sprintf-chk.c

来自「linux下编程用 编译软件」· C语言 代码 · 共 198 行

/* Copyright (C) 2004, 2005  Free Software Foundation.

   Ensure builtin __sprintf_chk performs correctly.  */

extern void abort (void);
typedef __SIZE_TYPE__ size_t;
extern size_t strlen(const char *);
extern void *memcpy (void *, const void *, size_t);
extern char *strcpy (char *, const char *);
extern int memcmp (const void *, const void *, size_t);
extern void *memset (void *, int, size_t);
extern int sprintf (char *, const char *, ...);

#include "chk.h"

const char s1[] = "123";
char p[32] = "";
char *s2 = "defg";
char *s3 = "FGH";
char *s4;
size_t l1 = 1;
static char buffer[32];
char *ptr = "barf";

void
__attribute__((noinline))
test1 (void)
{
  chk_calls = 0;
  sprintf_disallowed = 1;

  memset (buffer, 'A', 32);
  sprintf (buffer, "foo");
  if (memcmp (buffer, "foo", 4) || buffer[4] != 'A')
    abort ();

  memset (buffer, 'A', 32);
  if (sprintf (buffer, "foo") != 3)
    abort ();
  if (memcmp (buffer, "foo", 4) || buffer[4] != 'A')
    abort ();

  memset (buffer, 'A', 32);
  sprintf (buffer, "%s", "bar");
  if (memcmp (buffer, "bar", 4) || buffer[4] != 'A')
    abort ();

  memset (buffer, 'A', 32);
  if (sprintf (buffer, "%s", "bar") != 3)
    abort ();
  if (memcmp (buffer, "bar", 4) || buffer[4] != 'A')
    abort ();

  if (chk_calls)
    abort ();
  sprintf_disallowed = 0;

  memset (buffer, 'A', 32);
  sprintf (buffer, "%s", ptr);
  if (memcmp (buffer, "barf", 5) || buffer[5] != 'A')
    abort ();

  memset (buffer, 'A', 32);
  sprintf (buffer, "%d - %c", (int) l1 + 27, *ptr);
  if (memcmp (buffer, "28 - b\0AAAAA", 12))
    abort ();

  if (chk_calls != 2)
    abort ();
  chk_calls = 0;

  sprintf (s4, "%d - %c", (int) l1 - 17, ptr[1]);
  if (memcmp (s4, "-16 - a", 8))
    abort ();
  if (chk_calls)
    abort ();
}

/* Test whether compile time checking is done where it should
   and so is runtime object size checking.  */
void
__attribute__((noinline))
test2 (void)
{
  struct A { char buf1[10]; char buf2[10]; } a;
  char *r = l1 == 1 ? &a.buf1[5] : &a.buf2[4];
  char buf3[20];
  int i;

  /* The following calls should do runtime checking
     - source length is not known, but destination is.  */
  chk_calls = 0;
  sprintf (a.buf1 + 2, "%s", s3 + 3);
  sprintf (r, "%s%c", s3 + 3, s3[3]);
  r = l1 == 1 ? __builtin_alloca (4) : &a.buf2[7];
  sprintf (r, "%c %s", s2[2], s2 + 4);
  sprintf (r + 2, s3 + 3);
  r = buf3;
  for (i = 0; i < 4; ++i)
    {
      if (i == l1 - 1)
	r = &a.buf1[1];
      else if (i == l1)
	r = &a.buf2[7];
      else if (i == l1 + 1)
	r = &buf3[5];
      else if (i == l1 + 2)
	r = &a.buf1[9];
    }
  sprintf (r, s2 + 4);
  if (chk_calls != 5)
    abort ();

  /* Following have known destination and known source length,
     so if optimizing certainly shouldn't result in the checking
     variants.  */
  chk_calls = 0;
  sprintf_disallowed = 1;
  sprintf (a.buf1 + 2, "");
  sprintf (r, "a");
  r = l1 == 1 ? __builtin_alloca (4) : &a.buf2[7];
  sprintf (r, "%s", s1 + 1);
  r = buf3;
  for (i = 0; i < 4; ++i)
    {
      if (i == l1 - 1)
	r = &a.buf1[1];
      else if (i == l1)
	r = &a.buf2[7];
      else if (i == l1 + 1)
	r = &buf3[5];
      else if (i == l1 + 2)
	r = &a.buf1[9];
    }
  sprintf (r, "%s", "");
  sprintf_disallowed = 0;
  /* Unknown destination and source, no checking.  */
  sprintf (s4, "%s %d", s3, 0);
  if (chk_calls)
    abort ();
}

/* Test whether runtime and/or compile time checking catches
   buffer overflows.  */
void
__attribute__((noinline))
test3 (void)
{
  struct A { char buf1[10]; char buf2[10]; } a;
  char buf3[20];

  chk_fail_allowed = 1;
  /* Runtime checks.  */
  if (__builtin_setjmp (chk_fail_buf) == 0)
    {
      sprintf (&a.buf2[9], "%c%s", s2[3], s2 + 4);
      abort ();
    }
  if (__builtin_setjmp (chk_fail_buf) == 0)
    {
      sprintf (&a.buf2[7], "%s%c", s3 + strlen (s3) - 2, *s3);
      abort ();
    }
  if (__builtin_setjmp (chk_fail_buf) == 0)
    {
      sprintf (&a.buf2[7], "%d", (int) l1 + 9999);
      abort ();
    }
  /* This should be detectable at compile time already.  */
  if (__builtin_setjmp (chk_fail_buf) == 0)
    {
      sprintf (&buf3[19], "a");
      abort ();
    }
  if (__builtin_setjmp (chk_fail_buf) == 0)
    {
      sprintf (&buf3[17], "%s", "abc");
      abort ();
    }
  chk_fail_allowed = 0;
}

void
main_test (void)
{
#ifndef __OPTIMIZE__
  /* Object size checking is only intended for -O[s123].  */
  return;
#endif
  __asm ("" : "=r" (s2) : "0" (s2));
  __asm ("" : "=r" (s3) : "0" (s3));
  __asm ("" : "=r" (l1) : "0" (l1));
  s4 = p;
  test1 ();
  test2 ();
  test3 ();
}