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138 lines
3.3 KiB
138 lines
3.3 KiB
/* |
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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/jbd2.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 = dentry->d_inode; |
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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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res = ext4_get_encryption_info(inode); |
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if (res) |
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return ERR_PTR(res); |
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if (ext4_inode_is_fast_symlink(inode)) { |
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caddr = (char *) EXT4_I(dentry->d_inode)->i_data; |
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max_size = sizeof(EXT4_I(dentry->d_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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return cpage; |
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caddr = page_address(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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pstr.len = plen; |
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res = _ext4_fname_disk_to_usr(inode, 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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if (cpage) |
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page_cache_release(cpage); |
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return NULL; |
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errout: |
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if (cpage) |
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page_cache_release(cpage); |
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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(dentry->d_inode); |
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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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