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Commit 8b326c61 authored by Miklos Szeredi's avatar Miklos Szeredi
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ovl: copy_up_xattr(): use strnlen 



Be defensive about what underlying fs provides us in the returned xattr
list buffer.  strlen() may overrun the buffer, so use strnlen() and WARN if
the contents are not properly null terminated.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
parent 9395452b

fs/overlayfs/copy_up.c

+11 −1
Original line number Diff line number Diff line
@@ -57,6 +57,7 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) 
	ssize_t list_size, size, value_size = 0;

	char *buf, *name, *value = NULL;

	int uninitialized_var(error);

	size_t slen;



	if (!old->d_inode->i_op->getxattr ||

	    !new->d_inode->i_op->getxattr)
@@ -79,7 +80,16 @@ int ovl_copy_xattr(struct dentry *old, struct dentry *new) 
		goto out;

	}



	for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {

	for (name = buf; list_size; name += slen) {

		slen = strnlen(name, list_size) + 1;



		/* underlying fs providing us with an broken xattr list? */

		if (WARN_ON(slen > list_size)) {

			error = -EIO;

			break;

		}

		list_size -= slen;



		if (ovl_is_private_xattr(name))

			continue;

retry: