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| 1 | +// SPDX-License-Identifier: GPL-2.0 |
| 2 | + |
| 3 | +#include <linux/quotaops.h> |
| 4 | +#include <linux/uuid.h> |
| 5 | + |
| 6 | +#include "ext4.h" |
| 7 | +#include "xattr.h" |
| 8 | +#include "ext4_jbd2.h" |
| 9 | + |
| 10 | +static void ext4_fname_from_fscrypt_name(struct ext4_filename *dst, |
| 11 | + const struct fscrypt_name *src) |
| 12 | +{ |
| 13 | + memset(dst, 0, sizeof(*dst)); |
| 14 | + |
| 15 | + dst->usr_fname = src->usr_fname; |
| 16 | + dst->disk_name = src->disk_name; |
| 17 | + dst->hinfo.hash = src->hash; |
| 18 | + dst->hinfo.minor_hash = src->minor_hash; |
| 19 | + dst->crypto_buf = src->crypto_buf; |
| 20 | +} |
| 21 | + |
| 22 | +int ext4_fname_setup_filename(struct inode *dir, const struct qstr *iname, |
| 23 | + int lookup, struct ext4_filename *fname) |
| 24 | +{ |
| 25 | + struct fscrypt_name name; |
| 26 | + int err; |
| 27 | + |
| 28 | + err = fscrypt_setup_filename(dir, iname, lookup, &name); |
| 29 | + if (err) |
| 30 | + return err; |
| 31 | + |
| 32 | + ext4_fname_from_fscrypt_name(fname, &name); |
| 33 | + |
| 34 | +#if IS_ENABLED(CONFIG_UNICODE) |
| 35 | + err = ext4_fname_setup_ci_filename(dir, iname, fname); |
| 36 | +#endif |
| 37 | + return err; |
| 38 | +} |
| 39 | + |
| 40 | +int ext4_fname_prepare_lookup(struct inode *dir, struct dentry *dentry, |
| 41 | + struct ext4_filename *fname) |
| 42 | +{ |
| 43 | + struct fscrypt_name name; |
| 44 | + int err; |
| 45 | + |
| 46 | + err = fscrypt_prepare_lookup(dir, dentry, &name); |
| 47 | + if (err) |
| 48 | + return err; |
| 49 | + |
| 50 | + ext4_fname_from_fscrypt_name(fname, &name); |
| 51 | + |
| 52 | +#if IS_ENABLED(CONFIG_UNICODE) |
| 53 | + err = ext4_fname_setup_ci_filename(dir, &dentry->d_name, fname); |
| 54 | +#endif |
| 55 | + return err; |
| 56 | +} |
| 57 | + |
| 58 | +void ext4_fname_free_filename(struct ext4_filename *fname) |
| 59 | +{ |
| 60 | + struct fscrypt_name name; |
| 61 | + |
| 62 | + name.crypto_buf = fname->crypto_buf; |
| 63 | + fscrypt_free_filename(&name); |
| 64 | + |
| 65 | + fname->crypto_buf.name = NULL; |
| 66 | + fname->usr_fname = NULL; |
| 67 | + fname->disk_name.name = NULL; |
| 68 | + |
| 69 | +#if IS_ENABLED(CONFIG_UNICODE) |
| 70 | + kfree(fname->cf_name.name); |
| 71 | + fname->cf_name.name = NULL; |
| 72 | +#endif |
| 73 | +} |
| 74 | + |
| 75 | +static bool uuid_is_zero(__u8 u[16]) |
| 76 | +{ |
| 77 | + int i; |
| 78 | + |
| 79 | + for (i = 0; i < 16; i++) |
| 80 | + if (u[i]) |
| 81 | + return false; |
| 82 | + return true; |
| 83 | +} |
| 84 | + |
| 85 | +int ext4_ioctl_get_encryption_pwsalt(struct file *filp, void __user *arg) |
| 86 | +{ |
| 87 | + struct super_block *sb = file_inode(filp)->i_sb; |
| 88 | + struct ext4_sb_info *sbi = EXT4_SB(sb); |
| 89 | + int err, err2; |
| 90 | + handle_t *handle; |
| 91 | + |
| 92 | + if (!ext4_has_feature_encrypt(sb)) |
| 93 | + return -EOPNOTSUPP; |
| 94 | + |
| 95 | + if (uuid_is_zero(sbi->s_es->s_encrypt_pw_salt)) { |
| 96 | + err = mnt_want_write_file(filp); |
| 97 | + if (err) |
| 98 | + return err; |
| 99 | + handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); |
| 100 | + if (IS_ERR(handle)) { |
| 101 | + err = PTR_ERR(handle); |
| 102 | + goto pwsalt_err_exit; |
| 103 | + } |
| 104 | + err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh, |
| 105 | + EXT4_JTR_NONE); |
| 106 | + if (err) |
| 107 | + goto pwsalt_err_journal; |
| 108 | + lock_buffer(sbi->s_sbh); |
| 109 | + generate_random_uuid(sbi->s_es->s_encrypt_pw_salt); |
| 110 | + ext4_superblock_csum_set(sb); |
| 111 | + unlock_buffer(sbi->s_sbh); |
| 112 | + err = ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh); |
| 113 | +pwsalt_err_journal: |
| 114 | + err2 = ext4_journal_stop(handle); |
| 115 | + if (err2 && !err) |
| 116 | + err = err2; |
| 117 | +pwsalt_err_exit: |
| 118 | + mnt_drop_write_file(filp); |
| 119 | + if (err) |
| 120 | + return err; |
| 121 | + } |
| 122 | + |
| 123 | + if (copy_to_user(arg, sbi->s_es->s_encrypt_pw_salt, 16)) |
| 124 | + return -EFAULT; |
| 125 | + return 0; |
| 126 | +} |
| 127 | + |
| 128 | +static int ext4_get_context(struct inode *inode, void *ctx, size_t len) |
| 129 | +{ |
| 130 | + return ext4_xattr_get(inode, EXT4_XATTR_INDEX_ENCRYPTION, |
| 131 | + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, ctx, len); |
| 132 | +} |
| 133 | + |
| 134 | +static int ext4_set_context(struct inode *inode, const void *ctx, size_t len, |
| 135 | + void *fs_data) |
| 136 | +{ |
| 137 | + handle_t *handle = fs_data; |
| 138 | + int res, res2, credits, retries = 0; |
| 139 | + |
| 140 | + /* |
| 141 | + * Encrypting the root directory is not allowed because e2fsck expects |
| 142 | + * lost+found to exist and be unencrypted, and encrypting the root |
| 143 | + * directory would imply encrypting the lost+found directory as well as |
| 144 | + * the filename "lost+found" itself. |
| 145 | + */ |
| 146 | + if (inode->i_ino == EXT4_ROOT_INO) |
| 147 | + return -EPERM; |
| 148 | + |
| 149 | + if (WARN_ON_ONCE(IS_DAX(inode) && i_size_read(inode))) |
| 150 | + return -EINVAL; |
| 151 | + |
| 152 | + if (ext4_test_inode_flag(inode, EXT4_INODE_DAX)) |
| 153 | + return -EOPNOTSUPP; |
| 154 | + |
| 155 | + res = ext4_convert_inline_data(inode); |
| 156 | + if (res) |
| 157 | + return res; |
| 158 | + |
| 159 | + /* |
| 160 | + * If a journal handle was specified, then the encryption context is |
| 161 | + * being set on a new inode via inheritance and is part of a larger |
| 162 | + * transaction to create the inode. Otherwise the encryption context is |
| 163 | + * being set on an existing inode in its own transaction. Only in the |
| 164 | + * latter case should the "retry on ENOSPC" logic be used. |
| 165 | + */ |
| 166 | + |
| 167 | + if (handle) { |
| 168 | + res = ext4_xattr_set_handle(handle, inode, |
| 169 | + EXT4_XATTR_INDEX_ENCRYPTION, |
| 170 | + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, |
| 171 | + ctx, len, 0); |
| 172 | + if (!res) { |
| 173 | + ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); |
| 174 | + ext4_clear_inode_state(inode, |
| 175 | + EXT4_STATE_MAY_INLINE_DATA); |
| 176 | + /* |
| 177 | + * Update inode->i_flags - S_ENCRYPTED will be enabled, |
| 178 | + * S_DAX may be disabled |
| 179 | + */ |
| 180 | + ext4_set_inode_flags(inode, false); |
| 181 | + } |
| 182 | + return res; |
| 183 | + } |
| 184 | + |
| 185 | + res = dquot_initialize(inode); |
| 186 | + if (res) |
| 187 | + return res; |
| 188 | +retry: |
| 189 | + res = ext4_xattr_set_credits(inode, len, false /* is_create */, |
| 190 | + &credits); |
| 191 | + if (res) |
| 192 | + return res; |
| 193 | + |
| 194 | + handle = ext4_journal_start(inode, EXT4_HT_MISC, credits); |
| 195 | + if (IS_ERR(handle)) |
| 196 | + return PTR_ERR(handle); |
| 197 | + |
| 198 | + res = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_ENCRYPTION, |
| 199 | + EXT4_XATTR_NAME_ENCRYPTION_CONTEXT, |
| 200 | + ctx, len, 0); |
| 201 | + if (!res) { |
| 202 | + ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT); |
| 203 | + /* |
| 204 | + * Update inode->i_flags - S_ENCRYPTED will be enabled, |
| 205 | + * S_DAX may be disabled |
| 206 | + */ |
| 207 | + ext4_set_inode_flags(inode, false); |
| 208 | + res = ext4_mark_inode_dirty(handle, inode); |
| 209 | + if (res) |
| 210 | + EXT4_ERROR_INODE(inode, "Failed to mark inode dirty"); |
| 211 | + } |
| 212 | + res2 = ext4_journal_stop(handle); |
| 213 | + |
| 214 | + if (res == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) |
| 215 | + goto retry; |
| 216 | + if (!res) |
| 217 | + res = res2; |
| 218 | + return res; |
| 219 | +} |
| 220 | + |
| 221 | +static const union fscrypt_policy *ext4_get_dummy_policy(struct super_block *sb) |
| 222 | +{ |
| 223 | + return EXT4_SB(sb)->s_dummy_enc_policy.policy; |
| 224 | +} |
| 225 | + |
| 226 | +static bool ext4_has_stable_inodes(struct super_block *sb) |
| 227 | +{ |
| 228 | + return ext4_has_feature_stable_inodes(sb); |
| 229 | +} |
| 230 | + |
| 231 | +static void ext4_get_ino_and_lblk_bits(struct super_block *sb, |
| 232 | + int *ino_bits_ret, int *lblk_bits_ret) |
| 233 | +{ |
| 234 | + *ino_bits_ret = 8 * sizeof(EXT4_SB(sb)->s_es->s_inodes_count); |
| 235 | + *lblk_bits_ret = 8 * sizeof(ext4_lblk_t); |
| 236 | +} |
| 237 | + |
| 238 | +const struct fscrypt_operations ext4_cryptops = { |
| 239 | + .key_prefix = "ext4:", |
| 240 | + .get_context = ext4_get_context, |
| 241 | + .set_context = ext4_set_context, |
| 242 | + .get_dummy_policy = ext4_get_dummy_policy, |
| 243 | + .empty_dir = ext4_empty_dir, |
| 244 | + .has_stable_inodes = ext4_has_stable_inodes, |
| 245 | + .get_ino_and_lblk_bits = ext4_get_ino_and_lblk_bits, |
| 246 | +}; |
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