From 70dd455c8e97ba60ab9f8983a4b98372c9ec615e Mon Sep 17 00:00:00 2001 From: Zbigniew Jędrzejewski-Szmek Date: Tue, 17 Jan 2017 22:38:55 -0500 Subject: pid1: provide a more detailed error message when execution fails (#5074) Fixes #5000. --- src/core/execute.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 69 insertions(+), 11 deletions(-) (limited to 'src') diff --git a/src/core/execute.c b/src/core/execute.c index 4ff6f4ebd0..3a7f997522 100644 --- a/src/core/execute.c +++ b/src/core/execute.c @@ -2386,7 +2386,8 @@ static int exec_child( int *fds, unsigned n_fds, char **files_env, int user_lookup_fd, - int *exit_status) { + int *exit_status, + char **error_message) { _cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **accum_env = NULL, **final_argv = NULL; _cleanup_free_ char *mac_selinux_context_net = NULL; @@ -2405,6 +2406,9 @@ static int exec_child( assert(context); assert(params); assert(exit_status); + assert(error_message); + /* We don't always set error_message, hence it must be initialized */ + assert(*error_message == NULL); rename_process_from_path(command->path); @@ -2422,6 +2426,8 @@ static int exec_child( r = reset_signal_mask(); if (r < 0) { *exit_status = EXIT_SIGNAL_MASK; + *error_message = strdup("Failed to reset signal mask"); + /* If strdup fails, here and below, we will just print the generic error message. */ return r; } @@ -2437,6 +2443,7 @@ static int exec_child( r = close_remaining_fds(params, runtime, dcreds, user_lookup_fd, socket_fd, fds, n_fds); if (r < 0) { *exit_status = EXIT_FDS; + *error_message = strdup("Failed to close remaining fds"); return r; } @@ -2465,6 +2472,7 @@ static int exec_child( return 0; } *exit_status = EXIT_CONFIRM; + *error_message = strdup("Execution cancelled"); return -ECANCELED; } } @@ -2474,17 +2482,27 @@ static int exec_child( /* Make sure we bypass our own NSS module for any NSS checks */ if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) { *exit_status = EXIT_USER; + *error_message = strdup("Failed to update environment"); return -errno; } r = dynamic_creds_realize(dcreds, &uid, &gid); if (r < 0) { *exit_status = EXIT_USER; + *error_message = strdup("Failed to update dynamic user credentials"); return r; } - if (!uid_is_valid(uid) || !gid_is_valid(gid)) { + if (!uid_is_valid(uid)) { *exit_status = EXIT_USER; + (void) asprintf(error_message, "UID validation failed for \""UID_FMT"\"", uid); + /* If asprintf fails, here and below, we will just print the generic error message. */ + return -ESRCH; + } + + if (!gid_is_valid(gid)) { + *exit_status = EXIT_USER; + (void) asprintf(error_message, "GID validation failed for \""GID_FMT"\"", gid); return -ESRCH; } @@ -2495,12 +2513,14 @@ static int exec_child( r = get_fixed_user(context, &username, &uid, &gid, &home, &shell); if (r < 0) { *exit_status = EXIT_USER; + *error_message = strdup("Failed to determine user credentials"); return r; } r = get_fixed_group(context, &groupname, &gid); if (r < 0) { *exit_status = EXIT_GROUP; + *error_message = strdup("Failed to determine group credentials"); return r; } } @@ -2510,12 +2530,14 @@ static int exec_child( &supplementary_gids, &ngids); if (r < 0) { *exit_status = EXIT_GROUP; + *error_message = strdup("Failed to determine supplementary groups"); return r; } r = send_user_lookup(unit, user_lookup_fd, uid, gid); if (r < 0) { *exit_status = EXIT_USER; + *error_message = strdup("Failed to send user credentials to PID1"); return r; } @@ -2529,18 +2551,21 @@ static int exec_child( r = setup_input(context, params, socket_fd, named_iofds); if (r < 0) { *exit_status = EXIT_STDIN; + *error_message = strdup("Failed to set up stdin"); return r; } r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDOUT; + *error_message = strdup("Failed to set up stdout"); return r; } r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino); if (r < 0) { *exit_status = EXIT_STDERR; + *error_message = strdup("Failed to set up stderr"); return r; } @@ -2548,6 +2573,7 @@ static int exec_child( r = cg_attach_everywhere(params->cgroup_supported, params->cgroup_path, 0, NULL, NULL); if (r < 0) { *exit_status = EXIT_CGROUP; + (void) asprintf(error_message, "Failed to attach to cgroup %s", params->cgroup_path); return r; } } @@ -2568,6 +2594,7 @@ static int exec_child( log_close(); } else if (r < 0) { *exit_status = EXIT_OOM_ADJUST; + *error_message = strdup("Failed to write /proc/self/oom_score_adj"); return -errno; } } @@ -2812,6 +2839,7 @@ static int exec_child( r = capability_bounding_set_drop(context->capability_bounding_set, false); if (r < 0) { *exit_status = EXIT_CAPABILITIES; + *error_message = strdup("Failed to drop capabilities"); return r; } } @@ -2822,6 +2850,7 @@ static int exec_child( r = capability_ambient_set_apply(context->capability_ambient_set, true); if (r < 0) { *exit_status = EXIT_CAPABILITIES; + *error_message = strdup("Failed to apply ambient capabilities (before UID change)"); return r; } } @@ -2830,6 +2859,7 @@ static int exec_child( r = enforce_user(context, uid); if (r < 0) { *exit_status = EXIT_USER; + (void) asprintf(error_message, "Failed to change UID to "UID_FMT, uid); return r; } if (context->capability_ambient_set != 0) { @@ -2838,6 +2868,7 @@ static int exec_child( r = capability_ambient_set_apply(context->capability_ambient_set, false); if (r < 0) { *exit_status = EXIT_CAPABILITIES; + *error_message = strdup("Failed to apply ambient capabilities (after UID change)"); return r; } @@ -2865,6 +2896,7 @@ static int exec_child( r = setexeccon(exec_context); if (r < 0) { *exit_status = EXIT_SELINUX_CONTEXT; + (void) asprintf(error_message, "Failed to set SELinux context to %s", exec_context); return r; } } @@ -2874,6 +2906,7 @@ static int exec_child( r = setup_smack(context, command); if (r < 0) { *exit_status = EXIT_SMACK_PROCESS_LABEL; + *error_message = strdup("Failed to set SMACK process label"); return r; } @@ -2882,6 +2915,9 @@ static int exec_child( r = aa_change_onexec(context->apparmor_profile); if (r < 0 && !context->apparmor_profile_ignore) { *exit_status = EXIT_APPARMOR_PROFILE; + (void) asprintf(error_message, + "Failed to prepare AppArmor profile change to %s", + context->apparmor_profile); return -errno; } } @@ -2894,12 +2930,14 @@ static int exec_child( if (prctl(PR_GET_SECUREBITS) != secure_bits) if (prctl(PR_SET_SECUREBITS, secure_bits) < 0) { *exit_status = EXIT_SECUREBITS; + *error_message = strdup("Failed to set secure bits"); return -errno; } if (context_has_no_new_privileges(context)) if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) { *exit_status = EXIT_NO_NEW_PRIVILEGES; + *error_message = strdup("Failed to disable new privileges"); return -errno; } @@ -2908,6 +2946,7 @@ static int exec_child( r = apply_address_families(unit, context); if (r < 0) { *exit_status = EXIT_ADDRESS_FAMILIES; + *error_message = strdup("Failed to restrict address families"); return r; } } @@ -2916,6 +2955,7 @@ static int exec_child( r = apply_memory_deny_write_execute(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to disable writing to executable memory"); return r; } } @@ -2924,6 +2964,7 @@ static int exec_child( r = apply_restrict_realtime(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to apply realtime restrictions"); return r; } } @@ -2931,6 +2972,7 @@ static int exec_child( r = apply_restrict_namespaces(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to apply namespace restrictions"); return r; } @@ -2938,6 +2980,7 @@ static int exec_child( r = apply_protect_sysctl(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to apply sysctl restrictions"); return r; } } @@ -2946,6 +2989,7 @@ static int exec_child( r = apply_protect_kernel_modules(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to apply module loading restrictions"); return r; } } @@ -2954,6 +2998,7 @@ static int exec_child( r = apply_private_devices(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to set up private devices"); return r; } } @@ -2964,6 +3009,7 @@ static int exec_child( r = apply_seccomp(unit, context); if (r < 0) { *exit_status = EXIT_SECCOMP; + *error_message = strdup("Failed to apply syscall filters"); return r; } } @@ -2973,6 +3019,7 @@ static int exec_child( final_argv = replace_env_argv(argv, accum_env); if (!final_argv) { *exit_status = EXIT_MEMORY; + *error_message = strdup("Failed to prepare process arguments"); return -ENOMEM; } @@ -3059,6 +3106,7 @@ int exec_spawn(Unit *unit, if (pid == 0) { int exit_status; + _cleanup_free_ char *error_message = NULL; r = exec_child(unit, command, @@ -3072,17 +3120,27 @@ int exec_spawn(Unit *unit, fds, n_fds, files_env, unit->manager->user_lookup_fds[1], - &exit_status); + &exit_status, + &error_message); if (r < 0) { log_open(); - log_struct_errno(LOG_ERR, r, - LOG_MESSAGE_ID(SD_MESSAGE_SPAWN_FAILED), - LOG_UNIT_ID(unit), - LOG_UNIT_MESSAGE(unit, "Failed at step %s spawning %s: %m", - exit_status_to_string(exit_status, EXIT_STATUS_SYSTEMD), - command->path), - "EXECUTABLE=%s", command->path, - NULL); + if (error_message) + log_struct_errno(LOG_ERR, r, + LOG_MESSAGE_ID(SD_MESSAGE_SPAWN_FAILED), + LOG_UNIT_ID(unit), + LOG_UNIT_MESSAGE(unit, "%s: %m", + error_message), + "EXECUTABLE=%s", command->path, + NULL); + else + log_struct_errno(LOG_ERR, r, + LOG_MESSAGE_ID(SD_MESSAGE_SPAWN_FAILED), + LOG_UNIT_ID(unit), + LOG_UNIT_MESSAGE(unit, "Failed at step %s spawning %s: %m", + exit_status_to_string(exit_status, EXIT_STATUS_SYSTEMD), + command->path), + "EXECUTABLE=%s", command->path, + NULL); } _exit(exit_status); -- cgit v1.2.3-54-g00ecf