1232 lines
46 KiB
C
1232 lines
46 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <sys/mount.h>
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#include <unistd.h>
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#include "acl-util.h"
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#include "cgroup.h"
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#include "creds-util.h"
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#include "errno-util.h"
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#include "exec-credential.h"
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#include "execute.h"
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#include "fileio.h"
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#include "fs-util.h"
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#include "glob-util.h"
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#include "io-util.h"
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#include "iovec-util.h"
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#include "label-util.h"
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#include "log.h"
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#include "mkdir-label.h"
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#include "mount-util.h"
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#include "mountpoint-util.h"
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#include "ordered-set.h"
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#include "path-lookup.h"
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#include "path-util.h"
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#include "process-util.h"
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#include "random-util.h"
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#include "recurse-dir.h"
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#include "rm-rf.h"
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#include "siphash24.h"
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#include "stat-util.h"
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#include "strv.h"
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#include "tmpfile-util.h"
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#include "user-util.h"
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ExecSetCredential* exec_set_credential_free(ExecSetCredential *sc) {
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if (!sc)
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return NULL;
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free(sc->id);
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free(sc->data);
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return mfree(sc);
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}
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ExecLoadCredential* exec_load_credential_free(ExecLoadCredential *lc) {
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if (!lc)
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return NULL;
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free(lc->id);
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free(lc->path);
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return mfree(lc);
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}
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ExecImportCredential* exec_import_credential_free(ExecImportCredential *ic) {
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if (!ic)
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return NULL;
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free(ic->glob);
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free(ic->rename);
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return mfree(ic);
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}
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static void exec_import_credential_hash_func(const ExecImportCredential *ic, struct siphash *state) {
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assert(ic);
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assert(state);
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siphash24_compress_string(ic->glob, state);
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if (ic->rename)
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siphash24_compress_string(ic->rename, state);
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}
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static int exec_import_credential_compare_func(const ExecImportCredential *a, const ExecImportCredential *b) {
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int r;
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assert(a);
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assert(b);
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r = strcmp(a->glob, b->glob);
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if (r != 0)
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return r;
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return strcmp_ptr(a->rename, b->rename);
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}
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DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
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exec_set_credential_hash_ops,
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char, string_hash_func, string_compare_func,
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ExecSetCredential, exec_set_credential_free);
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DEFINE_PRIVATE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
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exec_load_credential_hash_ops,
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char, string_hash_func, string_compare_func,
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ExecLoadCredential, exec_load_credential_free);
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DEFINE_PRIVATE_HASH_OPS_WITH_KEY_DESTRUCTOR(
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exec_import_credential_hash_ops,
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ExecImportCredential,
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exec_import_credential_hash_func,
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exec_import_credential_compare_func,
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exec_import_credential_free);
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int exec_context_put_load_credential(ExecContext *c, const char *id, const char *path, bool encrypted) {
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ExecLoadCredential *old;
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int r;
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assert(c);
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assert(id);
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assert(path);
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old = hashmap_get(c->load_credentials, id);
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if (old) {
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r = free_and_strdup(&old->path, path);
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if (r < 0)
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return r;
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old->encrypted = encrypted;
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} else {
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_cleanup_(exec_load_credential_freep) ExecLoadCredential *lc = NULL;
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lc = new(ExecLoadCredential, 1);
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if (!lc)
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return -ENOMEM;
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*lc = (ExecLoadCredential) {
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.id = strdup(id),
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.path = strdup(path),
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.encrypted = encrypted,
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};
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if (!lc->id || !lc->path)
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return -ENOMEM;
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r = hashmap_ensure_put(&c->load_credentials, &exec_load_credential_hash_ops, lc->id, lc);
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assert(r != -EEXIST);
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if (r < 0)
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return r;
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TAKE_PTR(lc);
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}
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return 0;
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}
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int exec_context_put_set_credential(
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ExecContext *c,
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const char *id,
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void *data_consume,
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size_t size,
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bool encrypted) {
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_cleanup_free_ void *data = data_consume;
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ExecSetCredential *old;
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int r;
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/* Takes the ownership of data both on success and failure */
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assert(c);
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assert(id);
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assert(data || size == 0);
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old = hashmap_get(c->set_credentials, id);
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if (old) {
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free_and_replace(old->data, data);
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old->size = size;
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old->encrypted = encrypted;
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} else {
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_cleanup_(exec_set_credential_freep) ExecSetCredential *sc = NULL;
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sc = new(ExecSetCredential, 1);
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if (!sc)
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return -ENOMEM;
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*sc = (ExecSetCredential) {
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.id = strdup(id),
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.data = TAKE_PTR(data),
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.size = size,
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.encrypted = encrypted,
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};
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if (!sc->id)
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return -ENOMEM;
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r = hashmap_ensure_put(&c->set_credentials, &exec_set_credential_hash_ops, sc->id, sc);
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assert(r != -EEXIST);
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if (r < 0)
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return r;
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TAKE_PTR(sc);
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}
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return 0;
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}
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int exec_context_put_import_credential(ExecContext *c, const char *glob, const char *rename) {
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_cleanup_(exec_import_credential_freep) ExecImportCredential *ic = NULL;
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int r;
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assert(c);
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assert(glob);
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rename = empty_to_null(rename);
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ic = new(ExecImportCredential, 1);
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if (!ic)
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return -ENOMEM;
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*ic = (ExecImportCredential) {
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.glob = strdup(glob),
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};
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if (!ic->glob)
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return -ENOMEM;
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if (rename) {
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ic->rename = strdup(rename);
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if (!ic->rename)
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return -ENOMEM;
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}
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if (ordered_set_contains(c->import_credentials, ic))
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return 0;
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r = ordered_set_ensure_put(&c->import_credentials, &exec_import_credential_hash_ops, ic);
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assert(r != -EEXIST);
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if (r < 0)
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return r;
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TAKE_PTR(ic);
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return 0;
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}
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bool exec_params_need_credentials(const ExecParameters *p) {
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assert(p);
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return p->flags & (EXEC_SETUP_CREDENTIALS|EXEC_SETUP_CREDENTIALS_FRESH);
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}
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bool exec_context_has_credentials(const ExecContext *c) {
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assert(c);
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return !hashmap_isempty(c->set_credentials) ||
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!hashmap_isempty(c->load_credentials) ||
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!ordered_set_isempty(c->import_credentials);
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}
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bool mount_point_is_credentials(const char *runtime_prefix, const char *path) {
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const char *e;
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assert(runtime_prefix);
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assert(path);
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e = path_startswith(path, runtime_prefix);
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if (!e)
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return false;
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return path_startswith(e, "credentials");
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}
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static int get_credential_directory(
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const char *runtime_prefix,
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const char *unit,
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char **ret) {
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char *p;
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assert(ret);
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if (!runtime_prefix || !unit) {
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*ret = NULL;
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return 0;
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}
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p = path_join(runtime_prefix, "credentials", unit);
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if (!p)
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return -ENOMEM;
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*ret = p;
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return 1;
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}
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int exec_context_get_credential_directory(
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const ExecContext *context,
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const ExecParameters *params,
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const char *unit,
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char **ret) {
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assert(context);
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assert(params);
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assert(unit);
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assert(ret);
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if (!exec_params_need_credentials(params) || !exec_context_has_credentials(context)) {
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*ret = NULL;
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return 0;
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}
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return get_credential_directory(params->prefix[EXEC_DIRECTORY_RUNTIME], unit, ret);
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}
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int exec_context_destroy_credentials(const ExecContext *c, const char *runtime_prefix, const char *unit) {
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_cleanup_free_ char *p = NULL;
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int r;
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assert(c);
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r = get_credential_directory(runtime_prefix, unit, &p);
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if (r <= 0)
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return r;
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/* This is either a tmpfs/ramfs of its own, or a plain directory. Either way, let's first try to
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* unmount it, and afterwards remove the mount point */
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(void) umount2(p, MNT_DETACH|UMOUNT_NOFOLLOW);
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(void) rm_rf(p, REMOVE_ROOT|REMOVE_CHMOD);
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return 0;
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}
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static int write_credential(
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int dfd,
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const char *id,
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const void *data,
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size_t size,
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uid_t uid,
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gid_t gid,
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bool ownership_ok) {
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_cleanup_free_ char *tmp = NULL;
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_cleanup_close_ int fd = -EBADF;
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int r;
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assert(dfd >= 0);
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assert(id);
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assert(data || size == 0);
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r = tempfn_random_child("", "cred", &tmp);
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if (r < 0)
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return r;
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fd = openat(dfd, tmp, O_CREAT|O_RDWR|O_CLOEXEC|O_EXCL|O_NOFOLLOW|O_NOCTTY, 0600);
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if (fd < 0)
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return -errno;
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CLEANUP_TMPFILE_AT(dfd, tmp);
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r = loop_write(fd, data, size);
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if (r < 0)
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return r;
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r = RET_NERRNO(fchmod(fd, 0400)); /* Take away "w" bit */
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if (r < 0)
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return r;
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if (uid_is_valid(uid) && uid != getuid()) {
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r = fd_add_uid_acl_permission(fd, uid, ACL_READ);
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/* Ideally we use ACLs, since we can neatly express what we want to express:
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* the user gets read access and nothing else. But if the backing fs can't
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* support that (e.g. ramfs), then we can use file ownership instead. But that's
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* only safe if we can then re-mount the whole thing read-only, so that the user
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* can no longer chmod() the file to gain write access. */
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if ((ERRNO_IS_NEG_NOT_SUPPORTED(r) || ERRNO_IS_NEG_PRIVILEGE(r)) && ownership_ok)
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r = RET_NERRNO(fchown(fd, uid, gid));
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if (r < 0)
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return r;
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}
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r = RET_NERRNO(renameat(dfd, tmp, dfd, id));
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if (r < 0)
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return r;
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tmp = mfree(tmp); /* disarm CLEANUP_TMPFILE_AT() */
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return 0;
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}
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typedef enum CredentialSearchPath {
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CREDENTIAL_SEARCH_PATH_TRUSTED,
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CREDENTIAL_SEARCH_PATH_ENCRYPTED,
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CREDENTIAL_SEARCH_PATH_ALL,
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_CREDENTIAL_SEARCH_PATH_MAX,
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_CREDENTIAL_SEARCH_PATH_INVALID = -EINVAL,
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} CredentialSearchPath;
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static int credential_search_path(const ExecParameters *params, CredentialSearchPath path, char ***ret) {
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_cleanup_strv_free_ char **l = NULL;
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int r;
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assert(params);
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assert(path >= 0 && path < _CREDENTIAL_SEARCH_PATH_MAX);
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assert(ret);
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/* Assemble a search path to find credentials in. For non-encrypted credentials, We'll look in
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* /etc/credstore/ (and similar directories in /usr/lib/ + /run/). If we're looking for encrypted
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* credentials, we'll look in /etc/credstore.encrypted/ (and similar dirs). */
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if (IN_SET(path, CREDENTIAL_SEARCH_PATH_ENCRYPTED, CREDENTIAL_SEARCH_PATH_ALL)) {
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r = strv_extend(&l, params->received_encrypted_credentials_directory);
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if (r < 0)
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return r;
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_cleanup_strv_free_ char **add = NULL;
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r = credential_store_path_encrypted(params->runtime_scope, &add);
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if (r < 0)
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return r;
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r = strv_extend_strv_consume(&l, TAKE_PTR(add), /* filter_duplicates= */ false);
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if (r < 0)
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return r;
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}
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if (IN_SET(path, CREDENTIAL_SEARCH_PATH_TRUSTED, CREDENTIAL_SEARCH_PATH_ALL)) {
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r = strv_extend(&l, params->received_credentials_directory);
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if (r < 0)
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return r;
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_cleanup_strv_free_ char **add = NULL;
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r = credential_store_path(params->runtime_scope, &add);
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if (r < 0)
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return r;
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r = strv_extend_strv_consume(&l, TAKE_PTR(add), /* filter_duplicates= */ false);
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if (r < 0)
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return r;
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}
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if (DEBUG_LOGGING) {
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_cleanup_free_ char *t = strv_join(l, ":");
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log_debug("Credential search path is: %s", strempty(t));
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}
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*ret = TAKE_PTR(l);
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return 0;
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}
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static bool device_nodes_restricted(
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const ExecContext *c,
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const CGroupContext *cgroup_context) {
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assert(c);
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assert(cgroup_context);
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/* Returns true if we have any reason to believe we might not be able to access the TPM device
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* directly, even if we run as root/PID 1. This could be because /dev/ is replaced by a private
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* version, or because a device node access list is configured. */
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if (c->private_devices)
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return true;
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if (cgroup_context_has_device_policy(cgroup_context))
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return true;
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return false;
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}
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struct load_cred_args {
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const ExecContext *context;
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const CGroupContext *cgroup_context;
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const ExecParameters *params;
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const char *unit;
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bool encrypted;
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int write_dfd;
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uid_t uid;
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gid_t gid;
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bool ownership_ok;
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uint64_t left;
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};
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static int maybe_decrypt_and_write_credential(
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struct load_cred_args *args,
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const char *id,
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const char *data,
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size_t size,
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bool graceful) {
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_cleanup_(iovec_done_erase) struct iovec plaintext = {};
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size_t add;
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int r;
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assert(args);
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assert(args->write_dfd >= 0);
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assert(id);
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assert(data || size == 0);
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|
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if (args->encrypted) {
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CredentialFlags flags = 0; /* only allow user creds in user scope */
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switch (args->params->runtime_scope) {
|
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|
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case RUNTIME_SCOPE_SYSTEM:
|
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/* In system mode talk directly to the TPM – unless we live in a device sandbox
|
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* which might block TPM device access. */
|
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|
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flags |= CREDENTIAL_ANY_SCOPE;
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|
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if (!device_nodes_restricted(args->context, args->cgroup_context)) {
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r = decrypt_credential_and_warn(
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id,
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now(CLOCK_REALTIME),
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/* tpm2_device= */ NULL,
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/* tpm2_signature_path= */ NULL,
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getuid(),
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&IOVEC_MAKE(data, size),
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flags,
|
||
&plaintext);
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break;
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||
}
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_fallthrough_;
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case RUNTIME_SCOPE_USER:
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/* In per user mode we'll not have access to the machine secret, nor to the TPM (most
|
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* likely), hence go via the IPC service instead. Do this if we are run in root's
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* per-user invocation too, to minimize differences and because isolating this logic
|
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* into a separate process is generally a good thing anyway. */
|
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r = ipc_decrypt_credential(
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id,
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now(CLOCK_REALTIME),
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getuid(),
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&IOVEC_MAKE(data, size),
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flags,
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&plaintext);
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break;
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||
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||
default:
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assert_not_reached();
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}
|
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if (r < 0) {
|
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if (graceful) {
|
||
log_warning_errno(r, "Unable to decrypt credential '%s', skipping: %m", id);
|
||
return 0;
|
||
}
|
||
|
||
return r;
|
||
}
|
||
|
||
data = plaintext.iov_base;
|
||
size = plaintext.iov_len;
|
||
}
|
||
|
||
add = strlen(id) + size;
|
||
if (add > args->left)
|
||
return -E2BIG;
|
||
|
||
r = write_credential(args->write_dfd, id, data, size, args->uid, args->gid, args->ownership_ok);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to write credential '%s': %m", id);
|
||
|
||
args->left -= add;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int load_credential_glob(
|
||
struct load_cred_args *args,
|
||
const ExecImportCredential *ic,
|
||
char * const *search_path,
|
||
ReadFullFileFlags flags) {
|
||
|
||
int r;
|
||
|
||
assert(args);
|
||
assert(args->write_dfd >= 0);
|
||
assert(ic);
|
||
assert(search_path);
|
||
|
||
STRV_FOREACH(d, search_path) {
|
||
_cleanup_strv_free_ char **paths = NULL;
|
||
_cleanup_free_ char *j = NULL;
|
||
|
||
j = path_join(*d, ic->glob);
|
||
if (!j)
|
||
return -ENOMEM;
|
||
|
||
r = safe_glob(j, /* flags = */ 0, &paths);
|
||
if (r == -ENOENT)
|
||
continue;
|
||
if (r < 0)
|
||
return r;
|
||
|
||
STRV_FOREACH(p, paths) {
|
||
_cleanup_free_ char *fn = NULL;
|
||
_cleanup_(erase_and_freep) char *data = NULL;
|
||
size_t size;
|
||
|
||
r = path_extract_filename(*p, &fn);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to extract filename from '%s': %m", *p);
|
||
|
||
if (ic->rename) {
|
||
_cleanup_free_ char *renamed = NULL;
|
||
|
||
renamed = strjoin(ic->rename, fn + strlen(ic->glob) - !!endswith(ic->glob, "*"));
|
||
if (!renamed)
|
||
return log_oom_debug();
|
||
|
||
free_and_replace(fn, renamed);
|
||
}
|
||
|
||
if (!credential_name_valid(fn)) {
|
||
log_debug("Skipping credential with invalid name: %s", fn);
|
||
continue;
|
||
}
|
||
|
||
if (faccessat(args->write_dfd, fn, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) {
|
||
log_debug("Skipping credential with duplicated ID %s at %s", fn, *p);
|
||
continue;
|
||
}
|
||
if (errno != ENOENT)
|
||
return log_debug_errno(errno, "Failed to test if credential %s exists: %m", fn);
|
||
|
||
/* path is absolute, hence pass AT_FDCWD as nop dir fd here */
|
||
r = read_full_file_full(
|
||
AT_FDCWD,
|
||
*p,
|
||
UINT64_MAX,
|
||
args->encrypted ? CREDENTIAL_ENCRYPTED_SIZE_MAX : CREDENTIAL_SIZE_MAX,
|
||
flags,
|
||
NULL,
|
||
&data, &size);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to read credential '%s': %m", *p);
|
||
|
||
r = maybe_decrypt_and_write_credential(args, fn, data, size, /* graceful= */ true);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int load_credential(
|
||
struct load_cred_args *args,
|
||
const char *id,
|
||
int read_dfd,
|
||
const char *path) {
|
||
|
||
ReadFullFileFlags flags = READ_FULL_FILE_SECURE|READ_FULL_FILE_FAIL_WHEN_LARGER;
|
||
_cleanup_strv_free_ char **search_path = NULL;
|
||
_cleanup_free_ char *bindname = NULL;
|
||
const char *source = NULL;
|
||
bool missing_ok;
|
||
_cleanup_(erase_and_freep) char *data = NULL;
|
||
size_t size, maxsz;
|
||
int r;
|
||
|
||
assert(args);
|
||
assert(args->context);
|
||
assert(args->params);
|
||
assert(args->unit);
|
||
assert(args->write_dfd >= 0);
|
||
assert(id);
|
||
assert(read_dfd >= 0 || read_dfd == AT_FDCWD);
|
||
assert(path);
|
||
|
||
if (read_dfd >= 0) {
|
||
/* If a directory fd is specified, then read the file directly from that dir. In this case we
|
||
* won't do AF_UNIX stuff (we simply don't want to recursively iterate down a tree of AF_UNIX
|
||
* IPC sockets). It's OK if a file vanishes here in the time we enumerate it and intend to
|
||
* open it. */
|
||
|
||
if (!filename_is_valid(path)) /* safety check */
|
||
return -EINVAL;
|
||
|
||
missing_ok = true;
|
||
source = path;
|
||
|
||
} else if (path_is_absolute(path)) {
|
||
/* If this is an absolute path, read the data directly from it, and support AF_UNIX
|
||
* sockets */
|
||
|
||
if (!path_is_valid(path)) /* safety check */
|
||
return -EINVAL;
|
||
|
||
flags |= READ_FULL_FILE_CONNECT_SOCKET;
|
||
|
||
/* Pass some minimal info about the unit and the credential name we are looking to acquire
|
||
* via the source socket address in case we read off an AF_UNIX socket. */
|
||
if (asprintf(&bindname, "@%" PRIx64 "/unit/%s/%s", random_u64(), args->unit, id) < 0)
|
||
return -ENOMEM;
|
||
|
||
missing_ok = false;
|
||
source = path;
|
||
|
||
} else if (credential_name_valid(path)) {
|
||
/* If this is a relative path, take it as credential name relative to the credentials
|
||
* directory we received ourselves. We don't support the AF_UNIX stuff in this mode, since we
|
||
* are operating on a credential store, i.e. this is guaranteed to be regular files. */
|
||
|
||
r = credential_search_path(args->params, CREDENTIAL_SEARCH_PATH_ALL, &search_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
missing_ok = true;
|
||
} else
|
||
return -EINVAL;
|
||
|
||
if (args->encrypted) {
|
||
flags |= READ_FULL_FILE_UNBASE64;
|
||
maxsz = CREDENTIAL_ENCRYPTED_SIZE_MAX;
|
||
} else
|
||
maxsz = CREDENTIAL_SIZE_MAX;
|
||
|
||
if (search_path)
|
||
STRV_FOREACH(d, search_path) {
|
||
_cleanup_free_ char *j = NULL;
|
||
|
||
j = path_join(*d, path);
|
||
if (!j)
|
||
return -ENOMEM;
|
||
|
||
r = read_full_file_full(
|
||
AT_FDCWD, j, /* path is absolute, hence pass AT_FDCWD as nop dir fd here */
|
||
UINT64_MAX,
|
||
maxsz,
|
||
flags,
|
||
NULL,
|
||
&data, &size);
|
||
if (r != -ENOENT)
|
||
break;
|
||
}
|
||
else if (source)
|
||
r = read_full_file_full(
|
||
read_dfd, source,
|
||
UINT64_MAX,
|
||
maxsz,
|
||
flags,
|
||
bindname,
|
||
&data, &size);
|
||
else
|
||
assert_not_reached();
|
||
|
||
if (r == -ENOENT && (missing_ok || hashmap_contains(args->context->set_credentials, id))) {
|
||
/* Make a missing inherited credential non-fatal, let's just continue. After all apps
|
||
* will get clear errors if we don't pass such a missing credential on as they
|
||
* themselves will get ENOENT when trying to read them, which should not be much
|
||
* worse than when we handle the error here and make it fatal.
|
||
*
|
||
* Also, if the source file doesn't exist, but a fallback is set via SetCredentials=
|
||
* we are fine, too. */
|
||
log_full_errno(hashmap_contains(args->context->set_credentials, id) ? LOG_DEBUG : LOG_INFO,
|
||
r, "Couldn't read inherited credential '%s', skipping: %m", path);
|
||
return 0;
|
||
}
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to read credential '%s': %m", path);
|
||
|
||
return maybe_decrypt_and_write_credential(args, id, data, size, /* graceful= */ false);
|
||
}
|
||
|
||
static int load_cred_recurse_dir_cb(
|
||
RecurseDirEvent event,
|
||
const char *path,
|
||
int dir_fd,
|
||
int inode_fd,
|
||
const struct dirent *de,
|
||
const struct statx *sx,
|
||
void *userdata) {
|
||
|
||
struct load_cred_args *args = ASSERT_PTR(userdata);
|
||
_cleanup_free_ char *sub_id = NULL;
|
||
int r;
|
||
|
||
assert(path);
|
||
assert(de);
|
||
|
||
if (event != RECURSE_DIR_ENTRY)
|
||
return RECURSE_DIR_CONTINUE;
|
||
|
||
if (!IN_SET(de->d_type, DT_REG, DT_SOCK))
|
||
return RECURSE_DIR_CONTINUE;
|
||
|
||
sub_id = strreplace(path, "/", "_");
|
||
if (!sub_id)
|
||
return -ENOMEM;
|
||
|
||
if (!credential_name_valid(sub_id))
|
||
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "Credential would get ID '%s', which is not valid, refusing.", sub_id);
|
||
|
||
if (faccessat(args->write_dfd, sub_id, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) {
|
||
log_debug("Skipping credential with duplicated ID %s at %s", sub_id, path);
|
||
return RECURSE_DIR_CONTINUE;
|
||
}
|
||
if (errno != ENOENT)
|
||
return log_debug_errno(errno, "Failed to test if credential %s exists: %m", sub_id);
|
||
|
||
r = load_credential(args,
|
||
sub_id,
|
||
dir_fd, de->d_name);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return RECURSE_DIR_CONTINUE;
|
||
}
|
||
|
||
static int acquire_credentials(
|
||
const ExecContext *context,
|
||
const CGroupContext *cgroup_context,
|
||
const ExecParameters *params,
|
||
const char *unit,
|
||
const char *p,
|
||
uid_t uid,
|
||
gid_t gid,
|
||
bool ownership_ok) {
|
||
|
||
_cleanup_close_ int dfd = -EBADF;
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(cgroup_context);
|
||
assert(params);
|
||
assert(unit);
|
||
assert(p);
|
||
|
||
dfd = open(p, O_DIRECTORY|O_CLOEXEC);
|
||
if (dfd < 0)
|
||
return -errno;
|
||
|
||
r = fd_acl_make_writable(dfd); /* Add the "w" bit, if we are reusing an already set up credentials dir where it was unset */
|
||
if (r < 0)
|
||
return r;
|
||
|
||
struct load_cred_args args = {
|
||
.context = context,
|
||
.cgroup_context = cgroup_context,
|
||
.params = params,
|
||
.unit = unit,
|
||
.write_dfd = dfd,
|
||
.uid = uid,
|
||
.gid = gid,
|
||
.ownership_ok = ownership_ok,
|
||
.left = CREDENTIALS_TOTAL_SIZE_MAX,
|
||
};
|
||
|
||
/* First, load credentials off disk (or acquire via AF_UNIX socket) */
|
||
ExecLoadCredential *lc;
|
||
HASHMAP_FOREACH(lc, context->load_credentials) {
|
||
_cleanup_close_ int sub_fd = -EBADF;
|
||
|
||
args.encrypted = lc->encrypted;
|
||
|
||
/* If this is an absolute path, then try to open it as a directory. If that works, then we'll
|
||
* recurse into it. If it is an absolute path but it isn't a directory, then we'll open it as
|
||
* a regular file. Finally, if it's a relative path we will use it as a credential name to
|
||
* propagate a credential passed to us from further up. */
|
||
|
||
if (path_is_absolute(lc->path)) {
|
||
sub_fd = open(lc->path, O_DIRECTORY|O_CLOEXEC);
|
||
if (sub_fd < 0 && !IN_SET(errno,
|
||
ENOTDIR, /* Not a directory */
|
||
ENOENT)) /* Doesn't exist? */
|
||
return log_debug_errno(errno, "Failed to open credential source '%s': %m", lc->path);
|
||
}
|
||
|
||
if (sub_fd < 0)
|
||
/* Regular file (incl. a credential passed in from higher up) */
|
||
r = load_credential(&args,
|
||
lc->id,
|
||
AT_FDCWD, lc->path);
|
||
else
|
||
/* Directory */
|
||
r = recurse_dir(sub_fd,
|
||
/* path= */ lc->id, /* recurse_dir() will suffix the subdir paths from here to the top-level id */
|
||
/* statx_mask= */ 0,
|
||
/* n_depth_max= */ UINT_MAX,
|
||
RECURSE_DIR_SORT|RECURSE_DIR_IGNORE_DOT|RECURSE_DIR_ENSURE_TYPE,
|
||
load_cred_recurse_dir_cb,
|
||
&args);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
/* Next, look for system credentials and credentials in the credentials store. Note that these do not
|
||
* override any credentials found earlier. */
|
||
ExecImportCredential *ic;
|
||
ORDERED_SET_FOREACH(ic, context->import_credentials) {
|
||
_cleanup_free_ char **search_path = NULL;
|
||
|
||
r = credential_search_path(params, CREDENTIAL_SEARCH_PATH_TRUSTED, &search_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
args.encrypted = false;
|
||
|
||
r = load_credential_glob(
|
||
&args,
|
||
ic,
|
||
search_path,
|
||
READ_FULL_FILE_SECURE|READ_FULL_FILE_FAIL_WHEN_LARGER);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
search_path = strv_free(search_path);
|
||
|
||
r = credential_search_path(params, CREDENTIAL_SEARCH_PATH_ENCRYPTED, &search_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
args.encrypted = true;
|
||
|
||
r = load_credential_glob(
|
||
&args,
|
||
ic,
|
||
search_path,
|
||
READ_FULL_FILE_SECURE|READ_FULL_FILE_FAIL_WHEN_LARGER|READ_FULL_FILE_UNBASE64);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
/* Finally, we add in literally specified credentials. If the credentials already exist, we'll not
|
||
* add them, so that they can act as a "default" if the same credential is specified multiple times. */
|
||
ExecSetCredential *sc;
|
||
HASHMAP_FOREACH(sc, context->set_credentials) {
|
||
args.encrypted = sc->encrypted;
|
||
|
||
if (faccessat(dfd, sc->id, F_OK, AT_SYMLINK_NOFOLLOW) >= 0) {
|
||
log_debug("Skipping credential with duplicated ID %s", sc->id);
|
||
continue;
|
||
}
|
||
if (errno != ENOENT)
|
||
return log_debug_errno(errno, "Failed to test if credential %s exists: %m", sc->id);
|
||
|
||
r = maybe_decrypt_and_write_credential(&args, sc->id, sc->data, sc->size, /* graceful= */ false);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = fd_acl_make_read_only(dfd); /* Now take away the "w" bit */
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* After we created all keys with the right perms, also make sure the credential store as a whole is
|
||
* accessible */
|
||
|
||
if (uid_is_valid(uid) && uid != getuid()) {
|
||
r = fd_add_uid_acl_permission(dfd, uid, ACL_READ | ACL_EXECUTE);
|
||
if (r < 0) {
|
||
if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r))
|
||
return r;
|
||
|
||
if (!ownership_ok)
|
||
return r;
|
||
|
||
if (fchown(dfd, uid, gid) < 0)
|
||
return -errno;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int setup_credentials_internal(
|
||
const ExecContext *context,
|
||
const CGroupContext *cgroup_context,
|
||
const ExecParameters *params,
|
||
const char *unit,
|
||
const char *final, /* This is where the credential store shall eventually end up at */
|
||
const char *workspace, /* This is where we can prepare it before moving it to the final place */
|
||
bool reuse_workspace, /* Whether to reuse any existing workspace mount if it already is a mount */
|
||
bool must_mount, /* Whether to require that we mount something, it's not OK to use the plain directory fall back */
|
||
uid_t uid,
|
||
gid_t gid) {
|
||
|
||
bool final_mounted;
|
||
int r, workspace_mounted; /* negative if we don't know yet whether we have/can mount something; true
|
||
* if we mounted something; false if we definitely can't mount anything */
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(unit);
|
||
assert(final);
|
||
assert(workspace);
|
||
|
||
r = path_is_mount_point(final);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to determine if '%s' is a mountpoint: %m", final);
|
||
final_mounted = r > 0;
|
||
|
||
if (final_mounted) {
|
||
if (FLAGS_SET(params->flags, EXEC_SETUP_CREDENTIALS_FRESH)) {
|
||
r = umount_verbose(LOG_DEBUG, final, MNT_DETACH|UMOUNT_NOFOLLOW);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
final_mounted = false;
|
||
} else {
|
||
/* We can reuse the previous credential dir */
|
||
r = dir_is_empty(final, /* ignore_hidden_or_backup = */ false);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0) {
|
||
log_debug("Credential dir for unit '%s' already set up, skipping.", unit);
|
||
return 0;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (reuse_workspace) {
|
||
r = path_is_mount_point(workspace);
|
||
if (r < 0)
|
||
return r;
|
||
if (r > 0)
|
||
workspace_mounted = true; /* If this is already a mount, and we are supposed to reuse
|
||
* it, let's keep this in mind */
|
||
else
|
||
workspace_mounted = -1; /* We need to figure out if we can mount something to the workspace */
|
||
} else
|
||
workspace_mounted = -1; /* ditto */
|
||
|
||
/* If both the final place and the workspace are mounted, we have no mounts to set up, based on
|
||
* the assumption that they're actually the same tmpfs (but the latter with MS_RDONLY different).
|
||
* If the workspace is not mounted, we just bind the final place over and make it writable. */
|
||
must_mount = must_mount || final_mounted;
|
||
|
||
if (workspace_mounted < 0) {
|
||
if (!final_mounted)
|
||
/* Nothing is mounted on the workspace yet, let's try to mount a new tmpfs if
|
||
* not using the final place. */
|
||
r = mount_credentials_fs(workspace, CREDENTIALS_TOTAL_SIZE_MAX, /* ro= */ false);
|
||
if (final_mounted || r < 0) {
|
||
/* If using final place or failed to mount new tmpfs, make a bind mount from
|
||
* the final to the workspace, so that we can make it writable there. */
|
||
r = mount_nofollow_verbose(LOG_DEBUG, final, workspace, NULL, MS_BIND|MS_REC, NULL);
|
||
if (r < 0) {
|
||
if (!ERRNO_IS_PRIVILEGE(r))
|
||
/* Propagate anything that isn't a permission problem. */
|
||
return r;
|
||
|
||
if (must_mount)
|
||
/* If it's not OK to use the plain directory fallback, propagate all
|
||
* errors too. */
|
||
return r;
|
||
|
||
/* If we lack privileges to bind mount stuff, then let's gracefully proceed
|
||
* for compat with container envs, and just use the final dir as is.
|
||
* Final place must not be mounted in this case (refused by must_mount
|
||
* above) */
|
||
|
||
workspace_mounted = false;
|
||
} else {
|
||
/* Make the new bind mount writable (i.e. drop MS_RDONLY) */
|
||
r = mount_nofollow_verbose(LOG_DEBUG,
|
||
NULL,
|
||
workspace,
|
||
NULL,
|
||
MS_BIND|MS_REMOUNT|credentials_fs_mount_flags(/* ro= */ false),
|
||
NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
workspace_mounted = true;
|
||
}
|
||
} else
|
||
workspace_mounted = true;
|
||
}
|
||
|
||
assert(workspace_mounted >= 0);
|
||
assert(!must_mount || workspace_mounted);
|
||
|
||
const char *where = workspace_mounted ? workspace : final;
|
||
|
||
(void) label_fix_full(AT_FDCWD, where, final, 0);
|
||
|
||
r = acquire_credentials(context, cgroup_context, params, unit, where, uid, gid, workspace_mounted);
|
||
if (r < 0) {
|
||
/* If we're using final place as workspace, and failed to acquire credentials, we might
|
||
* have left half-written creds there. Let's get rid of the whole mount, so future
|
||
* calls won't reuse it. */
|
||
if (final_mounted)
|
||
(void) umount_verbose(LOG_DEBUG, final, MNT_DETACH|UMOUNT_NOFOLLOW);
|
||
|
||
return r;
|
||
}
|
||
|
||
if (workspace_mounted) {
|
||
if (!final_mounted) {
|
||
/* Make workspace read-only now, so that any bind mount we make from it defaults to
|
||
* read-only too */
|
||
r = mount_nofollow_verbose(LOG_DEBUG, NULL, workspace, NULL, MS_BIND|MS_REMOUNT|credentials_fs_mount_flags(/* ro= */ true), NULL);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* And mount it to the final place, read-only */
|
||
r = mount_nofollow_verbose(LOG_DEBUG, workspace, final, NULL, MS_MOVE, NULL);
|
||
} else
|
||
/* Otherwise we just get rid of the bind mount of final place */
|
||
r = umount_verbose(LOG_DEBUG, workspace, MNT_DETACH|UMOUNT_NOFOLLOW);
|
||
if (r < 0)
|
||
return r;
|
||
} else {
|
||
_cleanup_free_ char *parent = NULL;
|
||
|
||
/* If we do not have our own mount put used the plain directory fallback, then we need to
|
||
* open access to the top-level credential directory and the per-service directory now */
|
||
|
||
r = path_extract_directory(final, &parent);
|
||
if (r < 0)
|
||
return r;
|
||
if (chmod(parent, 0755) < 0)
|
||
return -errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
int exec_setup_credentials(
|
||
const ExecContext *context,
|
||
const CGroupContext *cgroup_context,
|
||
const ExecParameters *params,
|
||
const char *unit,
|
||
uid_t uid,
|
||
gid_t gid) {
|
||
|
||
_cleanup_free_ char *p = NULL, *q = NULL;
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(unit);
|
||
|
||
if (!exec_params_need_credentials(params) || !exec_context_has_credentials(context))
|
||
return 0;
|
||
|
||
if (!params->prefix[EXEC_DIRECTORY_RUNTIME])
|
||
return -EINVAL;
|
||
|
||
/* This is where we'll place stuff when we are done; the main credentials directory is world-readable,
|
||
* and the subdir we mount over with a read-only file system readable by the service's user. */
|
||
q = path_join(params->prefix[EXEC_DIRECTORY_RUNTIME], "credentials");
|
||
if (!q)
|
||
return -ENOMEM;
|
||
|
||
r = mkdir_label(q, 0755); /* top-level dir: world readable/searchable */
|
||
if (r < 0 && r != -EEXIST)
|
||
return r;
|
||
|
||
p = path_join(q, unit);
|
||
if (!p)
|
||
return -ENOMEM;
|
||
|
||
r = mkdir_label(p, 0700); /* per-unit dir: private to user */
|
||
if (r < 0 && r != -EEXIST)
|
||
return r;
|
||
|
||
r = safe_fork("(sd-mkdcreds)", FORK_DEATHSIG_SIGTERM|FORK_WAIT|FORK_NEW_MOUNTNS, NULL);
|
||
if (r < 0) {
|
||
_cleanup_(rmdir_and_freep) char *u = NULL; /* remove the temporary workspace if we can */
|
||
_cleanup_free_ char *t = NULL;
|
||
|
||
/* If this is not a privilege or support issue then propagate the error */
|
||
if (!ERRNO_IS_NOT_SUPPORTED(r) && !ERRNO_IS_PRIVILEGE(r))
|
||
return r;
|
||
|
||
/* Temporary workspace, that remains inaccessible all the time. We prepare stuff there before moving
|
||
* it into place, so that users can't access half-initialized credential stores. */
|
||
t = path_join(params->prefix[EXEC_DIRECTORY_RUNTIME], "systemd/temporary-credentials");
|
||
if (!t)
|
||
return -ENOMEM;
|
||
|
||
/* We can't set up a mount namespace. In that case operate on a fixed, inaccessible per-unit
|
||
* directory outside of /run/credentials/ first, and then move it over to /run/credentials/
|
||
* after it is fully set up */
|
||
u = path_join(t, unit);
|
||
if (!u)
|
||
return -ENOMEM;
|
||
|
||
FOREACH_STRING(i, t, u) {
|
||
r = mkdir_label(i, 0700);
|
||
if (r < 0 && r != -EEXIST)
|
||
return log_debug_errno(r, "Failed to make directory '%s': %m", i);
|
||
}
|
||
|
||
r = setup_credentials_internal(
|
||
context,
|
||
cgroup_context,
|
||
params,
|
||
unit,
|
||
p, /* final mount point */
|
||
u, /* temporary workspace to overmount */
|
||
true, /* reuse the workspace if it is already a mount */
|
||
false, /* it's OK to fall back to a plain directory if we can't mount anything */
|
||
uid,
|
||
gid);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
} else if (r == 0) {
|
||
|
||
/* We managed to set up a mount namespace, and are now in a child. That's great. In this case
|
||
* we can use the same directory for all cases, after turning off propagation. Question
|
||
* though is: where do we turn off propagation exactly, and where do we place the workspace
|
||
* directory? We need some place that is guaranteed to be a mount point in the host, and
|
||
* which is guaranteed to have a subdir we can mount over. /run/ is not suitable for this,
|
||
* since we ultimately want to move the resulting file system there, i.e. we need propagation
|
||
* for /run/ eventually. We could use our own /run/systemd/bind mount on itself, but that
|
||
* would be visible in the host mount table all the time, which we want to avoid. Hence, what
|
||
* we do here instead we use /dev/ and /dev/shm/ for our purposes. We know for sure that
|
||
* /dev/ is a mount point and we now for sure that /dev/shm/ exists. Hence we can turn off
|
||
* propagation on the former, and then overmount the latter.
|
||
*
|
||
* Yes it's nasty playing games with /dev/ and /dev/shm/ like this, since it does not exist
|
||
* for this purpose, but there are few other candidates that work equally well for us, and
|
||
* given that we do this in a privately namespaced short-lived single-threaded process that
|
||
* no one else sees this should be OK to do. */
|
||
|
||
/* Turn off propagation from our namespace to host */
|
||
r = mount_nofollow_verbose(LOG_DEBUG, NULL, "/dev", NULL, MS_SLAVE|MS_REC, NULL);
|
||
if (r < 0)
|
||
goto child_fail;
|
||
|
||
r = setup_credentials_internal(
|
||
context,
|
||
cgroup_context,
|
||
params,
|
||
unit,
|
||
p, /* final mount point */
|
||
"/dev/shm", /* temporary workspace to overmount */
|
||
false, /* do not reuse /dev/shm if it is already a mount, under no circumstances */
|
||
true, /* insist that something is mounted, do not allow fallback to plain directory */
|
||
uid,
|
||
gid);
|
||
if (r < 0)
|
||
goto child_fail;
|
||
|
||
_exit(EXIT_SUCCESS);
|
||
|
||
child_fail:
|
||
_exit(EXIT_FAILURE);
|
||
}
|
||
|
||
/* If the credentials dir is empty and not a mount point, then there's no point in having it. Let's
|
||
* try to remove it. This matters in particular if we created the dir as mount point but then didn't
|
||
* actually end up mounting anything on it. In that case we'd rather have ENOENT than EACCESS being
|
||
* seen by users when trying access this inode. */
|
||
(void) rmdir(p);
|
||
return 0;
|
||
}
|