| 1 | /* |
| 2 | * linux/fs/ext4/symlink.c |
| 3 | * |
| 4 | * Only fast symlinks left here - the rest is done by generic code. AV, 1999 |
| 5 | * |
| 6 | * Copyright (C) 1992, 1993, 1994, 1995 |
| 7 | * Remy Card (card@masi.ibp.fr) |
| 8 | * Laboratoire MASI - Institut Blaise Pascal |
| 9 | * Universite Pierre et Marie Curie (Paris VI) |
| 10 | * |
| 11 | * from |
| 12 | * |
| 13 | * linux/fs/minix/symlink.c |
| 14 | * |
| 15 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 16 | * |
| 17 | * ext4 symlink handling code |
| 18 | */ |
| 19 | |
| 20 | #include <linux/fs.h> |
| 21 | #include <linux/namei.h> |
| 22 | #include "ext4.h" |
| 23 | #include "xattr.h" |
| 24 | |
| 25 | static const char *ext4_encrypted_get_link(struct dentry *dentry, |
| 26 | struct inode *inode, |
| 27 | struct delayed_call *done) |
| 28 | { |
| 29 | struct page *cpage = NULL; |
| 30 | char *caddr, *paddr = NULL; |
| 31 | struct fscrypt_str cstr, pstr; |
| 32 | struct fscrypt_symlink_data *sd; |
| 33 | loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1); |
| 34 | int res; |
| 35 | u32 max_size = inode->i_sb->s_blocksize; |
| 36 | |
| 37 | if (!dentry) |
| 38 | return ERR_PTR(-ECHILD); |
| 39 | |
| 40 | res = fscrypt_get_encryption_info(inode); |
| 41 | if (res) |
| 42 | return ERR_PTR(res); |
| 43 | |
| 44 | if (ext4_inode_is_fast_symlink(inode)) { |
| 45 | caddr = (char *) EXT4_I(inode)->i_data; |
| 46 | max_size = sizeof(EXT4_I(inode)->i_data); |
| 47 | } else { |
| 48 | cpage = read_mapping_page(inode->i_mapping, 0, NULL); |
| 49 | if (IS_ERR(cpage)) |
| 50 | return ERR_CAST(cpage); |
| 51 | caddr = page_address(cpage); |
| 52 | caddr[size] = 0; |
| 53 | } |
| 54 | |
| 55 | /* Symlink is encrypted */ |
| 56 | sd = (struct fscrypt_symlink_data *)caddr; |
| 57 | cstr.name = sd->encrypted_path; |
| 58 | cstr.len = le16_to_cpu(sd->len); |
| 59 | if ((cstr.len + sizeof(struct fscrypt_symlink_data) - 1) > max_size) { |
| 60 | /* Symlink data on the disk is corrupted */ |
| 61 | res = -EFSCORRUPTED; |
| 62 | goto errout; |
| 63 | } |
| 64 | |
| 65 | res = fscrypt_fname_alloc_buffer(inode, cstr.len, &pstr); |
| 66 | if (res) |
| 67 | goto errout; |
| 68 | |
| 69 | res = fscrypt_fname_disk_to_usr(inode, 0, 0, &cstr, &pstr); |
| 70 | if (res < 0) |
| 71 | goto errout; |
| 72 | |
| 73 | paddr = pstr.name; |
| 74 | |
| 75 | /* Null-terminate the name */ |
| 76 | if (res <= pstr.len) |
| 77 | paddr[res] = '\0'; |
| 78 | if (cpage) |
| 79 | put_page(cpage); |
| 80 | set_delayed_call(done, kfree_link, paddr); |
| 81 | return paddr; |
| 82 | errout: |
| 83 | if (cpage) |
| 84 | put_page(cpage); |
| 85 | kfree(paddr); |
| 86 | return ERR_PTR(res); |
| 87 | } |
| 88 | |
| 89 | const struct inode_operations ext4_encrypted_symlink_inode_operations = { |
| 90 | .readlink = generic_readlink, |
| 91 | .get_link = ext4_encrypted_get_link, |
| 92 | .setattr = ext4_setattr, |
| 93 | .setxattr = generic_setxattr, |
| 94 | .getxattr = generic_getxattr, |
| 95 | .listxattr = ext4_listxattr, |
| 96 | .removexattr = generic_removexattr, |
| 97 | }; |
| 98 | |
| 99 | const struct inode_operations ext4_symlink_inode_operations = { |
| 100 | .readlink = generic_readlink, |
| 101 | .get_link = page_get_link, |
| 102 | .setattr = ext4_setattr, |
| 103 | .setxattr = generic_setxattr, |
| 104 | .getxattr = generic_getxattr, |
| 105 | .listxattr = ext4_listxattr, |
| 106 | .removexattr = generic_removexattr, |
| 107 | }; |
| 108 | |
| 109 | const struct inode_operations ext4_fast_symlink_inode_operations = { |
| 110 | .readlink = generic_readlink, |
| 111 | .get_link = simple_get_link, |
| 112 | .setattr = ext4_setattr, |
| 113 | .setxattr = generic_setxattr, |
| 114 | .getxattr = generic_getxattr, |
| 115 | .listxattr = ext4_listxattr, |
| 116 | .removexattr = generic_removexattr, |
| 117 | }; |