vfs: Distinguish between full xattr names and proper prefixes

Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 0 insertions, 12 deletions

diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index e41a010cd89c..ab01530b4930 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -431,9 +431,6 @@ int hfsplus_setxattr(struct dentry *dentry, const char *name,
         char *xattr_name;
         int res;
 
-        if (!strcmp(name, ""))
-                return -EINVAL;
-
         xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
                 GFP_KERNEL);
         if (!xattr_name)
@@ -589,9 +586,6 @@ ssize_t hfsplus_getxattr(struct dentry *dentry, const char *name,
         int res;
         char *xattr_name;
 
-        if (!strcmp(name, ""))
-                return -EINVAL;
-
         xattr_name = kmalloc(NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN + 1,
                              GFP_KERNEL);
         if (!xattr_name)
@@ -853,9 +847,6 @@ static int hfsplus_osx_getxattr(const struct xattr_handler *handler,
                                 struct dentry *dentry, const char *name,
                                 void *buffer, size_t size)
 {
-        if (!strcmp(name, ""))
-                return -EINVAL;
-
         /*
          * Don't allow retrieving properly prefixed attributes
          * by prepending them with "osx."
@@ -876,9 +867,6 @@ static int hfsplus_osx_setxattr(const struct xattr_handler *handler,
                                 struct dentry *dentry, const char *name,
                                 const void *buffer, size_t size, int flags)
 {
-        if (!strcmp(name, ""))
-                return -EINVAL;
-
         /*
          * Don't allow setting properly prefixed attributes
          * by prepending them with "osx."