1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
|
/* Proof-of-concept of a -fanalyzer plugin for the Linux kernel. */
/* { dg-options "-g" } */
#define INCLUDE_MEMORY
#include "gcc-plugin.h"
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tree.h"
#include "function.h"
#include "basic-block.h"
#include "gimple.h"
#include "gimple-iterator.h"
#include "diagnostic-core.h"
#include "graphviz.h"
#include "options.h"
#include "cgraph.h"
#include "tree-dfa.h"
#include "stringpool.h"
#include "convert.h"
#include "target.h"
#include "fold-const.h"
#include "tree-pretty-print.h"
#include "diagnostic-color.h"
#include "diagnostic-metadata.h"
#include "tristate.h"
#include "bitmap.h"
#include "selftest.h"
#include "function.h"
#include "json.h"
#include "analyzer/analyzer.h"
#include "analyzer/analyzer-logging.h"
#include "ordered-hash-map.h"
#include "options.h"
#include "cgraph.h"
#include "cfg.h"
#include "digraph.h"
#include "analyzer/supergraph.h"
#include "sbitmap.h"
#include "analyzer/call-string.h"
#include "analyzer/program-point.h"
#include "analyzer/store.h"
#include "analyzer/region-model.h"
#include "analyzer/call-details.h"
#include "analyzer/call-info.h"
#include "make-unique.h"
int plugin_is_GPL_compatible;
#if ENABLE_ANALYZER
namespace ana {
/* Implementation of "copy_from_user" and "copy_to_user". */
class copy_across_boundary_fn : public known_function
{
public:
virtual bool untrusted_source_p () const = 0;
virtual bool untrusted_destination_p () const = 0;
bool matches_call_types_p (const call_details &cd) const final override
{
return cd.num_args () == 3;
}
void impl_call_pre (const call_details &cd) const final override
{
region_model_manager *mgr = cd.get_manager ();
region_model *model = cd.get_model ();
region_model_context *ctxt = cd.get_ctxt ();
const svalue *dest_sval = cd.get_arg_svalue (0);
const svalue *src_sval = cd.get_arg_svalue (1);
const svalue *num_bytes_sval = cd.get_arg_svalue (2);
const region *dest_reg = model->deref_rvalue (dest_sval,
cd.get_arg_tree (0),
ctxt);
const region *src_reg = model->deref_rvalue (src_sval,
cd.get_arg_tree (1),
ctxt);
if (const svalue *bounded_sval
= model->maybe_get_copy_bounds (src_reg, num_bytes_sval))
num_bytes_sval = bounded_sval;
if (tree cst = num_bytes_sval->maybe_get_constant ())
if (zerop (cst))
{
/* No-op. */
model->update_for_zero_return (cd, true);
return;
}
const region *sized_src_reg = mgr->get_sized_region (src_reg,
NULL_TREE,
num_bytes_sval);
const svalue *copied_sval
= model->get_store_value (sized_src_reg, ctxt);
const region *sized_dest_reg = mgr->get_sized_region (dest_reg,
NULL_TREE,
num_bytes_sval);
if (ctxt)
{
/* Bifurcate state, creating a "failure" out-edge. */
ctxt->bifurcate (make_unique<copy_failure> (cd));
/* The "unbifurcated" state is the "success" case. */
copy_success success (cd,
sized_dest_reg,
copied_sval,
sized_src_reg,
untrusted_source_p (),
untrusted_destination_p ());
success.update_model (model, NULL, ctxt);
}
}
private:
class copy_success : public success_call_info
{
public:
copy_success (const call_details &cd,
const region *sized_dest_reg,
const svalue *copied_sval,
const region *sized_src_reg,
bool untrusted_source,
bool untrusted_destination)
: success_call_info (cd),
m_sized_dest_reg (sized_dest_reg),
m_copied_sval (copied_sval),
m_sized_src_reg (sized_src_reg),
m_untrusted_source (untrusted_source),
m_untrusted_destination (untrusted_destination)
{}
bool update_model (region_model *model,
const exploded_edge *,
region_model_context *ctxt) const final override
{
call_details cd (get_call_details (model, ctxt));
model->update_for_zero_return (cd, true);
model->set_value (m_sized_dest_reg, m_copied_sval, ctxt);
if (ctxt && m_untrusted_source)
model->mark_as_tainted (m_copied_sval, ctxt);
if (m_untrusted_destination)
model->maybe_complain_about_infoleak (m_sized_dest_reg,
m_copied_sval,
m_sized_src_reg,
ctxt);
return true;
}
const region *m_sized_dest_reg;
const svalue *m_copied_sval;
const region *m_sized_src_reg;
bool m_untrusted_source;
bool m_untrusted_destination;
};
class copy_failure : public failed_call_info
{
public:
copy_failure (const call_details &cd)
: failed_call_info (cd)
{}
bool update_model (region_model *model,
const exploded_edge *,
region_model_context *ctxt) const final override
{
call_details cd (get_call_details (model, ctxt));
model->update_for_nonzero_return (cd);
/* Leave the destination region untouched. */
return true;
}
};
};
/* "copy_from_user". */
class known_function_copy_from_user : public copy_across_boundary_fn
{
public:
bool untrusted_source_p () const final override
{
return true;
}
bool untrusted_destination_p () const final override
{
return false;
}
};
/* "copy_to_user". */
class known_function_copy_to_user : public copy_across_boundary_fn
{
public:
bool untrusted_source_p () const final override
{
return false;
}
bool untrusted_destination_p () const final override
{
return true;
}
};
/* Implementation of "__check_object_size". */
class known_function___check_object_size : public known_function
{
public:
bool matches_call_types_p (const call_details &cd) const final override
{
return cd.num_args () == 2;
}
void impl_call_pre (const call_details &) const final override
{
/* No-op. */
}
};
/* Callback handler for the PLUGIN_ANALYZER_INIT event. */
static void
kernel_analyzer_init_cb (void *gcc_data, void */*user_data*/)
{
ana::plugin_analyzer_init_iface *iface
= (ana::plugin_analyzer_init_iface *)gcc_data;
LOG_SCOPE (iface->get_logger ());
if (0)
inform (input_location, "got here: kernel_analyzer_init_cb");
iface->register_known_function
("copy_from_user",
make_unique<known_function_copy_from_user> ());
iface->register_known_function ("copy_to_user",
make_unique<known_function_copy_to_user> ());
iface->register_known_function ("__check_object_size",
make_unique<known_function___check_object_size> ());
}
} // namespace ana
#endif /* #if ENABLE_ANALYZER */
int
plugin_init (struct plugin_name_args *plugin_info,
struct plugin_gcc_version *version)
{
#if ENABLE_ANALYZER
const char *plugin_name = plugin_info->base_name;
if (0)
inform (input_location, "got here; %qs", plugin_name);
register_callback (plugin_info->base_name,
PLUGIN_ANALYZER_INIT,
ana::kernel_analyzer_init_cb,
NULL); /* void *user_data */
#else
sorry_no_analyzer ();
#endif
return 0;
}
|