1 /* 2 * Copyright (C) 2010 Dan Carpenter. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation; either version 2 7 * of the License, or (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt 16 */ 17 18 #include "smatch.h" 19 20 static void match_sprintf(const char *fn, struct expression *expr, void *unused) 21 { 22 struct expression *dest; 23 struct expression *format_string; 24 struct expression *data; 25 char *data_name = NULL; 26 int dest_size; 27 char *format; 28 int data_size; 29 30 dest = get_argument_from_call_expr(expr->args, 0); 31 format_string = get_argument_from_call_expr(expr->args, 1); 32 data = get_argument_from_call_expr(expr->args, 2); 33 34 dest_size = get_array_size_bytes(dest); 35 if (!dest_size) 36 return; 37 format = expr_to_var(format_string); 38 if (!format) 39 return; 40 if (strcmp(format, "\"%s\"")) 41 goto free; 42 data_name = expr_to_str(data); 43 data_size = get_size_from_strlen(data); 44 if (!data_size) 45 data_size = get_array_size_bytes(data); 46 if (dest_size < data_size) 47 sm_error("sprintf() copies too much data from '%s': %d vs %d", 48 data_name, data_size, dest_size); 49 free: 50 free_string(data_name); 51 free_string(format); 52 } 53 54 void check_sprintf_overflow(int id) 55 { 56 add_function_hook("sprintf", &match_sprintf, NULL); 57 } 58