* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
*/
-#include <keys/encrypted-type.h>
#include <keys/user-type.h>
-#include <linux/random.h>
#include <linux/scatterlist.h>
-#include <uapi/linux/keyctl.h>
#include <linux/fscrypto.h>
static void derive_crypt_complete(struct crypto_async_request *req, int rc)
return res;
}
+static int validate_user_key(struct fscrypt_info *crypt_info,
+ struct fscrypt_context *ctx, u8 *raw_key,
+ u8 *prefix, int prefix_size)
+{
+ u8 *full_key_descriptor;
+ struct key *keyring_key;
+ struct fscrypt_key *master_key;
+ const struct user_key_payload *ukp;
+ int full_key_len = prefix_size + (FS_KEY_DESCRIPTOR_SIZE * 2) + 1;
+ int res;
+
+ full_key_descriptor = kmalloc(full_key_len, GFP_NOFS);
+ if (!full_key_descriptor)
+ return -ENOMEM;
+
+ memcpy(full_key_descriptor, prefix, prefix_size);
+ sprintf(full_key_descriptor + prefix_size,
+ "%*phN", FS_KEY_DESCRIPTOR_SIZE,
+ ctx->master_key_descriptor);
+ full_key_descriptor[full_key_len - 1] = '\0';
+ keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
+ kfree(full_key_descriptor);
+ if (IS_ERR(keyring_key))
+ return PTR_ERR(keyring_key);
+
+ if (keyring_key->type != &key_type_logon) {
+ printk_once(KERN_WARNING
+ "%s: key type must be logon\n", __func__);
+ res = -ENOKEY;
+ goto out;
+ }
+ down_read(&keyring_key->sem);
+ ukp = user_key_payload(keyring_key);
+ if (ukp->datalen != sizeof(struct fscrypt_key)) {
+ res = -EINVAL;
+ up_read(&keyring_key->sem);
+ goto out;
+ }
+ master_key = (struct fscrypt_key *)ukp->data;
+ BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
+
+ if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
+ printk_once(KERN_WARNING
+ "%s: key size incorrect: %d\n",
+ __func__, master_key->size);
+ res = -ENOKEY;
+ up_read(&keyring_key->sem);
+ goto out;
+ }
+ res = derive_key_aes(ctx->nonce, master_key->raw, raw_key);
+ up_read(&keyring_key->sem);
+ if (res)
+ goto out;
+
+ crypt_info->ci_keyring_key = keyring_key;
+ return 0;
+out:
+ key_put(keyring_key);
+ return res;
+}
+
+static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
+ const char **cipher_str_ret, int *keysize_ret)
+{
+ if (S_ISREG(inode->i_mode)) {
+ if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
+ *cipher_str_ret = "xts(aes)";
+ *keysize_ret = FS_AES_256_XTS_KEY_SIZE;
+ return 0;
+ }
+ pr_warn_once("fscrypto: unsupported contents encryption mode "
+ "%d for inode %lu\n",
+ ci->ci_data_mode, inode->i_ino);
+ return -ENOKEY;
+ }
+
+ if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
+ if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) {
+ *cipher_str_ret = "cts(cbc(aes))";
+ *keysize_ret = FS_AES_256_CTS_KEY_SIZE;
+ return 0;
+ }
+ pr_warn_once("fscrypto: unsupported filenames encryption mode "
+ "%d for inode %lu\n",
+ ci->ci_filename_mode, inode->i_ino);
+ return -ENOKEY;
+ }
+
+ pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n",
+ (inode->i_mode & S_IFMT), inode->i_ino);
+ return -ENOKEY;
+}
+
static void put_crypt_info(struct fscrypt_info *ci)
{
if (!ci)
int get_crypt_info(struct inode *inode)
{
struct fscrypt_info *crypt_info;
- u8 full_key_descriptor[FS_KEY_DESC_PREFIX_SIZE +
- (FS_KEY_DESCRIPTOR_SIZE * 2) + 1];
- struct key *keyring_key = NULL;
- struct fscrypt_key *master_key;
struct fscrypt_context ctx;
- const struct user_key_payload *ukp;
struct crypto_skcipher *ctfm;
const char *cipher_str;
+ int keysize;
u8 raw_key[FS_MAX_KEY_SIZE];
- u8 mode;
int res;
res = fscrypt_initialize();
if (res < 0) {
if (!fscrypt_dummy_context_enabled(inode))
return res;
+ ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
ctx.flags = 0;
} else if (res != sizeof(ctx)) {
return -EINVAL;
}
- res = 0;
+
+ if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
+ return -EINVAL;
+
+ if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
+ return -EINVAL;
crypt_info = kmem_cache_alloc(fscrypt_info_cachep, GFP_NOFS);
if (!crypt_info)
crypt_info->ci_keyring_key = NULL;
memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
sizeof(crypt_info->ci_master_key));
- if (S_ISREG(inode->i_mode))
- mode = crypt_info->ci_data_mode;
- else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
- mode = crypt_info->ci_filename_mode;
- else
- BUG();
-
- switch (mode) {
- case FS_ENCRYPTION_MODE_AES_256_XTS:
- cipher_str = "xts(aes)";
- break;
- case FS_ENCRYPTION_MODE_AES_256_CTS:
- cipher_str = "cts(cbc(aes))";
- break;
- default:
- printk_once(KERN_WARNING
- "%s: unsupported key mode %d (ino %u)\n",
- __func__, mode, (unsigned) inode->i_ino);
- res = -ENOKEY;
+
+ res = determine_cipher_type(crypt_info, inode, &cipher_str, &keysize);
+ if (res)
goto out;
- }
+
if (fscrypt_dummy_context_enabled(inode)) {
memset(raw_key, 0x42, FS_AES_256_XTS_KEY_SIZE);
goto got_key;
}
- memcpy(full_key_descriptor, FS_KEY_DESC_PREFIX,
- FS_KEY_DESC_PREFIX_SIZE);
- sprintf(full_key_descriptor + FS_KEY_DESC_PREFIX_SIZE,
- "%*phN", FS_KEY_DESCRIPTOR_SIZE,
- ctx.master_key_descriptor);
- full_key_descriptor[FS_KEY_DESC_PREFIX_SIZE +
- (2 * FS_KEY_DESCRIPTOR_SIZE)] = '\0';
- keyring_key = request_key(&key_type_logon, full_key_descriptor, NULL);
- if (IS_ERR(keyring_key)) {
- res = PTR_ERR(keyring_key);
- keyring_key = NULL;
- goto out;
- }
- crypt_info->ci_keyring_key = keyring_key;
- if (keyring_key->type != &key_type_logon) {
- printk_once(KERN_WARNING
- "%s: key type must be logon\n", __func__);
- res = -ENOKEY;
- goto out;
- }
- down_read(&keyring_key->sem);
- ukp = user_key_payload(keyring_key);
- if (ukp->datalen != sizeof(struct fscrypt_key)) {
- res = -EINVAL;
- up_read(&keyring_key->sem);
- goto out;
- }
- master_key = (struct fscrypt_key *)ukp->data;
- BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
- if (master_key->size != FS_AES_256_XTS_KEY_SIZE) {
- printk_once(KERN_WARNING
- "%s: key size incorrect: %d\n",
- __func__, master_key->size);
- res = -ENOKEY;
- up_read(&keyring_key->sem);
+ res = validate_user_key(crypt_info, &ctx, raw_key,
+ FS_KEY_DESC_PREFIX, FS_KEY_DESC_PREFIX_SIZE);
+ if (res && inode->i_sb->s_cop->key_prefix) {
+ u8 *prefix = NULL;
+ int prefix_size, res2;
+
+ prefix_size = inode->i_sb->s_cop->key_prefix(inode, &prefix);
+ res2 = validate_user_key(crypt_info, &ctx, raw_key,
+ prefix, prefix_size);
+ if (res2) {
+ if (res2 == -ENOKEY)
+ res = -ENOKEY;
+ goto out;
+ }
+ } else if (res) {
goto out;
}
- res = derive_key_aes(ctx.nonce, master_key->raw, raw_key);
- up_read(&keyring_key->sem);
- if (res)
- goto out;
got_key:
ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
if (!ctfm || IS_ERR(ctfm)) {
crypt_info->ci_ctfm = ctfm;
crypto_skcipher_clear_flags(ctfm, ~0);
crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
- res = crypto_skcipher_setkey(ctfm, raw_key, fscrypt_key_size(mode));
+ res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
if (res)
goto out;
projects / cascardo / linux.git / blobdiff