libstdc++: Fix undefined behaviour in random dist serialization (PR93205)

Message ID 20200109164408.GA1304986@redhat.com
State New
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Series
  • libstdc++: Fix undefined behaviour in random dist serialization (PR93205)
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Commit Message

Jonathan Wakely Jan. 9, 2020, 4:44 p.m.
The deserialization functions for random number distributions fail to
check the stream state before using the extracted values. In some cases
this leads to using indeterminate values to resize a vector, and then
filling that vector with indeterminate values.

No values that affect control flow should be used without checking that a
good value was read from the stream.

Additionally, where reasonable to do so, defer modifying any state in
the distribution until all values have been successfully read, to avoid
modifying some of the distribution's parameters and leaving others
unchanged.

	PR libstdc++/93205
	* include/bits/random.h (operator>>): Check stream operation succeeds.
	* include/bits/random.tcc (operator<<): Remove redundant __ostream_type
	typedefs.
	(operator>>): Remove redundant __istream_type typedefs. Check stream
	operations succeed.
	(__extract_params): New function to fill a vector from a stream.
	* testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error line.

Tested powerpc64le-linux, committed to trunk.

I think some parts of this should be backported too, since it can lead
to crashes or worse.
commit 66851cd6d1fd84c963974b5142d9364ec4c018f6
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jan 9 16:17:36 2020 +0000

    libstdc++: Fix undefined behaviour in random dist serialization (PR93205)
    
    The deserialization functions for random number distributions fail to
    check the stream state before using the extracted values. In some cases
    this leads to using indeterminate values to resize a vector, and then
    filling that vector with indeterminate values.
    
    No values that affect control flow should be used without checking that a
    good value was read from the stream.
    
    Additionally, where reasonable to do so, defer modifying any state in
    the distribution until all values have been successfully read, to avoid
    modifying some of the distribution's parameters and leaving others
    unchanged.
    
            PR libstdc++/93205
            * include/bits/random.h (operator>>): Check stream operation succeeds.
            * include/bits/random.tcc (operator<<): Remove redundant __ostream_type
            typedefs.
            (operator>>): Remove redundant __istream_type typedefs. Check stream
            operations succeed.
            (__extract_params): New function to fill a vector from a stream.
            * testsuite/26_numerics/random/pr60037-neg.cc: Adjust dg-error line.

Patch

diff --git a/libstdc++-v3/include/bits/random.h b/libstdc++-v3/include/bits/random.h
index 9e8a77c9a63..3eefdefc96f 100644
--- a/libstdc++-v3/include/bits/random.h
+++ b/libstdc++-v3/include/bits/random.h
@@ -3720,13 +3720,13 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
    * @returns The input stream with @p __x extracted or in an error state.
    */
   template<typename _CharT, typename _Traits>
-    std::basic_istream<_CharT, _Traits>&
+    inline std::basic_istream<_CharT, _Traits>&
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       std::bernoulli_distribution& __x)
     {
       double __p;
-      __is >> __p;
-      __x.param(bernoulli_distribution::param_type(__p));
+      if (__is >> __p)
+	__x.param(bernoulli_distribution::param_type(__p));
       return __is;
     }
 
diff --git a/libstdc++-v3/include/bits/random.tcc b/libstdc++-v3/include/bits/random.tcc
index 0beef1febd0..f67b2fe48f4 100644
--- a/libstdc++-v3/include/bits/random.tcc
+++ b/libstdc++-v3/include/bits/random.tcc
@@ -155,8 +155,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       const linear_congruential_engine<_UIntType,
 						__a, __c, __m>& __lcr)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -176,8 +175,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       linear_congruential_engine<_UIntType, __a, __c, __m>& __lcr)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec);
@@ -477,8 +475,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       const mersenne_twister_engine<_UIntType, __w, __n, __m,
 	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -505,8 +502,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       mersenne_twister_engine<_UIntType, __w, __n, __m,
 	       __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
@@ -633,8 +629,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       const subtract_with_carry_engine<_UIntType,
 						__w, __s, __r>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -657,8 +652,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       subtract_with_carry_engine<_UIntType, __w, __s, __r>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
@@ -703,8 +697,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	       const discard_block_engine<_RandomNumberEngine,
 	       __p, __r>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -725,8 +718,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       discard_block_engine<_RandomNumberEngine, __p, __r>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
@@ -831,8 +823,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const shuffle_order_engine<_RandomNumberEngine, __k>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -856,8 +847,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       shuffle_order_engine<_RandomNumberEngine, __k>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
@@ -877,8 +867,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const uniform_int_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -898,16 +887,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       uniform_int_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename uniform_int_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _IntType __a, __b;
-      __is >> __a >> __b;
-      __x.param(typename uniform_int_distribution<_IntType>::
-		param_type(__a, __b));
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
 
       __is.flags(__flags);
       return __is;
@@ -936,8 +925,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const uniform_real_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -960,16 +948,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       uniform_real_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename uniform_real_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::skipws);
 
       _RealType __a, __b;
-      __is >> __a >> __b;
-      __x.param(typename uniform_real_distribution<_RealType>::
-		param_type(__a, __b));
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
 
       __is.flags(__flags);
       return __is;
@@ -998,8 +986,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const bernoulli_distribution& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1080,8 +1067,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const geometric_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1104,15 +1090,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       geometric_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename geometric_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::skipws);
 
       double __p;
-      __is >> __p;
-      __x.param(typename geometric_distribution<_IntType>::param_type(__p));
+      if (__is >> __p)
+	__x.param(param_type(__p));
 
       __is.flags(__flags);
       return __is;
@@ -1195,8 +1181,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const negative_binomial_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1220,17 +1205,17 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       negative_binomial_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename negative_binomial_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::skipws);
 
       _IntType __k;
       double __p;
-      __is >> __k >> __p >> __x._M_gd;
-      __x.param(typename negative_binomial_distribution<_IntType>::
-		param_type(__k, __p));
+      if (__is >> __k >> __p >> __x._M_gd)
+	__x.param(param_type(__k, __p));
 
       __is.flags(__flags);
       return __is;
@@ -1406,8 +1391,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const poisson_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1431,15 +1415,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       poisson_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename poisson_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::skipws);
 
       double __mean;
-      __is >> __mean >> __x._M_nd;
-      __x.param(typename poisson_distribution<_IntType>::param_type(__mean));
+      if (__is >> __mean >> __x._M_nd)
+	__x.param(param_type(__mean));
 
       __is.flags(__flags);
       return __is;
@@ -1673,8 +1657,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const binomial_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1699,17 +1682,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       binomial_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename binomial_distribution<_IntType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _IntType __t;
       double __p;
-      __is >> __t >> __p >> __x._M_nd;
-      __x.param(typename binomial_distribution<_IntType>::
-		param_type(__t, __p));
+      if (__is >> __t >> __p >> __x._M_nd)
+	__x.param(param_type(__t, __p));
 
       __is.flags(__flags);
       return __is;
@@ -1737,8 +1719,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const exponential_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1760,16 +1741,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       exponential_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename exponential_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __lambda;
-      __is >> __lambda;
-      __x.param(typename exponential_distribution<_RealType>::
-		param_type(__lambda));
+      if (__is >> __lambda)
+	__x.param(param_type(__lambda));
 
       __is.flags(__flags);
       return __is;
@@ -1904,8 +1885,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const normal_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1931,19 +1911,22 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       normal_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename normal_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       double __mean, __stddev;
-      __is >> __mean >> __stddev
-	   >> __x._M_saved_available;
-      if (__x._M_saved_available)
-	__is >> __x._M_saved;
-      __x.param(typename normal_distribution<_RealType>::
-		param_type(__mean, __stddev));
+      bool __saved_avail;
+      if (__is >> __mean >> __stddev >> __saved_avail)
+	{
+	  if (__saved_avail && (__is >> __x._M_saved))
+	    {
+	      __x._M_saved_available = __saved_avail;
+	      __x.param(param_type(__mean, __stddev));
+	    }
+	}
 
       __is.flags(__flags);
       return __is;
@@ -1969,8 +1952,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const lognormal_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -1994,16 +1976,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       lognormal_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename lognormal_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __m, __s;
-      __is >> __m >> __s >> __x._M_nd;
-      __x.param(typename lognormal_distribution<_RealType>::
-		param_type(__m, __s));
+      if (__is >> __m >> __s >> __x._M_nd)
+	__x.param(param_type(__m, __s));
 
       __is.flags(__flags);
       return __is;
@@ -2042,8 +2024,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const chi_squared_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2066,16 +2047,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       chi_squared_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename chi_squared_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __n;
-      __is >> __n >> __x._M_gd;
-      __x.param(typename chi_squared_distribution<_RealType>::
-		param_type(__n));
+      if (__is >> __n >> __x._M_gd)
+	__x.param(param_type(__n));
 
       __is.flags(__flags);
       return __is;
@@ -2129,8 +2110,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const cauchy_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2153,16 +2133,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       cauchy_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename cauchy_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __a, __b;
-      __is >> __a >> __b;
-      __x.param(typename cauchy_distribution<_RealType>::
-		param_type(__a, __b));
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
 
       __is.flags(__flags);
       return __is;
@@ -2206,8 +2185,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const fisher_f_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2231,16 +2209,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       fisher_f_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename fisher_f_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __m, __n;
-      __is >> __m >> __n >> __x._M_gd_x >> __x._M_gd_y;
-      __x.param(typename fisher_f_distribution<_RealType>::
-		param_type(__m, __n));
+      if (__is >> __m >> __n >> __x._M_gd_x >> __x._M_gd_y)
+	__x.param(param_type(__m, __n));
 
       __is.flags(__flags);
       return __is;
@@ -2281,8 +2259,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const student_t_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2305,15 +2282,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       student_t_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename student_t_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __n;
-      __is >> __n >> __x._M_nd >> __x._M_gd;
-      __x.param(typename student_t_distribution<_RealType>::param_type(__n));
+      if (__is >> __n >> __x._M_nd >> __x._M_gd)
+	__x.param(param_type(__n));
 
       __is.flags(__flags);
       return __is;
@@ -2450,8 +2428,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const gamma_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2475,16 +2452,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       gamma_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename gamma_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __alpha_val, __beta_val;
-      __is >> __alpha_val >> __beta_val >> __x._M_nd;
-      __x.param(typename gamma_distribution<_RealType>::
-		param_type(__alpha_val, __beta_val));
+      if (__is >> __alpha_val >> __beta_val >> __x._M_nd)
+	__x.param(param_type(__alpha_val, __beta_val));
 
       __is.flags(__flags);
       return __is;
@@ -2528,8 +2504,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const weibull_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2552,16 +2527,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       weibull_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type = typename weibull_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __a, __b;
-      __is >> __a >> __b;
-      __x.param(typename weibull_distribution<_RealType>::
-		param_type(__a, __b));
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
 
       __is.flags(__flags);
       return __is;
@@ -2604,8 +2578,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const extreme_value_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2628,16 +2601,16 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       extreme_value_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using param_type
+	= typename extreme_value_distribution<_RealType>::param_type;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       _RealType __a, __b;
-      __is >> __a >> __b;
-      __x.param(typename extreme_value_distribution<_RealType>::
-		param_type(__a, __b));
+      if (__is >> __a >> __b)
+	__x.param(param_type(__a, __b));
 
       __is.flags(__flags);
       return __is;
@@ -2740,8 +2713,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const discrete_distribution<_IntType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2762,32 +2734,44 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
       return __os;
     }
 
+namespace __detail
+{
+  template<typename _ValT, typename _CharT, typename _Traits>
+    basic_istream<_CharT, _Traits>&
+    __extract_params(basic_istream<_CharT, _Traits>& __is,
+		     vector<_ValT>& __vals, size_t __n)
+    {
+      __vals.reserve(__n);
+      while (__n--)
+	{
+	  _ValT __val;
+	  if (__is >> __val)
+	    __vals.push_back(__val);
+	  else
+	    break;
+	}
+      return __is;
+    }
+} // namespace __detail
+
   template<typename _IntType, typename _CharT, typename _Traits>
     std::basic_istream<_CharT, _Traits>&
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       discrete_distribution<_IntType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
-      size_t __n = 0;
-      __is >> __n;
-
-      std::vector<double> __prob_vec;
-      __prob_vec.reserve(__n);
-      for (; __n != 0; --__n)
+      size_t __n;
+      if (__is >> __n)
 	{
-	  double __prob;
-	  __is >> __prob;
-	  __prob_vec.push_back(__prob);
+	  std::vector<double> __prob_vec;
+	  if (__detail::__extract_params(__is, __prob_vec, __n))
+	    __x.param({__prob_vec.begin(), __prob_vec.end()});
 	}
 
-      __x.param(typename discrete_distribution<_IntType>::
-		param_type(__prob_vec.begin(), __prob_vec.end()));
-
       __is.flags(__flags);
       return __is;
     }
@@ -2950,8 +2934,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const piecewise_constant_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -2982,36 +2965,26 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       piecewise_constant_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       size_t __n;
-      __is >> __n;
-
-      std::vector<_RealType> __int_vec;
-      __int_vec.reserve(__n + 1);
-      for (size_t __i = 0; __i <= __n; ++__i)
+      if (__is >> __n)
 	{
-	  _RealType __int;
-	  __is >> __int;
-	  __int_vec.push_back(__int);
+	  std::vector<_RealType> __int_vec;
+	  if (__detail::__extract_params(__is, __int_vec, __n + 1))
+	    {
+	      std::vector<double> __den_vec;
+	      if (__detail::__extract_params(__is, __den_vec, __n))
+		{
+		  __x.param({ __int_vec.begin(), __int_vec.end(),
+			      __den_vec.begin() });
+		}
+	    }
 	}
 
-      std::vector<double> __den_vec;
-      __den_vec.reserve(__n);
-      for (size_t __i = 0; __i < __n; ++__i)
-	{
-	  double __den;
-	  __is >> __den;
-	  __den_vec.push_back(__den);
-	}
-
-      __x.param(typename piecewise_constant_distribution<_RealType>::
-	  param_type(__int_vec.begin(), __int_vec.end(), __den_vec.begin()));
-
       __is.flags(__flags);
       return __is;
     }
@@ -3166,8 +3139,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator<<(std::basic_ostream<_CharT, _Traits>& __os,
 	       const piecewise_linear_distribution<_RealType>& __x)
     {
-      typedef std::basic_ostream<_CharT, _Traits>  __ostream_type;
-      typedef typename __ostream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_ostream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __os.flags();
       const _CharT __fill = __os.fill();
@@ -3198,36 +3170,25 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     operator>>(std::basic_istream<_CharT, _Traits>& __is,
 	       piecewise_linear_distribution<_RealType>& __x)
     {
-      typedef std::basic_istream<_CharT, _Traits>  __istream_type;
-      typedef typename __istream_type::ios_base    __ios_base;
+      using __ios_base = typename basic_istream<_CharT, _Traits>::ios_base;
 
       const typename __ios_base::fmtflags __flags = __is.flags();
       __is.flags(__ios_base::dec | __ios_base::skipws);
 
       size_t __n;
-      __is >> __n;
-
-      std::vector<_RealType> __int_vec;
-      __int_vec.reserve(__n + 1);
-      for (size_t __i = 0; __i <= __n; ++__i)
+      if (__is >> __n)
 	{
-	  _RealType __int;
-	  __is >> __int;
-	  __int_vec.push_back(__int);
+	  vector<_RealType> __int_vec;
+	  if (__detail::__extract_params(__is, __int_vec, __n + 1))
+	    {
+	      vector<double> __den_vec;
+	      if (__detail::__extract_params(__is, __den_vec, __n + 1))
+		{
+		  __x.param({ __int_vec.begin(), __int_vec.end(),
+			      __den_vec.begin() });
+		}
+	    }
 	}
-
-      std::vector<double> __den_vec;
-      __den_vec.reserve(__n + 1);
-      for (size_t __i = 0; __i <= __n; ++__i)
-	{
-	  double __den;
-	  __is >> __den;
-	  __den_vec.push_back(__den);
-	}
-
-      __x.param(typename piecewise_linear_distribution<_RealType>::
-	  param_type(__int_vec.begin(), __int_vec.end(), __den_vec.begin()));
-
       __is.flags(__flags);
       return __is;
     }
diff --git a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
index 9f7b0cec565..201b87e9c52 100644
--- a/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
+++ b/libstdc++-v3/testsuite/26_numerics/random/pr60037-neg.cc
@@ -12,4 +12,4 @@  auto x = std::generate_canonical<std::size_t,
 
 // { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 171 }
 
-// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 3320 }
+// { dg-error "static assertion failed: template argument must be a floating point type" "" { target *-*-* } 3281 }