From: Johannes Kliemann <kliemann@adacore.com>
Date: Fri, 5 Jul 2024 11:27:44 +0000 (+0000)
Subject: ada: Improve documenation about security of PRGNs
X-Git-Tag: basepoints/gcc-16~6888
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=dc72d4dca9e6ee5af2ea2af0353a994a7a109db3;p=thirdparty%2Fgcc.git

ada: Improve documenation about security of PRGNs

The pseudo random number generators used in GNAT are not
suitable for applications that require cryptographic
security. While this was mentioned in some places others
did not have a corresponding note, leading to these
generators being used in a non-suitable context.

gcc/ada/

	* doc/gnat_rm/standard_library_routines.rst: Add note to section
	of Ada.Numerics.Discrete_Random and Ada.Numerics.Float_Random.
	* doc/gnat_rm/the_gnat_library.rst: Add note to section about
	GNAT.Random_Numbers.
	* libgnat/a-nudira.ads: Add note about cryptographic properties.
	* gnat_rm.texi: Regenerate.
	* gnat_ugn.texi: Regenerate.
---

diff --git a/gcc/ada/doc/gnat_rm/standard_library_routines.rst b/gcc/ada/doc/gnat_rm/standard_library_routines.rst
index 27659a40463..2e7642652b2 100644
--- a/gcc/ada/doc/gnat_rm/standard_library_routines.rst
+++ b/gcc/ada/doc/gnat_rm/standard_library_routines.rst
@@ -302,12 +302,14 @@ the unit is not implemented.
 
 ``Ada.Numerics.Discrete_Random``
   This generic package provides a random number generator suitable for generating
-  uniformly distributed values of a specified discrete subtype.
+  uniformly distributed values of a specified discrete subtype. It should not be
+  used as a cryptographic pseudo-random source.
 
 
 ``Ada.Numerics.Float_Random``
   This package provides a random number generator suitable for generating
-  uniformly distributed floating point values in the unit interval.
+  uniformly distributed floating point values in the unit interval. It should not
+  be used as a cryptographic pseudo-random source.
 
 
 ``Ada.Numerics.Generic_Complex_Elementary_Functions``
diff --git a/gcc/ada/doc/gnat_rm/the_gnat_library.rst b/gcc/ada/doc/gnat_rm/the_gnat_library.rst
index 88204d4cfe7..ac45b5eb7af 100644
--- a/gcc/ada/doc/gnat_rm/the_gnat_library.rst
+++ b/gcc/ada/doc/gnat_rm/the_gnat_library.rst
@@ -1329,7 +1329,9 @@ convenient for use with realtime applications.
 .. index:: Random number generation
 
 Provides random number capabilities which extend those available in the
-standard Ada library and are more convenient to use.
+standard Ada library and are more convenient to use. This package is
+however NOT suitable for situations requiring cryptographically secure
+randomness.
 
 .. _`GNAT.Regexp_(g-regexp.ads)`:
 
diff --git a/gcc/ada/gnat_rm.texi b/gcc/ada/gnat_rm.texi
index d15d6204cd8..d6e2f265ab9 100644
--- a/gcc/ada/gnat_rm.texi
+++ b/gcc/ada/gnat_rm.texi
@@ -21142,12 +21142,14 @@ build the type @code{Complex} and @code{Imaginary}.
 @item @code{Ada.Numerics.Discrete_Random}
 
 This generic package provides a random number generator suitable for generating
-uniformly distributed values of a specified discrete subtype.
+uniformly distributed values of a specified discrete subtype. It should not be
+used as a cryptographic pseudo-random source.
 
 @item @code{Ada.Numerics.Float_Random}
 
 This package provides a random number generator suitable for generating
-uniformly distributed floating point values in the unit interval.
+uniformly distributed floating point values in the unit interval. It should not
+be used as a cryptographic pseudo-random source.
 
 @item @code{Ada.Numerics.Generic_Complex_Elementary_Functions}
 
@@ -24688,7 +24690,9 @@ convenient for use with realtime applications.
 @geindex Random number generation
 
 Provides random number capabilities which extend those available in the
-standard Ada library and are more convenient to use.
+standard Ada library and are more convenient to use. This package is
+however NOT suitable for situations requiring cryptographically secure
+randomness.
 
 @node GNAT Regexp g-regexp ads,GNAT Registry g-regist ads,GNAT Random_Numbers g-rannum ads,The GNAT Library
 @anchor{gnat_rm/the_gnat_library gnat-regexp-g-regexp-ads}@anchor{270}@anchor{gnat_rm/the_gnat_library id90}@anchor{39b}
diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi
index 0e3ee935552..ea1d2f9d71a 100644
--- a/gcc/ada/gnat_ugn.texi
+++ b/gcc/ada/gnat_ugn.texi
@@ -29670,8 +29670,8 @@ to permit their use in free software.
 
 @printindex ge
 
-@anchor{d1}@w{                              }
 @anchor{gnat_ugn/gnat_utility_programs switches-related-to-project-files}@w{                              }
+@anchor{d1}@w{                              }
 
 @c %**end of body
 @bye
diff --git a/gcc/ada/libgnat/a-nudira.ads b/gcc/ada/libgnat/a-nudira.ads
index 1b3eacb897d..c6d95731821 100644
--- a/gcc/ada/libgnat/a-nudira.ads
+++ b/gcc/ada/libgnat/a-nudira.ads
@@ -35,6 +35,8 @@
 
 --  Note: the implementation used in this package is a version of the
 --  Mersenne Twister. See s-rannum.adb for details and references.
+--  It is suitable for simulations, but should not be used as a cryptographic
+--  pseudo-random source.
 
 with System.Random_Numbers;