mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-15 09:30:06 +00:00
9333498794
Bug 25487 reports stack corruption in ldbl-96 sinl on a pseudo-zero argument (an representation where all the significand bits, including the explicit high bit, are zero, but the exponent is not zero, which is not a valid representation for the long double type). Although this is not a valid long double representation, existing practice in this area (see bug 4586, originally marked invalid but subsequently fixed) is that we still seek to avoid invalid memory accesses as a result, in case of programs that treat arbitrary binary data as long double representations, although the invalid representations of the ldbl-96 format do not need to be consistently handled the same as any particular valid representation. This patch makes the range reduction detect pseudo-zero and unnormal representations that would otherwise go to __kernel_rem_pio2, and returns a NaN for them instead of continuing with the range reduction process. (Pseudo-zero and unnormal representations whose unbiased exponent is less than -1 have already been safely returned from the function before this point without going through the rest of range reduction.) Pseudo-zero representations would previously result in the value passed to __kernel_rem_pio2 being all-zero, which is definitely unsafe; unnormal representations would previously result in a value passed whose high bit is zero, which might well be unsafe since that is not a form of input expected by __kernel_rem_pio2. Tested for x86_64.
42 lines
1.3 KiB
C
42 lines
1.3 KiB
C
/* Test sinl for pseudo-zeros and unnormals for ldbl-96 (bug 25487).
|
|
Copyright (C) 2020 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 <math.h>
|
|
#include <math_ldbl.h>
|
|
#include <stdint.h>
|
|
|
|
static int
|
|
do_test (void)
|
|
{
|
|
for (int i = 0; i < 64; i++)
|
|
{
|
|
uint64_t sig = i == 63 ? 0 : 1ULL << i;
|
|
long double ld;
|
|
SET_LDOUBLE_WORDS (ld, 0x4141,
|
|
sig >> 32, sig & 0xffffffffULL);
|
|
/* The requirement is that no stack overflow occurs when the
|
|
pseudo-zero or unnormal goes through range reduction. */
|
|
volatile long double ldr;
|
|
ldr = sinl (ld);
|
|
(void) ldr;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#include <support/test-driver.c>
|