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- /*
- * 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,
- };
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