FsCrypt update: support fscrypt policies v1 and v2
This patchset introduces support decryption for Android 11.
In this update we deprecate ext4crypt. To specify the
policy version to use, use TW_USE_FSCRYPT_POLICY := 1 or
TW_USE_FSCRYPT_POLICY := 2. By default policy version will
be set to 2 if this variable is omitted.
Change-Id: I62a29c1bef36c259ec4b11259f71be613d20a112
diff --git a/crypto/fscrypt/fscrypt_policy.cpp b/crypto/fscrypt/fscrypt_policy.cpp
index 43d9552..99833f8 100755
--- a/crypto/fscrypt/fscrypt_policy.cpp
+++ b/crypto/fscrypt/fscrypt_policy.cpp
@@ -14,8 +14,6 @@
* limitations under the License.
*/
-#include "fscrypt/fscrypt.h"
-
#include <array>
#include <asm/ioctl.h>
@@ -34,44 +32,23 @@
#include <cutils/properties.h>
#include <logwrap/logwrap.h>
#include <utils/misc.h>
+#include <fscrypt/fscrypt.h>
#include "fscrypt_policy.h"
static int encryption_mode = FS_ENCRYPTION_MODE_PRIVATE;
bool fscrypt_is_native() {
+ LOG(ERROR) << "fscrypt_is_native::ro.crypto.type";
char value[PROPERTY_VALUE_MAX];
property_get("ro.crypto.type", value, "none");
return !strcmp(value, "file");
}
-static void log_ls(const char* dirname) {
- std::array<const char*, 3> argv = {"ls", "-laZ", dirname};
- int status = 0;
- auto res =
- android_fork_execvp(argv.size(), const_cast<char**>(argv.data()), &status, false, true);
- if (res != 0) {
- PLOG(ERROR) << argv[0] << " " << argv[1] << " " << argv[2] << "failed";
- return;
- }
- if (!WIFEXITED(status)) {
- LOG(ERROR) << argv[0] << " " << argv[1] << " " << argv[2]
- << " did not exit normally, status: " << status;
- return;
- }
- if (WEXITSTATUS(status) != 0) {
- LOG(ERROR) << argv[0] << " " << argv[1] << " " << argv[2]
- << " returned failure: " << WEXITSTATUS(status);
- return;
- }
-}
-
-extern "C" void policy_to_hex(const uint8_t* policy, char* hex) {
- for (size_t i = 0, j = 0; i < FS_KEY_DESCRIPTOR_SIZE; i++) {
- hex[j++] = HEX_LOOKUP[(policy[i] & 0xF0) >> 4];
- hex[j++] = HEX_LOOKUP[policy[i] & 0x0F];
- }
- hex[FS_KEY_DESCRIPTOR_SIZE_HEX - 1] = '\0';
+extern "C" void bytes_to_hex(const uint8_t *bytes, size_t num_bytes, char *hex) {
+ for (size_t i = 0; i < num_bytes; i++) {
+ sprintf(&hex[2 * i], "%02x", bytes[i]);
+ }
}
static bool is_dir_empty(const char *dirname, bool *is_empty)
@@ -121,153 +98,6 @@
return FS_POLICY_FLAGS_PAD_16;
}
-static bool fscrypt_policy_set(const char *directory, uint8_t *policy,
- size_t policy_length,
- int contents_encryption_mode,
- int filenames_encryption_mode) {
- if (policy_length != FS_KEY_DESCRIPTOR_SIZE) {
- LOG(ERROR) << "Policy wrong length: " << policy_length;
- return false;
- }
- char policy_hex[FS_KEY_DESCRIPTOR_SIZE_HEX];
- policy_to_hex(policy, policy_hex);
-
- int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
- if (fd == -1) {
- PLOG(ERROR) << "Failed to open directory " << directory;
- return false;
- }
-
- fscrypt_policy fp;
- fp.version = 0;
- fp.contents_encryption_mode = contents_encryption_mode;
- fp.filenames_encryption_mode = filenames_encryption_mode;
- fp.flags = fscrypt_get_policy_flags(filenames_encryption_mode);
- memcpy(fp.master_key_descriptor, policy, FS_KEY_DESCRIPTOR_SIZE);
- if (ioctl(fd, FS_IOC_SET_ENCRYPTION_POLICY, &fp)) {
- PLOG(ERROR) << "Failed to set encryption policy for " << directory << " to " << policy_hex
- << " modes " << contents_encryption_mode << "/" << filenames_encryption_mode;
- close(fd);
- return false;
- }
- close(fd);
-
- LOG(INFO) << "Policy for " << directory << " set to " << policy_hex
- << " modes " << contents_encryption_mode << "/" << filenames_encryption_mode;
- return true;
-}
-
-static bool fscrypt_policy_get(const char *directory, uint8_t *policy,
- size_t policy_length,
- int contents_encryption_mode,
- int filenames_encryption_mode) {
- if (policy_length != FS_KEY_DESCRIPTOR_SIZE) {
- LOG(ERROR) << "Policy wrong length: " << policy_length;
- return false;
- }
-
- int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
- if (fd == -1) {
- PLOG(ERROR) << "Failed to open directory " << directory;
- return false;
- }
-
- fscrypt_policy fp;
- memset(&fp, 0, sizeof(fscrypt_policy));
- if (ioctl(fd, FS_IOC_GET_ENCRYPTION_POLICY, &fp) != 0) {
- PLOG(ERROR) << "Failed to get encryption policy for " << directory;
- close(fd);
- log_ls(directory);
- return false;
- }
- close(fd);
-
- if ((fp.version != 0)
- || (fp.contents_encryption_mode != contents_encryption_mode)
- || (fp.filenames_encryption_mode != filenames_encryption_mode)
- || (fp.flags !=
- fscrypt_get_policy_flags(filenames_encryption_mode))) {
- LOG(ERROR) << "Failed to find matching encryption policy for " << directory;
- return false;
- }
- memcpy(policy, fp.master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE);
-
- return true;
-}
-
-static bool fscrypt_policy_check(const char *directory, uint8_t *policy,
- size_t policy_length,
- int contents_encryption_mode,
- int filenames_encryption_mode) {
- if (policy_length != FS_KEY_DESCRIPTOR_SIZE) {
- LOG(ERROR) << "Policy wrong length: " << policy_length;
- return false;
- }
- uint8_t existing_policy[FS_KEY_DESCRIPTOR_SIZE];
- if (!fscrypt_policy_get(directory, existing_policy, FS_KEY_DESCRIPTOR_SIZE,
- contents_encryption_mode,
- filenames_encryption_mode)) return false;
- char existing_policy_hex[FS_KEY_DESCRIPTOR_SIZE_HEX];
-
- policy_to_hex(existing_policy, existing_policy_hex);
-
- if (memcmp(policy, existing_policy, FS_KEY_DESCRIPTOR_SIZE) != 0) {
- char policy_hex[FS_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;
- log_ls(directory);
- return false;
- }
- LOG(INFO) << "Found policy " << existing_policy_hex << " at " << directory
- << " which matches expected value";
- return true;
-}
-
-int fscrypt_policy_ensure(const char *directory, uint8_t *policy,
- size_t policy_length,
- const char *contents_encryption_mode,
- const char *filenames_encryption_mode) {
- int contents_mode = 0;
- int filenames_mode = 0;
-
- if (!strcmp(contents_encryption_mode, "software") ||
- !strcmp(contents_encryption_mode, "aes-256-xts")) {
- contents_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
- } else if (!strcmp(contents_encryption_mode, "adiantum")) {
- contents_mode = FS_ENCRYPTION_MODE_ADIANTUM;
- } else if (!strcmp(contents_encryption_mode, "ice")) {
- contents_mode = FS_ENCRYPTION_MODE_PRIVATE;
- } else {
- LOG(ERROR) << "Invalid file contents encryption mode: "
- << contents_encryption_mode;
- return -1;
- }
-
- if (!strcmp(filenames_encryption_mode, "aes-256-cts")) {
- filenames_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- } else if (!strcmp(filenames_encryption_mode, "aes-256-heh")) {
- filenames_mode = FS_ENCRYPTION_MODE_AES_256_HEH;
- } else if (!strcmp(filenames_encryption_mode, "adiantum")) {
- filenames_mode = FS_ENCRYPTION_MODE_ADIANTUM;
- } else {
- LOG(ERROR) << "Invalid file names encryption mode: "
- << filenames_encryption_mode;
- return -1;
- }
-
- bool is_empty;
- if (!is_dir_empty(directory, &is_empty)) return -1;
- if (is_empty) {
- if (!fscrypt_policy_set(directory, policy, policy_length,
- contents_mode, filenames_mode)) return -1;
- } else {
- if (!fscrypt_policy_check(directory, policy, policy_length,
- contents_mode, filenames_mode)) return -1;
- }
- return 0;
-}
-
extern "C" bool fscrypt_set_mode() {
const char* mode_file = "/data/unencrypted/mode";
struct stat st;
@@ -292,12 +122,10 @@
std::string contents_encryption_mode_string = std::string(contents_encryption_mode);
int pos = contents_encryption_mode_string.find(":");
- PLOG(ERROR) << "contents_encryption_mode_string: " << contents_encryption_mode_string.substr(0, pos);
+ LOG(INFO) << "contents_encryption_mode_string: " << contents_encryption_mode_string.substr(0, pos);
- // if (!strcmp(contents_encryption_mode, "software")) {
if (contents_encryption_mode_string.substr(0, pos) == "software") {
encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
- // } else if (!strcmp(contents_encryption_mode, "ice")) {
} else if (contents_encryption_mode_string.substr(0, pos) == "ice") {
encryption_mode = FS_ENCRYPTION_MODE_PRIVATE;
} else {
@@ -309,15 +137,11 @@
return true;
}
-extern "C" void fscrypt_policy_fill_default_struct(fscrypt_encryption_policy *fep) {
- fep->version = 0;
- fep->contents_encryption_mode = encryption_mode;
- fep->filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- fep->flags = 0;
- memset((void*)&fep->master_key_descriptor[0], 0, FS_KEY_DESCRIPTOR_SIZE);
-}
-
-extern "C" bool fscrypt_policy_set_struct(const char *directory, const fscrypt_encryption_policy *fep) {
+#ifdef USE_FSCRYPT_POLICY_V1
+extern "C" bool fscrypt_policy_set_struct(const char *directory, const struct fscrypt_policy_v1 *fep) {
+#else
+extern "C" bool fscrypt_policy_set_struct(const char *directory, const struct fscrypt_policy_v2 *fep) {
+#endif
int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
if (fd == -1) {
printf("failed to open %s\n", directory);
@@ -325,7 +149,6 @@
return false;
}
if (ioctl(fd, FS_IOC_SET_ENCRYPTION_POLICY, fep)) {
- printf("failed to set policy for '%s'\n", directory);
PLOG(ERROR) << "Failed to set encryption policy for " << directory;
close(fd);
return false;
@@ -334,56 +157,30 @@
return true;
}
-extern "C" bool fscrypt_policy_get_struct(const char *directory, fscrypt_encryption_policy *fep) {
- int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
+#ifdef USE_FSCRYPT_POLICY_V1
+extern "C" bool fscrypt_policy_get_struct(const char *directory, struct fscrypt_policy_v1 *fep) {
+#else
+extern "C" bool fscrypt_policy_get_struct(const char *directory, struct fscrypt_policy_v2 *fep) {
+#endif
+ int fd = open(directory, O_DIRECTORY | O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
if (fd == -1) {
- printf("Failed to open '%s'\n", directory);
PLOG(ERROR) << "Failed to open directory " << directory;
return false;
}
- memset(fep, 0, sizeof(fscrypt_encryption_policy));
- if (ioctl(fd, FS_IOC_GET_ENCRYPTION_POLICY, fep) != 0) {
+#ifdef USE_FSCRYPT_POLICY_V1
+ memset(fep, 0, sizeof(fscrypt_policy_v1));
+#else
+ memset(fep, 0, sizeof(fscrypt_policy_v2));
+#endif
+
+ struct fscrypt_get_policy_ex_arg ex_policy = {0};
+ ex_policy.policy_size = sizeof(ex_policy.policy);
+ if (ioctl(fd, FS_IOC_GET_ENCRYPTION_POLICY_EX, &ex_policy) != 0) {
PLOG(ERROR) << "Failed to get encryption policy for " << directory;
close(fd);
return false;
}
- printf("fscrypt_policy_get_struct::fep->version::%d\n", fep->version);
+ memcpy(fep, &ex_policy.policy.v2, sizeof(ex_policy.policy.v2));
close(fd);
return true;
}
-
-extern "C" bool fscrypt_policy_set(const char *directory, uint8_t *policy,
- size_t policy_length, int contents_encryption_mode) {
- if (contents_encryption_mode == 0)
- contents_encryption_mode = encryption_mode;
- if (policy_length != FS_KEY_DESCRIPTOR_SIZE) {
- printf("policy wrong length\n");
- LOG(ERROR) << "Policy wrong length: " << policy_length;
- return false;
- }
- int fd = open(directory, O_DIRECTORY | O_NOFOLLOW | O_CLOEXEC);
- if (fd == -1) {
- printf("failed to open %s\n", directory);
- PLOG(ERROR) << "Failed to open directory " << directory;
- return false;
- }
-
- fscrypt_encryption_policy fep;
- fep.version = 0;
- fep.contents_encryption_mode = contents_encryption_mode;
- fep.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
- fep.flags = 0;
- memcpy(fep.master_key_descriptor, policy, FS_KEY_DESCRIPTOR_SIZE);
- if (ioctl(fd, FS_IOC_SET_ENCRYPTION_POLICY, &fep)) {
- printf("failed to set policy for '%s' '%s'\n", directory, policy);
- PLOG(ERROR) << "Failed to set encryption policy for " << directory;
- close(fd);
- return false;
- }
- close(fd);
-
- char policy_hex[FS_KEY_DESCRIPTOR_SIZE_HEX];
- policy_to_hex(policy, policy_hex);
- LOG(INFO) << "Policy for " << directory << " set to " << policy_hex;
- return true;
-}