mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-29 05:51:10 +00:00
0d50f477f4
This shows up as an assertion failure when sprintf is called with a specifier like "%.8g" and libquadmath is linked in: Fatal glibc error: printf_buffer_as_file.c:31 (__printf_buffer_as_file_commit): assertion failed: file->stream._IO_write_ptr <= file->next->write_end Fix this by detecting pointer wraparound in __vsprintf_internal and saturate the addition to the end of the address space instead. Reviewed-by: Carlos O'Donell <carlos@redhat.com> Tested-by: Carlos O'Donell <carlos@redhat.com>
81 lines
3.0 KiB
C
81 lines
3.0 KiB
C
/* Copyright (C) 1993-2023 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/>.
|
|
|
|
As a special exception, if you link the code in this file with
|
|
files compiled with a GNU compiler to produce an executable,
|
|
that does not cause the resulting executable to be covered by
|
|
the GNU Lesser General Public License. This exception does not
|
|
however invalidate any other reasons why the executable file
|
|
might be covered by the GNU Lesser General Public License.
|
|
This exception applies to code released by its copyright holders
|
|
in files containing the exception. */
|
|
|
|
#include "libioP.h"
|
|
|
|
#include <printf.h>
|
|
#include <stdint.h>
|
|
#include <printf_buffer.h>
|
|
|
|
int
|
|
__vsprintf_internal (char *string, size_t maxlen,
|
|
const char *format, va_list args,
|
|
unsigned int mode_flags)
|
|
{
|
|
struct __printf_buffer buf;
|
|
|
|
/* When called from fortified sprintf/vsprintf, erase the destination
|
|
buffer and try to detect overflows. When called from regular
|
|
sprintf/vsprintf, do not erase the destination buffer, because
|
|
known user code relies on this behavior (even though its undefined
|
|
by ISO C), nor try to detect overflows. */
|
|
if ((mode_flags & PRINTF_CHK) != 0)
|
|
{
|
|
string[0] = '\0';
|
|
/* In some cases, __sprintf_chk is called with an unknown buffer
|
|
size (the special value -1). Prevent pointer wraparound in
|
|
this case and saturate to the end of the address space. */
|
|
uintptr_t end;
|
|
if (__builtin_add_overflow ((uintptr_t) string, maxlen, &end))
|
|
end = -1;
|
|
__printf_buffer_init_end (&buf, string, (char *) end,
|
|
__printf_buffer_mode_sprintf_chk);
|
|
}
|
|
else
|
|
/* Use end of address space. */
|
|
__printf_buffer_init_end (&buf, string, (char *) ~(uintptr_t) 0,
|
|
__printf_buffer_mode_sprintf);
|
|
|
|
__printf_buffer (&buf, format, args, mode_flags);
|
|
|
|
/* Write the NUL terminator if there is room. Do not use the putc
|
|
operation to avoid overflowing the character write count. */
|
|
if ((mode_flags & PRINTF_CHK) != 0 && buf.write_ptr == buf.write_end)
|
|
__chk_fail ();
|
|
*buf.write_ptr = '\0';
|
|
|
|
return __printf_buffer_done (&buf);
|
|
}
|
|
|
|
int
|
|
__vsprintf (char *string, const char *format, va_list args)
|
|
{
|
|
return __vsprintf_internal (string, -1, format, args, 0);
|
|
}
|
|
|
|
ldbl_strong_alias (__vsprintf, _IO_vsprintf)
|
|
ldbl_weak_alias (__vsprintf, vsprintf)
|