shared: make libcryptsetup dep dlopen

Let's make libcryptsetup a dlopen() style dep for PID 1 (i.e. for
RootImage= and stuff), systemd-growfs and systemd-repart. (But leave to
be a regulra dep in systemd-cryptsetup, systemd-veritysetup and
systemd-homed since for them the libcryptsetup support is not auxiliary
but pretty much at the core of what they do.)

This should be useful for container images that want systemd in the
payload but don't care for the cryptsetup logic since dm-crypt and stuff
isn't available in containers anyway.

Fixes: #8249

1 files changed, 79 insertions, 2 deletions

diff --git a/src/shared/cryptsetup-util.c b/src/shared/cryptsetup-util.c
index 9bc85a1739..9d86478b06 100644
--- a/src/shared/cryptsetup-util.c
+++ b/src/shared/cryptsetup-util.c
@@ -1,10 +1,79 @@
 /* SPDX-License-Identifier: LGPL-2.1+ */
 
 #if HAVE_LIBCRYPTSETUP
+#include "alloc-util.h"
 #include "cryptsetup-util.h"
+#include "dlfcn-util.h"
 #include "log.h"
 
+static void *cryptsetup_dl = NULL;
+
+int (*sym_crypt_activate_by_passphrase)(struct crypt_device *cd, const char *name, int keyslot, const char *passphrase, size_t passphrase_size, uint32_t flags);
+#if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
+int (*sym_crypt_activate_by_signed_key)(struct crypt_device *cd, const char *name, const char *volume_key, size_t volume_key_size, const char *signature, size_t signature_size, uint32_t flags);
+#endif
+int (*sym_crypt_activate_by_volume_key)(struct crypt_device *cd, const char *name, const char *volume_key, size_t volume_key_size, uint32_t flags);
+int (*sym_crypt_deactivate_by_name)(struct crypt_device *cd, const char *name, uint32_t flags);
+int (*sym_crypt_format)(struct crypt_device *cd, const char *type, const char *cipher, const char *cipher_mode, const char *uuid, const char *volume_key, size_t volume_key_size, void *params);
+void (*sym_crypt_free)(struct crypt_device *cd);
+const char *(*sym_crypt_get_dir)(void);
+int (*sym_crypt_get_verity_info)(struct crypt_device *cd, struct crypt_params_verity *vp);
+int (*sym_crypt_init)(struct crypt_device **cd, const char *device);
+int (*sym_crypt_init_by_name)(struct crypt_device **cd, const char *name);
+int (*sym_crypt_keyslot_add_by_volume_key)(struct crypt_device *cd, int keyslot, const char *volume_key, size_t volume_key_size, const char *passphrase, size_t passphrase_size);
+int (*sym_crypt_load)(struct crypt_device *cd, const char *requested_type, void *params);
+int (*sym_crypt_resize)(struct crypt_device *cd, const char *name, uint64_t new_size);
+int (*sym_crypt_set_data_device)(struct crypt_device *cd, const char *device);
+void (*sym_crypt_set_debug_level)(int level);
+void (*sym_crypt_set_log_callback)(struct crypt_device *cd, void (*log)(int level, const char *msg, void *usrptr), void *usrptr);
+int (*sym_crypt_volume_key_get)(struct crypt_device *cd, int keyslot, char *volume_key, size_t *volume_key_size, const char *passphrase, size_t passphrase_size);
+
+int dlopen_cryptsetup(void) {
+        _cleanup_(dlclosep) void *dl = NULL;
+        int r;
+
+        if (cryptsetup_dl)
+                return 0; /* Already loaded */
+
+        dl = dlopen("libcryptsetup.so.12", RTLD_LAZY);
+        if (!dl)
+                return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP),
+                                       "libcryptsetup support is not installed: %s", dlerror());
+
+        r = dlsym_many_and_warn(
+                        dl,
+                        LOG_DEBUG,
+                        &sym_crypt_activate_by_passphrase, "crypt_activate_by_passphrase",
+#if HAVE_CRYPT_ACTIVATE_BY_SIGNED_KEY
+                        &sym_crypt_activate_by_signed_key, "crypt_activate_by_signed_key",
+#endif
+                        &sym_crypt_activate_by_volume_key, "crypt_activate_by_volume_key",
+                        &sym_crypt_deactivate_by_name, "crypt_deactivate_by_name",
+                        &sym_crypt_format, "crypt_format",
+                        &sym_crypt_free, "crypt_free",
+                        &sym_crypt_get_dir, "crypt_get_dir",
+                        &sym_crypt_get_verity_info, "crypt_get_verity_info",
+                        &sym_crypt_init, "crypt_init",
+                        &sym_crypt_init_by_name, "crypt_init_by_name",
+                        &sym_crypt_keyslot_add_by_volume_key, "crypt_keyslot_add_by_volume_key",
+                        &sym_crypt_load, "crypt_load",
+                        &sym_crypt_resize, "crypt_resize",
+                        &sym_crypt_set_data_device, "crypt_set_data_device",
+                        &sym_crypt_set_debug_level, "crypt_set_debug_level",
+                        &sym_crypt_set_log_callback, "crypt_set_log_callback",
+                        &sym_crypt_volume_key_get, "crypt_volume_key_get",
+                        NULL);
+        if (r < 0)
+                return r;
+
+        /* Note that we never release the reference here, because there's no real reason to, after all this
+         * was traditionally a regular shared library dependency which lives forever too. */
+        cryptsetup_dl = TAKE_PTR(dl);
+        return 1;
+}
+
 static void cryptsetup_log_glue(int level, const char *msg, void *usrptr) {
+
         switch (level) {
         case CRYPT_LOG_NORMAL:
                 level = LOG_NOTICE;
@@ -27,8 +96,16 @@ static void cryptsetup_log_glue(int level, const char *msg, void *usrptr) {
 }
 
 void cryptsetup_enable_logging(struct crypt_device *cd) {
-        crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
-        crypt_set_debug_level(DEBUG_LOGGING ? CRYPT_DEBUG_ALL : CRYPT_DEBUG_NONE);
+        if (!cd)
+                return;
+
+        if (dlopen_cryptsetup() < 0) /* If this fails, let's gracefully ignore the issue, this is just debug
+                                      * logging after all, and if this failed we already generated a debug
+                                      * log message that should help to track things down. */
+                return;
+
+        sym_crypt_set_log_callback(cd, cryptsetup_log_glue, NULL);
+        sym_crypt_set_debug_level(DEBUG_LOGGING ? CRYPT_DEBUG_ALL : CRYPT_DEBUG_NONE);
 }
 
 #endif