/*
- * Copyright (c) 2015 Google, Inc.
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
*/
-#define TAG "ext4_utils"
-
-#include "ext4_crypt_init_extensions.h"
+#include "ext4_crypt.h"
#include <dirent.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
-#include <cutils/klog.h>
-
-#include "unencrypted_properties.h"
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <cutils/properties.h>
#define XATTR_NAME_ENCRYPTION_POLICY "encryption.policy"
#define EXT4_KEYREF_DELIMITER ((char)'.')
// ext4enc:TODO Include structure from somewhere sensible
// MUST be in sync with ext4_crypto.c in kernel
#define EXT4_KEY_DESCRIPTOR_SIZE 8
+#define EXT4_KEY_DESCRIPTOR_SIZE_HEX 17
+
struct ext4_encryption_policy {
char version;
char contents_encryption_mode;
#define EXT4_ENCRYPTION_MODE_AES_256_XTS 1
#define EXT4_ENCRYPTION_MODE_AES_256_CTS 4
+#define EXT4_ENCRYPTION_MODE_PRIVATE 127
// ext4enc:TODO Get value from somewhere sensible
-#define EXT4_IOC_SET_ENCRYPTION_POLICY \
- _IOR('f', 19, struct ext4_encryption_policy)
+#define EXT4_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct ext4_encryption_policy)
+#define EXT4_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct ext4_encryption_policy)
-/* Validate that all path items are available and accessible. */
-static int is_path_valid(const char *path)
-{
- if (access(path, W_OK)) {
- KLOG_ERROR(TAG, "Can't access %s: %s\n",strerror(errno), path);
- return 0;
- }
+#define HEX_LOOKUP "0123456789abcdef"
- return 1;
+bool e4crypt_is_native() {
+ char value[PROPERTY_VALUE_MAX];
+ property_get("ro.crypto.type", value, "none");
+ return !strcmp(value, "file");
}
-static int is_dir_empty(const char *dirname)
+static void policy_to_hex(const char* policy, char* hex) {
+ for (size_t i = 0, j = 0; i < EXT4_KEY_DESCRIPTOR_SIZE; i++) {
+ hex[j++] = HEX_LOOKUP[(policy[i] & 0xF0) >> 4];
+ hex[j++] = HEX_LOOKUP[policy[i] & 0x0F];
+ }
+ hex[EXT4_KEY_DESCRIPTOR_SIZE_HEX - 1] = '\0';
+}
+
+static bool is_dir_empty(const char *dirname, bool *is_empty)
{
int n = 0;
- struct dirent *d;
- DIR *dir;
-
- dir = opendir(dirname);
- while ((d = readdir(dir)) != NULL) {
- if (strcmp(d->d_name, "lost+found") == 0) {
- // Skip lost+found directory
- } else if (++n > 2) {
+ auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(dirname), closedir);
+ if (!dirp) {
+ PLOG(ERROR) << "Unable to read directory: " << dirname;
+ return false;
+ }
+ for (;;) {
+ errno = 0;
+ auto entry = readdir(dirp.get());
+ if (!entry) {
+ if (errno) {
+ PLOG(ERROR) << "Unable to read directory: " << dirname;
+ return false;
+ }
break;
}
+ if (strcmp(entry->d_name, "lost+found") != 0) { // Skip lost+found
+ ++n;
+ if (n > 2) {
+ *is_empty = false;
+ return true;
+ }
+ }
}
- closedir(dir);
- return n <= 2;
+ *is_empty = true;
+ return true;
}
-int do_policy_set(const char *directory, const char *policy, int policy_length)
-{
- struct stat st;
- ssize_t ret;
-
+static bool e4crypt_policy_set(const char *directory, const char *policy,
+ size_t policy_length, int contents_encryption_mode) {
if (policy_length != EXT4_KEY_DESCRIPTOR_SIZE) {
- KLOG_ERROR("Policy wrong length\n");
- return -EINVAL;
+ LOG(ERROR) << "Policy wrong length: " << policy_length;
+ return false;
}
-
- if (!is_path_valid(directory)) {
- return -EINVAL;
+ int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+ if (fd == -1) {
+ PLOG(ERROR) << "Failed to open directory " << directory;
+ return false;
}
- stat(directory, &st);
- if (!S_ISDIR(st.st_mode)) {
- KLOG_ERROR(TAG, "Can only set policy on a directory (%s)\n", directory);
- return -EINVAL;
+ ext4_encryption_policy eep;
+ eep.version = 0;
+ eep.contents_encryption_mode = contents_encryption_mode;
+ eep.filenames_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_CTS;
+ eep.flags = 0;
+ memcpy(eep.master_key_descriptor, policy, EXT4_KEY_DESCRIPTOR_SIZE);
+ if (ioctl(fd, EXT4_IOC_SET_ENCRYPTION_POLICY, &eep)) {
+ PLOG(ERROR) << "Failed to set encryption policy for " << directory;
+ close(fd);
+ return false;
}
+ close(fd);
- if (!is_dir_empty(directory)) {
- KLOG_ERROR(TAG, "Can only set policy on an empty directory (%s)\n",
- directory);
- return -EINVAL;
+ char policy_hex[EXT4_KEY_DESCRIPTOR_SIZE_HEX];
+ policy_to_hex(policy, policy_hex);
+ LOG(INFO) << "Policy for " << directory << " set to " << policy_hex;
+ return true;
+}
+
+static bool e4crypt_policy_get(const char *directory, char *policy,
+ size_t policy_length, int contents_encryption_mode) {
+ if (policy_length != EXT4_KEY_DESCRIPTOR_SIZE) {
+ LOG(ERROR) << "Policy wrong length: " << policy_length;
+ return false;
}
- int fd = open(directory, O_DIRECTORY);
+ int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
if (fd == -1) {
- KLOG_ERROR(TAG, "Failed to open directory (%s)\n", directory);
- return -EINVAL;
+ PLOG(ERROR) << "Failed to open directory " << directory;
+ return false;
}
ext4_encryption_policy eep;
- eep.version = 0;
- eep.contents_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
- eep.filenames_encryption_mode = EXT4_ENCRYPTION_MODE_AES_256_CTS;
- eep.flags = 0;
- memcpy(eep.master_key_descriptor, policy, EXT4_KEY_DESCRIPTOR_SIZE);
- ret = ioctl(fd, EXT4_IOC_SET_ENCRYPTION_POLICY, &eep);
- auto preserve_errno = errno;
+ memset(&eep, 0, sizeof(ext4_encryption_policy));
+ if (ioctl(fd, EXT4_IOC_GET_ENCRYPTION_POLICY, &eep) != 0) {
+ PLOG(ERROR) << "Failed to get encryption policy for " << directory;
+ close(fd);
+ return -1;
+ }
close(fd);
- if (ret) {
- KLOG_ERROR(TAG, "Failed to set encryption policy for %s: %s\n",
- directory, strerror(preserve_errno));
- return -EINVAL;
+ if ((eep.version != 0)
+ || (eep.contents_encryption_mode != contents_encryption_mode)
+ || (eep.filenames_encryption_mode != EXT4_ENCRYPTION_MODE_AES_256_CTS)
+ || (eep.flags != 0)) {
+ LOG(ERROR) << "Failed to find matching encryption policy for " << directory;
+ return false;
}
+ memcpy(policy, eep.master_key_descriptor, EXT4_KEY_DESCRIPTOR_SIZE);
- KLOG_INFO(TAG, "Encryption policy for %s is set to %02x%02x%02x%02x\n",
- directory, policy[0], policy[1], policy[2], policy[3]);
- return 0;
+ return true;
}
-bool e4crypt_non_default_key(const char* dir)
-{
- UnencryptedProperties props(dir);
- return props.Get<int>(properties::is_default, 1) != 1;
+static bool e4crypt_policy_check(const char *directory, const char *policy,
+ size_t policy_length, int contents_encryption_mode) {
+ if (policy_length != EXT4_KEY_DESCRIPTOR_SIZE) {
+ LOG(ERROR) << "Policy wrong length: " << policy_length;
+ return false;
+ }
+ char existing_policy[EXT4_KEY_DESCRIPTOR_SIZE];
+ if (!e4crypt_policy_get(directory, existing_policy, EXT4_KEY_DESCRIPTOR_SIZE,
+ contents_encryption_mode)) return false;
+ char existing_policy_hex[EXT4_KEY_DESCRIPTOR_SIZE_HEX];
+
+ policy_to_hex(existing_policy, existing_policy_hex);
+
+ if (memcmp(policy, existing_policy, EXT4_KEY_DESCRIPTOR_SIZE) != 0) {
+ char policy_hex[EXT4_KEY_DESCRIPTOR_SIZE_HEX];
+ policy_to_hex(policy, policy_hex);
+ LOG(ERROR) << "Found policy " << existing_policy_hex << " at " << directory
+ << " which doesn't match expected value " << policy_hex;
+ return false;
+ }
+ LOG(INFO) << "Found policy " << existing_policy_hex << " at " << directory
+ << " which matches expected value";
+ return true;
+}
+
+int e4crypt_policy_ensure(const char *directory, const char *policy,
+ size_t policy_length, const char* contents_encryption_mode) {
+ int mode = 0;
+ if (!strcmp(contents_encryption_mode, "software")) {
+ mode = EXT4_ENCRYPTION_MODE_AES_256_XTS;
+ } else if (!strcmp(contents_encryption_mode, "ice")) {
+ mode = EXT4_ENCRYPTION_MODE_PRIVATE;
+ } else {
+ LOG(ERROR) << "Invalid encryption mode";
+ return -1;
+ }
+
+ bool is_empty;
+ if (!is_dir_empty(directory, &is_empty)) return -1;
+ if (is_empty) {
+ if (!e4crypt_policy_set(directory, policy, policy_length,
+ mode)) return -1;
+ } else {
+ if (!e4crypt_policy_check(directory, policy, policy_length,
+ mode)) return -1;
+ }
+ return 0;
}
OSDN Git Service
