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6144c7fc7f82bb6566248dd3e0d9fb956187484e
FastSync/src/shared/config.c
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TapTap 6144c7fc7f fix(identity): rsync ownership parity for numeric-ids, dirs, maps, fake-super (#286, #294) 
- #286: --numeric-ids is a mapping modifier only; it no longer activates
  chown by itself (identity_active_enabled/owner/group predicates), and
  --fake-super stores the resolved mapping instead of real-chowning.
- #286: apply owner/group to directories via the deferred directory
  metadata path; capture+transmit+apply directory xattrs/ACLs (-aX/-aA),
  including default ACLs, in STATUS_MKDIR/STATUS_DIR_TIMES.
- #294: --usermap/--groupmap support inclusive ranges, '*', empty FROM
  (unnamed ids), and receiver-side TO name resolution; --chown mixing with
  a same-side map is rejected like rsync.
- Protocol 2.22.0 -> 2.23.0 (map wire entry gains from_hi + to_name;
  dir frames gain a bounded xattr block).
2026-09-15 22:10:02 +02:00

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#include "config.h"
#include "charset.h"
#include "chmod.h"
#include "credentials.h"
#include "daemon_conf.h"
#include "delay_updates.h"
#include "delta.h"
#include "file_list.h"
#include "identity.h"
#include "log.h"
#include "protocol.h"
#include "utils.h"
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <errno.h>
static void config_set_defaults(Config* config) {
config->scanner_threads = 0;
config->metadata_explicitly_disabled = false;
config->preserve_perms_explicit_off = false;
config->preserve_times_explicit_off = false;
config->show_progress = false;
config->compression_threads = 0;
config->ssh_port = 22;
config->transport = TRANSPORT_TCP;
config->ssh_destination = NULL;
config->auth_password = NULL;
config->password_file = NULL;
config->fastsync_server_path = NULL;
config->exclude_patterns = NULL;
config->exclude_count = 0;
config->include_patterns = NULL;
config->include_count = 0;
config->max_size = 0;
config->min_size = 0;
config->whole_file = false;
config->use_tls = false;
config->tls_cert = NULL;
config->tls_key = NULL;
config->tls_ca = NULL;
config->server_host = str_dup("127.0.0.1");
config->server_port = 8080;
config->server_port_set = false;
config->server_host_set = false;
/* 0 means "--timeout not given": the transport keeps its own built-in 30 s
* socket timeout (tcp_set_timeouts ignores non-positive values) and the
* protocol layer keeps its built-in 60 s per-message deadline. A positive
* value overrides BOTH (see protocol_session_set_io_timeout). */
config->timeout = 0;
config->contimeout = 10;
config->quiet = false;
config->stats = false;
config->max_depth = 0;
config->log_file = NULL;
config->copy_dirlinks = false;
config->itemize_changes = false;
config->out_format = NULL;
config->log_file_format = NULL;
config->info_level = 0;
config->debug_level = 0;
config->list_only = false;
config->human_readable = false;
config->ignore_errors = false;
config->ignore_missing_args = false;
config->filters = NULL;
config->files_from = NULL;
config->files_from_set = NULL;
config->from0 = false;
config->cvs_exclude = false;
config->per_dir_filter = false;
config->one_file_system = false;
config->no_implied_dirs = false;
config->dirs = false;
config->rsh_command = NULL;
config->blocking_io = false;
config->outbuf = OUTBUF_BLOCK;
config->old_args = false;
config->remote_options = NULL;
config->remote_option_count = 0;
config->address = NULL;
config->ipv6 = false;
config->ipv4 = false;
config->sockopts = NULL;
config->sockopt_count = 0;
config->daemon = false;
config->no_motd = false;
config->delay_context = NULL;
config->open_noatime = false;
config->use_xattrs = false;
config->trust_sender = false;
config->stop_after_mins = 0;
config->stop_at = 0;
config->stop_at_set = false;
config->write_batch = NULL;
config->only_write_batch = NULL;
config->read_batch = NULL;
/* Serialized fields: defaults come from the CONFIG_WIRE_FIELDS table so the
* member declaration, default and wire codec can never drift apart. */
#define CONFIG_DEFAULT_FIELD(name, ctype, def, kind) config->name = def;
CONFIG_WIRE_FIELDS(CONFIG_DEFAULT_FIELD)
#undef CONFIG_DEFAULT_FIELD
}
static bool valid_wire_bool(int value) {
return value == 0 || value == 1;
}
static bool receive_wire_bool(int fd, bool* value) {
int wire_value;
if (!receive_int(fd, &wire_value) || !valid_wire_bool(wire_value))
return false;
*value = wire_value != 0;
return true;
}
/* Cumulative budget for the strings retained by one received Config (see
* MAX_CONFIG_STRING_BYTES). Config strings are received once per connection
* before authentication and live for its whole lifetime, so the charge is never
* released. */
typedef struct {
unsigned long long used;
} ConfigStringBudget;
/* Charge `bytes` (the retained allocation: string body plus NUL) against the
* aggregate config-string budget. Returns false when the ceiling would be
* exceeded, letting the caller reject the frame with a clear error instead of
* retaining unbounded pre-auth memory. */
static bool config_string_budget_charge(ConfigStringBudget* budget, size_t bytes) {
if ((unsigned long long)bytes > MAX_CONFIG_STRING_BYTES ||
budget->used > MAX_CONFIG_STRING_BYTES - (unsigned long long)bytes) {
log_message(LOG_LEVEL_ERROR, "Config string budget exceeded (%llu + %zu > %llu bytes)",
budget->used, bytes, (unsigned long long)MAX_CONFIG_STRING_BYTES);
return false;
}
budget->used += (unsigned long long)bytes;
return true;
}
static char* config_receive_str(int fd, ConfigStringBudget* budget) {
char* value = receive_str(fd);
if (!value)
return NULL;
if (!config_string_budget_charge(budget, strlen(value) + 1)) {
free(value);
return NULL;
}
return value;
}
static char* config_receive_str_redacted(int fd, ConfigStringBudget* budget) {
char* value = receive_str_redacted(fd);
if (!value)
return NULL;
if (!config_string_budget_charge(budget, strlen(value) + 1)) {
free(value);
return NULL;
}
return value;
}
static bool validate_received_config(const Config* config) {
/* Cross-field invariants live in one place (config_invariants_error) so the
receiver enforces every combination the client relies on; a hostile peer
can forge a frame that violates any clause of the shared predicate. */
if (config_invariants_error(config) != NULL)
return false;
return valid_wire_bool(config->save_to_disk) && valid_wire_bool(config->use_multithreading) &&
valid_wire_bool(config->use_chunk_serialization) &&
valid_wire_bool(config->use_compression) && valid_wire_bool(config->use_metadata) &&
valid_wire_bool(config->use_executability) && valid_wire_bool(config->use_sendfile) &&
valid_wire_bool(config->use_delete) && valid_wire_bool(config->use_incremental) &&
valid_wire_bool(config->size_only) && valid_wire_bool(config->ignore_times) &&
valid_wire_bool(config->use_delta) && valid_wire_bool(config->backup) &&
valid_wire_bool(config->fuzzy) && valid_wire_bool(config->remove_source_files) &&
valid_wire_bool(config->follow_symlinks) && valid_wire_bool(config->copy_links) &&
valid_wire_bool(config->safe_links) && valid_wire_bool(config->copy_unsafe_links) &&
valid_wire_bool(config->preserve_hard_links) && valid_wire_bool(config->preserve_acls) &&
valid_wire_bool(config->preserve_xattrs) && valid_wire_bool(config->preserve_devices) &&
valid_wire_bool(config->preserve_sparse) && valid_wire_bool(config->preserve_specials) &&
valid_wire_bool(config->copy_devices) && valid_wire_bool(config->write_devices) &&
valid_wire_bool(config->ignore_existing) && valid_wire_bool(config->existing) &&
valid_wire_bool(config->update) && valid_wire_bool(config->inplace) &&
valid_wire_bool(config->append) && valid_wire_bool(config->use_fsync) &&
valid_wire_bool(config->append_verify) && valid_wire_bool(config->delete_excluded) &&
valid_wire_bool(config->force_delete) && valid_wire_bool(config->delete_missing_args) &&
valid_wire_bool(config->delete_after) && valid_wire_bool(config->preallocate) &&
valid_wire_bool(config->delete_delay) && valid_wire_bool(config->delete_during) &&
valid_wire_bool(config->relative) && valid_wire_bool(config->prune_empty_dirs) &&
valid_wire_bool(config->delay_updates) && valid_wire_bool(config->mkpath) &&
valid_wire_bool(config->partial) && valid_wire_bool(config->delete_before) &&
valid_wire_bool(config->checksum) && valid_wire_bool(config->eight_bit_output) &&
valid_wire_bool(config->dry_run) && checksum_algo_valid(config->checksum_algo) &&
identity_wire_valid(config) && valid_wire_bool(config->preserve_atimes) &&
valid_wire_bool(config->preserve_crtimes) && valid_wire_bool(config->omit_dir_times) &&
valid_wire_bool(config->omit_link_times) && valid_wire_bool(config->preserve_perms) &&
valid_wire_bool(config->preserve_times) && valid_wire_bool(config->preserve_owner) &&
valid_wire_bool(config->preserve_group) && valid_wire_bool(config->munge_links) &&
valid_wire_bool(config->keep_dirlinks) && valid_wire_bool(config->fake_super) &&
(!config->copy_as_set || (config->copy_as_uid >= 0 && config->copy_as_gid >= 0)) &&
(!config->use_compression ||
(config->compression_level >= 1 && config->compression_level <= 22)) &&
config->chunk_size > 0 && config->chunk_size <= MAX_CHUNK_SIZE &&
config->delta_block_size >= DELTA_BLOCK_SIZE_MIN &&
config->delta_block_size <= DELTA_BLOCK_SIZE_MAX &&
config->delta_max_file_size <= DELTA_MAX_FILE_SIZE && config->modify_window >= 0 &&
config->max_delete >= -1 && config->skip_compress_count >= 0 &&
config->skip_compress_count <= MAX_SKIP_COMPRESS_SUFFIXES && config->max_alloc > 0 &&
(!config->chmod_spec || !*config->chmod_spec ||
chmod_apply(0, config->chmod_spec, &(mode_t){0})) &&
config->super_mode >= SUPER_MODE_AUTO && config->super_mode <= SUPER_MODE_OFF;
}
Config* config_create(void) {
Config* config = malloc(sizeof(Config));
if (!config)
return NULL;
config_set_defaults(config);
return config;
}
bool config_delete_timing_early(const Config* config) {
if (!config)
return false;
return config->delete_before || config->delete_during;
}
/* A delete-timing flag is only meaningful together with --delete. At most one
of the four flags may be set; several simultaneous timings are a client bug
and are rejected on both ends. */
bool config_has_valid_delete_timing(const Config* config) {
if (!config)
return false;
if (!config->use_delete)
return !config->delete_before && !config->delete_during && !config->delete_delay &&
!config->delete_after;
int timing_count = (config->delete_before ? 1 : 0) + (config->delete_during ? 1 : 0) +
(config->delete_delay ? 1 : 0) + (config->delete_after ? 1 : 0);
return timing_count <= 1;
}
/* The cross-field invariants FastSync relies on, in one place. Every message
* here was previously duplicated (verbatim) in client_validation.c and/or
* config.c; the client reports the returned string for UX and the server
* enforces the same rules at its trust boundary. Pure: no I/O, no logging.
* The order is deliberate (most specific structural conflicts first). */
const char* config_invariants_error(const Config* config) {
if (!config)
return "Invalid configuration";
if (config_has_basis(config) && config->use_chunk_serialization)
return "--compare-dest/--copy-dest/--link-dest require per-file incremental checks and cannot "
"be combined with -s (chunk serialization)";
if (config->use_sendfile && (config->use_chunk_serialization || config->use_compression))
return "-f/--sendfile cannot be combined with -c (compression) or -s (chunk serialization)";
if (config->use_incremental && config->use_chunk_serialization)
return "--incremental is not supported with -s (chunk serialization)";
if (config->skip_compress_set && config->use_chunk_serialization)
return "--skip-compress cannot be combined with -s (chunk serialization)";
if (config->use_delta && !config->whole_file && !config->use_incremental)
return "--delta requires --incremental";
if (config->use_delta && !config->whole_file && config->use_chunk_serialization)
return "--delta cannot be combined with -s (chunk serialization)";
if (config->use_delta && !config->whole_file && config->use_sendfile)
return "--delta cannot be combined with -f (sendfile)";
/* --append / --append-verify resume a shorter existing destination by
transmitting only the tail. The resume needs the per-file STATUS_CHECK
handshake (so the dest length is learned), which chunk serialization -s
disables; whole-file is the opposite intent (send everything). */
if ((config->append || config->append_verify) && config->use_chunk_serialization)
return "--append/--append-verify require the per-file incremental check and cannot be "
"combined with -s (chunk serialization)";
if ((config->append || config->append_verify) && config->whole_file)
return "--append/--append-verify are incompatible with --whole-file (which forces a full "
"transfer)";
/* -H transmits each later hard-link group member as a dedicated per-file
STATUS_HARDLINK frame, which -s does not support; and a hard-links sibling
carries no payload, so the tail-resume of --append is meaningless. */
if (config->preserve_hard_links && config->use_chunk_serialization)
return "--hard-links/-H cannot be combined with -s (chunk serialization)";
/* -X/-A ride the per-file metadata frame; the chunk-serialization wire format
does not carry the xattr block. */
if ((config->preserve_xattrs || config->preserve_acls) && config->use_chunk_serialization)
return "--xattrs/-X and --acls/-A cannot be combined with -s (chunk serialization)";
if (config->preserve_hard_links && (config->append || config->append_verify))
return "--hard-links/-H cannot be combined with --append/--append-verify";
if (config->delay_updates && config->inplace)
return "--delay-updates does not work with --inplace";
if (config->delay_updates && delay_updates_staging_name_conflict(config->backup_dir))
return "--backup-dir is reserved when --delay-updates is active (used for the internal "
"staging directory)";
if (!config_has_valid_delete_timing(config))
return "--delete-before/--delete-during/--delete-delay/--delete-after select the delete "
"timing; at most one may be given and each implies --delete";
if (config->iconv_spec && !charset_spec_valid(config->iconv_spec))
return "--iconv requires LOCAL[,REMOTE] charset names supported by iconv";
if ((config->preserve_perms || config->preserve_times || config->preserve_owner ||
config->preserve_group || config->preserve_atimes || config->preserve_crtimes ||
config->use_executability) &&
!config->use_metadata)
return "a preservation attribute requires metadata transmission";
if (config->copy_as_set && !config->use_metadata)
return "--copy-as requires metadata preservation and cannot be combined with --no-preserve";
return NULL;
}
bool config_derived_use_metadata(const Config* config) {
if (!config)
return false;
if (config->preserve_perms || config->preserve_times || config->preserve_owner ||
config->preserve_group || config->preserve_atimes || config->preserve_crtimes ||
config->use_executability || config->preserve_xattrs || config->preserve_acls ||
config->fake_super || config->preserve_devices || config->preserve_specials ||
config->copy_devices || config->write_devices ||
(config->chmod_spec && config->chmod_spec[0]) || config->copy_as_set ||
config->chown_uid_set || config->chown_gid_set || config->usermap_count > 0 ||
config->groupmap_count > 0 || config->update)
return true;
return (config->use_incremental || config->use_delta) && !config->metadata_explicitly_disabled;
}
bool config_has_basis(const Config* config) {
return config && config->basis_count > 0;
}
/* A basis-dir path travels from the client to the receiver and is resolved
* below the destination root, so it must be a non-empty relative path with no
* "." or ".." component and no traversal: an absolute or escaping path would
* make the receiver read or link files outside its authorized root.
*
* Returns a malloc'd CANONICAL copy of an accepted path, or NULL when the path
* is rejected. Canonicalization collapses interior empty components ("a//b" ->
* "a/b"), drops "." components and trailing "/"s, so validation, the delete
* walker prefix match and the receiver's basis lookup all agree on one form.
* The normalizer is the single source of truth for both config_basis_path_valid
* and config_basis_append. */
static char* basis_path_normalize(const char* path) {
if (!path || path[0] == '\0' || path[0] == '/' || has_path_traversal(path))
return NULL;
if (strcmp(path, ".") == 0)
return NULL;
char* dup = str_dup(path);
if (!dup)
return NULL;
size_t out_len = 0;
char* out = malloc(strlen(path) + 1);
if (!out) {
free(dup);
return NULL;
}
char* saveptr = NULL;
bool ok = true;
for (char* part = strtok_r(dup, "/", &saveptr); part; part = strtok_r(NULL, "/", &saveptr)) {
if (strcmp(part, "..") == 0) {
ok = false;
break;
}
if (strcmp(part, ".") == 0)
continue;
if (out_len > 0)
out[out_len++] = '/';
size_t len = strlen(part);
memcpy(out + out_len, part, len);
out_len += len;
}
free(dup);
if (!ok || out_len == 0) {
free(out);
return NULL;
}
out[out_len] = '\0';
return out;
}
bool config_basis_path_valid(const char* path) {
char* normalized = basis_path_normalize(path);
if (!normalized)
return false;
free(normalized);
return true;
}
int config_basis_append(Config* config, BasisDestType type, const char* path) {
if (!config ||
(type != BASIS_DEST_COMPARE && type != BASIS_DEST_COPY && type != BASIS_DEST_LINK) ||
config->basis_count >= MAX_BASIS_DIRS)
return -1;
char* normalized = basis_path_normalize(path);
if (!normalized)
return -1;
BasisDest* grown = realloc(config->basis_dirs, (config->basis_count + 1) * sizeof(BasisDest));
if (!grown) {
free(normalized);
return -1;
}
config->basis_dirs = grown;
config->basis_dirs[config->basis_count].type = type;
config->basis_dirs[config->basis_count].path = normalized;
config->basis_count++;
return 0;
}
/* Strict --sockopts allowlist: map an option NAME to its SockOptId, or -1 when
* the name is not on the allowlist. The list is intentionally closed so an
* unknown option is an error, never a silent no-op. */
static int sockopt_id_from_name(const char* name) {
if (strcmp(name, "TCP_NODELAY") == 0)
return SOCKOPT_TCP_NODELAY;
if (strcmp(name, "SO_KEEPALIVE") == 0)
return SOCKOPT_SO_KEEPALIVE;
if (strcmp(name, "SO_RCVBUF") == 0)
return SOCKOPT_SO_RCVBUF;
if (strcmp(name, "SO_SNDBUF") == 0)
return SOCKOPT_SO_SNDBUF;
if (strcmp(name, "SO_REUSEADDR") == 0)
return SOCKOPT_SO_REUSEADDR;
return -1;
}
static bool sockopt_is_boolean(SockOptId id) {
return id == SOCKOPT_TCP_NODELAY || id == SOCKOPT_SO_KEEPALIVE || id == SOCKOPT_SO_REUSEADDR;
}
/* Parse one SockOptId's value. Booleans accept only 0/1 (a numeric "on" is
* rejected rather than coerced); buffer sizes accept any non-negative int.
* Returns 0 on success, -1 on a bad value. */
static int sockopt_parse_value(SockOptId id, const char* value, int* out) {
if (sockopt_is_boolean(id)) {
if (strcmp(value, "0") == 0) {
*out = 0;
return 0;
}
if (strcmp(value, "1") == 0) {
*out = 1;
return 0;
}
return -1;
}
if (!value || *value == '\0')
return -1;
char* end;
errno = 0;
long v = strtol(value, &end, 10);
if (errno != 0 || *end != '\0' || v < 0 || v > INT_MAX)
return -1;
*out = (int)v;
return 0;
}
int config_sockopts_parse(const char* spec, SockOptEntry** out, int* out_count) {
if (!spec || *spec == '\0' || !out || !out_count)
return -1;
char* copy = str_dup(spec);
if (!copy)
return -1;
int count = 0;
int capacity = 0;
SockOptEntry* entries = NULL;
char* saveptr = NULL;
bool ok = true;
for (const char* token = strtok_r(copy, ",", &saveptr); token != NULL;
token = strtok_r(NULL, ",", &saveptr)) {
if (*token == '\0') {
ok = false; /* empty entry: a stray/trailing comma */
break;
}
char* eq = strchr(token, '=');
if (eq)
*eq = '\0';
int id = sockopt_id_from_name(token);
if (id < 0) {
ok = false; /* unknown option name */
break;
}
int val;
/* rsync's --sockopts are OPT=VAL; a value is required for every option, so
* a bare option name (no '=') is rejected rather than coerced. */
if (eq == NULL || eq[1] == '\0') {
ok = false; /* missing '=' or missing value */
break;
}
if (sockopt_parse_value((SockOptId)id, eq + 1, &val) != 0) {
ok = false; /* bad value for an allowed option */
break;
}
if (count == capacity) {
int new_cap = capacity == 0 ? 4 : capacity * 2;
SockOptEntry* grown = realloc(entries, (size_t)new_cap * sizeof(SockOptEntry));
if (!grown) {
ok = false;
break;
}
entries = grown;
capacity = new_cap;
}
entries[count].id = (SockOptId)id;
entries[count].value = val;
count++;
}
free(copy);
if (!ok) {
free(entries);
return -1;
}
*out = entries;
*out_count = count;
return 0;
}
bool config_is_remote_dest(const char* s) {
if (s == NULL)
return false;
const char* colon = strchr(s, ':');
if (colon == NULL)
return false;
if (colon == s)
return false;
for (const char* p = s; p < colon; p++) {
if (*p == '/')
return false;
}
return true;
}
/* Daemon destination detection: rsync's host::module[/path] marker is a "::"
* immediately after the host part (the first ':' is immediately followed by a
* second ':'), with no '/' before it. A single ':' (host:path) stays the SSH
* form even when the path itself later contains colons, and a "[::1]"-style
* bracketed IPv6 literal is not recognized as a daemon destination this wave
* (its first "::" is inside the brackets). */
bool config_is_daemon_dest(const char* s) {
if (s == NULL)
return false;
const char* colon = strchr(s, ':');
if (colon == NULL || colon == s || colon[1] != ':')
return false;
for (const char* p = s; p < colon; p++) {
if (*p == '/')
return false;
}
return true;
}
/* Log an escaped message with an 8-bit-safe output policy and return -1 (the
* caller-visible parse failure code). */
static int daemon_dest_parse_error(const char* message, const char* detail) {
char* escaped = output_escape(detail ? detail : "", false);
log_message(LOG_LEVEL_ERROR, "%s: %s", message, escaped ? escaped : "<allocation failed>");
free(escaped);
return -1;
}
int config_parse_daemon_dest(Config* config) {
if (!config || !config->receive_root_directory)
return 0;
const char* dest = config->receive_root_directory;
if (!config_is_daemon_dest(dest))
return 0;
const char* colon = strchr(dest, ':');
/* user@host::module names a daemon auth user. FastSync takes the username
* from the --password-file (its first user:password line) so there is a
* single source of truth; an @user that could contradict it is rejected
* with a pointer to the supported form. */
if (memchr(dest, '@', (size_t)(colon - dest)) != NULL)
return daemon_dest_parse_error(
"daemon destination user@host::module is not supported: supply the username with "
"--password-file (first line: user:password)",
dest);
const char* host_start = dest;
const char* module_and_path = colon + 2;
if (*module_and_path == '\0')
return daemon_dest_parse_error("daemon destination is missing its module name", dest);
const char* slash = strchr(module_and_path, '/');
size_t module_len = slash ? (size_t)(slash - module_and_path) : strlen(module_and_path);
char* module = malloc(module_len + 1);
if (!module)
return daemon_dest_parse_error("out of memory parsing daemon destination", dest);
memcpy(module, module_and_path, module_len);
module[module_len] = '\0';
if (!daemon_module_name_valid(module)) {
free(module);
return daemon_dest_parse_error(
"invalid daemon module name (must be 1-200 chars of [A-Za-z0-9._-])", dest);
}
const char* path = slash ? slash + 1 : "";
while (*path == '/')
path++; /* normalize "mod//a" to "mod/a"; keeps path module-relative */
if (has_path_traversal(path)) {
free(module);
return daemon_dest_parse_error("daemon destination path must not contain '..'", dest);
}
size_t host_len = (size_t)(colon - host_start);
char* host = malloc(host_len + 1);
if (!host) {
free(module);
return daemon_dest_parse_error("out of memory parsing daemon destination", dest);
}
memcpy(host, host_start, host_len);
host[host_len] = '\0';
if (*host == '\0') {
free(host);
free(module);
return daemon_dest_parse_error("daemon destination has no host", dest);
}
char* path_dup = str_dup(path);
if (!path_dup) {
free(host);
free(module);
return daemon_dest_parse_error("out of memory parsing daemon destination", dest);
}
free(config->server_host);
config->server_host = host;
free(config->module);
config->module = module;
free(config->receive_root_directory);
config->receive_root_directory = path_dup;
config->transport = TRANSPORT_TCP;
return 1;
}
int config_parse_transport_dest(Config* config) {
if (!config || !config->receive_root_directory)
return 0;
/* Daemon (host::module[/path]) first: the single-colon SSH parser would
* otherwise mis-split the double colon. Returns 1 (parsed as daemon), 0
* (not daemon syntax -> try SSH below), or -1 (invalid daemon destination,
* already logged). */
int daemon_ret = config_parse_daemon_dest(config);
if (daemon_ret != 0)
return daemon_ret;
/* 0 for a local destination (nothing parsed) or a valid SSH destination;
* -1 (already logged) for an injection-shaped user@host. */
return config_parse_ssh_dest(config);
}
int config_parse_ssh_dest(Config* config) {
if (!config || !config->receive_root_directory)
return 0;
if (!config_is_remote_dest(config->receive_root_directory))
return 0;
const char* dest = config->receive_root_directory;
const char* colon = strchr(dest, ':');
/* The user@host token is passed to ssh in option position, so a user or host
* beginning with '-' would be consumed by ssh as an option (argument
* injection: e.g. "-oProxyCommand=..."). An empty host is likewise not a
* valid destination. Validate before any wire/argv construction. */
const char* at = memchr(dest, '@', (size_t)(colon - dest));
const char* host = at ? at + 1 : dest;
size_t host_len = (size_t)(colon - host);
size_t user_len = at ? (size_t)(at - dest) : 0;
if (host_len == 0 || host[0] == '-' || (user_len > 0 && dest[0] == '-'))
return daemon_dest_parse_error("invalid remote destination user@host (must not be empty or "
"start with '-')",
dest);
config->transport = TRANSPORT_SSH;
config->ssh_destination = str_dup(dest);
char* path = str_dup(colon + 1);
free(config->receive_root_directory);
config->receive_root_directory = path;
return 0;
}
void config_burn_auth(Config* config) {
if (!config)
return;
if (config->auth_password) {
credentials_burn(config->auth_password, strlen(config->auth_password));
free(config->auth_password);
config->auth_password = NULL;
}
if (config->auth_user) {
free(config->auth_user);
config->auth_user = NULL;
}
}
void config_delete(Config* config) {
if (config == NULL)
return;
if (config->log_file) {
/* The logging subsystem borrows this FILE*; detach it before closing so a
* concurrent log call can never touch the freed handle. */
log_set_file(NULL);
fclose(config->log_file);
config->log_file = NULL;
}
free(config->version);
free(config->send_directory);
free(config->receive_root_directory);
free(config->ssh_destination);
free(config->module);
config_burn_auth(config);
free(config->password_file);
free(config->iconv_spec);
free(config->write_batch);
free(config->only_write_batch);
free(config->read_batch);
free(config->fastsync_server_path);
for (int i = 0; i < config->exclude_count; i++)
free(config->exclude_patterns[i]);
free(config->exclude_patterns);
for (int i = 0; i < config->include_count; i++)
free(config->include_patterns[i]);
free(config->include_patterns);
free(config->tls_cert);
free(config->tls_key);
free(config->tls_ca);
free(config->backup_dir);
free(config->server_host);
free(config->out_format);
free(config->log_file_format);
free(config->files_from);
file_list_destroy((FileListSet*)config->files_from_set);
free(config->rsh_command);
free(config->temp_dir);
if (config->remote_options) {
for (int i = 0; i < config->remote_option_count; i++)
free(config->remote_options[i]);
free(config->remote_options);
}
config->remote_options = NULL;
config->remote_option_count = 0;
if (config->basis_dirs) {
for (int i = 0; i < config->basis_count; i++) {
free(config->basis_dirs[i].path);
config->basis_dirs[i].path = NULL;
}
free(config->basis_dirs);
}
config->basis_dirs = NULL;
config->basis_count = 0;
free(config->partial_dir);
free(config->suffix);
free(config->address);
free(config->sockopts);
free(config->compress_choice);
free(config->chmod_spec);
if (config->skip_compress_suffixes) {
for (int i = 0; i < config->skip_compress_count; i++)
free(config->skip_compress_suffixes[i]);
free(config->skip_compress_suffixes);
}
if (config->usermap) {
for (int i = 0; i < config->usermap_count; i++)
free(config->usermap[i].to_name);
free(config->usermap);
}
config->usermap = NULL;
config->usermap_count = 0;
if (config->groupmap) {
for (int i = 0; i < config->groupmap_count; i++)
free(config->groupmap[i].to_name);
free(config->groupmap);
}
config->groupmap = NULL;
config->groupmap_count = 0;
if (config->filters) {
array_list_delete(config->filters);
}
/* A --delay-updates staging tree is transient receiver state: remove any
leftovers on every exit path (success already emptied it). */
if (config->delay_context)
delay_updates_cleanup(config->delay_context);
delay_updates_context_destroy(config->delay_context);
config->delay_context = NULL;
free(config);
}
/* ---------------------------------------------------------------------------
* Wire codec helpers.
*
* The CONFIG_WIRE_*_FIELDS tables in config.h drive the send/receive
* sequences below. Each field's KIND names a CONFIG_SEND_<KIND> /
* CONFIG_RECV_<KIND> macro (defined after the helpers) that expands to the
* exact primitive call the previous hand-written code used, so the byte
* stream is unchanged. Fields whose per-field logic is not a plain scalar
* (bounded enums, redacted auth, repeated count+array blocks) delegate to a
* dedicated helper here.
* ------------------------------------------------------------------------- */
/* --max-alloc: raw 64-bit value, clamped server-side and installed as the
* session allocation ceiling. A zero value is rejected. */
static bool config_receive_max_alloc(int fd, unsigned long long* value) {
if (!receive_n_data(fd, value, sizeof(*value)) || *value == 0)
return false;
if (*value > MAX_SERVER_ALLOC)
*value = MAX_SERVER_ALLOC;
protocol_session_set_max_alloc(NULL, *value);
return true;
}
/* Optional string: the sender serializes an unset (NULL) string as "", so the
* receiver canonicalizes the empty wire value back to NULL to preserve
* NULL-vs-empty semantics. */
static bool config_receive_optional_str(int fd, ConfigStringBudget* budget, char** out) {
char* value = config_receive_str(fd, budget);
if (!value)
return false;
if (*value == '\0') {
free(value);
*out = NULL;
return true;
}
*out = value;
return true;
}
/* Daemon module name (Wave A, protocol 2.15.0): an unset module is "" (-> NULL
* on receive). A hostile over-long/invalid name is rejected with an explicit
* STATUS_ERROR rather than logged and accepted. */
static bool config_receive_module(int fd, Config* c, ConfigStringBudget* budget) {
char* module = config_receive_str(fd, budget);
if (!module)
return false;
if (*module != '\0' && !daemon_module_name_valid(module)) {
log_message(LOG_LEVEL_WARNING, "Daemon client sent an invalid or over-long module name");
send_error_detail(fd, "invalid or over-long daemon module name");
free(module);
return false;
}
if (*module != '\0') {
c->module = module;
} else {
free(module);
}
return true;
}
/* Daemon auth username (A7 remediation, protocol 2.19.0): a presence int is
* followed, when set, by ONLY the redacted username; the password is never
* serialized. */
static bool config_receive_auth_user(int fd, Config* c, ConfigStringBudget* budget) {
int present;
if (!receive_int(fd, &present) || !valid_wire_bool(present))
return false;
if (!present)
return true;
char* user = config_receive_str_redacted(fd, budget);
if (!user)
return false;
if (!credentials_username_valid(user)) {
free(user);
log_message(LOG_LEVEL_WARNING, "Daemon client sent malformed auth credentials");
return false;
}
c->auth_user = user;
return true;
}
static bool config_send_auth_user(int fd, const Config* c) {
bool present = c->auth_user != NULL && c->auth_user[0] != '\0';
if (!send_int(fd, present ? 1 : 0))
return false;
if (!present)
return true;
/* Redacted send: the username must never reach a --verbose debug log. */
return send_str_redacted(fd, c->auth_user);
}
static bool config_receive_checksum_algo(int fd, int* value) {
int algo;
if (!receive_int(fd, &algo) || !checksum_algo_valid(algo))
return false;
*value = algo;
return true;
}
static bool config_receive_super_mode(int fd, SuperMode* value) {
int mode;
if (!receive_int(fd, &mode) || mode < SUPER_MODE_AUTO || mode > SUPER_MODE_OFF)
return false;
*value = (SuperMode)mode;
return true;
}
/* chown override ids: IDENTITY_MATCH_ANY (-1) is the lowest legal value. */
static bool config_receive_identity_id(int fd, int32_t* value) {
int v;
if (!receive_int(fd, &v) || v < IDENTITY_MATCH_ANY)
return false;
*value = v;
return true;
}
/* Read a peer-controlled count into a LOCAL, validate the range, and only then
* publish it through `*value`. Writing through `*value` before validating
* leaves the Config holding an over-cap count (e.g. 999999999) whose backing
* array is still NULL; the receive error path then runs config_delete(), which
* walks the array and dereferences NULL. Leaving `*value` untouched on failure
* also keeps the failed Config in a coherent, safely-deletable state. */
static bool config_receive_skip_count(int fd, int* value) {
int v;
if (!receive_int(fd, &v) || v < 0 || v > MAX_SKIP_COMPRESS_SUFFIXES)
return false;
*value = v;
return true;
}
static bool config_receive_basis_count(int fd, int* value) {
int v;
if (!receive_int(fd, &v) || v < 0 || v > MAX_BASIS_DIRS)
return false;
*value = v;
return true;
}
static bool config_receive_idmap_count(int fd, int* value) {
int v;
if (!receive_int(fd, &v) || v < 0 || v > MAX_IDENTITY_MAP)
return false;
*value = v;
return true;
}
static bool config_receive_copy_as_presence(int fd, bool* value) {
int present;
if (!receive_int(fd, &present) || !valid_wire_bool(present))
return false;
*value = present != 0;
return true;
}
/* --copy-as ids are forced onto the ownership path, so a hostile peer must not
* smuggle a negative sentinel. */
static bool config_receive_copy_as_id(int fd, int32_t* value) {
int v;
if (!receive_int(fd, &v) || v < 0)
return false;
*value = v;
return true;
}
static bool send_skip_compress_suffixes(int fd, const Config* c) {
for (int i = 0; i < c->skip_compress_count; i++) {
if (!send_str(fd, c->skip_compress_suffixes[i]))
return false;
}
return true;
}
static bool receive_skip_compress_suffixes(int fd, Config* c, ConfigStringBudget* budget) {
if (c->skip_compress_count <= 0)
return true;
c->skip_compress_suffixes = calloc((size_t)c->skip_compress_count, sizeof(char*));
if (!c->skip_compress_suffixes)
return false;
for (int i = 0; i < c->skip_compress_count; i++) {
c->skip_compress_suffixes[i] = config_receive_str(fd, budget);
if (!c->skip_compress_suffixes[i])
return false;
}
return true;
}
static bool send_basis_entries(int fd, const Config* c) {
for (int i = 0; i < c->basis_count; i++) {
if (!send_int(fd, (int)c->basis_dirs[i].type) ||
!send_str(fd, c->basis_dirs[i].path ? c->basis_dirs[i].path : ""))
return false;
}
return true;
}
static bool receive_basis_entries(int fd, Config* c, ConfigStringBudget* budget) {
/* The count was read by the preceding INT_BASISCOUNT entry; config_basis_append
* rebuilds basis_count as it validates and canonicalizes each path. */
int count = c->basis_count;
c->basis_count = 0;
for (int i = 0; i < count; i++) {
int type;
if (!receive_int(fd, &type) || type <= BASIS_DEST_NONE || type > BASIS_DEST_LINK)
return false;
char* path = config_receive_str(fd, budget);
if (!path)
return false;
bool ok = config_basis_append(c, (BasisDestType)type, path) == 0;
free(path);
if (!ok)
return false;
}
return true;
}
static bool send_identity_entries(int fd, const IdentityMap* map, int count) {
for (int i = 0; i < count; i++) {
if (!send_int(fd, map[i].from) || !send_int(fd, map[i].from_hi) || !send_int(fd, map[i].to) ||
!send_str(fd, map[i].to_name ? map[i].to_name : ""))
return false;
}
return true;
}
static bool receive_identity_entries(int fd, ConfigStringBudget* budget, int count,
IdentityMap** out) {
if (count <= 0)
return true;
IdentityMap* map = calloc((size_t)count, sizeof(IdentityMap));
if (!map)
return false;
for (int i = 0; i < count; i++) {
if (!receive_int(fd, &map[i].from) || !receive_int(fd, &map[i].from_hi) ||
!receive_int(fd, &map[i].to))
goto fail;
char* name = config_receive_str(fd, budget);
if (!name)
goto fail;
if (name[0] == '\0') {
free(name);
map[i].to_name = NULL;
} else {
map[i].to_name = name;
}
}
*out = map;
return true;
fail:
for (int i = 0; i < count; i++)
free(map[i].to_name);
free(map);
return false;
}
/* ---------------------------------------------------------------------------
* KIND dispatch. A table entry X(member, ctype, def, KIND) expands to
* CONFIG_SEND_<KIND>(member) in a sender and CONFIG_RECV_<KIND>(member) in a
* receiver. Send macros are bool expressions; receive macros are bool
* expressions too (strings allocate through `budget`).
* ------------------------------------------------------------------------- */
#define CONFIG_SEND_BOOL(name) send_int(fd, c->name)
#define CONFIG_RECV_BOOL(name) receive_wire_bool(fd, &c->name)
#define CONFIG_SEND_INT(name) send_int(fd, c->name)
#define CONFIG_RECV_INT(name) receive_int(fd, &c->name)
#define CONFIG_SEND_RAW(name) send_n_data(fd, &c->name, sizeof(c->name))
#define CONFIG_RECV_RAW(name) receive_n_data(fd, &c->name, sizeof(c->name))
#define CONFIG_SEND_BOOL_8BIT(name) \
(send_int(fd, c->name) && (protocol_set_8_bit_output(c->name), true))
#define CONFIG_RECV_BOOL_8BIT(name) \
(receive_wire_bool(fd, &c->name) && (protocol_set_8_bit_output(c->name), true))
#define CONFIG_SEND_RAW_MAXALLOC(name) send_n_data(fd, &c->name, sizeof(c->name))
#define CONFIG_RECV_RAW_MAXALLOC(name) config_receive_max_alloc(fd, &c->name)
/* --delta is sent as (use_delta && !whole_file); whole_file never crosses the
* wire, so the receiver observes the effective bit. */
#define CONFIG_SEND_DERIVED_DELTA(name) send_int(fd, c->name && !c->whole_file)
#define CONFIG_RECV_DERIVED_DELTA(name) receive_wire_bool(fd, &c->name)
#define CONFIG_SEND_STR(name) send_str(fd, c->name)
#define CONFIG_RECV_STR(name) ((c->name = config_receive_str(fd, budget)) != NULL)
#define CONFIG_SEND_STR_OPT(name) send_str(fd, c->name ? c->name : "")
#define CONFIG_RECV_STR_OPT(name) config_receive_optional_str(fd, budget, &c->name)
#define CONFIG_SEND_STR_KEEP(name) send_str(fd, c->name ? c->name : "")
#define CONFIG_RECV_STR_KEEP(name) ((c->name = config_receive_str(fd, budget)) != NULL)
#define CONFIG_SEND_STR_MODULE(name) send_str(fd, c->name ? c->name : "")
#define CONFIG_RECV_STR_MODULE(name) config_receive_module(fd, c, budget)
#define CONFIG_SEND_STR_REDACTED_AUTH(name) config_send_auth_user(fd, c)
#define CONFIG_RECV_STR_REDACTED_AUTH(name) config_receive_auth_user(fd, c, budget)
#define CONFIG_SEND_INT_CHECKSUM_ALGO(name) send_int(fd, c->name)
#define CONFIG_RECV_INT_CHECKSUM_ALGO(name) config_receive_checksum_algo(fd, &c->name)
#define CONFIG_SEND_SUPERMODE(name) send_int(fd, (int)c->name)
#define CONFIG_RECV_SUPERMODE(name) config_receive_super_mode(fd, &c->name)
#define CONFIG_SEND_INT_IDENTITY(name) send_int(fd, c->name)
#define CONFIG_RECV_INT_IDENTITY(name) config_receive_identity_id(fd, &c->name)
#define CONFIG_SEND_INT_SKIPCOUNT(name) send_int(fd, c->name)
#define CONFIG_RECV_INT_SKIPCOUNT(name) config_receive_skip_count(fd, &c->name)
#define CONFIG_SEND_INT_BASISCOUNT(name) send_int(fd, c->name)
#define CONFIG_RECV_INT_BASISCOUNT(name) config_receive_basis_count(fd, &c->name)
#define CONFIG_SEND_INT_IDMAPCOUNT(name) send_int(fd, c->name)
#define CONFIG_RECV_INT_IDMAPCOUNT(name) config_receive_idmap_count(fd, &c->name)
/* use_xattrs is derived receiver-side from the xattr/acl preservation flags
* that crossed the wire in the file-options block. */
#define CONFIG_SEND_BOOL_XATTR_DERIVE(name) send_int(fd, c->name)
#define CONFIG_RECV_BOOL_XATTR_DERIVE(name) \
(receive_wire_bool(fd, &c->name) && \
(c->use_xattrs = (c->preserve_acls || c->preserve_xattrs), true))
#define CONFIG_SEND_COPY_AS_PRESENCE(name) send_int(fd, c->name ? 1 : 0)
#define CONFIG_RECV_COPY_AS_PRESENCE(name) config_receive_copy_as_presence(fd, &c->name)
/* The uid/gid follow the presence int only when --copy-as is set. */
#define CONFIG_SEND_COPY_AS_ID(name) (!c->copy_as_set || send_int(fd, c->name))
#define CONFIG_RECV_COPY_AS_ID(name) (!c->copy_as_set || config_receive_copy_as_id(fd, &c->name))
#define CONFIG_SEND_BLOCK_SKIP_SUFFIXES(name) send_skip_compress_suffixes(fd, c)
#define CONFIG_RECV_BLOCK_SKIP_SUFFIXES(name) receive_skip_compress_suffixes(fd, c, budget)
#define CONFIG_SEND_BLOCK_BASIS(name) send_basis_entries(fd, c)
#define CONFIG_RECV_BLOCK_BASIS(name) receive_basis_entries(fd, c, budget)
#define CONFIG_SEND_BLOCK_IDMAP(name) send_identity_entries(fd, c->name, c->name##_count)
#define CONFIG_RECV_BLOCK_IDMAP(name) \
receive_identity_entries(fd, budget, c->name##_count, &c->name)
/* One table entry, applied in sequence. XSEND/XRECV are statement macros so
* consecutive entries read as a plain sequence of assignments. */
#define XSEND(name, ctype, def, kind) ok = ok && (CONFIG_SEND_##kind(name));
#define XRECV(name, ctype, def, kind) ok = ok && (CONFIG_RECV_##kind(name));
#define CONFIG_DEFINE_SEND(fn, fields) \
static bool fn(int fd, const Config* c) { \
bool ok = true; \
fields(XSEND) return ok; \
}
#define CONFIG_DEFINE_RECV(fn, fields) \
static bool fn(int fd, Config* c, ConfigStringBudget* budget) { \
(void)budget; \
bool ok = true; \
fields(XRECV) return ok; \
}
CONFIG_DEFINE_SEND(send_core_fields, CONFIG_WIRE_CORE_FIELDS)
CONFIG_DEFINE_SEND(send_delta_fields, CONFIG_WIRE_DELTA_FIELDS)
CONFIG_DEFINE_SEND(send_file_options, CONFIG_WIRE_FILE_OPTIONS_FIELDS)
CONFIG_DEFINE_SEND(send_selection_options, CONFIG_WIRE_SELECTION_FIELDS)
CONFIG_DEFINE_SEND(send_resume_options, CONFIG_WIRE_RESUME_FIELDS)
CONFIG_DEFINE_SEND(send_basis_options, CONFIG_WIRE_BASIS_FIELDS)
CONFIG_DEFINE_SEND(send_fuzzy_option, CONFIG_WIRE_FUZZY_FIELDS)
CONFIG_DEFINE_SEND(send_checksum_options, CONFIG_WIRE_CHECKSUM_FIELDS)
CONFIG_DEFINE_SEND(send_identity_options, CONFIG_WIRE_IDENTITY_FIELDS)
CONFIG_DEFINE_SEND(send_metadata_times_options, CONFIG_WIRE_METADATA_TIMES_FIELDS)
CONFIG_DEFINE_SEND(send_symlink_trust_options, CONFIG_WIRE_SYMLINK_TRUST_FIELDS)
CONFIG_DEFINE_SEND(send_phase4_xattr_options, CONFIG_WIRE_XATTR_FIELDS)
CONFIG_DEFINE_SEND(send_daemon_module, CONFIG_WIRE_MODULE_FIELDS)
CONFIG_DEFINE_SEND(send_daemon_auth, CONFIG_WIRE_DAEMON_AUTH_FIELDS)
CONFIG_DEFINE_SEND(send_iconv_spec, CONFIG_WIRE_ICONV_FIELDS)
CONFIG_DEFINE_SEND(send_privilege_options, CONFIG_WIRE_PRIVILEGE_FIELDS)
CONFIG_DEFINE_SEND(send_copy_as_options, CONFIG_WIRE_COPY_AS_FIELDS)
CONFIG_DEFINE_RECV(receive_core_fields, CONFIG_WIRE_CORE_FIELDS)
CONFIG_DEFINE_RECV(receive_delta_fields, CONFIG_WIRE_DELTA_FIELDS)
CONFIG_DEFINE_RECV(receive_file_options, CONFIG_WIRE_FILE_OPTIONS_FIELDS)
CONFIG_DEFINE_RECV(receive_selection_options, CONFIG_WIRE_SELECTION_FIELDS)
CONFIG_DEFINE_RECV(receive_resume_options, CONFIG_WIRE_RESUME_FIELDS)
CONFIG_DEFINE_RECV(receive_basis_options, CONFIG_WIRE_BASIS_FIELDS)
CONFIG_DEFINE_RECV(receive_fuzzy_option, CONFIG_WIRE_FUZZY_FIELDS)
CONFIG_DEFINE_RECV(receive_checksum_options, CONFIG_WIRE_CHECKSUM_FIELDS)
CONFIG_DEFINE_RECV(receive_identity_options, CONFIG_WIRE_IDENTITY_FIELDS)
CONFIG_DEFINE_RECV(receive_metadata_times_options, CONFIG_WIRE_METADATA_TIMES_FIELDS)
CONFIG_DEFINE_RECV(receive_symlink_trust_options, CONFIG_WIRE_SYMLINK_TRUST_FIELDS)
CONFIG_DEFINE_RECV(receive_phase4_xattr_options, CONFIG_WIRE_XATTR_FIELDS)
CONFIG_DEFINE_RECV(receive_daemon_module, CONFIG_WIRE_MODULE_FIELDS)
CONFIG_DEFINE_RECV(receive_daemon_auth, CONFIG_WIRE_DAEMON_AUTH_FIELDS)
CONFIG_DEFINE_RECV(receive_iconv_spec, CONFIG_WIRE_ICONV_FIELDS)
CONFIG_DEFINE_RECV(receive_privilege_options, CONFIG_WIRE_PRIVILEGE_FIELDS)
CONFIG_DEFINE_RECV(receive_copy_as_options, CONFIG_WIRE_COPY_AS_FIELDS)
#undef XSEND
#undef XRECV
/* Client half of the SCRAM challenge/response (A7 remediation). Called by
* config_send after the config frame is written and the server answered
* STATUS_AUTH_CHALLENGE. The plaintext password lives only in
* config->auth_password and every derived buffer is wiped on the way out. */
static bool client_auth_exchange(int fd, const Config* c) {
if (!c->auth_user || !c->auth_password)
return false;
int iters = 0;
if (!receive_int(fd, &iters))
return false;
if (iters < (int)CREDENTIAL_MIN_ITERS || iters > (int)CREDENTIAL_MAX_ITERS) {
log_message(LOG_LEVEL_ERROR, "Daemon sent an out-of-range auth iteration count");
return false;
}
char* salt_b64 = receive_str(fd);
char* snonce_b64 = receive_str(fd);
uint8_t salt[CREDENTIAL_SALT_LEN];
uint8_t snonce[CREDENTIAL_NONCE_LEN];
uint8_t cnonce[CREDENTIAL_NONCE_LEN];
size_t salt_len = 0;
size_t snonce_len = 0;
bool ok = salt_b64 && snonce_b64 &&
credentials_b64_decode(salt_b64, salt, sizeof(salt), &salt_len) &&
salt_len == CREDENTIAL_SALT_LEN &&
credentials_b64_decode(snonce_b64, snonce, sizeof(snonce), &snonce_len) &&
snonce_len == CREDENTIAL_NONCE_LEN && credentials_random_bytes(cnonce, sizeof(cnonce));
credentials_burn(salt_b64, salt_b64 ? strlen(salt_b64) : 0);
credentials_burn(snonce_b64, snonce_b64 ? strlen(snonce_b64) : 0);
free(salt_b64);
free(snonce_b64);
if (!ok) {
log_message(LOG_LEVEL_ERROR, "Daemon sent a malformed auth challenge");
return false;
}
uint8_t client_key[CREDENTIAL_KEY_LEN];
uint8_t stored_key[CREDENTIAL_KEY_LEN];
uint8_t server_key[CREDENTIAL_KEY_LEN];
uint8_t auth_msg[CREDENTIAL_AUTH_MESSAGE_MAX];
size_t msg_len = 0;
uint8_t proof[CREDENTIAL_KEY_LEN];
uint8_t expected_sig[CREDENTIAL_KEY_LEN];
ok = credentials_compute_keys(c->auth_password, salt, (uint32_t)iters, client_key, stored_key,
server_key) &&
credentials_build_auth_message(c->auth_user, snonce, cnonce, auth_msg, sizeof(auth_msg),
&msg_len) &&
credentials_client_proof(client_key, stored_key, server_key, auth_msg, msg_len, proof,
expected_sig);
char cnonce_b64[45];
char proof_b64[45];
if (ok)
ok = credentials_b64_encode(cnonce, sizeof(cnonce), cnonce_b64, sizeof(cnonce_b64)) &&
credentials_b64_encode(proof, sizeof(proof), proof_b64, sizeof(proof_b64));
if (!ok) {
log_message(LOG_LEVEL_ERROR, "Failed to compute the daemon auth response");
} else {
ok = send_status(fd, STATUS_AUTH_RESPONSE) && send_str_redacted(fd, cnonce_b64) &&
send_str_redacted(fd, proof_b64);
}
if (ok) {
Status status = STATUS_ERROR;
char* sig_b64 = NULL;
uint8_t sig[CREDENTIAL_KEY_LEN];
size_t sig_len = 0;
ok = receive_status(fd, &status) && status == STATUS_AUTH_OK &&
(sig_b64 = receive_str_redacted(fd)) != NULL &&
credentials_b64_decode(sig_b64, sig, sizeof(sig), &sig_len) &&
sig_len == CREDENTIAL_KEY_LEN &&
credentials_secure_equal((const char*)sig, (const char*)expected_sig, CREDENTIAL_KEY_LEN);
if (!ok)
log_message(LOG_LEVEL_ERROR, "Daemon authentication failed");
credentials_burn(sig_b64, sig_b64 ? strlen(sig_b64) : 0);
credentials_burn((char*)sig, sizeof(sig));
free(sig_b64);
}
credentials_burn((char*)client_key, sizeof(client_key));
credentials_burn((char*)stored_key, sizeof(stored_key));
credentials_burn((char*)server_key, sizeof(server_key));
credentials_burn((char*)auth_msg, sizeof(auth_msg));
credentials_burn((char*)proof, sizeof(proof));
credentials_burn((char*)expected_sig, sizeof(expected_sig));
credentials_burn((char*)salt, sizeof(salt));
credentials_burn((char*)snonce, sizeof(snonce));
credentials_burn((char*)cnonce, sizeof(cnonce));
credentials_burn(cnonce_b64, sizeof(cnonce_b64));
credentials_burn(proof_b64, sizeof(proof_b64));
return ok;
}
/* The --iconv, --super/--no-super and --copy-as segment functions are
* generated above from CONFIG_WIRE_ICONV_FIELDS, CONFIG_WIRE_PRIVILEGE_FIELDS
* and CONFIG_WIRE_COPY_AS_FIELDS. */
bool config_send_wire_block(int file_descriptor, const Config* config) {
protocol_session_set_max_alloc(NULL, config->max_alloc);
/* The version is the frame header: the receiver validates it before parsing
* any other field (see config_receive_with_validate), so it is not part of
* the generated segment sequence. It is still declared once, in
* CONFIG_WIRE_HEADER_FIELDS. */
return send_str(file_descriptor, config->version) && send_core_fields(file_descriptor, config) &&
send_delta_fields(file_descriptor, config) && send_file_options(file_descriptor, config) &&
send_selection_options(file_descriptor, config) &&
send_resume_options(file_descriptor, config) &&
send_basis_options(file_descriptor, config) &&
send_fuzzy_option(file_descriptor, config) &&
send_checksum_options(file_descriptor, config) &&
send_identity_options(file_descriptor, config) &&
send_metadata_times_options(file_descriptor, config) &&
send_symlink_trust_options(file_descriptor, config) &&
send_phase4_xattr_options(file_descriptor, config) &&
send_daemon_module(file_descriptor, config) && send_daemon_auth(file_descriptor, config) &&
send_iconv_spec(file_descriptor, config) &&
send_privilege_options(file_descriptor, config) &&
send_copy_as_options(file_descriptor, config);
}
bool config_send(int file_descriptor, const Config* config) {
if (!config_send_wire_block(file_descriptor, config))
return false;
Status status;
if (!receive_status(file_descriptor, &status))
return false;
if (status == STATUS_AUTH_CHALLENGE) {
/* Daemon auth (protocol 2.19.0): run the SCRAM exchange, then wait for the
* ordinary STATUS_OK the server sends once authentication succeeded. */
if (!client_auth_exchange(file_descriptor, config))
return false;
if (!receive_status(file_descriptor, &status))
return false;
}
if (status != STATUS_OK) {
const char* detail = protocol_last_error();
if (detail && detail[0] != '\0') {
/* The detail is peer-controlled: escape it before logging. */
char* escaped = output_escape(detail, log_get_8_bit_output());
log_message(LOG_LEVEL_ERROR, "Error transmitting config: %s",
escaped ? escaped : "<allocation failed>");
free(escaped);
} else {
log_message(LOG_LEVEL_ERROR, "Error transmitting config");
}
return false;
}
return true;
}
Config* config_receive_with_validate(int file_descriptor, ConfigValidateFunc validate,
void* context) {
Config* config = config_create();
if (!config)
return NULL;
ConfigStringBudget budget = {0};
free(config->version);
config->version = config_receive_str(file_descriptor, &budget);
if (!config->version)
goto error;
if (strcmp(config->version, PROTOCOL_VERSION) != 0) {
char* escaped_version = output_escape(config->version, false);
log_message(LOG_LEVEL_ERROR, "Protocol version mismatch: client=%s, server=%s",
escaped_version ? escaped_version : "<allocation failed>", PROTOCOL_VERSION);
char detail[160];
snprintf(detail, sizeof(detail), "protocol version mismatch (client=%s, server=%s)",
escaped_version ? escaped_version : "<allocation failed>", PROTOCOL_VERSION);
send_error_detail(file_descriptor, detail);
free(escaped_version);
goto error;
}
if (!receive_core_fields(file_descriptor, config, &budget) ||
!receive_delta_fields(file_descriptor, config, &budget) ||
!receive_file_options(file_descriptor, config, &budget) ||
!receive_selection_options(file_descriptor, config, &budget) ||
!receive_resume_options(file_descriptor, config, &budget) ||
!receive_basis_options(file_descriptor, config, &budget) ||
!receive_fuzzy_option(file_descriptor, config, &budget) ||
!receive_checksum_options(file_descriptor, config, &budget) ||
!receive_identity_options(file_descriptor, config, &budget) ||
!receive_metadata_times_options(file_descriptor, config, &budget) ||
!receive_symlink_trust_options(file_descriptor, config, &budget) ||
!receive_phase4_xattr_options(file_descriptor, config, &budget) ||
!receive_daemon_module(file_descriptor, config, &budget) ||
!receive_daemon_auth(file_descriptor, config, &budget) ||
!receive_iconv_spec(file_descriptor, config, &budget) ||
!receive_privilege_options(file_descriptor, config, &budget) ||
!receive_copy_as_options(file_descriptor, config, &budget))
goto error;
if (config->compress_choice[0] != '\0' && strcmp(config->compress_choice, "zstd") != 0 &&
strcmp(config->compress_choice, "none") != 0) {
char* escaped_choice = output_escape(config->compress_choice, config->eight_bit_output);
log_message(LOG_LEVEL_ERROR, "Unsupported compression choice: %s",
escaped_choice ? escaped_choice : "<allocation failed>");
char detail[128];
snprintf(detail, sizeof(detail), "unsupported compression choice: %s",
escaped_choice ? escaped_choice : "<allocation failed>");
send_error_detail(file_descriptor, detail);
free(escaped_choice);
goto error;
}
if (!validate_received_config(config)) {
log_message(LOG_LEVEL_ERROR, "Invalid configuration received from client");
send_error_detail(file_descriptor, "invalid configuration received from client");
goto error;
}
if (validate) {
const char* rejection = validate(config, context);
if (rejection != NULL) {
/* Daemon module gate (unknown module / read-only module / auth-required
* module): refuse BEFORE the STATUS_OK so the client aborts at the
* config handshake and no file data is ever exchanged. The auth
* handshake already sent STATUS_AUTH_FAILED when it failed, signalled by
* the CONFIG_VALIDATE_ALREADY_TERMINATED sentinel, so no second status is
* written. */
if (rejection != CONFIG_VALIDATE_ALREADY_TERMINATED) {
log_message(LOG_LEVEL_ERROR, "%s", rejection);
send_error_detail(file_descriptor, rejection);
}
goto error;
}
}
if (!send_status(file_descriptor, STATUS_OK))
goto error;
return config;
error:
config_delete(config);
return NULL;
}
Config* config_receive(int file_descriptor) {
return config_receive_with_validate(file_descriptor, NULL, NULL);
}
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