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Use PRINTF_FORTIFY instead of _IO_FLAGS2_FORTIFY (bug 11319)

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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 7ca890b88e
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.
This commit is contained in:
Zack Weinberg
2018-03-07 14:32:03 -05:00
committed by Gabriel F. T. Gomes
parent 124fc732c1
commit 4e2f43f842
35 changed files with 413 additions and 551 deletions
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68
debug/vasprintf_chk.c
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@@ -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)