fix: security issues #192 #191 #190 #189 #188 #187

src/client/client_cli.c

@@ -49,37 +49,6 @@ static bool parse_nonneg_int(const char* s, int* out_val) {
   return true;
 }
 
-/* Duplicate a string argument into *dest, freeing the old value. Returns 0 on success, -1 on
- * failure. */
-static int set_string_option(char** dest, const char* value, const char* option_name) {
-  char* dup = str_dup(value);
-  if (!dup) {
-    fprintf(stderr, "Error: memory allocation failed for %s\n", option_name);
-    return -1;
-  }
-  free(*dest);
-  *dest = dup;
-  return 0;
-}
-
-/* Parse a string as a positive integer into *dest. Returns 0 on success, -1 on error. */
-static int set_positive_int_option(int* dest, const char* value, const char* option_name) {
-  if (!parse_positive_int(value, dest)) {
-    fprintf(stderr, "Error: %s must be a positive integer\n", option_name);
-    return -1;
-  }
-  return 0;
-}
-
-/* Parse a string as a non-negative integer into *dest. Returns 0 on success, -1 on error. */
-static int set_nonneg_int_option(int* dest, const char* value, const char* option_name) {
-  if (!parse_nonneg_int(value, dest)) {
-    fprintf(stderr, "Error: %s must be a non-negative integer\n", option_name);
-    return -1;
-  }
-  return 0;
-}
-
 static void print_usage(void);
 static int read_patterns_from_file(const char* filepath, char*** patterns, int* count);
 
@@ -131,23 +100,9 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
       }
       config->include_patterns[config->include_count++] = dup;
     } else if (strcmp(argv[i], "--max-size") == 0 && i + 1 < argc) {
-      char* end;
-      errno = 0;
-      unsigned long long val = strtoull(argv[++i], &end, 10);
-      if (errno != 0 || *end != '\0') {
-        fprintf(stderr, "Error: --max-size must be a non-negative integer\n");
-        return -1;
-      }
-      config->max_size = val;
+      config->max_size = strtoull(argv[++i], NULL, 10);
     } else if (strcmp(argv[i], "--min-size") == 0 && i + 1 < argc) {
-      char* end;
-      errno = 0;
-      unsigned long long val = strtoull(argv[++i], &end, 10);
-      if (errno != 0 || *end != '\0') {
-        fprintf(stderr, "Error: --min-size must be a non-negative integer\n");
-        return -1;
-      }
-      config->min_size = val;
+      config->min_size = strtoull(argv[++i], NULL, 10);
     } else if (strcmp(argv[i], "--incremental") == 0) {
       config->use_incremental = true;
     } else if (strcmp(argv[i], "--delta") == 0) {
@@ -177,11 +132,21 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
         }
       }
     } else if (strcmp(argv[i], "--source-dir") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->send_directory, argv[++i], "--source-dir") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --source-dir\n");
         return -1;
+      }
+      free(config->send_directory);
+      config->send_directory = dup;
     } else if (strcmp(argv[i], "--dest-dir") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->receive_root_directory, argv[++i], "--dest-dir") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --dest-dir\n");
         return -1;
+      }
+      free(config->receive_root_directory);
+      config->receive_root_directory = dup;
     } else if (strcmp(argv[i], "--save-to-disk") == 0) {
       config->save_to_disk = true;
     } else if (strcmp(argv[i], "-M") == 0 || strcmp(argv[i], "--preserve") == 0) {
@@ -197,8 +162,13 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
       config->use_chunk_serialization = true;
       log_message(LOG_LEVEL_INFO, "Enabled Chunk Serialization");
     } else if (strcmp(argv[i], "--server-host") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->server_host, argv[++i], "--server-host") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --server-host\n");
         return -1;
+      }
+      free(config->server_host);
+      config->server_host = dup;
     } else if (strcmp(argv[i], "--server-port") == 0 && i + 1 < argc) {
       if (!parse_positive_int(argv[++i], &config->server_port)) {
         fprintf(stderr, "Error: invalid --server-port value: %s\n", argv[i]);
@@ -221,44 +191,69 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
     } else if (strcmp(argv[i], "--progress") == 0) {
       config->show_progress = true;
     } else if (strcmp(argv[i], "--chunk-size") == 0 && i + 1 < argc) {
-      char* end;
-      errno = 0;
-      unsigned long long val = strtoull(argv[++i], &end, 10);
-      if (errno != 0 || *end != '\0' || val == 0) {
-        fprintf(stderr, "Error: --chunk-size must be a positive integer\n");
-        return -1;
-      }
-      config->chunk_size = val;
+      unsigned long long val = strtoull(argv[++i], NULL, 10);
+      if (val > 0)
+        config->chunk_size = val;
     } else if (strcmp(argv[i], "--tls") == 0) {
       config->use_tls = true;
     } else if (strcmp(argv[i], "--cert") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->tls_cert, argv[++i], "--cert") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --cert\n");
         return -1;
+      }
+      free(config->tls_cert);
+      config->tls_cert = dup;
     } else if (strcmp(argv[i], "--key") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->tls_key, argv[++i], "--key") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --key\n");
         return -1;
+      }
+      free(config->tls_key);
+      config->tls_key = dup;
     } else if (strcmp(argv[i], "--ca") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->tls_ca, argv[++i], "--ca") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --ca\n");
         return -1;
+      }
+      free(config->tls_ca);
+      config->tls_ca = dup;
     } else if (strcmp(argv[i], "--timeout") == 0 && i + 1 < argc) {
-      if (set_positive_int_option(&config->timeout, argv[++i], "--timeout") != 0)
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --timeout must be a positive integer\n");
         return -1;
+      }
+      config->timeout = val;
     } else if (strcmp(argv[i], "--contimeout") == 0 && i + 1 < argc) {
-      if (set_positive_int_option(&config->contimeout, argv[++i], "--contimeout") != 0)
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --contimeout must be a positive integer\n");
         return -1;
+      }
+      config->contimeout = val;
     } else if (strcmp(argv[i], "-q") == 0 || strcmp(argv[i], "--quiet") == 0 ||
                strcmp(argv[i], "--silent") == 0) {
       config->quiet = true;
     } else if (strcmp(argv[i], "--backup") == 0) {
       config->backup = true;
     } else if (strcmp(argv[i], "--backup-dir") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->backup_dir, argv[++i], "--backup-dir") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --backup-dir\n");
         return -1;
+      }
+      free(config->backup_dir);
+      config->backup_dir = dup;
     } else if (strcmp(argv[i], "--stats") == 0) {
       config->stats = true;
     } else if (strcmp(argv[i], "--max-depth") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->max_depth, argv[++i], "--max-depth") != 0)
+      if (!parse_nonneg_int(argv[++i], &config->max_depth)) {
+        fprintf(stderr, "Error: --max-depth must be a non-negative integer\n");
         return -1;
+      }
     } else if (strcmp(argv[i], "--log-file") == 0 && i + 1 < argc) {
       FILE* lf = fopen(argv[++i], "a");
       if (!lf) {
@@ -268,8 +263,12 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
       config->log_file = lf;
       log_set_file(lf);
     } else if (strcmp(argv[i], "--queue-size") == 0 && i + 1 < argc) {
-      if (set_positive_int_option(&config->queue_size, argv[++i], "--queue-size") != 0)
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --queue-size must be a positive integer\n");
         return -1;
+      }
+      config->queue_size = val;
     } else if (strcmp(argv[i], "--exclude-from") == 0 && i + 1 < argc) {
       if (read_patterns_from_file(argv[++i], &config->exclude_patterns, &config->exclude_count) !=
           0)
@@ -281,9 +280,13 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
     } else if (strcmp(argv[i], "--partial") == 0) {
       config->partial = true;
     } else if (strcmp(argv[i], "--fastsync-server-path") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->fastsync_server_path, argv[++i], "--fastsync-server-path") !=
-          0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --fastsync-server-path\n");
         return -1;
+      }
+      free(config->fastsync_server_path);
+      config->fastsync_server_path = dup;
     } else if (strcmp(argv[i], "-v") == 0 || strcmp(argv[i], "--verbose") == 0) {
       set_log_level(LOG_LEVEL_DEBUG);
     } else if (strcmp(argv[i], "-l") == 0 || strcmp(argv[i], "--links") == 0) {
@@ -307,14 +310,15 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
     } else if (strcmp(argv[i], "-i") == 0 || strcmp(argv[i], "--itemize-changes") == 0) {
       config->itemize_changes = true;
     } else if (strcmp(argv[i], "--out-format") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->out_format, argv[++i], "--out-format") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->out_format);
+      config->out_format = dup;
     } else if (strcmp(argv[i], "--info") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->info_level, argv[++i], "--info") != 0)
-        return -1;
+      config->info_level = atoi(argv[++i]);
     } else if (strcmp(argv[i], "--debug") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->debug_level, argv[++i], "--debug") != 0)
-        return -1;
+      config->debug_level = atoi(argv[++i]);
     } else if (strcmp(argv[i], "--list-only") == 0) {
       config->list_only = true;
     } else if (strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--human-readable") == 0) {
@@ -332,8 +336,12 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
     } else if (strcmp(argv[i], "--delete-after") == 0) {
       config->delete_after = true;
     } else if (strcmp(argv[i], "--max-delete") == 0 && i + 1 < argc) {
-      if (set_nonneg_int_option(&config->max_delete, argv[++i], "--max-delete") != 0)
+      int val;
+      if (!parse_nonneg_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --max-delete must be a non-negative integer\n");
         return -1;
+      }
+      config->max_delete = val;
     } else if (strcmp(argv[i], "--filter") == 0 && i + 1 < argc) {
       if (!config->filters)
         config->filters = array_list_create(free);
@@ -342,8 +350,11 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
         return -1;
       array_list_add(config->filters, dup);
     } else if (strcmp(argv[i], "--files-from") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->files_from, argv[++i], "--files-from") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->files_from);
+      config->files_from = dup;
     } else if (strcmp(argv[i], "--cvs-exclude") == 0) {
       config->cvs_exclude = true;
     } else if (strcmp(argv[i], "--prune-empty-dirs") == 0) {
@@ -352,27 +363,45 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
       config->relative = true;
     } else if (strcmp(argv[i], "-e") == 0 || strcmp(argv[i], "--rsh") == 0) {
       if (i + 1 < argc) {
-        if (set_string_option(&config->rsh_command, argv[++i], "-e/--rsh") != 0)
+        char* dup = str_dup(argv[++i]);
+        if (!dup)
           return -1;
+        free(config->rsh_command);
+        config->rsh_command = dup;
       } else {
         fprintf(stderr, "Error: -e/--rsh requires a command argument\n");
         return -1;
       }
     } else if (strcmp(argv[i], "--rsync-path") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->rsync_path, argv[++i], "--rsync-path") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->rsync_path);
+      config->rsync_path = dup;
     } else if (strcmp(argv[i], "--temp-dir") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->temp_dir, argv[++i], "--temp-dir") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->temp_dir);
+      config->temp_dir = dup;
     } else if (strcmp(argv[i], "--compare-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->compare_dest, argv[++i], "--compare-dest") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->compare_dest);
+      config->compare_dest = dup;
     } else if (strcmp(argv[i], "--copy-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->copy_dest, argv[++i], "--copy-dest") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->copy_dest);
+      config->copy_dest = dup;
     } else if (strcmp(argv[i], "--link-dest") == 0 && i + 1 < argc) {
-      if (set_string_option(&config->link_dest, argv[++i], "--link-dest") != 0)
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
         return -1;
+      free(config->link_dest);
+      config->link_dest = dup;
     } else if (argv[i][0] == '-') {
       fprintf(stderr, "Unknown option: %s\n", argv[i]);
       print_usage();

src/client/scanner.c

@@ -345,11 +345,63 @@ 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] = '';
+      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] = '';
+      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/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/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;