7 files changed, 57 insertions, 47 deletions

diff --git a/fs/xattr.c b/fs/xattr.c
index 6645b7313b33..1858552a6a1a 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -105,6 +105,33 @@ out:
 EXPORT_SYMBOL_GPL(vfs_setxattr);
 
 ssize_t
+xattr_getsecurity(struct inode *inode, const char *name, void *value,
+                        size_t size)
+{
+        void *buffer = NULL;
+        ssize_t len;
+
+        if (!value || !size) {
+                len = security_inode_getsecurity(inode, name, &buffer, false);
+                goto out_noalloc;
+        }
+
+        len = security_inode_getsecurity(inode, name, &buffer, true);
+        if (len < 0)
+                return len;
+        if (size < len) {
+                len = -ERANGE;
+                goto out;
+        }
+        memcpy(value, buffer, len);
+out:
+        security_release_secctx(buffer, len);
+out_noalloc:
+        return len;
+}
+EXPORT_SYMBOL_GPL(xattr_getsecurity);
+
+ssize_t
 vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size)
 {
         struct inode *inode = dentry->d_inode;
@@ -126,8 +153,7 @@ vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size)
         if (!strncmp(name, XATTR_SECURITY_PREFIX,
                                 XATTR_SECURITY_PREFIX_LEN)) {
                 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
-                int ret = security_inode_getsecurity(inode, suffix, value,
-                                                     size, error);
+                int ret = xattr_getsecurity(inode, suffix, value, size);
                 /*
                  * Only overwrite the return value if a security module
                  * is actually active.
diff --git a/include/linux/security.h b/include/linux/security.h
index d24974262dc6..9d289e726fd8 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -423,15 +423,12 @@ struct request_sock;
  *      identified by @name for @dentry.
  *      Return 0 if permission is granted.
  * @inode_getsecurity:
- *      Copy the extended attribute representation of the security label 
- *      associated with @name for @inode into @buffer.  @buffer may be
- *      NULL to request the size of the buffer required.  @size indicates
- *      the size of @buffer in bytes.  Note that @name is the remainder
- *      of the attribute name after the security. prefix has been removed.
- *      @err is the return value from the preceding fs getxattr call,
- *      and can be used by the security module to determine whether it
- *      should try and canonicalize the attribute value.
- *      Return number of bytes used/required on success.
+ *      Retrieve a copy of the extended attribute representation of the
+ *      security label associated with @name for @inode via @buffer.  Note that
+ *      @name is the remainder of the attribute name after the security prefix
+ *      has been removed. @alloc is used to specify of the call should return a
+ *      value via the buffer or just the value length Return size of buffer on
+ *      success.
  * @inode_setsecurity:
  *      Set the security label associated with @name for @inode from the
  *      extended attribute value @value.  @size indicates the size of the
@@ -1304,7 +1301,7 @@ struct security_operations {
         int (*inode_removexattr) (struct dentry *dentry, char *name);
         int (*inode_need_killpriv) (struct dentry *dentry);
         int (*inode_killpriv) (struct dentry *dentry);
-        int (*inode_getsecurity)(const struct inode *inode, const char *name, void *buffer, size_t size, int err);
+        int (*inode_getsecurity)(const struct inode *inode, const char *name, void **buffer, bool alloc);
         int (*inode_setsecurity)(struct inode *inode, const char *name, const void *value, size_t size, int flags);
         int (*inode_listsecurity)(struct inode *inode, char *buffer, size_t buffer_size);
 
@@ -1565,7 +1562,7 @@ int security_inode_listxattr(struct dentry *dentry);
 int security_inode_removexattr(struct dentry *dentry, char *name);
 int security_inode_need_killpriv(struct dentry *dentry);
 int security_inode_killpriv(struct dentry *dentry);
-int security_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err);
+int security_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc);
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags);
 int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
 int security_file_permission(struct file *file, int mask);
@@ -1967,7 +1964,7 @@ static inline int security_inode_killpriv(struct dentry *dentry)
         return cap_inode_killpriv(dentry);
 }
 
-static inline int security_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err)
+static inline int security_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
 {
         return -EOPNOTSUPP;
 }
diff --git a/include/linux/xattr.h b/include/linux/xattr.h
index def131a5ac70..df6b95d2218e 100644
--- a/include/linux/xattr.h
+++ b/include/linux/xattr.h
@@ -46,6 +46,7 @@ struct xattr_handler {
                    size_t size, int flags);
 };
 
+ssize_t xattr_getsecurity(struct inode *, const char *, void *, size_t);
 ssize_t vfs_getxattr(struct dentry *, char *, void *, size_t);
 ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size);
 int vfs_setxattr(struct dentry *, char *, void *, size_t, int);
diff --git a/mm/shmem.c b/mm/shmem.c
index ee9024483f60..0f246c44a574 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1955,8 +1955,7 @@ static int shmem_xattr_security_get(struct inode *inode, const char *name,
 {
         if (strcmp(name, "") == 0)
                 return -EINVAL;
-        return security_inode_getsecurity(inode, name, buffer, size,
-                                          -EOPNOTSUPP);
+        return xattr_getsecurity(inode, name, buffer, size);
 }
 
 static int shmem_xattr_security_set(struct inode *inode, const char *name,
diff --git a/security/dummy.c b/security/dummy.c
index 48d4b0a52737..c505122e22db 100644
--- a/security/dummy.c
+++ b/security/dummy.c
@@ -402,7 +402,7 @@ static int dummy_inode_killpriv(struct dentry *dentry)
         return 0;
 }
 
-static int dummy_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err)
+static int dummy_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
 {
         return -EOPNOTSUPP;
 }
diff --git a/security/security.c b/security/security.c
index ca475ca206e4..b6c57a6b2ff5 100644
--- a/security/security.c
+++ b/security/security.c
@@ -493,11 +493,11 @@ int security_inode_killpriv(struct dentry *dentry)
         return security_ops->inode_killpriv(dentry);
 }
 
-int security_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err)
+int security_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
 {
         if (unlikely(IS_PRIVATE(inode)))
                 return 0;
-        return security_ops->inode_getsecurity(inode, name, buffer, size, err);
+        return security_ops->inode_getsecurity(inode, name, buffer, alloc);
 }
 
 int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index be6de0b8734f..e5ed07510309 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -136,32 +136,6 @@ static DEFINE_SPINLOCK(sb_security_lock);
 
 static struct kmem_cache *sel_inode_cache;
 
-/* Return security context for a given sid or just the context 
-   length if the buffer is null or length is 0 */
-static int selinux_getsecurity(u32 sid, void *buffer, size_t size)
-{
-        char *context;
-        unsigned len;
-        int rc;
-
-        rc = security_sid_to_context(sid, &context, &len);
-        if (rc)
-                return rc;
-
-        if (!buffer || !size)
-                goto getsecurity_exit;
-
-        if (size < len) {
-                len = -ERANGE;
-                goto getsecurity_exit;
-        }
-        memcpy(buffer, context, len);
-
-getsecurity_exit:
-        kfree(context);
-        return len;
-}
-
 /**
  * selinux_secmark_enabled - Check to see if SECMARK is currently enabled
  *
@@ -2675,14 +2649,27 @@ static int selinux_inode_removexattr (struct dentry *dentry, char *name)
  *
  * Permission check is handled by selinux_inode_getxattr hook.
  */
-static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void *buffer, size_t size, int err)
+static int selinux_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc)
 {
+        u32 size;
+        int error;
+        char *context = NULL;
         struct inode_security_struct *isec = inode->i_security;
 
         if (strcmp(name, XATTR_SELINUX_SUFFIX))
                 return -EOPNOTSUPP;
 
-        return selinux_getsecurity(isec->sid, buffer, size);
+        error = security_sid_to_context(isec->sid, &context, &size);
+        if (error)
+                return error;
+        error = size;
+        if (alloc) {
+                *buffer = context;
+                goto out_nofree;
+        }
+        kfree(context);
+out_nofree:
+        return error;
 }
 
 static int selinux_inode_setsecurity(struct inode *inode, const char *name,