xattr: define vfs_getxattr_alloc and vfs_xattr_cmp

vfs_getxattr_alloc() and vfs_xattr_cmp() are two new kernel xattr helper
functions.  vfs_getxattr_alloc() first allocates memory for the requested
xattr and then retrieves it. vfs_xattr_cmp() compares a given value with
the contents of an extended attribute.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
security: new security_inode_init_security API adds function callback

This patch changes the security_inode_init_security API by adding a
filesystem specific callback to write security extended attributes.
This change is in preparation for supporting the initialization of
multiple LSM xattrs and the EVM xattr.  Initially the callback function
walks an array of xattrs, writing each xattr separately, but could be
optimized to write multiple xattrs at once.

For existing security_inode_init_security() calls, which have not yet
been converted to use the new callback function, such as those in
reiserfs and ocfs2, this patch defines security_old_inode_init_security().

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
yaffs: fix getxattr support

When passed a buffer size of 0, getxattr(2) is documented to return the
size of the attribute value.  However, yaffs returns -ERANGE instead.
This breaks SELinux usage of getxattr.  Fix yaffs to return the
attribute size in this case.

Change-Id: I410e96ad36741b8fd6aef70d0aabc22391c8d5ac
Signed-off-by:  Stephen Smalley <sds@tycho.nsa.gov>
yaffs: set security attribute at file creation

Add support to yaffs to set the security attribute of new inodes when
they are created. This parallels similar support in other filesystems,
and is a requirement for SELinux and other MAC systems. This support
is used by SE Android, http://selinuxproject.org/page/SEAndroid.

Change-Id: Ifad16ca6016583c9beee3b6afd2584e171297205
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
fs: yaffs2: Add null pointer check before dereferencing inode

In yaffs_rename(), d_entry->d_inode can be NULL if the
target directory doesn't exist or if there is any race
condition such as target directory being deleted while
renaming another directory to target directory name.
Avoid dereferencing d_inode in such cases.

CRs-Fixed: 360748
Change-Id: If95b4992f1056fea78f2e1bd54253cd5c8aac93d
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>