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
|
#include <stdbool.h>
typedef struct CTX
{
int data[16];
} CTX;
union low_level_t
{
CTX md5;
};
typedef struct HIGH_LEVEL_MD
{
unsigned long flags;
} HIGH_LEVEL_MD;
typedef struct HIGH_LEVEL_MD_CTX
{
HIGH_LEVEL_MD *digest;
unsigned long flags;
} HIGH_LEVEL_MD_CTX;
struct high_level_digest_t
{
HIGH_LEVEL_MD_CTX *ctx;
};
struct high_level_t
{
struct high_level_digest_t first;
struct high_level_digest_t second;
};
typedef struct state_t
{
union
{
union low_level_t low_level;
struct high_level_t high_level;
} digest;
} state_t;
bool nondet_bool();
bool is_high_level()
{
static bool latch = false;
static bool once = false;
if(!once)
{
latch = nondet_bool();
once = true;
}
return latch;
}
int update(state_t *state, bool also_second)
// clang-format off
__CPROVER_requires(__CPROVER_is_fresh(state, sizeof(*state)))
__CPROVER_requires(
is_high_level() ==>
__CPROVER_is_fresh(state->digest.high_level.first.ctx,
sizeof(*(state->digest.high_level.first.ctx))) &&
__CPROVER_is_fresh(state->digest.high_level.first.ctx->digest,
sizeof(*(state->digest.high_level.first.ctx->digest))))
__CPROVER_requires(
is_high_level() && also_second ==>
__CPROVER_is_fresh(state->digest.high_level.second.ctx,
sizeof(*(state->digest.high_level.second.ctx))) &&
__CPROVER_is_fresh(state->digest.high_level.second.ctx->digest,
sizeof(*(state->digest.high_level.second.ctx->digest))))
__CPROVER_assigns(
is_high_level():
__CPROVER_object_whole(state->digest.high_level.first.ctx->digest),
state->digest.high_level.first.ctx->flags;
is_high_level() && also_second:
__CPROVER_object_whole(state->digest.high_level.second.ctx->digest),
state->digest.high_level.second.ctx->flags;
)
// clang-format on
{
if(is_high_level())
{
// must pass
__CPROVER_havoc_object(state->digest.high_level.first.ctx->digest);
state->digest.high_level.first.ctx->flags = 0;
if(also_second)
{
// must pass
__CPROVER_havoc_object(state->digest.high_level.second.ctx->digest);
state->digest.high_level.second.ctx->flags = 0;
}
// must fail
__CPROVER_havoc_object(state->digest.high_level.second.ctx->digest);
state->digest.high_level.second.ctx->flags = 0;
}
// must fail
__CPROVER_havoc_object(state->digest.high_level.first.ctx->digest);
state->digest.high_level.first.ctx->flags = 0;
// must fail
__CPROVER_havoc_object(state->digest.high_level.second.ctx->digest);
state->digest.high_level.second.ctx->flags = 0;
return 0;
}
int main()
{
state_t *state;
bool also_second;
update(state, also_second);
return 0;
}
|
