summaryrefslogtreecommitdiff
path: root/scripts/coverity-model.c
blob: 4c99a85cfc292caa9edd9d041e2683ee53490a8d (plain)
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
/* Coverity Scan model
 *
 * Copyright (C) 2014 Red Hat, Inc.
 *
 * Authors:
 *  Markus Armbruster <armbru@redhat.com>
 *  Paolo Bonzini <pbonzini@redhat.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or, at your
 * option, any later version.  See the COPYING file in the top-level directory.
 */


/*
 * This is the source code for our Coverity user model file.  The
 * purpose of user models is to increase scanning accuracy by explaining
 * code Coverity can't see (out of tree libraries) or doesn't
 * sufficiently understand.  Better accuracy means both fewer false
 * positives and more true defects.  Memory leaks in particular.
 *
 * - A model file can't import any header files.  Some built-in primitives are
 *   available but not wchar_t, NULL etc.
 * - Modeling doesn't need full structs and typedefs. Rudimentary structs
 *   and similar types are sufficient.
 * - An uninitialized local variable signifies that the variable could be
 *   any value.
 *
 * The model file must be uploaded by an admin in the analysis settings of
 * http://scan.coverity.com/projects/378
 */

#define NULL ((void *)0)

typedef unsigned char uint8_t;
typedef char int8_t;
typedef unsigned int uint32_t;
typedef int int32_t;
typedef long ssize_t;
typedef unsigned long long uint64_t;
typedef long long int64_t;
typedef _Bool bool;

/* exec.c */

typedef struct AddressSpace AddressSpace;
typedef uint64_t hwaddr;

static void __write(uint8_t *buf, ssize_t len)
{
    int first, last;
    __coverity_negative_sink__(len);
    if (len == 0) return;
    buf[0] = first;
    buf[len-1] = last;
    __coverity_writeall__(buf);
}

static void __read(uint8_t *buf, ssize_t len)
{
    __coverity_negative_sink__(len);
    if (len == 0) return;
    int first = buf[0];
    int last = buf[len-1];
}

bool address_space_rw(AddressSpace *as, hwaddr addr, uint8_t *buf,
                      int len, bool is_write)
{
    bool result;

    // TODO: investigate impact of treating reads as producing
    // tainted data, with __coverity_tainted_data_argument__(buf).
    if (is_write) __write(buf, len); else __read(buf, len);

    return result;
}

/* Tainting */

typedef struct {} name2keysym_t;
static int get_keysym(const name2keysym_t *table,
                      const char *name)
{
    int result;
    if (result > 0) {
        __coverity_tainted_string_sanitize_content__(name);
        return result;
    } else {
        return 0;
    }
}

/* glib memory allocation functions.
 *
 * Note that we ignore the fact that g_malloc of 0 bytes returns NULL,
 * and g_realloc of 0 bytes frees the pointer.
 *
 * Modeling this would result in Coverity flagging a lot of memory
 * allocations as potentially returning NULL, and asking us to check
 * whether the result of the allocation is NULL or not.  However, the
 * resulting pointer should never be dereferenced anyway, and in fact
 * it is not in the vast majority of cases.
 *
 * If a dereference did happen, this would suppress a defect report
 * for an actual null pointer dereference.  But it's too unlikely to
 * be worth wading through the false positives, and with some luck
 * we'll get a buffer overflow reported anyway.
 */

void *malloc(size_t);
void *calloc(size_t, size_t);
void *realloc(void *, size_t);
void free(void *);

void *
g_malloc(size_t n_bytes)
{
    void *mem;
    __coverity_negative_sink__(n_bytes);
    mem = malloc(n_bytes == 0 ? 1 : n_bytes);
    if (!mem) __coverity_panic__();
    return mem;
}

void *
g_malloc0(size_t n_bytes)
{
    void *mem;
    __coverity_negative_sink__(n_bytes);
    mem = calloc(1, n_bytes == 0 ? 1 : n_bytes);
    if (!mem) __coverity_panic__();
    return mem;
}

void g_free(void *mem)
{
    free(mem);
}

void *g_realloc(void * mem, size_t n_bytes)
{
    __coverity_negative_sink__(n_bytes);
    mem = realloc(mem, n_bytes == 0 ? 1 : n_bytes);
    if (!mem) __coverity_panic__();
    return mem;
}

void *g_try_malloc(size_t n_bytes)
{
    __coverity_negative_sink__(n_bytes);
    return malloc(n_bytes == 0 ? 1 : n_bytes);
}

void *g_try_malloc0(size_t n_bytes)
{
    __coverity_negative_sink__(n_bytes);
    return calloc(1, n_bytes == 0 ? 1 : n_bytes);
}

void *g_try_realloc(void *mem, size_t n_bytes)
{
    __coverity_negative_sink__(n_bytes);
    return realloc(mem, n_bytes == 0 ? 1 : n_bytes);
}

/* Other glib functions */

typedef struct _GIOChannel GIOChannel;
GIOChannel *g_io_channel_unix_new(int fd)
{
    GIOChannel *c = g_malloc0(sizeof(GIOChannel));
    __coverity_escape__(fd);
    return c;
}

void g_assertion_message_expr(const char     *domain,
                              const char     *file,
                              int             line,
                              const char     *func,
                              const char     *expr)
{
    __coverity_panic__();
}