gcc/testsuite/gcc.dg/builtin-stringop-chk-8.c

   1 /* Test exercising -Wstringop-overflow warnings for reading past the end.  */
   2 /* { dg-do compile } */
   3 /* { dg-options "-O2 -Wstringop-overflow=1 -ftrack-macro-expansion=0" } */
   4
   5 #define PTRDIFF_MAX   __PTRDIFF_MAX__
   6 #define SIZE_MAX      __SIZE_MAX__
   7
   8 #define offsetof(type, mem)   __builtin_offsetof (type, mem)
   9
  10 /* Return the number of bytes from member MEM of TYPE to the end
  11    of object OBJ.  */
  12 #define offsetfrom(type, obj, mem) (sizeof (obj) - offsetof (type, mem))
  13
  14
  15 typedef __SIZE_TYPE__ size_t;
  16 extern void* memchr (const void*, int, size_t);
  17 extern int memcmp (const void*, const void*, size_t);
  18 extern void* memcpy (void*, const void*, size_t);
  19 extern void* memmove (void*, const void*, size_t);
  20 extern void* mempcpy (void*, const void*, size_t);
  21
  22 #define memchr(d, s, n) sink (memchr (d, s, n))
  23 #define memcmp(d, s, n) sink (d, memcmp (d, s, n))
  24 #define memcpy(d, s, n) sink (memcpy (d, s, n))
  25 #define memmove(d, s, n) sink (memmove (d, s, n))
  26 #define mempcpy(d, s, n) sink (mempcpy (d, s, n))
  27
  28 struct A { char a, b; };
  29 struct B { struct A a; char c, d; };
  30
  31 /* Function to call to "escape" pointers from tests below to prevent
  32    GCC from assuming the values of the objects they point to stay
  33    the unchanged.  */
  34 void sink (void*, ...);
  35
  36 /* Function to "generate" a random number each time it's called.  Declared
  37    (but not defined) and used to prevent GCC from making assumptions about
  38    their values based on the variables uses in the tested expressions.  */
  39 size_t random_unsigned_value (void);
  40
  41 /* Return a random unsigned value between MIN and MAX.  */
  42
  43 static inline size_t
  44 range (size_t min, size_t max)
  45 {
  46   const size_t val = random_unsigned_value ();
  47   return val < min || max < val ? min : val;
  48 }
  49
  50 #define R(min, max)   range (min, max)
  51
  52 /* Verify that reading beyond the end of a local array is diagnosed.  */
  53
  54 void test_memop_warn_local (void *p, const void *q)
  55 {
  56   memcpy (p, "1234", R (6, 7));   /* { dg-warning "reading between 6 and 7 bytes from a region of size 5" } */
  57
  58   struct A a[2];
  59
  60   memcpy (p, a, R (7, 8));   /* { dg-warning "reading between 7 and 8 bytes from a region of size 4" } */
  61
  62   /* At -Wstringop-overflow=1 the destination is considered to be
  63      the whole array and its size is therefore sizeof a.  */
  64   memcpy (p, &a[0], R (8, 9));   /* { dg-warning "reading between 8 and 9 bytes from a region of size 4" } */
  65
  66   /* Verify the same as above but by reading from the first mmeber
  67      of the first element of the array.  */
  68   memcpy (p, &a[0].a, R (8, 9));   /* { dg-warning "reading between 8 and 9 bytes from a region of size 4" } */
  69
  70   struct B b[2];
  71
  72   memcpy (p, &b[0], R (12, 32));   /* { dg-warning "reading between 12 and 32 bytes from a region of size 8" } */
  73
  74   /* Verify memchr/memcmp.  */
  75   int i = R (0, 255);
  76   memchr ("", i, 2);   /* { dg-warning "reading 2 bytes from a region of size 1" } */
  77   memchr ("", i, 2);   /* { dg-warning "reading 2 bytes from a region of size 1" } */
  78   memchr ("123", i, 5);   /* { dg-warning "reading 5 bytes from a region of size 4" } */
  79   memchr (a, i, sizeof a + 1);   /* { dg-warning "reading 5 bytes from a region of size 4" } */
  80
  81   memcmp (p, "", 2);   /* { dg-warning "reading 2 bytes from a region of size 1" } */
  82   memcmp (p, "123", 5);   /* { dg-warning "reading 5 bytes from a region of size 4" } */
  83   memcmp (p, a, sizeof a + 1);   /* { dg-warning "reading 5 bytes from a region of size 4" } */
  84
  85   size_t n = PTRDIFF_MAX + (size_t)1;
  86   memchr (p, 1, n);   /* { dg-warning "exceeds maximum object size" } */
  87   memcmp (p, q, n);   /* { dg-warning "exceeds maximum object size" } */
  88
  89   n = SIZE_MAX;
  90   memchr (p, 1, n);   /* { dg-warning "exceeds maximum object size" } */
  91   memcmp (p, q, n);   /* { dg-warning "exceeds maximum object size" } */
  92 }
  93
  94 /* Verify that reading beyond the end of a dynamically allocated array
  95    of known size is diagnosed.  */
  96
  97 void test_memop_warn_alloc (void *p)
  98 {
  99   size_t n;
 100
 101   n = range (8, 32);
 102
 103   struct A *a = __builtin_malloc (sizeof *a * 2);
 104
 105   memcpy (p, a, n);   /* { dg-warning "reading between 8 and 32 bytes from region of size 4" "memcpy from allocated" { xfail *-*-*} } */
 106
 107   memcpy (p, &a[0], n);   /* { dg-warning "reading between 8 and 32 bytes from a region of size 4" "memcpy from allocated" { xfail *-*-*} } */
 108
 109   memcpy (p, &a[0].a, n);   /* { dg-warning "reading between 8 and 32 bytes from a region of size 4" "memcpy from allocated" { xfail *-*-*} } */
 110
 111   n = range (12, 32);
 112
 113   struct B *b = __builtin_malloc (sizeof *b * 2);
 114
 115   memcpy (p, &b[0], n);   /* { dg-warning "reading between 12 and 32 bytes from a region of size 8" "memcpy from allocated" { xfail *-*-*} } */
 116
 117   /* Verify memchr/memcmp.  */
 118   n = sizeof *b * 2 + 1;
 119
 120   memchr (b, 1, n);   /* { dg-warning "reading 5 bytes from a region of size 4" "memcmp from allocated" { xfail *-*-* } } */
 121   memcmp (p, b, n);   /* { dg-warning "reading 5 bytes from a region of size 4" "memcmp from allocated" { xfail *-*-* } } */
 122 }
 123
 124
 125 void test_memop_nowarn (void *p)
 126 {
 127   struct B b[2];
 128
 129   size_t n = range (sizeof b, 32);
 130
 131   /* Verify that copying the whole array is not diagnosed regardless
 132      of whether the expression pointing to its beginning is obtained
 133      from the array itself or its first member(s).  */
 134   memcpy (p, b, n);
 135
 136   memcpy (p, &b[0], n);
 137
 138   memcpy (p, &b[0].a, n);
 139
 140   memcpy (p, &b[0].a.a, n);
 141
 142   /* Verify that memchr/memcmp doesn't cause a warning.  */
 143   memchr (p, 1, n);
 144   memchr (b, 2, n);
 145   memchr (&b[0], 3, n);
 146   memchr (&b[0].a, 4, n);
 147   memchr (&b[0].a.a, 5, n);
 148   memchr ("01234567", R (0, 255), n);
 149
 150   memcmp (p, p, n);
 151   memcmp (p, b, n);
 152   memcmp (p, &b[0], n);
 153   memcmp (p, &b[0].a, n);
 154   memcmp (p, &b[0].a.a, n);
 155   memcmp (p, "01234567", n);
 156 }
 157
 158
 159 /* The following function could specify in its API that it takes
 160    an array of exactly two elements, as shown below (or simply be
 161    called with such an array).  Verify that reading from both
 162    elements is not diagnosed.  */
 163 void test_memop_nowarn_arg (void*, const struct A[2]);
 164
 165 void test_memop_nowarn_arg (void *p, const struct A *a)
 166 {
 167   memcpy (p, a, 2 * sizeof *a);
 168
 169   memcpy (p, a, range (2 * sizeof *a, 123));
 170
 171   memchr (p, 1, 1234);
 172   memcmp (p, a, 1234);
 173 }