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_extra.h"
27 #include "smatch_slist.h"
28
29 static int my_id;
30
31 STATE(fresh);
32
33 struct alloc_info *alloc_funcs;
34
35 struct alloc_info kernel_allocation_funcs[] = {
36 {"kmalloc", 0},
37 {"kmalloc_node", 0},
38 {"kzalloc", 0},
39 {"kzalloc_node", 0},
40 {"vmalloc", 0},
41 {"__vmalloc", 0},
42 {"kvmalloc", 0},
43 {"kcalloc", 0, 1},
44 {"kmalloc_array", 0, 1},
45 {"sock_kmalloc", 1},
46 {"kmemdup", 1},
47 {"kmemdup_user", 1},
48 {"dma_alloc_attrs", 1},
49 {"pci_alloc_consistent", 1},
50 {"pci_alloc_coherent", 1},
51 {"devm_kmalloc", 1},
52 {"devm_kzalloc", 1},
53 {"krealloc", 1},
54 {"__alloc_bootmem", 0},
55 {"alloc_bootmem", 0},
56 {"dma_alloc_contiguous", 1},
57 {"dma_alloc_coherent", 1},
58 {},
59 };
60
61 struct alloc_info general_allocation_funcs[] = {
62 {"malloc", 0},
63 {"calloc", 0, 1},
64 {"memdup", 1},
65 {"realloc", 1},
66 {},
67 };
68
pre_merge_hook(struct sm_state * cur,struct sm_state * other)69 static void pre_merge_hook(struct sm_state *cur, struct sm_state *other)
70 {
71 struct smatch_state *state;
72 sval_t sval;
73
74 state = get_state(SMATCH_EXTRA, cur->name, cur->sym);
75 if (estate_get_single_value(state, &sval) && sval.value == 0)
76 set_state(my_id, cur->name, cur->sym, &undefined);
77 }
78
fresh_callback(void * fresh,int argc,char ** argv,char ** azColName)79 static int fresh_callback(void *fresh, int argc, char **argv, char **azColName)
80 {
81 *(int *)fresh = 1;
82 return 0;
83 }
84
fresh_from_db(struct expression * call)85 static int fresh_from_db(struct expression *call)
86 {
87 int fresh = 0;
88
89 /* for function pointers assume everything is used */
90 if (call->fn->type != EXPR_SYMBOL)
91 return 0;
92
93 run_sql(&fresh_callback, &fresh,
94 "select * from return_states where %s and type = %d and parameter = -1 and key = '$' limit 1;",
95 get_static_filter(call->fn->symbol), FRESH_ALLOC);
96 return fresh;
97 }
98
is_fresh_alloc_var_sym(const char * var,struct symbol * sym)99 bool is_fresh_alloc_var_sym(const char *var, struct symbol *sym)
100 {
101 return get_state(my_id, var, sym) == &fresh;
102 }
103
is_fresh_alloc(struct expression * expr)104 bool is_fresh_alloc(struct expression *expr)
105 {
106 sval_t sval;
107 int i;
108
109 if (!expr)
110 return false;
111
112 if (get_implied_value_fast(expr, &sval) && sval.value == 0)
113 return false;
114
115 if (get_state_expr(my_id, expr) == &fresh)
116 return true;
117
118 if (expr->type != EXPR_CALL)
119 return false;
120 if (fresh_from_db(expr))
121 return true;
122 i = -1;
123 while (alloc_funcs[++i].fn) {
124 if (sym_name_is(kernel_allocation_funcs[i].fn, expr->fn))
125 return true;
126 }
127 return false;
128 }
129
record_alloc_func(int return_id,char * return_ranges,struct expression * expr)130 static void record_alloc_func(int return_id, char *return_ranges, struct expression *expr)
131 {
132 if (!is_fresh_alloc(expr))
133 return;
134 sql_insert_return_states(return_id, return_ranges, FRESH_ALLOC, -1, "$", "");
135 }
136
set_unfresh(struct expression * expr)137 static void set_unfresh(struct expression *expr)
138 {
139 struct sm_state *sm;
140
141 sm = get_sm_state_expr(my_id, expr);
142 if (!sm)
143 return;
144 if (!slist_has_state(sm->possible, &fresh))
145 return;
146 // TODO call unfresh hooks
147 set_state_expr(my_id, expr, &undefined);
148 }
149
match_assign(struct expression * expr)150 static void match_assign(struct expression *expr)
151 {
152 set_unfresh(expr->right);
153 }
154
match_call(struct expression * expr)155 static void match_call(struct expression *expr)
156 {
157 struct expression *arg;
158
159 FOR_EACH_PTR(expr->args, arg) {
160 set_unfresh(arg);
161 } END_FOR_EACH_PTR(arg);
162 }
163
164 static struct expression *handled;
set_fresh(struct expression * expr)165 static void set_fresh(struct expression *expr)
166 {
167 struct range_list *rl;
168
169 expr = strip_expr(expr);
170 if (expr->type != EXPR_SYMBOL)
171 return;
172 if (expr == handled)
173 return;
174
175 get_absolute_rl(expr, &rl);
176 rl = rl_intersection(rl, valid_ptr_rl);
177 if (!rl)
178 return;
179 set_state_expr(my_id, expr, &fresh);
180 handled = expr;
181 }
182
returns_fresh_alloc(struct expression * expr,int param,char * key,char * value)183 static void returns_fresh_alloc(struct expression *expr, int param, char *key, char *value)
184 {
185 if (param != -1 || !key || strcmp(key, "$") != 0)
186 return;
187 if (expr->type != EXPR_ASSIGNMENT)
188 return;
189
190 set_fresh(expr->left);
191 }
192
match_alloc(const char * fn,struct expression * expr,void * _size_arg)193 static void match_alloc(const char *fn, struct expression *expr, void *_size_arg)
194 {
195 set_fresh(expr->left);
196 }
197
register_fresh_alloc(int id)198 void register_fresh_alloc(int id)
199 {
200 int i;
201
202 my_id = id;
203
204 if (option_project == PROJ_KERNEL)
205 alloc_funcs = kernel_allocation_funcs;
206 else
207 alloc_funcs = general_allocation_funcs;
208
209 i = -1;
210 while (alloc_funcs[++i].fn)
211 add_function_assign_hook(alloc_funcs[i].fn, &match_alloc, 0);
212
213 add_split_return_callback(&record_alloc_func);
214 select_return_states_hook(FRESH_ALLOC, &returns_fresh_alloc);
215 add_hook(&match_assign, ASSIGNMENT_HOOK);
216 add_hook(&match_call, FUNCTION_CALL_HOOK);
217
218 add_pre_merge_hook(my_id, &pre_merge_hook);
219 }
220