146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/*
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* linux/fs/ext4/symlink.c
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*
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* Only fast symlinks left here - the rest is done by generic code. AV, 1999
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/symlink.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext4 symlink handling code
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*/
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#include <linux/fs.h>
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#include <linux/namei.h>
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#include "ext4.h"
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#include "xattr.h"
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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static void *ext4_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct page *cpage = NULL;
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char *caddr, *paddr = NULL;
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struct ext4_str cstr, pstr;
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struct inode *inode = d_inode(dentry);
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struct ext4_fname_crypto_ctx *ctx = NULL;
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struct ext4_encrypted_symlink_data *sd;
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loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
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int res;
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u32 plen, max_size = inode->i_sb->s_blocksize;
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if (!ext4_encrypted_inode(inode))
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return page_follow_link_light(dentry, nd);
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ctx = ext4_get_fname_crypto_ctx(inode, inode->i_sb->s_blocksize);
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if (IS_ERR(ctx))
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return ctx;
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if (ext4_inode_is_fast_symlink(inode)) {
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caddr = (char *) EXT4_I(inode)->i_data;
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max_size = sizeof(EXT4_I(inode)->i_data);
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} else {
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cpage = read_mapping_page(inode->i_mapping, 0, NULL);
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if (IS_ERR(cpage)) {
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ext4_put_fname_crypto_ctx(&ctx);
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return cpage;
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}
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caddr = kmap(cpage);
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caddr[size] = 0;
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}
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/* Symlink is encrypted */
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sd = (struct ext4_encrypted_symlink_data *)caddr;
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cstr.name = sd->encrypted_path;
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cstr.len = le32_to_cpu(sd->len);
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if ((cstr.len +
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sizeof(struct ext4_encrypted_symlink_data) - 1) >
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max_size) {
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/* Symlink data on the disk is corrupted */
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res = -EIO;
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goto errout;
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}
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plen = (cstr.len < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2) ?
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EXT4_FNAME_CRYPTO_DIGEST_SIZE*2 : cstr.len;
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paddr = kmalloc(plen + 1, GFP_NOFS);
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if (!paddr) {
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res = -ENOMEM;
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goto errout;
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}
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pstr.name = paddr;
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res = _ext4_fname_disk_to_usr(ctx, NULL, &cstr, &pstr);
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if (res < 0)
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goto errout;
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/* Null-terminate the name */
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if (res <= plen)
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paddr[res] = '\0';
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nd_set_link(nd, paddr);
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ext4_put_fname_crypto_ctx(&ctx);
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if (cpage) {
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kunmap(cpage);
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page_cache_release(cpage);
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}
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return NULL;
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errout:
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ext4_put_fname_crypto_ctx(&ctx);
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if (cpage) {
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kunmap(cpage);
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page_cache_release(cpage);
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}
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kfree(paddr);
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return ERR_PTR(res);
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}
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static void ext4_put_link(struct dentry *dentry, struct nameidata *nd,
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void *cookie)
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{
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struct page *page = cookie;
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if (!page) {
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kfree(nd_get_link(nd));
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} else {
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kunmap(page);
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page_cache_release(page);
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}
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}
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#endif
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static void *ext4_follow_fast_link(struct dentry *dentry, struct nameidata *nd)
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{
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struct ext4_inode_info *ei = EXT4_I(d_inode(dentry));
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nd_set_link(nd, (char *) ei->i_data);
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return NULL;
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}
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const struct inode_operations ext4_symlink_inode_operations = {
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.readlink = generic_readlink,
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#ifdef CONFIG_EXT4_FS_ENCRYPTION
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.follow_link = ext4_follow_link,
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.put_link = ext4_put_link,
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#else
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.follow_link = page_follow_link_light,
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.put_link = page_put_link,
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#endif
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.setattr = ext4_setattr,
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext4_listxattr,
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.removexattr = generic_removexattr,
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};
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const struct inode_operations ext4_fast_symlink_inode_operations = {
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.readlink = generic_readlink,
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.follow_link = ext4_follow_fast_link,
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.setattr = ext4_setattr,
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext4_listxattr,
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.removexattr = generic_removexattr,
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};
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