qemu/scripts/coverity-model.c
<<
>>
Prefs
   1/* Coverity Scan model
   2 *
   3 * Copyright (C) 2014 Red Hat, Inc.
   4 *
   5 * Authors:
   6 *  Markus Armbruster <armbru@redhat.com>
   7 *  Paolo Bonzini <pbonzini@redhat.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2 or, at your
  10 * option, any later version.  See the COPYING file in the top-level directory.
  11 */
  12
  13
  14/*
  15 * This is the source code for our Coverity user model file.  The
  16 * purpose of user models is to increase scanning accuracy by explaining
  17 * code Coverity can't see (out of tree libraries) or doesn't
  18 * sufficiently understand.  Better accuracy means both fewer false
  19 * positives and more true defects.  Memory leaks in particular.
  20 *
  21 * - A model file can't import any header files.  Some built-in primitives are
  22 *   available but not wchar_t, NULL etc.
  23 * - Modeling doesn't need full structs and typedefs. Rudimentary structs
  24 *   and similar types are sufficient.
  25 * - An uninitialized local variable signifies that the variable could be
  26 *   any value.
  27 *
  28 * The model file must be uploaded by an admin in the analysis settings of
  29 * http://scan.coverity.com/projects/378
  30 */
  31
  32#define NULL ((void *)0)
  33
  34typedef unsigned char uint8_t;
  35typedef char int8_t;
  36typedef unsigned int uint32_t;
  37typedef int int32_t;
  38typedef long ssize_t;
  39typedef unsigned long long uint64_t;
  40typedef long long int64_t;
  41typedef _Bool bool;
  42
  43typedef struct va_list_str *va_list;
  44
  45/* exec.c */
  46
  47typedef struct AddressSpace AddressSpace;
  48typedef uint64_t hwaddr;
  49typedef uint32_t MemTxResult;
  50typedef uint64_t MemTxAttrs;
  51
  52static void __bufwrite(uint8_t *buf, ssize_t len)
  53{
  54    int first, last;
  55    __coverity_negative_sink__(len);
  56    if (len == 0) return;
  57    buf[0] = first;
  58    buf[len-1] = last;
  59    __coverity_writeall__(buf);
  60}
  61
  62static void __bufread(uint8_t *buf, ssize_t len)
  63{
  64    __coverity_negative_sink__(len);
  65    if (len == 0) return;
  66    int first = buf[0];
  67    int last = buf[len-1];
  68}
  69
  70MemTxResult address_space_read(AddressSpace *as, hwaddr addr,
  71                               MemTxAttrs attrs,
  72                               uint8_t *buf, int len)
  73{
  74    MemTxResult result;
  75    // TODO: investigate impact of treating reads as producing
  76    // tainted data, with __coverity_tainted_data_argument__(buf).
  77    __bufwrite(buf, len);
  78    return result;
  79}
  80
  81MemTxResult address_space_write(AddressSpace *as, hwaddr addr,
  82                                MemTxAttrs attrs,
  83                                const uint8_t *buf, int len)
  84{
  85    MemTxResult result;
  86    __bufread(buf, len);
  87    return result;
  88}
  89
  90
  91/* Tainting */
  92
  93typedef struct {} name2keysym_t;
  94static int get_keysym(const name2keysym_t *table,
  95                      const char *name)
  96{
  97    int result;
  98    if (result > 0) {
  99        __coverity_tainted_string_sanitize_content__(name);
 100        return result;
 101    } else {
 102        return 0;
 103    }
 104}
 105
 106/*
 107 * GLib memory allocation functions.
 108 *
 109 * Note that we ignore the fact that g_malloc of 0 bytes returns NULL,
 110 * and g_realloc of 0 bytes frees the pointer.
 111 *
 112 * Modeling this would result in Coverity flagging a lot of memory
 113 * allocations as potentially returning NULL, and asking us to check
 114 * whether the result of the allocation is NULL or not.  However, the
 115 * resulting pointer should never be dereferenced anyway, and in fact
 116 * it is not in the vast majority of cases.
 117 *
 118 * If a dereference did happen, this would suppress a defect report
 119 * for an actual null pointer dereference.  But it's too unlikely to
 120 * be worth wading through the false positives, and with some luck
 121 * we'll get a buffer overflow reported anyway.
 122 */
 123
 124/*
 125 * Allocation primitives, cannot return NULL
 126 * See also Coverity's library/generic/libc/all/all.c
 127 */
 128
 129void *g_malloc_n(size_t nmemb, size_t size)
 130{
 131    size_t sz;
 132    void *ptr;
 133
 134    __coverity_negative_sink__(nmemb);
 135    __coverity_negative_sink__(size);
 136    sz = nmemb * size;
 137    ptr = __coverity_alloc__(sz);
 138    __coverity_mark_as_uninitialized_buffer__(ptr);
 139    __coverity_mark_as_afm_allocated__(ptr, "g_free");
 140    return ptr;
 141}
 142
 143void *g_malloc0_n(size_t nmemb, size_t size)
 144{
 145    size_t sz;
 146    void *ptr;
 147
 148    __coverity_negative_sink__(nmemb);
 149    __coverity_negative_sink__(size);
 150    sz = nmemb * size;
 151    ptr = __coverity_alloc__(sz);
 152    __coverity_writeall0__(ptr);
 153    __coverity_mark_as_afm_allocated__(ptr, "g_free");
 154    return ptr;
 155}
 156
 157void *g_realloc_n(void *ptr, size_t nmemb, size_t size)
 158{
 159    size_t sz;
 160
 161    __coverity_negative_sink__(nmemb);
 162    __coverity_negative_sink__(size);
 163    sz = nmemb * size;
 164    __coverity_escape__(ptr);
 165    ptr = __coverity_alloc__(sz);
 166    /*
 167     * Memory beyond the old size isn't actually initialized.  Can't
 168     * model that.  See Coverity's realloc() model
 169     */
 170    __coverity_writeall__(ptr);
 171    __coverity_mark_as_afm_allocated__(ptr, "g_free");
 172    return ptr;
 173}
 174
 175void g_free(void *ptr)
 176{
 177    __coverity_free__(ptr);
 178    __coverity_mark_as_afm_freed__(ptr, "g_free");
 179}
 180
 181/*
 182 * Derive the g_try_FOO_n() from the g_FOO_n() by adding indeterminate
 183 * out of memory conditions
 184 */
 185
 186void *g_try_malloc_n(size_t nmemb, size_t size)
 187{
 188    int nomem;
 189
 190    if (nomem) {
 191        return NULL;
 192    }
 193    return g_malloc_n(nmemb, size);
 194}
 195
 196void *g_try_malloc0_n(size_t nmemb, size_t size)
 197{
 198    int nomem;
 199
 200    if (nomem) {
 201        return NULL;
 202    }
 203    return g_malloc0_n(nmemb, size);
 204}
 205
 206void *g_try_realloc_n(void *ptr, size_t nmemb, size_t size)
 207{
 208    int nomem;
 209
 210    if (nomem) {
 211        return NULL;
 212    }
 213    return g_realloc_n(ptr, nmemb, size);
 214}
 215
 216/* Trivially derive the g_FOO() from the g_FOO_n() */
 217
 218void *g_malloc(size_t size)
 219{
 220    return g_malloc_n(1, size);
 221}
 222
 223void *g_malloc0(size_t size)
 224{
 225    return g_malloc0_n(1, size);
 226}
 227
 228void *g_realloc(void *ptr, size_t size)
 229{
 230    return g_realloc_n(ptr, 1, size);
 231}
 232
 233void *g_try_malloc(size_t size)
 234{
 235    return g_try_malloc_n(1, size);
 236}
 237
 238void *g_try_malloc0(size_t size)
 239{
 240    return g_try_malloc0_n(1, size);
 241}
 242
 243void *g_try_realloc(void *ptr, size_t size)
 244{
 245    return g_try_realloc_n(ptr, 1, size);
 246}
 247
 248/* Other memory allocation functions */
 249
 250void *g_memdup(const void *ptr, unsigned size)
 251{
 252    unsigned char *dup;
 253    unsigned i;
 254
 255    if (!ptr) {
 256        return NULL;
 257    }
 258
 259    dup = g_malloc(size);
 260    for (i = 0; i < size; i++)
 261        dup[i] = ((unsigned char *)ptr)[i];
 262    return dup;
 263}
 264
 265/*
 266 * GLib string allocation functions
 267 */
 268
 269char *g_strdup(const char *s)
 270{
 271    char *dup;
 272    size_t i;
 273
 274    if (!s) {
 275        return NULL;
 276    }
 277
 278    __coverity_string_null_sink__(s);
 279    __coverity_string_size_sink__(s);
 280    dup = __coverity_alloc_nosize__();
 281    __coverity_mark_as_afm_allocated__(dup, "g_free");
 282    for (i = 0; (dup[i] = s[i]); i++) ;
 283    return dup;
 284}
 285
 286char *g_strndup(const char *s, size_t n)
 287{
 288    char *dup;
 289    size_t i;
 290
 291    __coverity_negative_sink__(n);
 292
 293    if (!s) {
 294        return NULL;
 295    }
 296
 297    dup = g_malloc(n + 1);
 298    for (i = 0; i < n && (dup[i] = s[i]); i++) ;
 299    dup[i] = 0;
 300    return dup;
 301}
 302
 303char *g_strdup_printf(const char *format, ...)
 304{
 305    char ch, *s;
 306    size_t len;
 307
 308    __coverity_string_null_sink__(format);
 309    __coverity_string_size_sink__(format);
 310
 311    ch = *format;
 312
 313    s = __coverity_alloc_nosize__();
 314    __coverity_writeall__(s);
 315    __coverity_mark_as_afm_allocated__(s, "g_free");
 316    return s;
 317}
 318
 319char *g_strdup_vprintf(const char *format, va_list ap)
 320{
 321    char ch, *s;
 322    size_t len;
 323
 324    __coverity_string_null_sink__(format);
 325    __coverity_string_size_sink__(format);
 326
 327    ch = *format;
 328    ch = *(char *)ap;
 329
 330    s = __coverity_alloc_nosize__();
 331    __coverity_writeall__(s);
 332    __coverity_mark_as_afm_allocated__(s, "g_free");
 333
 334    return len;
 335}
 336
 337char *g_strconcat(const char *s, ...)
 338{
 339    char *s;
 340
 341    /*
 342     * Can't model: last argument must be null, the others
 343     * null-terminated strings
 344     */
 345
 346    s = __coverity_alloc_nosize__();
 347    __coverity_writeall__(s);
 348    __coverity_mark_as_afm_allocated__(s, "g_free");
 349    return s;
 350}
 351
 352/* Other glib functions */
 353
 354typedef struct pollfd GPollFD;
 355
 356int poll();
 357
 358int g_poll (GPollFD *fds, unsigned nfds, int timeout)
 359{
 360    return poll(fds, nfds, timeout);
 361}
 362
 363typedef struct _GIOChannel GIOChannel;
 364GIOChannel *g_io_channel_unix_new(int fd)
 365{
 366    GIOChannel *c = g_malloc0(sizeof(GIOChannel));
 367    __coverity_escape__(fd);
 368    return c;
 369}
 370
 371void g_assertion_message_expr(const char     *domain,
 372                              const char     *file,
 373                              int             line,
 374                              const char     *func,
 375                              const char     *expr)
 376{
 377    __coverity_panic__();
 378}
 379