llama : check that all the tensor data is in the model file (#6885)

* llama : check that all the tensor data is in the model file

* also check for unsigned overflow

llama.cpp

@@ -2999,9 +2999,13 @@ struct llama_model_loader {
 
         ggml_tensor * tensor;
 
-        llama_tensor_weight(uint16_t idx, const char * name, const struct gguf_context * gguf_ctx, ggml_tensor * tensor) : idx(idx), tensor(tensor) {
+        llama_tensor_weight(const llama_file * file, uint16_t idx, const char * name, const struct gguf_context * gguf_ctx, ggml_tensor * tensor) : idx(idx), tensor(tensor) {
             const int tensor_idx = gguf_find_tensor(gguf_ctx, name);
             offs = gguf_get_data_offset(gguf_ctx) + gguf_get_tensor_offset(gguf_ctx, tensor_idx);
+
+            if (offs + ggml_nbytes(tensor) < offs || offs + ggml_nbytes(tensor) > file->size) {
+                throw std::runtime_error(format("tensor '%s' data is not within the file bounds, model is corrupted or incomplete", name));
+            }
         }
     };
     std::vector<llama_tensor_weight> weights;
@@ -3040,15 +3044,15 @@ struct llama_model_loader {
         get_key(llm_kv(LLM_KV_GENERAL_ARCHITECTURE), arch_name, false);
         llm_kv = LLM_KV(llm_arch_from_string(arch_name));
 
+        files.emplace_back(new llama_file(fname.c_str(), "rb"));
+        contexts.emplace_back(ctx);
+
         // Save tensors data offset of the main file.
         // For subsidiary files, `meta` tensor data offset must not be used,
         // so we build a unified tensors index for weights.
         for (ggml_tensor * cur = ggml_get_first_tensor(ctx); cur; cur = ggml_get_next_tensor(ctx, cur)) {
-            weights.emplace_back(0, cur->name, meta, cur);
+            weights.emplace_back(files.back().get(), 0, cur->name, meta, cur);
         }
-        files.emplace_back(new llama_file(fname.c_str(), "rb"));
-        contexts.emplace_back(ctx);
-
         uint16_t n_split = 0;
         get_key(llm_kv(LLM_KV_SPLIT_COUNT), n_split, false);
 
@@ -3082,12 +3086,13 @@ struct llama_model_loader {
                     throw std::runtime_error(format("%s: failed to load GGUF split from %s\n", __func__, split_path));
                 }
 
+                files.emplace_back(new llama_file(split_path, "rb"));
+                contexts.emplace_back(ctx);
+
                 // Save tensors data offset info of the shard.
                 for (ggml_tensor * cur = ggml_get_first_tensor(ctx); cur; cur = ggml_get_next_tensor(ctx, cur)) {
-                    weights.emplace_back(idx, cur->name, ctx_gguf, cur);
+                    weights.emplace_back(files.back().get(), idx, cur->name, ctx_gguf, cur);
                 }
-                files.emplace_back(new llama_file(split_path, "rb"));
-                contexts.emplace_back(ctx);
 
                 gguf_free(ctx_gguf);
             }