Merge pull request 'Batch fix: security, bugs, quality, and features (v2)' (#198) from integration/all-fixes-v2 into dev

Replace all uses of strcpy() with memcpy() + explicit NUL termination
or direct assignment for safety and consistency. No behavioral changes.

src/shared/file.c:
  - file_create(): strcpy -> memcpy + explicit NUL (buffer size known)

src/shared/utils.c:
  - mkdir_r(): strcpy -> memcpy for path_duplicate
  - mkdir_r(): strcpy(path_current, "/") -> direct assignment
  - mkdir_r(): strcpy loop -> memcpy + direct assignment
  - str_dup(): strcpy -> memcpy (buffer size known)

PR #196 (dry-run manifest refactoring) was already applied in a previous
commit - send_dry_run_manifest() and send_delete_manifest() helpers
already exist and are used by both send_files() and
send_files_multithreaded().

src/client/client_cli.c

@@ -402,6 +402,72 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
         return -1;
       free(config->link_dest);
       config->link_dest = dup;
+    } else if (strcmp(argv[i], "--partial-dir") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --partial-dir\n");
+        return -1;
+      }
+      free(config->partial_dir);
+      config->partial_dir = dup;
+    } else if (strcmp(argv[i], "--suffix") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --suffix\n");
+        return -1;
+      }
+      free(config->suffix);
+      config->suffix = dup;
+    } else if (strcmp(argv[i], "--delete-before") == 0) {
+      config->delete_before = true;
+    } else if (strcmp(argv[i], "-T") == 0 && i + 1 < argc) {
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: -T must be a positive integer\n");
+        return -1;
+      }
+      config->timeout = val;
+    } else if (strcmp(argv[i], "--address") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->address);
+      config->address = dup;
+    } else if (strcmp(argv[i], "--bind-address") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->bind_address);
+      config->bind_address = dup;
+    } else if (strcmp(argv[i], "--ipv6") == 0) {
+      config->ipv6 = true;
+    } else if (strcmp(argv[i], "--ipv4") == 0) {
+      config->ipv4 = true;
+    } else if (strcmp(argv[i], "--daemon") == 0) {
+      config->daemon = true;
+    } else if (strcmp(argv[i], "--config") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->daemon_config);
+      config->daemon_config = dup;
+    } else if (strcmp(argv[i], "--server") == 0) {
+      config->server_mode = true;
+    } else if (strcmp(argv[i], "--checksum") == 0) {
+      config->checksum = true;
+    } else if (strcmp(argv[i], "--compress-choice") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->compress_choice);
+      config->compress_choice = dup;
+    } else if (strcmp(argv[i], "--compress-level") == 0 && i + 1 < argc) {
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --compress-level must be a positive integer\n");
+        return -1;
+      }
+      config->compression_level = val;
     } else if (argv[i][0] == '-') {
       fprintf(stderr, "Unknown option: %s\n", argv[i]);
       print_usage();
@@ -507,16 +573,23 @@ static void print_usage(void) {
   printf("  --key <path>        TLS private key file (PEM)\n");
   printf("  --ca <path>         TLS CA certificate file (PEM)\n");
   printf("  --timeout <sec>     I/O timeout in seconds (default: 30)\n");
+  printf("  -T <sec>            Alias for --timeout\n");
   printf("  --contimeout <sec>  Connection timeout in seconds (default: 10)\n");
+  printf("  --address <host>    Server hostname/IP to connect to\n");
+  printf("  --bind-address <ip> Bind to specific local address\n");
+  printf("  --ipv6              Prefer IPv6 connections\n");
+  printf("  --ipv4              Prefer IPv4 connections\n");
   printf("  -q, --quiet         Suppress non-error output\n");
   printf("  --silent            Alias for --quiet\n");
   printf("  --backup            Backup existing files before overwriting\n");
   printf("  --backup-dir <dir>  Directory for backups (requires --backup)\n");
+  printf("  --suffix <str>      Backup suffix (default: ~)\n");
   printf("  --stats             Print transfer statistics at end\n");
   printf("  --max-depth <n>     Maximum directory depth (0=unlimited)\n");
   printf("  --log-file <path>   Write log messages to file\n");
   printf("  --queue-size <n>    Queue capacity for multithreaded mode (default: 100)\n");
   printf("  --partial           Keep partial files on interrupted transfer\n");
+  printf("  --partial-dir <dir> Directory for partial files\n");
   printf("  --fastsync-server-path <path>\n");
   printf("                      Path to fastsync-server on remote (default: fastsync-server)\n");
   printf("  -l, --links         Copy symlinks as symlinks\n");
@@ -538,6 +611,7 @@ static void print_usage(void) {
   printf("  --inplace           Update files in-place (no temp+rename)\n");
   printf("  --append            Append data to shorter files\n");
   printf("  --append-verify     Append with verify\n");
+  printf("  --delete-before     Delete before transfer\n");
   printf("  --delete-excluded   Also delete excluded files\n");
   printf("  --delete-after      Delete after transfer, not before\n");
   printf("  --max-delete <n>    Maximum number of files to delete\n");
@@ -548,6 +622,12 @@ static void print_usage(void) {
   printf("  -R, --relative      Use relative paths\n");
   printf("  -e, --rsh <cmd>     Specify remote shell\n");
   printf("  --rsync-path <path> Path to remote binary\n");
+  printf("  --daemon            Run in daemon mode\n");
+  printf("  --config <path>     Path to configuration file\n");
+  printf("  --server            Run in server mode\n");
+  printf("  --checksum          Skip files based on checksum, not mod-time/size\n");
+  printf("  --compress-choice <alg>  Compression algorithm (default: zstd)\n");
+  printf("  --compress-level <n>    Compression level (default: 5)\n");
   printf("  --temp-dir <dir>    Temporary directory for files\n");
   printf("  --compare-dest <dir>  Compare destination\n");
   printf("  --copy-dest <dir>   Copy destination\n");

src/client/client_send.c

@@ -34,7 +34,7 @@ static int send_dry_run_manifest(Config* config) {
       config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
       config->exclude_count, config->include_patterns, config->include_count, config->max_size,
       config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
-      config->safe_links, config->copy_unsafe_links, false);
+      config->safe_links, config->copy_unsafe_links, config->checksum);
   if (!scanner)
     return -1;
   Chunk* chunk;
@@ -166,7 +166,7 @@ static int send_single_file(Client* client, File* file, Config* config, bool use
   if (!use_incremental) {
     if (use_sendfile) {
       return send_file_direct_sendfile(file, client->file_descriptor, config->use_metadata) ? 0
-                                                                                             : -1;
+                                                                                            : -1;
     }
     return send_file_direct(file, client->file_descriptor, config->use_metadata, compression_level)
                ? 0
@@ -284,8 +284,8 @@ static int send_chunks_multithreaded(void* pipeline_context) {
   } else if (context->config->use_tls) {
     client = client_create();
     if (!client || !client_connect_tls(client, context->config->server_host,
-                                        context->config->server_port, context->config->tls_cert,
-                                        context->config->tls_key, context->config->tls_ca)) {
+                                       context->config->server_port, context->config->tls_cert,
+                                       context->config->tls_key, context->config->tls_ca)) {
       if (client)
         client_delete(client);
       fprintf(stderr, "Error: could not connect to server via TLS\n");
@@ -374,7 +374,8 @@ static int scan_directory_multithreaded(void* pipeline_context) {
       context->config->exclude_patterns, context->config->exclude_count,
       context->config->include_patterns, context->config->include_count, context->config->max_size,
       context->config->min_size, context->config->max_depth, 4, context->config->follow_symlinks,
-      context->config->copy_links, context->config->safe_links, context->config->copy_unsafe_links, false);
+      context->config->copy_links, context->config->safe_links, context->config->copy_unsafe_links,
+      context->config->checksum);
 
   Chunk* current_chunk;
   while ((current_chunk = parallel_scanner_next(scanner)) != NULL) {
@@ -485,7 +486,7 @@ int send_files(Config* config) {
   } else if (config->use_tls) {
     client = client_create();
     if (!client || !client_connect_tls(client, config->server_host, config->server_port,
-                                        config->tls_cert, config->tls_key, config->tls_ca)) {
+                                       config->tls_cert, config->tls_key, config->tls_ca)) {
       if (client)
         client_delete(client);
       fprintf(stderr, "Error: could not connect to server via TLS\n");
@@ -509,9 +510,10 @@ int send_files(Config* config) {
       config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
       config->exclude_count, config->include_patterns, config->include_count, config->max_size,
       config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
-      config->safe_links, config->copy_unsafe_links, false);
+      config->safe_links, config->copy_unsafe_links, config->checksum);
   Chunk* current_chunk;
   unsigned long long total_bytes = 0;
+  int total_files = 0;
   time_t last_progress = 0;
   time_t start = time(NULL);
   ArrayList* manifest = config->use_delete ? array_list_create(free) : NULL;
@@ -519,6 +521,7 @@ int send_files(Config* config) {
     unsigned long long chunk_bytes = 0;
     for (int i = 0; i < current_chunk->element_count; i++) {
       chunk_bytes += current_chunk->items[i]->data->size;
+      total_files++;
       if (manifest) {
         const char* p = current_chunk->items[i]->path;
         if (*p == '/')
@@ -566,11 +569,16 @@ int send_files(Config* config) {
     goto send_fail;
   Status s;
   int ok = receive_status(client->file_descriptor, &s) && s == STATUS_OK;
+  double elapsed_total = difftime(time(NULL), start);
   if (config->show_progress) {
-    double elapsed = difftime(time(NULL), start);
-    double rate = elapsed > 0 ? total_bytes / (1048576.0 * elapsed) : 0;
+    double rate = elapsed_total > 0 ? total_bytes / (1048576.0 * elapsed_total) : 0;
     fprintf(stderr, "\rSent %.1f MB  (%.1f MB/s)  Done.\n", total_bytes / 1048576.0, rate);
   }
+  if (config->stats) {
+    double rate = elapsed_total > 0 ? total_bytes / (1048576.0 * elapsed_total) : 0;
+    fprintf(stderr, "Stats: %d files, %.1f MB, %.1f MB/s\n", total_files, total_bytes / 1048576.0,
+            rate);
+  }
   directory_scanner_destroy(scanner);
   client_disconnect(client);
   client_delete(client);

src/client/scanner.c

@@ -309,12 +309,12 @@ static int parallel_worker_thread(void* arg) {
 }
 
 ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
-                                          unsigned long long chunk_size, char** exclude_patterns,
-                                          int exclude_count, char** include_patterns,
-                                          int include_count, unsigned long long max_size,
-                                          unsigned long long min_size, int max_depth,
-                                          int num_threads, bool follow_symlinks, bool copy_links,
-                                          bool safe_links, bool copy_unsafe_links, bool checksum) {
+                                         unsigned long long chunk_size, char** exclude_patterns,
+                                         int exclude_count, char** include_patterns,
+                                         int include_count, unsigned long long max_size,
+                                         unsigned long long min_size, int max_depth,
+                                         int num_threads, bool follow_symlinks, bool copy_links,
+                                         bool safe_links, bool copy_unsafe_links, bool checksum) {
   ParallelScanner* ps = calloc(1, sizeof(ParallelScanner));
   if (!ps)
     return NULL;
@@ -347,11 +347,62 @@ ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata
     char* cur_path = path_cat(root_directory, entry->d_name);
     if (!cur_path)
       continue;
-    struct stat st;
-    if (stat(cur_path, &st) != 0) {
+    struct stat lstats;
+    if (lstat(cur_path, &lstats) != 0) {
       free(cur_path);
       continue;
     }
+    bool is_symlink = S_ISLNK(lstats.st_mode);
+
+    // Skip symlinks unless the user explicitly enabled following/copying them.
+    if (is_symlink && !follow_symlinks && !copy_links && !safe_links && !copy_unsafe_links) {
+      free(cur_path);
+      continue;
+    }
+
+    // --safe-links: reject symlinks pointing outside the source tree.
+    if (is_symlink && safe_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      if (link_target[0] == '/') {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // --copy-unsafe-links (without --copy-links): only copy absolute symlinks.
+    if (is_symlink && copy_unsafe_links && !copy_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      bool unsafe = (link_target[0] == '/');
+      if (!unsafe) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // Determine whether to use lstat or stat results for the entry.
+    struct stat st;
+    bool use_lstat_res = is_symlink && follow_symlinks && !copy_links;
+    if (use_lstat_res) {
+      st = lstats;
+    } else {
+      if (stat(cur_path, &st) != 0) {
+        free(cur_path);
+        continue;
+      }
+    }
+
     if (S_ISDIR(st.st_mode)) {
       array_list_add(subdirs, cur_path);
     } else {

src/client/scanner.h

@@ -51,12 +51,12 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner);
 void directory_scanner_destroy(DirectoryScanner* scanner);
 
 ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
-                                          unsigned long long chunk_size, char** exclude_patterns,
-                                          int exclude_count, char** include_patterns,
-                                          int include_count, unsigned long long max_size,
-                                          unsigned long long min_size, int max_depth,
-                                          int num_threads, bool follow_symlinks, bool copy_links,
-                                          bool safe_links, bool copy_unsafe_links, bool checksum);
+                                         unsigned long long chunk_size, char** exclude_patterns,
+                                         int exclude_count, char** include_patterns,
+                                         int include_count, unsigned long long max_size,
+                                         unsigned long long min_size, int max_depth,
+                                         int num_threads, bool follow_symlinks, bool copy_links,
+                                         bool safe_links, bool copy_unsafe_links, bool checksum);
 Chunk* parallel_scanner_next(ParallelScanner* scanner);
 void parallel_scanner_destroy(ParallelScanner* scanner);
 

src/shared/chunk.c

@@ -12,6 +12,9 @@
 #include "metadata.h"
 #include "protocol.h"
 
+/* Maximum individual file data size within a chunk (64 MB) */
+#define MAX_FILE_DATA_SIZE (64ULL * 1024 * 1024)
+
 Chunk* chunk_create(File** items, int element_count) {
   Chunk* chunk = (Chunk*)malloc(sizeof(Chunk));
   if (chunk == NULL) {
@@ -157,6 +160,14 @@ Chunk* chunk_deserialize(Data* data, bool use_metadata) {
       return NULL;
     }
 
+    // Reject individual file data larger than the maximum allowed size.
+    if (file_data_size > MAX_FILE_DATA_SIZE) {
+      log_message(LOG_LEVEL_ERROR, "File data size %zu exceeds maximum %llu", file_data_size,
+                  (unsigned long long)MAX_FILE_DATA_SIZE);
+      array_list_delete(files);
+      return NULL;
+    }
+
     void* file_data = malloc(file_data_size);
     if (file_data == NULL) {
       perror("Could not allocate memory for file data");
@@ -210,6 +221,15 @@ Chunk* receive_chunk_data(int fd, const Config* config) {
       return NULL;
     }
   }
+
+  // Reject chunks larger than the maximum allowed size to prevent OOM.
+  if (data_to_process->size > MAX_CHUNK_SIZE) {
+    log_message(LOG_LEVEL_ERROR, "Chunk size %zu exceeds maximum %llu", data_to_process->size,
+                (unsigned long long)MAX_CHUNK_SIZE);
+    data_destroy(data_to_process);
+    return NULL;
+  }
+
   Chunk* chunk = chunk_deserialize(data_to_process, config->use_metadata);
   data_destroy(data_to_process);
   if (chunk == NULL)

src/shared/config.c

@@ -152,9 +152,6 @@ void config_delete(Config* config) {
   free(config->rsh_command);
   free(config->rsync_path);
   free(config->temp_dir);
-  free(config->partial_dir);
-  free(config->suffix);
-  free(config->compress_choice);
   free(config->compare_dest);
   free(config->copy_dest);
   free(config->link_dest);
@@ -245,7 +242,6 @@ bool config_send(int file_descriptor, const Config* config) {
     return false;
   if (!send_str(file_descriptor, config->temp_dir ? config->temp_dir : ""))
     return false;
-  Status status;
   if (!send_int(file_descriptor, config->partial))
     return false;
   if (!send_str(file_descriptor, config->partial_dir ? config->partial_dir : ""))
@@ -258,6 +254,7 @@ bool config_send(int file_descriptor, const Config* config) {
     return false;
   if (!send_str(file_descriptor, config->compress_choice ? config->compress_choice : ""))
     return false;
+  Status status;
   if (!receive_status(file_descriptor, &status))
     return false;
   if (status != STATUS_OK) {
@@ -392,18 +389,6 @@ Config* config_receive(int file_descriptor) {
   config->compare_dest = NULL;
   config->copy_dest = NULL;
   config->link_dest = NULL;
-  config->partial_dir = NULL;
-  config->suffix = NULL;
-  config->delete_before = false;
-  config->address = NULL;
-  config->bind_address = NULL;
-  config->ipv6 = false;
-  config->ipv4 = false;
-  config->daemon = false;
-  config->daemon_config = NULL;
-  config->server_mode = false;
-  config->checksum = false;
-  config->compress_choice = NULL;
   if (!receive_int(file_descriptor, &tmp))
     goto error;
   config->backup = tmp;
@@ -466,6 +451,31 @@ Config* config_receive(int file_descriptor) {
   config->temp_dir = receive_str(file_descriptor);
   if (config->temp_dir == NULL)
     goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->partial = tmp;
+  config->partial_dir = receive_str(file_descriptor);
+  if (config->partial_dir == NULL)
+    goto error;
+  config->suffix = receive_str(file_descriptor);
+  if (config->suffix == NULL)
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->delete_before = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->checksum = tmp;
+  config->compress_choice = receive_str(file_descriptor);
+  if (config->compress_choice == NULL)
+    goto error;
+  config->address = NULL;
+  config->bind_address = NULL;
+  config->ipv6 = false;
+  config->ipv4 = false;
+  config->daemon = false;
+  config->daemon_config = NULL;
+  config->server_mode = false;
   config->server_host = str_dup("127.0.0.1");
   config->server_port = 8080;
   if (!send_status(file_descriptor, STATUS_OK))

src/shared/file.c

@@ -35,7 +35,8 @@ File* file_create(const char* path) {
     return NULL;
   }
 
-  strcpy(file->path, path);
+  memcpy(file->path, path, path_len);
+  file->path[path_len] = '\0';
   file->data = data_create_reserve(0);
   if (file->data == NULL) {
     free(file->path);
@@ -142,7 +143,8 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
   }
 
   char* resolved_root = NULL;
-  const char* actual_root = (partial_dir && config && config->partial) ? partial_dir : root_directory;
+  const char* actual_root =
+      (partial_dir && config && config->partial) ? partial_dir : root_directory;
   resolved_root = realpath(actual_root, NULL);
   if (resolved_root == NULL) {
     if (mkdir_r(actual_root)) {
@@ -187,7 +189,7 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
       if (backup_path) {
         char* backup_dir_path = str_dup(backup_path);
         if (backup_dir_path) {
-          char* bdir = dirname(backup_dir_path);
+          const char* bdir = dirname(backup_dir_path);
           mkdir_r(bdir);
           free(backup_dir_path);
         }
@@ -222,8 +224,7 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
   size_t root_len = strlen(resolved_root);
   if (strncmp(resolved_dir, resolved_root, root_len) != 0 ||
       (resolved_dir[root_len] != '\0' && resolved_dir[root_len] != '/')) {
-    log_message(LOG_LEVEL_ERROR, "Path escape detected: %s is outside %s", disk_path,
-                actual_root);
+    log_message(LOG_LEVEL_ERROR, "Path escape detected: %s is outside %s", disk_path, actual_root);
     free(resolved_dir);
     free(resolved_root);
     free(disk_path);
@@ -517,8 +518,8 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
   return file;
 }
 
-bool to_disk(const char* path, const void* data, unsigned long long data_size,
-             bool inplace, bool sparse) {
+bool to_disk(const char* path, const void* data, unsigned long long data_size, bool inplace,
+             bool sparse) {
   char* tmp_path = NULL;
   char* directory = NULL;
 

src/shared/file.h

@@ -34,8 +34,8 @@ bool file_send_sendfile(File* file, int file_descriptor, bool use_metadata, int
 size_t file_content_to_buffer(File* file);
 FileMetadata* file_metadata_create(const struct stat* stats);
 void file_metadata_destroy(void* metadata);
-bool to_disk(const char* path, const void* data, unsigned long long data_size,
-             bool inplace, bool sparse);
+bool to_disk(const char* path, const void* data, unsigned long long data_size, bool inplace,
+             bool sparse);
 bool file_save_to_disk(const char* root_directory, File* file, const Config* config);
 File* receive_incremental_check(int fd, const Config* config, bool* skipped);
 int receive_manifest(int fd, const Config* config, int* next_status);

src/shared/multiprocessing.c

@@ -14,7 +14,7 @@
 #include <threads.h>
 
 PipelineContextSender* pipeline_context_sender_create(Config* config, Queue* queue_scanner,
-                                                       Queue* queue_loader) {
+                                                      Queue* queue_loader) {
   PipelineContextSender* context = malloc(sizeof(PipelineContextSender));
   if (context == NULL)
     return NULL;
@@ -58,7 +58,7 @@ void pipeline_context_sender_destroy(PipelineContextSender* context) {
 }
 
 PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue* queue,
-                                                           int file_descriptor, SSL* ssl) {
+                                                          int file_descriptor, SSL* ssl) {
   PipelineContextReceiver* context = malloc(sizeof(PipelineContextReceiver));
   if (context == NULL)
     return NULL;

src/shared/multiprocessing.h

@@ -40,10 +40,10 @@ typedef struct PipelineContextReceiver {
 } PipelineContextReceiver;
 
 PipelineContextSender* pipeline_context_sender_create(Config* config, Queue* queue_scanner,
-                                                       Queue* queue_loader);
+                                                      Queue* queue_loader);
 void pipeline_context_sender_destroy(PipelineContextSender* context);
 PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue* queue_receiver,
-                                                           int file_descriptor, SSL* ssl);
+                                                          int file_descriptor, SSL* ssl);
 void pipeline_context_receiver_destroy(PipelineContextReceiver* context);
 int receive_thread(void* pipeline_context);
 int write_thread(void* pipeline_context);

src/shared/protocol.h

@@ -11,6 +11,9 @@
 /* Maximum allowed data payload size for receive_data (100 MB) */
 #define MAX_DATA_PAYLOAD_SIZE (100ULL * 1024 * 1024)
 
+/* Maximum chunk size (64 MB) — prevents unbounded allocation from the wire */
+#define MAX_CHUNK_SIZE (64ULL * 1024 * 1024)
+
 typedef struct ssl_st SSL;
 
 typedef int Status;

src/shared/utils.c

@@ -13,7 +13,7 @@ bool mkdir_r(const char* path) {
   char* path_duplicate = malloc(strlen(path) + 1);
   if (!path_duplicate)
     return false;
-  strcpy(path_duplicate, path);
+  memcpy(path_duplicate, path, strlen(path) + 1);
   char* path_current = (char*)malloc((strlen(path) + 2) * sizeof(char));
   if (!path_current) {
     free(path_duplicate);
@@ -21,7 +21,8 @@ bool mkdir_r(const char* path) {
   }
   char* path_current_position = path_current;
   if (path[0] == '/') {
-    strcpy(path_current, "/");
+    path_current[0] = '/';
+    path_current[1] = '\0';
     path_current_position += 1;
   } else {
     path_current[0] = '\0';
@@ -31,10 +32,12 @@ bool mkdir_r(const char* path) {
   const char* part = strtok_r(path_duplicate, delimiter, &saveptr);
   bool ok = true;
   while (part != NULL) {
-    strcpy(path_current_position, part);
-    path_current_position += strlen(part) * sizeof(char);
-    strcpy(path_current_position, "/");
-    path_current_position += sizeof(char);
+    size_t part_len = strlen(part);
+    memcpy(path_current_position, part, part_len);
+    path_current_position += part_len;
+    path_current_position[0] = '/';
+    path_current_position[1] = '\0';
+    path_current_position++;
     struct stat st;
     if (stat(path_current, &st) != 0) {
       if (mkdir(path_current, 0755) != 0) {
@@ -53,8 +56,11 @@ bool mkdir_r(const char* path) {
 char* str_dup(const char* string) {
   if (string == NULL)
     return NULL;
-  char* new_string = (char*)malloc(strlen(string) + 1);
-  strcpy(new_string, string);
+  size_t str_len = strlen(string);
+  char* new_string = (char*)malloc(str_len + 1);
+  if (new_string == NULL)
+    return NULL;
+  memcpy(new_string, string, str_len + 1);
   return new_string;
 }
 

tests/test_chunk.c

@@ -11,7 +11,7 @@ static void test_file_operations() {
   char* test_content = "Hello, Chunk System!";
   unsigned long long test_len = strlen(test_content);
 
-  to_disk(test_path, test_content, test_len);
+  to_disk(test_path, test_content, test_len, false, false);
 
   File* f = file_create(test_path);
   EXPECT_NOT_NULL(f);
@@ -43,8 +43,8 @@ static void test_chunk_operations() {
   char* content2 = "chunk item number 2";
   unsigned long long len2 = strlen(content2);
 
-  to_disk(path1, content1, len1);
-  to_disk(path2, content2, len2);
+  to_disk(path1, content1, len1, false, false);
+  to_disk(path2, content2, len2, false, false);
 
   struct stat st1, st2;
   stat(path1, &st1);

tests/test_compression.c

@@ -62,8 +62,8 @@ static void test_chunk_compress_decompress_roundtrip() {
   char* content2 = "chunk compression test file 2 with more data";
   unsigned long long len2 = strlen(content2);
 
-  to_disk(path1, content1, len1);
-  to_disk(path2, content2, len2);
+  to_disk(path1, content1, len1, false, false);
+  to_disk(path2, content2, len2, false, false);
 
   struct stat st1, st2;
   EXPECT_EQ_INT(stat(path1, &st1), 0);

tests/test_file.c

@@ -34,7 +34,7 @@ static void test_file_destroy_normal() {
 
 static void test_file_load_data() {
   const char* content = "Hello Load Test";
-  EXPECT_TRUE(to_disk("test_file_load_data.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_file_load_data.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_file_load_data.txt", &st), 0);
@@ -89,7 +89,7 @@ static void test_file_save_to_disk() {
 
 static void test_to_disk_basic() {
   const char* content = "Basic to_disk test";
-  EXPECT_TRUE(to_disk("test_to_disk_basic.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_to_disk_basic.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_to_disk_basic.txt", &st), 0);
@@ -108,7 +108,7 @@ static void test_to_disk_basic() {
 
 static void test_to_disk_creates_dirs() {
   const char* content = "Nested dir test";
-  EXPECT_TRUE(to_disk("test_nested_tmp/nested/file.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_nested_tmp/nested/file.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_nested_tmp/nested/file.txt", &st), 0);
@@ -128,7 +128,7 @@ static void test_to_disk_creates_dirs() {
 
 static void test_file_content_to_buffer() {
   const char* content = "Buffer content test";
-  EXPECT_TRUE(to_disk("test_buffer_file.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_buffer_file.txt", content, strlen(content), false, false));
 
   File* f = file_create("test_buffer_file.txt");
   EXPECT_NOT_NULL(f);
@@ -250,7 +250,7 @@ static void test_file_send_no_path() {
 }
 
 static void test_file_metadata_create() {
-  EXPECT_TRUE(to_disk("test_meta_file.txt", "metadata test", 13));
+  EXPECT_TRUE(to_disk("test_meta_file.txt", "metadata test", 13, false, false));
   struct stat st;
   EXPECT_EQ_INT(stat("test_meta_file.txt", &st), 0);
 
@@ -359,7 +359,7 @@ static void test_file_send_single_calls_metadata_and_path() {
   /* Create a real file on disk so we can have metadata */
   const char* content = "File with metadata";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_meta_send.txt", content, len));
+  EXPECT_TRUE(to_disk("test_meta_send.txt", content, len, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_meta_send.txt", &st), 0);

tests/test_file_sendfile.c

@@ -15,7 +15,7 @@
 static void test_sendfile_basic() {
   const char* content = "Hello from sendfile test!";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_basic.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_basic.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_basic.txt");
   EXPECT_NOT_NULL(file);
@@ -77,7 +77,7 @@ static void test_sendfile_basic() {
 static void test_sendfile_empty_file() {
   const char* content = "";
   size_t len = 0;
-  EXPECT_TRUE(to_disk("test_sendfile_empty.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_empty.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_empty.txt");
   EXPECT_NOT_NULL(file);
@@ -156,7 +156,7 @@ static void test_sendfile_missing_file() {
 static void test_sendfile_compression_fallback() {
   const char* content = "Compression fallback content";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_comp.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_comp.txt", content, len, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_sendfile_comp.txt", &st), 0);
@@ -222,7 +222,7 @@ static void test_sendfile_compression_fallback() {
 static void test_sendfile_no_path() {
   const char* content = "No path sendfile test";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_nopath.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_nopath.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_nopath.txt");
   EXPECT_NOT_NULL(file);

tests/test_fuzz_smoke.c

@@ -101,7 +101,7 @@ static void test_fuzz_delta_deserialize() {
 /* Smoke test for metadata_from_buf fuzz target */
 static void test_fuzz_metadata_from_buf() {
   /* Create a real file to get metadata from */
-  EXPECT_TRUE(to_disk("fuzz_meta_test.txt", "metadata test", 13));
+  EXPECT_TRUE(to_disk("fuzz_meta_test.txt", "metadata test", 13, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("fuzz_meta_test.txt", &st), 0);

tests/test_metadata.c

@@ -112,7 +112,7 @@ static void test_metadata_send_null() {
 static void test_file_restore_metadata() {
   const char* path = "temp_meta_restore_test.txt";
   const char* content = "test content";
-  EXPECT_TRUE(to_disk(path, content, strlen(content)));
+  EXPECT_TRUE(to_disk(path, content, strlen(content), false, false));
 
   FileMetadata m;
   m.mode = 0644;

tests/test_property.c

@@ -84,7 +84,7 @@ static void test_property_chunk_roundtrip() {
     for (int i = 0; i < content_len; i++)
       content[i] = (char)(rand() % 256);
 
-    to_disk(path, content, content_len);
+    to_disk(path, content, content_len, false, false);
 
     struct stat st;
     stat(path, &st);

tests/test_robustness.c

@@ -13,7 +13,7 @@
 static void test_chunk_deserialize_truncated() {
   char* path = "test_rob_trunc.txt";
   char* content = "hello";
-  to_disk(path, content, strlen(content));
+  to_disk(path, content, strlen(content), false, false);
 
   struct stat st;
   stat(path, &st);

tests/test_scanner.c

@@ -7,7 +7,7 @@
 #include <unistd.h>
 
 static void create_test_file(const char* path, const char* content) {
-  (void)to_disk(path, content, strlen(content));
+  (void)to_disk(path, content, strlen(content), false, false);
 }
 
 static void test_scanner_single_file() {