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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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54
libio/iovsprintf.c
View File

@ -27,8 +27,47 @@
#include "libioP.h"
#include "strfile.h"
static int __THROW
_IO_str_chk_overflow (FILE *fp, int c)
{
/* If we get here, the user-supplied buffer would be overrun by
further output. */
__chk_fail ();
}
static const struct _IO_jump_t _IO_str_chk_jumps libio_vtable =
{
JUMP_INIT_DUMMY,
JUMP_INIT(finish, _IO_str_finish),
JUMP_INIT(overflow, _IO_str_chk_overflow),
JUMP_INIT(underflow, _IO_str_underflow),
JUMP_INIT(uflow, _IO_default_uflow),
JUMP_INIT(pbackfail, _IO_str_pbackfail),
JUMP_INIT(xsputn, _IO_default_xsputn),
JUMP_INIT(xsgetn, _IO_default_xsgetn),
JUMP_INIT(seekoff, _IO_str_seekoff),
JUMP_INIT(seekpos, _IO_default_seekpos),
JUMP_INIT(setbuf, _IO_default_setbuf),
JUMP_INIT(sync, _IO_default_sync),
JUMP_INIT(doallocate, _IO_default_doallocate),
JUMP_INIT(read, _IO_default_read),
JUMP_INIT(write, _IO_default_write),
JUMP_INIT(seek, _IO_default_seek),
JUMP_INIT(close, _IO_default_close),
JUMP_INIT(stat, _IO_default_stat),
JUMP_INIT(showmanyc, _IO_default_showmanyc),
JUMP_INIT(imbue, _IO_default_imbue)
};
/* This function is called by regular vsprintf with maxlen set to -1,
and by vsprintf_chk with maxlen set to the size of the output
string. In the former case, _IO_str_chk_overflow will never be
called; in the latter case it will crash the program if the buffer
overflows. */
int
__vsprintf_internal (char *string, const char *format, va_list args,
__vsprintf_internal (char *string, size_t maxlen,
const char *format, va_list args,
unsigned int mode_flags)
{
_IO_strfile sf;
@ -38,17 +77,22 @@ __vsprintf_internal (char *string, const char *format, va_list args,
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, -1, string);
_IO_JUMPS (&sf._sbf) = &_IO_str_chk_jumps;
string[0] = '\0';
_IO_str_init_static_internal (&sf, string,
(maxlen == -1) ? -1 : maxlen - 1,
string);
ret = __vfprintf_internal (&sf._sbf._f, format, args, mode_flags);
_IO_putc_unlocked ('\0', &sf._sbf._f);
*sf._sbf._f._IO_write_ptr = '\0';
return ret;
}
int
__vsprintf (char *string, const char *format, va_list args)
{
return __vsprintf_internal (string, format, args, 0);
return __vsprintf_internal (string, -1, format, args, 0);
}
ldbl_strong_alias (__vsprintf, _IO_vsprintf)