glibc/stdlib/Versions
Joseph Myers 8f5e8b01a1 Fix nan functions handling of payload strings (bug 16961, bug 16962).
The nan, nanf and nanl functions handle payload strings by doing e.g.:

  if (tagp[0] != '\0')
    {
      char buf[6 + strlen (tagp)];
      sprintf (buf, "NAN(%s)", tagp);
      return strtod (buf, NULL);
    }

This is an unbounded stack allocation based on the length of the
argument.  Furthermore, if the argument starts with an n-char-sequence
followed by ')', that n-char-sequence is wrongly treated as
significant for determining the payload of the resulting NaN, when ISO
C says the call should be equivalent to strtod ("NAN", NULL), without
being affected by that initial n-char-sequence.  This patch fixes both
those problems by using the __strtod_nan etc. functions recently
factored out of strtod etc. for that purpose, with those functions
being exported from libc at version GLIBC_PRIVATE.

Tested for x86_64, x86, mips64 and powerpc.

	[BZ #16961]
	[BZ #16962]
	* math/s_nan.c (__nan): Use __strtod_nan instead of constructing a
	string on the stack for strtod.
	* math/s_nanf.c (__nanf): Use __strtof_nan instead of constructing
	a string on the stack for strtof.
	* math/s_nanl.c (__nanl): Use __strtold_nan instead of
	constructing a string on the stack for strtold.
	* stdlib/Versions (libc): Add __strtof_nan, __strtod_nan and
	__strtold_nan to GLIBC_PRIVATE.
	* math/test-nan-overflow.c: New file.
	* math/test-nan-payload.c: Likewise.
	* math/Makefile (tests): Add test-nan-overflow and
	test-nan-payload.
2015-12-04 20:36:28 +00:00

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libc {
GLIBC_2.0 {
# functions with required interface outside normal name space
__xpg_basename;
# functions used in inline functions or macros
__strto*_internal;
# compatibility symbol
__secure_getenv;
# a*
a64l; abort; abs; atexit; atof; atoi; atol; atoll;
# b*
bsearch;
# c*
canonicalize_file_name; clearenv;
# d*
div; drand48; drand48_r;
# e*
erand48; erand48_r; exit;
# g*
getenv; getsubopt;
# i*
initstate; initstate_r;
# l*
l64a; labs; lcong48; lcong48_r; ldiv; llabs; lldiv; lrand48; lrand48_r;
# m*
mblen; mbrlen; mbrtowc; mbsinit; mbsnrtowcs; mbsrtowcs; mbstowcs;
mbtowc; mcheck; mcount; mrand48; mrand48_r;
# n*
nrand48; nrand48_r;
# o*
on_exit;
# p*
putenv;
# q*
qsort;
# r*
rand; rand_r; random; random_r; realpath; rpmatch;
# s*
seed48; seed48_r; setcontext; setenv; setstate; setstate_r; srand; srand48;
srand48_r; srandom; srandom_r; step; strfmon; strtod; strtof; strtol;
strtold; strtoll; strtoq; strtoul; strtoull; strtouq; system;
# u*
unsetenv;
# w*
wcstombs; wctomb;
}
GLIBC_2.1 {
# a*
addseverity;
# f*
fmtmsg;
# g*
getcontext;
# m*
makecontext;
# s*
strtoimax; strtoumax; swapcontext;
}
GLIBC_2.1.1 {
# _*
_Exit;
# i*
imaxabs; imaxdiv;
}
GLIBC_2.1.3 {
# used by new G++ ABI
__cxa_atexit; __cxa_finalize;
}
GLIBC_2.3 {
# Silent change in SUS.
realpath;
}
GLIBC_2.8 {
qsort_r;
}
GLIBC_2.10 {
quick_exit; __cxa_at_quick_exit;
}
GLIBC_2.13 {
__fentry__;
}
GLIBC_2.17 {
secure_getenv;
}
GLIBC_2.18 {
__cxa_thread_atexit_impl;
}
GLIBC_PRIVATE {
# functions which have an additional interface since they are
# are cancelable.
__libc_system;
# Variable which needs a dynamic symbol table entry.
__abort_msg;
# Used from other libraries
__libc_secure_getenv;
__call_tls_dtors;
__strtof_nan; __strtod_nan; __strtold_nan;
}
}