Account for grouping in printf width (bug 30068)

This is a partial fix for mishandling of grouping when formatting
integers.  It properly computes the width in the presence of grouping
characters when the width is larger than the number of significant
digits. The precision related issue is documented in bug 23432.

Co-authored-by: Andreas Schwab <schwab@suse.de>
(cherry picked from commit c980549cc6)
This commit is contained in:
Carlos O'Donell 2023-01-19 12:50:20 +01:00
parent fb7b95dc47
commit 07b9521fc6
3 changed files with 73 additions and 5 deletions

View File

@ -196,6 +196,7 @@ tests := \
tst-gets \ tst-gets \
tst-grouping \ tst-grouping \
tst-grouping2 \ tst-grouping2 \
tst-grouping3 \
tst-long-dbl-fphex \ tst-long-dbl-fphex \
tst-memstream-string \ tst-memstream-string \
tst-obprintf \ tst-obprintf \
@ -340,6 +341,7 @@ $(objpfx)tst-sscanf.out: $(gen-locales)
$(objpfx)tst-swprintf.out: $(gen-locales) $(objpfx)tst-swprintf.out: $(gen-locales)
$(objpfx)tst-vfprintf-mbs-prec.out: $(gen-locales) $(objpfx)tst-vfprintf-mbs-prec.out: $(gen-locales)
$(objpfx)tst-vfprintf-width-i18n.out: $(gen-locales) $(objpfx)tst-vfprintf-width-i18n.out: $(gen-locales)
$(objpfx)tst-grouping3.out: $(gen-locales)
endif endif
tst-printf-bz18872-ENV = MALLOC_TRACE=$(objpfx)tst-printf-bz18872.mtrace \ tst-printf-bz18872-ENV = MALLOC_TRACE=$(objpfx)tst-printf-bz18872.mtrace \

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@ -0,0 +1,54 @@
/* Test printf with grouping and padding (bug 30068)
Copyright (C) 2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <locale.h>
#include <stdio.h>
#include <support/check.h>
#include <support/support.h>
static int
do_test (void)
{
char buf[80];
xsetlocale (LC_NUMERIC, "de_DE.UTF-8");
/* The format string has the following conversion specifier:
' - Use thousands grouping.
+ - The result of a signed conversion shall begin with a sign.
- - Left justified.
13 - Minimum 13 bytes of width.
9 - Minimum 9 digits of precision.
In bug 30068 the grouping characters were not accounted for in
the width, and were added after the fact resulting in a 15-byte
output instead of a 13-byte output. The two additional bytes
come from the locale-specific thousands separator. This increase
in size could result in a buffer overflow if a reasonable caller
calculated the size of the expected buffer using nl_langinfo to
determine the sie of THOUSEP in bytes.
This bug is distinct from bug 23432 which has to do with the
minimum precision calculation (digit based). */
sprintf (buf, "%+-'13.9d", 1234567);
TEST_COMPARE_STRING (buf, "+001.234.567 ");
return 0;
}
#include <support/test-driver.c>

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@ -186,11 +186,17 @@ LABEL (unsigned_number): /* Unsigned number of base BASE. */
bool octal_marker = (prec <= number_length && number.word != 0 bool octal_marker = (prec <= number_length && number.word != 0
&& alt && base == 8); && alt && base == 8);
prec = MAX (0, prec - (workend - string)); /* At this point prec_inc is the additional bytes required for the
specificed precision. It is 0 if the precision would not have
required additional bytes i.e. the number of input digits is more
than the precision. It is greater than zero if the precision is
more than the number of digits without grouping (precision only
considers digits). */
unsigned int prec_inc = MAX (0, prec - (workend - string));
if (!left) if (!left)
{ {
width -= number_length + prec; width -= number_length + prec_inc;
if (number.word != 0 && alt && (base == 16 || base == 2)) if (number.word != 0 && alt && (base == 16 || base == 2))
/* Account for 0X, 0x, 0B or 0b hex or binary marker. */ /* Account for 0X, 0x, 0B or 0b hex or binary marker. */
@ -221,7 +227,7 @@ LABEL (unsigned_number): /* Unsigned number of base BASE. */
Xprintf_buffer_putc (buf, spec); Xprintf_buffer_putc (buf, spec);
} }
width += prec; width += prec_inc;
Xprintf_buffer_pad (buf, L_('0'), width); Xprintf_buffer_pad (buf, L_('0'), width);
if (octal_marker) if (octal_marker)
@ -237,6 +243,8 @@ LABEL (unsigned_number): /* Unsigned number of base BASE. */
} }
else else
{ {
/* Perform left justification adjustments. */
if (is_negative) if (is_negative)
{ {
Xprintf_buffer_putc (buf, L_('-')); Xprintf_buffer_putc (buf, L_('-'));
@ -263,9 +271,13 @@ LABEL (unsigned_number): /* Unsigned number of base BASE. */
if (octal_marker) if (octal_marker)
--width; --width;
width -= workend - string + prec; /* Adjust the width by subtracting the number of bytes
required to represent the number with grouping characters
(NUMBER_LENGTH) and any additional bytes required for
precision. */
width -= number_length + prec_inc;
Xprintf_buffer_pad (buf, L_('0'), prec); Xprintf_buffer_pad (buf, L_('0'), prec_inc);
if (octal_marker) if (octal_marker)
Xprintf_buffer_putc (buf, L_('0')); Xprintf_buffer_putc (buf, L_('0'));