1 /* 2 * Copyright (C) 2013 Oracle. 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 #include "smatch_extra.h" 20 #include "smatch_slist.h" 21 22 static int my_id; 23 24 static int is_comparison_call(struct expression *expr) 25 { 26 expr = expr_get_parent_expr(expr); 27 if (!expr || expr->type != EXPR_COMPARE) 28 return 0; 29 if (expr->op != SPECIAL_EQUAL && expr->op != SPECIAL_NOTEQUAL) 30 return 0; 31 return 1; 32 } 33 34 static int next_line_is_if(struct expression *expr) 35 { 36 struct expression *next; 37 38 if (!__next_stmt || __next_stmt->type != STMT_IF) 39 return 0; 40 41 next = strip_expr(__next_stmt->if_conditional); 42 while (next->type == EXPR_PREOP && next->op == '!') 43 next = strip_expr(next->unop); 44 if (expr_equiv(expr, next)) 45 return 1; 46 return 0; 47 } 48 49 static int next_line_checks_IS_ERR(struct expression *call, struct expression *arg) 50 { 51 struct expression *next; 52 struct expression *tmp; 53 54 tmp = expr_get_parent_expr(call); 55 if (tmp && tmp->type == EXPR_ASSIGNMENT) { 56 if (next_line_checks_IS_ERR(NULL, tmp->left)) 57 return 1; 58 } 59 60 if (!__next_stmt || __next_stmt->type != STMT_IF) 61 return 0; 62 63 next = strip_expr(__next_stmt->if_conditional); 64 while (next->type == EXPR_PREOP && next->op == '!') 65 next = strip_expr(next->unop); 66 if (!next || next->type != EXPR_CALL) 67 return 0; 68 if (next->fn->type != EXPR_SYMBOL || !next->fn->symbol || 69 !next->fn->symbol->ident || 70 (strcmp(next->fn->symbol->ident->name, "IS_ERR") != 0 && 71 strcmp(next->fn->symbol->ident->name, "IS_ERR_OR_NULL") != 0)) 72 return 0; 73 next = get_argument_from_call_expr(next->args, 0); 74 return expr_equiv(next, arg); 75 } 76 77 static int is_valid_ptr(sval_t sval) 78 { 79 if (sval.type == &int_ctype && 80 (sval.value == INT_MIN || sval.value == INT_MAX)) 81 return 0; 82 83 if (sval_cmp(valid_ptr_min_sval, sval) <= 0 && 84 sval_cmp(valid_ptr_max_sval, sval) >= 0) 85 return 1; 86 return 0; 87 } 88 89 static void match_err_ptr(const char *fn, struct expression *expr, void *data) 90 { 91 struct expression *arg_expr; 92 struct sm_state *sm, *tmp; 93 sval_t sval; 94 95 arg_expr = get_argument_from_call_expr(expr->args, 0); 96 sm = get_sm_state_expr(SMATCH_EXTRA, arg_expr); 97 if (!sm) 98 return; 99 100 if (is_comparison_call(expr)) 101 return; 102 103 if (next_line_checks_IS_ERR(expr, arg_expr)) 104 return; 105 if (strcmp(fn, "ERR_PTR") == 0 && 106 next_line_is_if(arg_expr)) 107 return; 108 109 FOR_EACH_PTR(sm->possible, tmp) { 110 if (!estate_rl(tmp->state)) 111 continue; 112 if (is_valid_ptr(estate_min(tmp->state)) && 113 is_valid_ptr(estate_max(tmp->state))) { 114 sm_warning("passing a valid pointer to '%s'", fn); 115 return; 116 } 117 if (!rl_to_sval(estate_rl(tmp->state), &sval)) 118 continue; 119 if (sval.value != 0) 120 continue; 121 sm_warning("passing zero to '%s'", fn); 122 return; 123 } END_FOR_EACH_PTR(tmp); 124 } 125 126 void check_zero_to_err_ptr(int id) 127 { 128 if (option_project != PROJ_KERNEL) 129 return; 130 131 my_id = id; 132 add_function_hook("ERR_PTR", &match_err_ptr, NULL); 133 add_function_hook("ERR_CAST", &match_err_ptr, NULL); 134 add_function_hook("PTR_ERR", &match_err_ptr, NULL); 135 } 136