1 files changed, 119 insertions, 0 deletions
diff --git a/fs/ext4/symlink.c b/fs/ext4/symlink.c
new file mode 100644
index 000000000000..287c3980fa0b
--- /dev/null
+++ b/fs/ext4/symlink.c
@@ -0,0 +1,119 @@
+/*
+ *  linux/fs/ext4/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext4 symlink handling code
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include "ext4.h"
+#include "xattr.h"
+
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
+static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cookie)
+{
+	struct page *cpage = NULL;
+	char *caddr, *paddr = NULL;
+	struct ext4_str cstr, pstr;
+	struct inode *inode = d_inode(dentry);
+	struct ext4_encrypted_symlink_data *sd;
+	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
+	int res;
+	u32 plen, max_size = inode->i_sb->s_blocksize;
+
+	res = ext4_get_encryption_info(inode);
+	if (res)
+		return ERR_PTR(res);
+
+	if (ext4_inode_is_fast_symlink(inode)) {
+		caddr = (char *) EXT4_I(inode)->i_data;
+		max_size = sizeof(EXT4_I(inode)->i_data);
+	} else {
+		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
+		if (IS_ERR(cpage))
+			return ERR_CAST(cpage);
+		caddr = page_address(cpage);
+		caddr[size] = 0;
+	}
+
+	/* Symlink is encrypted */
+	sd = (struct ext4_encrypted_symlink_data *)caddr;
+	cstr.name = sd->encrypted_path;
+	cstr.len  = le16_to_cpu(sd->len);
+	if ((cstr.len +
+	     sizeof(struct ext4_encrypted_symlink_data) - 1) >
+	    max_size) {
+		/* Symlink data on the disk is corrupted */
+		res = -EFSCORRUPTED;
+		goto errout;
+	}
+	plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
+		EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
+	paddr = kmalloc(plen + 1, GFP_NOFS);
+	if (!paddr) {
+		res = -ENOMEM;
+		goto errout;
+	}
+	pstr.name = paddr;
+	pstr.len = plen;
+	res = _ext4_fname_disk_to_usr(inode, NULL, &cstr, &pstr);
+	if (res < 0)
+		goto errout;
+	/* Null-terminate the name */
+	if (res <= plen)
+		paddr[res] = '\0';
+	if (cpage)
+		page_cache_release(cpage);
+	return *cookie = paddr;
+errout:
+	if (cpage)
+		page_cache_release(cpage);
+	kfree(paddr);
+	return ERR_PTR(res);
+}
+
+const struct inode_operations ext4_encrypted_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link    = ext4_encrypted_follow_link,
+	.put_link       = kfree_put_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};
+#endif
+
+const struct inode_operations ext4_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};
+
+const struct inode_operations ext4_fast_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link    = simple_follow_link,
+	.setattr	= ext4_setattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext4_listxattr,
+	.removexattr	= generic_removexattr,
+};