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 }