                                     void **value, size_t *len)
 {
         char *isp = smk_of_inode(inode);
         char *dsp = smk_of_inode(dir);