1 /* 2 * Copyright (C) 2019 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 /* 19 * There are a bunch of allocation functions where we allocate some memory, 20 * set up some struct members and then return the allocated memory. One 21 * nice thing about this is that we just one pointer to the allocated memory 22 * so what we can do is we can generate a mtag alias for it in the caller. 23 */ 24 25 #include "smatch.h" 26 #include "smatch_slist.h" 27 28 static int my_id; 29 30 STATE(fresh); 31 32 struct alloc_info *alloc_funcs; 33 34 struct alloc_info kernel_allocation_funcs[] = { 35 {"kmalloc", 0}, 36 {"kmalloc_node", 0}, 37 {"kzalloc", 0}, 38 {"kzalloc_node", 0}, 39 {"vmalloc", 0}, 40 {"__vmalloc", 0}, 41 {"kvmalloc", 0}, 42 {"kcalloc", 0, 1}, 43 {"kmalloc_array", 0, 1}, 44 {"sock_kmalloc", 1}, 45 {"kmemdup", 1}, 46 {"kmemdup_user", 1}, 47 {"dma_alloc_attrs", 1}, 48 {"pci_alloc_consistent", 1}, 49 {"pci_alloc_coherent", 1}, 50 {"devm_kmalloc", 1}, 51 {"devm_kzalloc", 1}, 52 {"krealloc", 1}, 53 {"__alloc_bootmem", 0}, 54 {"alloc_bootmem", 0}, 55 {"dma_alloc_contiguous", 1}, 56 {"dma_alloc_coherent", 1}, 57 {}, 58 }; 59 60 struct alloc_info general_allocation_funcs[] = { 61 {"malloc", 0}, 62 {"calloc", 0, 1}, 63 {"memdup", 1}, 64 {"realloc", 1}, 65 {}, 66 }; 67 68 static int fresh_callback(void *fresh, int argc, char **argv, char **azColName) 69 { 70 *(int *)fresh = 1; 71 return 0; 72 } 73 74 static int fresh_from_db(struct expression *call) 75 { 76 int fresh = 0; 77 78 /* for function pointers assume everything is used */ 79 if (call->fn->type != EXPR_SYMBOL) 80 return 0; 81 82 run_sql(&fresh_callback, &fresh, 83 "select * from return_states where %s and type = %d and parameter = -1 and key = '$' limit 1;", 84 get_static_filter(call->fn->symbol), FRESH_ALLOC); 85 return fresh; 86 } 87 88 bool is_fresh_alloc_var_sym(const char *var, struct symbol *sym) 89 { 90 return get_state(my_id, var, sym) == &fresh; 91 } 92 93 bool is_fresh_alloc(struct expression *expr) 94 { 95 sval_t sval; 96 int i; 97 98 if (!expr) 99 return false; 100 101 if (get_implied_value_fast(expr, &sval) && sval.value == 0) 102 return false; 103 104 if (get_state_expr(my_id, expr) == &fresh) 105 return true; 106 107 if (expr->type != EXPR_CALL) 108 return false; 109 if (fresh_from_db(expr)) 110 return true; 111 i = -1; 112 while (alloc_funcs[++i].fn) { 113 if (sym_name_is(kernel_allocation_funcs[i].fn, expr->fn)) 114 return true; 115 } 116 return false; 117 } 118 119 static void record_alloc_func(int return_id, char *return_ranges, struct expression *expr) 120 { 121 if (!is_fresh_alloc(expr)) 122 return; 123 sql_insert_return_states(return_id, return_ranges, FRESH_ALLOC, -1, "$", ""); 124 } 125 126 static void set_unfresh(struct expression *expr) 127 { 128 struct sm_state *sm; 129 130 sm = get_sm_state_expr(my_id, expr); 131 if (!sm) 132 return; 133 if (!slist_has_state(sm->possible, &fresh)) 134 return; 135 // TODO call unfresh hooks 136 set_state_expr(my_id, expr, &undefined); 137 } 138 139 static void match_assign(struct expression *expr) 140 { 141 set_unfresh(expr->right); 142 } 143 144 static void match_call(struct expression *expr) 145 { 146 struct expression *arg; 147 148 FOR_EACH_PTR(expr->args, arg) { 149 set_unfresh(arg); 150 } END_FOR_EACH_PTR(arg); 151 } 152 153 static void set_fresh(struct expression *expr) 154 { 155 expr = strip_expr(expr); 156 if (expr->type != EXPR_SYMBOL) 157 return; 158 set_state_expr(my_id, expr, &fresh); 159 } 160 161 static void returns_fresh_alloc(struct expression *expr, int param, char *key, char *value) 162 { 163 if (param != -1 || !key || strcmp(key, "$") != 0) 164 return; 165 if (expr->type != EXPR_ASSIGNMENT) 166 return; 167 168 set_fresh(expr->left); 169 } 170 171 static void match_alloc(const char *fn, struct expression *expr, void *_size_arg) 172 { 173 set_fresh(expr->left); 174 } 175 176 void register_fresh_alloc(int id) 177 { 178 int i; 179 180 my_id = id; 181 182 if (option_project == PROJ_KERNEL) 183 alloc_funcs = kernel_allocation_funcs; 184 else 185 alloc_funcs = general_allocation_funcs; 186 187 i = -1; 188 while (alloc_funcs[++i].fn) 189 add_function_assign_hook(alloc_funcs[i].fn, &match_alloc, 0); 190 191 add_split_return_callback(&record_alloc_func); 192 select_return_states_hook(FRESH_ALLOC, &returns_fresh_alloc); 193 add_hook(&match_assign, ASSIGNMENT_HOOK); 194 add_hook(&match_call, FUNCTION_CALL_HOOK); 195 } 196