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-rw-r--r--src/home/homework-fscrypt.c697
1 files changed, 697 insertions, 0 deletions
diff --git a/src/home/homework-fscrypt.c b/src/home/homework-fscrypt.c
new file mode 100644
index 0000000..5106961
--- /dev/null
+++ b/src/home/homework-fscrypt.c
@@ -0,0 +1,697 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <linux/fs.h>
+#include <openssl/evp.h>
+#include <openssl/sha.h>
+#include <sys/ioctl.h>
+#include <sys/xattr.h>
+
+#include "errno-util.h"
+#include "fd-util.h"
+#include "hexdecoct.h"
+#include "homework-fscrypt.h"
+#include "homework-mount.h"
+#include "homework-quota.h"
+#include "memory-util.h"
+#include "missing_keyctl.h"
+#include "missing_syscall.h"
+#include "mkdir.h"
+#include "mount-util.h"
+#include "nulstr-util.h"
+#include "openssl-util.h"
+#include "parse-util.h"
+#include "process-util.h"
+#include "random-util.h"
+#include "rm-rf.h"
+#include "stdio-util.h"
+#include "strv.h"
+#include "tmpfile-util.h"
+#include "user-util.h"
+#include "xattr-util.h"
+
+static int fscrypt_upload_volume_key(
+ const uint8_t key_descriptor[static FS_KEY_DESCRIPTOR_SIZE],
+ const void *volume_key,
+ size_t volume_key_size,
+ key_serial_t where) {
+
+ _cleanup_free_ char *hex = NULL;
+ const char *description;
+ struct fscrypt_key key;
+ key_serial_t serial;
+
+ assert(key_descriptor);
+ assert(volume_key);
+ assert(volume_key_size > 0);
+
+ if (volume_key_size > sizeof(key.raw))
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Volume key too long.");
+
+ hex = hexmem(key_descriptor, FS_KEY_DESCRIPTOR_SIZE);
+ if (!hex)
+ return log_oom();
+
+ description = strjoina("fscrypt:", hex);
+
+ key = (struct fscrypt_key) {
+ .size = volume_key_size,
+ };
+ memcpy(key.raw, volume_key, volume_key_size);
+
+ /* Upload to the kernel */
+ serial = add_key("logon", description, &key, sizeof(key), where);
+ explicit_bzero_safe(&key, sizeof(key));
+
+ if (serial < 0)
+ return log_error_errno(errno, "Failed to install master key in keyring: %m");
+
+ log_info("Uploaded encryption key to kernel.");
+
+ return 0;
+}
+
+static void calculate_key_descriptor(
+ const void *key,
+ size_t key_size,
+ uint8_t ret_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE]) {
+
+ uint8_t hashed[512 / 8] = {}, hashed2[512 / 8] = {};
+
+ /* Derive the key descriptor from the volume key via double SHA512, in order to be compatible with e4crypt */
+
+ assert_se(SHA512(key, key_size, hashed) == hashed);
+ assert_se(SHA512(hashed, sizeof(hashed), hashed2) == hashed2);
+
+ assert_cc(sizeof(hashed2) >= FS_KEY_DESCRIPTOR_SIZE);
+
+ memcpy(ret_key_descriptor, hashed2, FS_KEY_DESCRIPTOR_SIZE);
+}
+
+static int fscrypt_slot_try_one(
+ const char *password,
+ const void *salt, size_t salt_size,
+ const void *encrypted, size_t encrypted_size,
+ const uint8_t match_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE],
+ void **ret_decrypted, size_t *ret_decrypted_size) {
+
+
+ _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
+ _cleanup_(erase_and_freep) void *decrypted = NULL;
+ uint8_t key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ int decrypted_size_out1, decrypted_size_out2;
+ uint8_t derived[512 / 8] = {};
+ size_t decrypted_size;
+ const EVP_CIPHER *cc;
+ int r;
+
+ assert(password);
+ assert(salt);
+ assert(salt_size > 0);
+ assert(encrypted);
+ assert(encrypted_size > 0);
+ assert(match_key_descriptor);
+
+ /* Our construction is like this:
+ *
+ * 1. In each key slot we store a salt value plus the encrypted volume key
+ *
+ * 2. Unlocking is via calculating PBKDF2-HMAC-SHA512 of the supplied password (in combination with
+ * the salt), then using the first 256 bit of the hash as key for decrypting the encrypted
+ * volume key in AES256 counter mode.
+ *
+ * 3. Writing a password is similar: calculate PBKDF2-HMAC-SHA512 of the supplied password (in
+ * combination with the salt), then encrypt the volume key in AES256 counter mode with the
+ * resulting hash.
+ */
+
+ if (PKCS5_PBKDF2_HMAC(
+ password, strlen(password),
+ salt, salt_size,
+ 0xFFFF, EVP_sha512(),
+ sizeof(derived), derived) != 1) {
+ r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "PBKDF2 failed");
+ goto finish;
+ }
+
+ context = EVP_CIPHER_CTX_new();
+ if (!context) {
+ r = log_oom();
+ goto finish;
+ }
+
+ /* We use AES256 in counter mode */
+ assert_se(cc = EVP_aes_256_ctr());
+
+ /* We only use the first half of the derived key */
+ assert(sizeof(derived) >= (size_t) EVP_CIPHER_key_length(cc));
+
+ if (EVP_DecryptInit_ex(context, cc, NULL, derived, NULL) != 1) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize decryption context.");
+ goto finish;
+ }
+
+ /* Flush out the derived key now, we don't need it anymore */
+ explicit_bzero_safe(derived, sizeof(derived));
+
+ decrypted_size = encrypted_size + EVP_CIPHER_key_length(cc) * 2;
+ decrypted = malloc(decrypted_size);
+ if (!decrypted)
+ return log_oom();
+
+ if (EVP_DecryptUpdate(context, (uint8_t*) decrypted, &decrypted_size_out1, encrypted, encrypted_size) != 1)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to decrypt volume key.");
+
+ assert((size_t) decrypted_size_out1 <= decrypted_size);
+
+ if (EVP_DecryptFinal_ex(context, (uint8_t*) decrypted_size + decrypted_size_out1, &decrypted_size_out2) != 1)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finish decryption of volume key.");
+
+ assert((size_t) decrypted_size_out1 + (size_t) decrypted_size_out2 < decrypted_size);
+ decrypted_size = (size_t) decrypted_size_out1 + (size_t) decrypted_size_out2;
+
+ calculate_key_descriptor(decrypted, decrypted_size, key_descriptor);
+
+ if (memcmp(key_descriptor, match_key_descriptor, FS_KEY_DESCRIPTOR_SIZE) != 0)
+ return -ENOANO; /* don't log here */
+
+ r = fscrypt_upload_volume_key(key_descriptor, decrypted, decrypted_size, KEY_SPEC_THREAD_KEYRING);
+ if (r < 0)
+ return r;
+
+ if (ret_decrypted)
+ *ret_decrypted = TAKE_PTR(decrypted);
+ if (ret_decrypted_size)
+ *ret_decrypted_size = decrypted_size;
+
+ return 0;
+
+finish:
+ explicit_bzero_safe(derived, sizeof(derived));
+ return r;
+}
+
+static int fscrypt_slot_try_many(
+ char **passwords,
+ const void *salt, size_t salt_size,
+ const void *encrypted, size_t encrypted_size,
+ const uint8_t match_key_descriptor[static FS_KEY_DESCRIPTOR_SIZE],
+ void **ret_decrypted, size_t *ret_decrypted_size) {
+
+ int r;
+
+ STRV_FOREACH(i, passwords) {
+ r = fscrypt_slot_try_one(*i, salt, salt_size, encrypted, encrypted_size, match_key_descriptor, ret_decrypted, ret_decrypted_size);
+ if (r != -ENOANO)
+ return r;
+ }
+
+ return -ENOANO;
+}
+
+static int fscrypt_setup(
+ const PasswordCache *cache,
+ char **password,
+ HomeSetup *setup,
+ void **ret_volume_key,
+ size_t *ret_volume_key_size) {
+
+ _cleanup_free_ char *xattr_buf = NULL;
+ const char *xa;
+ int r;
+
+ assert(setup);
+ assert(setup->root_fd >= 0);
+
+ r = flistxattr_malloc(setup->root_fd, &xattr_buf);
+ if (r < 0)
+ return log_error_errno(errno, "Failed to retrieve xattr list: %m");
+
+ NULSTR_FOREACH(xa, xattr_buf) {
+ _cleanup_free_ void *salt = NULL, *encrypted = NULL;
+ _cleanup_free_ char *value = NULL;
+ size_t salt_size, encrypted_size;
+ const char *nr, *e;
+ char **list;
+ int n;
+
+ /* Check if this xattr has the format 'trusted.fscrypt_slot<nr>' where '<nr>' is a 32bit unsigned integer */
+ nr = startswith(xa, "trusted.fscrypt_slot");
+ if (!nr)
+ continue;
+ if (safe_atou32(nr, NULL) < 0)
+ continue;
+
+ n = fgetxattr_malloc(setup->root_fd, xa, &value);
+ if (n == -ENODATA) /* deleted by now? */
+ continue;
+ if (n < 0)
+ return log_error_errno(n, "Failed to read %s xattr: %m", xa);
+
+ e = memchr(value, ':', n);
+ if (!e)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "xattr %s lacks ':' separator: %m", xa);
+
+ r = unbase64mem(value, e - value, &salt, &salt_size);
+ if (r < 0)
+ return log_error_errno(r, "Failed to decode salt of %s: %m", xa);
+ r = unbase64mem(e+1, n - (e - value) - 1, &encrypted, &encrypted_size);
+ if (r < 0)
+ return log_error_errno(r, "Failed to decode encrypted key of %s: %m", xa);
+
+ r = -ENOANO;
+ FOREACH_POINTER(list, cache->pkcs11_passwords, cache->fido2_passwords, password) {
+ r = fscrypt_slot_try_many(
+ list,
+ salt, salt_size,
+ encrypted, encrypted_size,
+ setup->fscrypt_key_descriptor,
+ ret_volume_key, ret_volume_key_size);
+ if (r != -ENOANO)
+ break;
+ }
+ if (r < 0) {
+ if (r != -ENOANO)
+ return r;
+ } else
+ return 0;
+ }
+
+ return log_error_errno(SYNTHETIC_ERRNO(ENOKEY), "Failed to set up home directory with provided passwords.");
+}
+
+int home_setup_fscrypt(
+ UserRecord *h,
+ HomeSetup *setup,
+ const PasswordCache *cache) {
+
+ _cleanup_(erase_and_freep) void *volume_key = NULL;
+ struct fscrypt_policy policy = {};
+ size_t volume_key_size = 0;
+ const char *ip;
+ int r;
+
+ assert(h);
+ assert(user_record_storage(h) == USER_FSCRYPT);
+ assert(setup);
+ assert(setup->root_fd < 0);
+
+ assert_se(ip = user_record_image_path(h));
+
+ setup->root_fd = open(ip, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
+ if (setup->root_fd < 0)
+ return log_error_errno(errno, "Failed to open home directory: %m");
+
+ if (ioctl(setup->root_fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) {
+ if (errno == ENODATA)
+ return log_error_errno(errno, "Home directory %s is not encrypted.", ip);
+ if (ERRNO_IS_NOT_SUPPORTED(errno)) {
+ log_error_errno(errno, "File system does not support fscrypt: %m");
+ return -ENOLINK; /* make recognizable */
+ }
+ return log_error_errno(errno, "Failed to acquire encryption policy of %s: %m", ip);
+ }
+
+ memcpy(setup->fscrypt_key_descriptor, policy.master_key_descriptor, FS_KEY_DESCRIPTOR_SIZE);
+
+ r = fscrypt_setup(
+ cache,
+ h->password,
+ setup,
+ &volume_key,
+ &volume_key_size);
+ if (r < 0)
+ return r;
+
+ /* Also install the access key in the user's own keyring */
+
+ if (uid_is_valid(h->uid)) {
+ r = safe_fork("(sd-addkey)",
+ FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS|FORK_DEATHSIG|FORK_LOG|FORK_WAIT|FORK_REOPEN_LOG,
+ NULL);
+ if (r < 0)
+ return log_error_errno(r, "Failed install encryption key in user's keyring: %m");
+ if (r == 0) {
+ gid_t gid;
+
+ /* Child */
+
+ gid = user_record_gid(h);
+ if (setresgid(gid, gid, gid) < 0) {
+ log_error_errno(errno, "Failed to change GID to " GID_FMT ": %m", gid);
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setgroups(0, NULL) < 0) {
+ log_error_errno(errno, "Failed to reset auxiliary groups list: %m");
+ _exit(EXIT_FAILURE);
+ }
+
+ if (setresuid(h->uid, h->uid, h->uid) < 0) {
+ log_error_errno(errno, "Failed to change UID to " UID_FMT ": %m", h->uid);
+ _exit(EXIT_FAILURE);
+ }
+
+ r = fscrypt_upload_volume_key(
+ setup->fscrypt_key_descriptor,
+ volume_key,
+ volume_key_size,
+ KEY_SPEC_USER_KEYRING);
+ if (r < 0)
+ _exit(EXIT_FAILURE);
+
+ _exit(EXIT_SUCCESS);
+ }
+ }
+
+ /* We'll bind mount the image directory to a new mount point where we'll start adjusting it. Only
+ * once that's complete we'll move the thing to its final place eventually. */
+ r = home_unshare_and_mkdir();
+ if (r < 0)
+ return r;
+
+ r = mount_follow_verbose(LOG_ERR, ip, HOME_RUNTIME_WORK_DIR, NULL, MS_BIND, NULL);
+ if (r < 0)
+ return r;
+
+ setup->undo_mount = true;
+
+ /* Turn off any form of propagation for this */
+ r = mount_nofollow_verbose(LOG_ERR, NULL, HOME_RUNTIME_WORK_DIR, NULL, MS_PRIVATE, NULL);
+ if (r < 0)
+ return r;
+
+ /* Adjust MS_SUID and similar flags */
+ r = mount_nofollow_verbose(LOG_ERR, NULL, HOME_RUNTIME_WORK_DIR, NULL, MS_BIND|MS_REMOUNT|user_record_mount_flags(h), NULL);
+ if (r < 0)
+ return r;
+
+ safe_close(setup->root_fd);
+ setup->root_fd = open(HOME_RUNTIME_WORK_DIR, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
+ if (setup->root_fd < 0)
+ return log_error_errno(errno, "Failed to open home directory: %m");
+
+ return 0;
+}
+
+static int fscrypt_slot_set(
+ int root_fd,
+ const void *volume_key,
+ size_t volume_key_size,
+ const char *password,
+ uint32_t nr) {
+
+ _cleanup_free_ char *salt_base64 = NULL, *encrypted_base64 = NULL, *joined = NULL;
+ char label[STRLEN("trusted.fscrypt_slot") + DECIMAL_STR_MAX(nr) + 1];
+ _cleanup_(EVP_CIPHER_CTX_freep) EVP_CIPHER_CTX *context = NULL;
+ int r, encrypted_size_out1, encrypted_size_out2;
+ uint8_t salt[64], derived[512 / 8] = {};
+ _cleanup_free_ void *encrypted = NULL;
+ const EVP_CIPHER *cc;
+ size_t encrypted_size;
+
+ r = crypto_random_bytes(salt, sizeof(salt));
+ if (r < 0)
+ return log_error_errno(r, "Failed to generate salt: %m");
+
+ if (PKCS5_PBKDF2_HMAC(
+ password, strlen(password),
+ salt, sizeof(salt),
+ 0xFFFF, EVP_sha512(),
+ sizeof(derived), derived) != 1) {
+ r = log_error_errno(SYNTHETIC_ERRNO(ENOTRECOVERABLE), "PBKDF2 failed");
+ goto finish;
+ }
+
+ context = EVP_CIPHER_CTX_new();
+ if (!context) {
+ r = log_oom();
+ goto finish;
+ }
+
+ /* We use AES256 in counter mode */
+ cc = EVP_aes_256_ctr();
+
+ /* We only use the first half of the derived key */
+ assert(sizeof(derived) >= (size_t) EVP_CIPHER_key_length(cc));
+
+ if (EVP_EncryptInit_ex(context, cc, NULL, derived, NULL) != 1) {
+ r = log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to initialize encryption context.");
+ goto finish;
+ }
+
+ /* Flush out the derived key now, we don't need it anymore */
+ explicit_bzero_safe(derived, sizeof(derived));
+
+ encrypted_size = volume_key_size + EVP_CIPHER_key_length(cc) * 2;
+ encrypted = malloc(encrypted_size);
+ if (!encrypted)
+ return log_oom();
+
+ if (EVP_EncryptUpdate(context, (uint8_t*) encrypted, &encrypted_size_out1, volume_key, volume_key_size) != 1)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to encrypt volume key.");
+
+ assert((size_t) encrypted_size_out1 <= encrypted_size);
+
+ if (EVP_EncryptFinal_ex(context, (uint8_t*) encrypted_size + encrypted_size_out1, &encrypted_size_out2) != 1)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Failed to finish encryption of volume key.");
+
+ assert((size_t) encrypted_size_out1 + (size_t) encrypted_size_out2 < encrypted_size);
+ encrypted_size = (size_t) encrypted_size_out1 + (size_t) encrypted_size_out2;
+
+ r = base64mem(salt, sizeof(salt), &salt_base64);
+ if (r < 0)
+ return log_oom();
+
+ r = base64mem(encrypted, encrypted_size, &encrypted_base64);
+ if (r < 0)
+ return log_oom();
+
+ joined = strjoin(salt_base64, ":", encrypted_base64);
+ if (!joined)
+ return log_oom();
+
+ xsprintf(label, "trusted.fscrypt_slot%" PRIu32, nr);
+ if (fsetxattr(root_fd, label, joined, strlen(joined), 0) < 0)
+ return log_error_errno(errno, "Failed to write xattr %s: %m", label);
+
+ log_info("Written key slot %s.", label);
+
+ return 0;
+
+finish:
+ explicit_bzero_safe(derived, sizeof(derived));
+ return r;
+}
+
+int home_create_fscrypt(
+ UserRecord *h,
+ HomeSetup *setup,
+ char **effective_passwords,
+ UserRecord **ret_home) {
+
+ _cleanup_(rm_rf_physical_and_freep) char *temporary = NULL;
+ _cleanup_(user_record_unrefp) UserRecord *new_home = NULL;
+ _cleanup_(erase_and_freep) void *volume_key = NULL;
+ _cleanup_close_ int mount_fd = -1;
+ struct fscrypt_policy policy = {};
+ size_t volume_key_size = 512 / 8;
+ _cleanup_free_ char *d = NULL;
+ uint32_t nr = 0;
+ const char *ip;
+ int r;
+
+ assert(h);
+ assert(user_record_storage(h) == USER_FSCRYPT);
+ assert(setup);
+ assert(ret_home);
+
+ assert_se(ip = user_record_image_path(h));
+
+ r = tempfn_random(ip, "homework", &d);
+ if (r < 0)
+ return log_error_errno(r, "Failed to allocate temporary directory: %m");
+
+ (void) mkdir_parents(d, 0755);
+
+ if (mkdir(d, 0700) < 0)
+ return log_error_errno(errno, "Failed to create temporary home directory %s: %m", d);
+
+ temporary = TAKE_PTR(d); /* Needs to be destroyed now */
+
+ r = home_unshare_and_mkdir();
+ if (r < 0)
+ return r;
+
+ setup->root_fd = open(temporary, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOFOLLOW);
+ if (setup->root_fd < 0)
+ return log_error_errno(errno, "Failed to open temporary home directory: %m");
+
+ if (ioctl(setup->root_fd, FS_IOC_GET_ENCRYPTION_POLICY, &policy) < 0) {
+ if (ERRNO_IS_NOT_SUPPORTED(errno)) {
+ log_error_errno(errno, "File system does not support fscrypt: %m");
+ return -ENOLINK; /* make recognizable */
+ }
+ if (errno != ENODATA)
+ return log_error_errno(errno, "Failed to get fscrypt policy of directory: %m");
+ } else
+ return log_error_errno(SYNTHETIC_ERRNO(EBUSY), "Parent of %s already encrypted, refusing.", d);
+
+ volume_key = malloc(volume_key_size);
+ if (!volume_key)
+ return log_oom();
+
+ r = crypto_random_bytes(volume_key, volume_key_size);
+ if (r < 0)
+ return log_error_errno(r, "Failed to acquire volume key: %m");
+
+ log_info("Generated volume key of size %zu.", volume_key_size);
+
+ policy = (struct fscrypt_policy) {
+ .contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS,
+ .filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS,
+ .flags = FS_POLICY_FLAGS_PAD_32,
+ };
+
+ calculate_key_descriptor(volume_key, volume_key_size, policy.master_key_descriptor);
+
+ r = fscrypt_upload_volume_key(policy.master_key_descriptor, volume_key, volume_key_size, KEY_SPEC_THREAD_KEYRING);
+ if (r < 0)
+ return r;
+
+ log_info("Uploaded volume key to kernel.");
+
+ if (ioctl(setup->root_fd, FS_IOC_SET_ENCRYPTION_POLICY, &policy) < 0)
+ return log_error_errno(errno, "Failed to set fscrypt policy on directory: %m");
+
+ log_info("Encryption policy set.");
+
+ STRV_FOREACH(i, effective_passwords) {
+ r = fscrypt_slot_set(setup->root_fd, volume_key, volume_key_size, *i, nr);
+ if (r < 0)
+ return r;
+
+ nr++;
+ }
+
+ (void) home_update_quota_classic(h, temporary);
+
+ r = home_shift_uid(setup->root_fd, HOME_RUNTIME_WORK_DIR, h->uid, h->uid, &mount_fd);
+ if (r > 0)
+ setup->undo_mount = true; /* If uidmaps worked we have a mount to undo again */
+
+ if (mount_fd >= 0) {
+ /* If we have established a new mount, then we can use that as new root fd to our home directory. */
+ safe_close(setup->root_fd);
+
+ setup->root_fd = fd_reopen(mount_fd, O_RDONLY|O_CLOEXEC|O_DIRECTORY);
+ if (setup->root_fd < 0)
+ return log_error_errno(setup->root_fd, "Unable to convert mount fd into proper directory fd: %m");
+
+ mount_fd = safe_close(mount_fd);
+ }
+
+ r = home_populate(h, setup->root_fd);
+ if (r < 0)
+ return r;
+
+ r = home_sync_and_statfs(setup->root_fd, NULL);
+ if (r < 0)
+ return r;
+
+ r = user_record_clone(h, USER_RECORD_LOAD_MASK_SECRET|USER_RECORD_PERMISSIVE, &new_home);
+ if (r < 0)
+ return log_error_errno(r, "Failed to clone record: %m");
+
+ r = user_record_add_binding(
+ new_home,
+ USER_FSCRYPT,
+ ip,
+ SD_ID128_NULL,
+ SD_ID128_NULL,
+ SD_ID128_NULL,
+ NULL,
+ NULL,
+ UINT64_MAX,
+ NULL,
+ NULL,
+ h->uid,
+ (gid_t) h->uid);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add binding to record: %m");
+
+ setup->root_fd = safe_close(setup->root_fd);
+
+ r = home_setup_undo_mount(setup, LOG_ERR);
+ if (r < 0)
+ return r;
+
+ if (rename(temporary, ip) < 0)
+ return log_error_errno(errno, "Failed to rename %s to %s: %m", temporary, ip);
+
+ temporary = mfree(temporary);
+
+ log_info("Everything completed.");
+
+ *ret_home = TAKE_PTR(new_home);
+ return 0;
+}
+
+int home_passwd_fscrypt(
+ UserRecord *h,
+ HomeSetup *setup,
+ const PasswordCache *cache, /* the passwords acquired via PKCS#11/FIDO2 security tokens */
+ char **effective_passwords /* new passwords */) {
+
+ _cleanup_(erase_and_freep) void *volume_key = NULL;
+ _cleanup_free_ char *xattr_buf = NULL;
+ size_t volume_key_size = 0;
+ uint32_t slot = 0;
+ const char *xa;
+ int r;
+
+ assert(h);
+ assert(user_record_storage(h) == USER_FSCRYPT);
+ assert(setup);
+
+ r = fscrypt_setup(
+ cache,
+ h->password,
+ setup,
+ &volume_key,
+ &volume_key_size);
+ if (r < 0)
+ return r;
+
+ STRV_FOREACH(p, effective_passwords) {
+ r = fscrypt_slot_set(setup->root_fd, volume_key, volume_key_size, *p, slot);
+ if (r < 0)
+ return r;
+
+ slot++;
+ }
+
+ r = flistxattr_malloc(setup->root_fd, &xattr_buf);
+ if (r < 0)
+ return log_error_errno(errno, "Failed to retrieve xattr list: %m");
+
+ NULSTR_FOREACH(xa, xattr_buf) {
+ const char *nr;
+ uint32_t z;
+
+ /* Check if this xattr has the format 'trusted.fscrypt_slot<nr>' where '<nr>' is a 32bit unsigned integer */
+ nr = startswith(xa, "trusted.fscrypt_slot");
+ if (!nr)
+ continue;
+ if (safe_atou32(nr, &z) < 0)
+ continue;
+
+ if (z < slot)
+ continue;
+
+ if (fremovexattr(setup->root_fd, xa) < 0)
+ if (errno != ENODATA)
+ log_warning_errno(errno, "Failed to remove xattr %s: %m", xa);
+ }
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-10 05:33:43 +0000