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authorZack Weinberg <zackw@panix.com>2018-03-07 14:32:03 -0500
committerGabriel F. T. Gomes <gabriel@inconstante.eti.br>2018-12-05 18:15:43 -0200
commit4e2f43f842ef5e253cc23383645adbaa03cedb86 (patch)
treeca359423ba6ed4bb4d5ec247905a6ee13d456864 /debug/vasprintf_chk.c
parent124fc732c15ef37b7ee9db25b1e9f9b20c799623 (diff)
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Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319)
The _chk variants of all of the printf functions become much simpler.
This is the last thing that we needed _IO_acquire_lock_clear_flags2
for, so it can go as well.  I took the opportunity to make the headers
included and the names of all local variables consistent across all the
affected files.

Since we ultimately want to get rid of __no_long_double as well, it
must be possible to get all of the nontrivial effects of the _chk
functions by calling the _internal functions with appropriate flags.
For most of the __(v)xprintf_chk functions, this is covered by
PRINTF_FORTIFY plus some up-front argument checks that can be
duplicated.  However, __(v)sprintf_chk installs a custom jump table so
that it can crash instead of overflowing the output buffer.  This
functionality is moved to __vsprintf_internal, which now has a
'maxlen' argument like __vsnprintf_internal; to get the unsafe
behavior of ordinary (v)sprintf, pass -1 for that argument.

obstack_printf_chk and obstack_vprintf_chk are no longer in the same
file.

As a side-effect of the unification of both fortified and non-fortified
vdprintf initialization, this patch fixes bug 11319 for __dprintf_chk
and __vdprintf_chk, which was previously fixed only for dprintf and
vdprintf by the commit

commit 7ca890b88e6ab7624afb1742a9fffb37ad5b3fc3
Author: Ulrich Drepper <drepper@redhat.com>
Date:   Wed Feb 24 16:07:57 2010 -0800

    Fix reporting of I/O errors in *dprintf functions.

This patch adds a test case to avoid regressions.

Tested for powerpc and powerpc64le.
Diffstat (limited to 'debug/vasprintf_chk.c')
-rw-r--r--debug/vasprintf_chk.c68
1 files changed, 5 insertions, 63 deletions
diff --git a/debug/vasprintf_chk.c b/debug/vasprintf_chk.c
index dbfebff83f..f5975ea02a 100644
--- a/debug/vasprintf_chk.c
+++ b/debug/vasprintf_chk.c
@@ -24,72 +24,14 @@
    This exception applies to code released by its copyright holders
    in files containing the exception.  */
 
-#include <malloc.h>
-#include <string.h>
-#include <stdio.h>
-#include <stdio_ext.h>
-#include "../libio/libioP.h"
-#include "../libio/strfile.h"
+#include <libio/libioP.h>
 
 int
-__vasprintf_chk (char **result_ptr, int flags, const char *format,
-		 va_list args)
+__vasprintf_chk (char **result_ptr, int flag, const char *format, va_list ap)
 {
-  /* Initial size of the buffer to be used.  Will be doubled each time an
-     overflow occurs.  */
-  const size_t init_string_size = 100;
-  char *string;
-  _IO_strfile sf;
-  int ret;
-  size_t needed;
-  size_t allocated;
-  /* No need to clear the memory here (unlike for open_memstream) since
-     we know we will never seek on the stream.  */
-  string = (char *) malloc (init_string_size);
-  if (string == NULL)
-    return -1;
-#ifdef _IO_MTSAFE_IO
-  sf._sbf._f._lock = NULL;
-#endif
-  _IO_no_init (&sf._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
-  _IO_JUMPS (&sf._sbf) = &_IO_str_jumps;
-  _IO_str_init_static_internal (&sf, string, init_string_size, string);
-  sf._sbf._f._flags &= ~_IO_USER_BUF;
-  sf._s._allocate_buffer_unused = (_IO_alloc_type) malloc;
-  sf._s._free_buffer_unused = (_IO_free_type) free;
-
-  /* For flags > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
+  /* For flag > 0 (i.e. __USE_FORTIFY_LEVEL > 1) request that %n
      can only come from read-only format strings.  */
-  if (flags > 0)
-    sf._sbf._f._flags2 |= _IO_FLAGS2_FORTIFY;
+  unsigned int mode = (flag > 0) ? PRINTF_FORTIFY : 0;
 
-  ret = __vfprintf_internal (&sf._sbf._f, format, args, 0);
-  if (ret < 0)
-    {
-      free (sf._sbf._f._IO_buf_base);
-      return ret;
-    }
-  /* Only use realloc if the size we need is of the same (binary)
-     order of magnitude then the memory we allocated.  */
-  needed = sf._sbf._f._IO_write_ptr - sf._sbf._f._IO_write_base + 1;
-  allocated = sf._sbf._f._IO_write_end - sf._sbf._f._IO_write_base;
-  if ((allocated >> 1) <= needed)
-    *result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
-  else
-    {
-      *result_ptr = (char *) malloc (needed);
-      if (*result_ptr != NULL)
-	{
-	  memcpy (*result_ptr, sf._sbf._f._IO_buf_base, needed - 1);
-	  free (sf._sbf._f._IO_buf_base);
-	}
-      else
-	/* We have no choice, use the buffer we already have.  */
-	*result_ptr = (char *) realloc (sf._sbf._f._IO_buf_base, needed);
-    }
-  if (*result_ptr == NULL)
-    *result_ptr = sf._sbf._f._IO_buf_base;
-  (*result_ptr)[needed - 1] = '\0';
-  return ret;
+  return __vasprintf_internal (result_ptr, format, ap, mode);
 }
-libc_hidden_def (__vasprintf_chk)