Change 19855 by [EMAIL PROTECTED] on 2003/06/26 05:36:41
Integrate:
[ 19851]
Fix [perl #21742] :
require() should always be called in scalar context,
even when it's the last statement in an eval("").
[ 19852]
Enhance some macro robustness.
[ 19853]
Subject: Re: P and V
From: "Philip Newton" <[EMAIL PROTECTED]>
Date: Wed, 25 Jun 2003 17:50:22 +0200
Message-ID: <[EMAIL PROTECTED]>
[ 19854]
Bite the bullet and apply the hash randomisation patch.
[perl #22371] Algorimic Complexity Attack on Perl 5.6.1, 5.8.0
Affected files ...
... //depot/maint-5.8/perl/INSTALL#11 integrate
... //depot/maint-5.8/perl/embedvar.h#20 integrate
... //depot/maint-5.8/perl/ext/Data/Dumper/Dumper.pm#5 integrate
... //depot/maint-5.8/perl/ext/Data/Dumper/t/dumper.t#3 integrate
... //depot/maint-5.8/perl/hv.h#5 integrate
... //depot/maint-5.8/perl/intrpvar.h#18 integrate
... //depot/maint-5.8/perl/lib/Thread/Semaphore.pm#2 integrate
... //depot/maint-5.8/perl/opcode.h#5 integrate
... //depot/maint-5.8/perl/opcode.pl#9 integrate
... //depot/maint-5.8/perl/perl.c#36 integrate
... //depot/maint-5.8/perl/perl.h#34 integrate
... //depot/maint-5.8/perl/perlapi.h#18 integrate
... //depot/maint-5.8/perl/pod/perlfunc.pod#25 integrate
... //depot/maint-5.8/perl/pod/perlrun.pod#21 integrate
... //depot/maint-5.8/perl/pod/perlsec.pod#4 integrate
... //depot/maint-5.8/perl/pp_ctl.c#29 integrate
... //depot/maint-5.8/perl/sv.c#55 integrate
... //depot/maint-5.8/perl/t/comp/require.t#4 integrate
Differences ...
==== //depot/maint-5.8/perl/INSTALL#11 (text) ====
Index: perl/INSTALL
--- perl/INSTALL#10~19759~ Fri Jun 13 00:22:57 2003
+++ perl/INSTALL Wed Jun 25 22:36:41 2003
@@ -836,6 +836,36 @@
_exit vs. exit. If you have this problem, the fix is to go back to
your sfio sources and correct iffe's guess about atexit.
+=head2 Algorithmic Complexity Attacks on Hashes
+
+In Perls 5.8.0 and earlier it was easy to create degenerate hashes.
+Processing such hashes would consume large amounts of CPU time,
+causing a "Denial of Service" attack against Perl. Such hashes may be
+a problem for example for mod_perl sites, sites with Perl CGI scripts
+and web services, that process data originating from external sources.
+
+In Perl 5.8.1 a security feature was introduced to make it harder
+to create such degenerate hashes.
+
+Because of this feature the keys(), values(), and each() functions
+will return the hash elements in different order between different
+runs of Perl even with the same data. One can still revert to the old
+predictable order by setting the environment variable PERL_HASH_SEED,
+see L<perlrun>. Another option is to add -DUSE_HASH_SEED_EXPLICIT to
+the compilation flags, in which case one has to explicitly set the
+PERL_HASH_SEED environment variable to enable the security feature,
+or -DNO_HASH_SEED to completely disable the feature.
+
+B<Perl does not guarantee any ordering of the hash keys>, and the
+ordering has already changed several times during the lifetime of
+Perl 5. Also, the ordering of hash keys already (in Perl 5.8.0 and
+earlier) depends on the insertion order.
+
+Note that because of this randomisation for example the Data::Dumper
+results will be different between different runs of Perl since
+Data::Dumper by default dumps hashes "unordered". The use of the
+Data::Dumper C<Sortkeys> filter is recommended.
+
=head2 SOCKS
Perl can be configured to be 'socksified', that is, to use the SOCKS
==== //depot/maint-5.8/perl/embedvar.h#20 (text+w) ====
Index: perl/embedvar.h
--- perl/embedvar.h#19~19745~ Wed Jun 11 23:35:47 2003
+++ perl/embedvar.h Wed Jun 25 22:36:41 2003
@@ -591,6 +591,7 @@
#define PL_gid (vTHX->Igid)
#define PL_glob_index (vTHX->Iglob_index)
#define PL_globalstash (vTHX->Iglobalstash)
+#define PL_hash_seed (vTHX->Ihash_seed)
#define PL_he_arenaroot (vTHX->Ihe_arenaroot)
#define PL_he_root (vTHX->Ihe_root)
#define PL_hintgv (vTHX->Ihintgv)
@@ -910,6 +911,7 @@
#define PL_Igid PL_gid
#define PL_Iglob_index PL_glob_index
#define PL_Iglobalstash PL_globalstash
+#define PL_Ihash_seed PL_hash_seed
#define PL_Ihe_arenaroot PL_he_arenaroot
#define PL_Ihe_root PL_he_root
#define PL_Ihintgv PL_hintgv
==== //depot/maint-5.8/perl/ext/Data/Dumper/Dumper.pm#5 (text) ====
Index: perl/ext/Data/Dumper/Dumper.pm
--- perl/ext/Data/Dumper/Dumper.pm#4~19061~ Wed Mar 26 11:23:37 2003
+++ perl/ext/Data/Dumper/Dumper.pm Wed Jun 25 22:36:41 2003
@@ -1193,6 +1193,17 @@
SCALAR objects have the weirdest looking C<bless> workaround.
+=head2 NOTE
+
+Starting from Perl 5.8.1 different runs of Perl will have different
+ordering of hash keys. The change was done for greater security,
+see L<perlsec/"Algorithmic Complexity Attacks">. This means that
+different runs of Perl will have different Data::Dumper outputs if
+the data contains hashes. If you need to have identical Data::Dumper
+outputs from different runs of Perl, use the environment variable
+PERL_HASH_SEED, see L<perlrun/PERL_HASH_SEED>. Using this restores
+the old (platform-specific) ordering: an even prettier solution might
+be to use the C<Sortkeys> filter of Data::Dumper.
=head1 AUTHOR
@@ -1201,7 +1212,6 @@
Copyright (c) 1996-98 Gurusamy Sarathy. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
-
=head1 VERSION
==== //depot/maint-5.8/perl/ext/Data/Dumper/t/dumper.t#3 (xtext) ====
Index: perl/ext/Data/Dumper/t/dumper.t
--- perl/ext/Data/Dumper/t/dumper.t#2~18448~ Sun Jan 5 07:29:54 2003
+++ perl/ext/Data/Dumper/t/dumper.t Wed Jun 25 22:36:41 2003
@@ -13,6 +13,9 @@
}
}
+# Since Perl 5.8.1 because otherwise hash ordering is really random.
+local $Data::Dumper::Sortkeys = 1;
+
use Data::Dumper;
use Config;
my $Is_ebcdic = defined($Config{'ebcdic'}) && $Config{'ebcdic'} eq 'define';
@@ -94,11 +97,11 @@
#$a = [
# 1,
# {
+# 'a' => $a,
+# 'b' => $a->[1],
# 'c' => [
# 'c'
-# ],
-# 'a' => $a,
-# 'b' => $a->[1]
+# ]
# },
# $a->[1]{'c'}
# ];
@@ -116,11 +119,11 @@
[EMAIL PROTECTED] = (
# 1,
# {
+# 'a' => [],
+# 'b' => {},
# 'c' => [
# 'c'
-# ],
-# 'a' => [],
-# 'b' => {}
+# ]
# },
# []
# );
@@ -138,19 +141,19 @@
##
$WANT = <<'EOT';
#%b = (
-# 'c' => [
-# 'c'
-# ],
# 'a' => [
# 1,
# {},
-# []
+# [
+# 'c'
+# ]
# ],
-# 'b' => {}
+# 'b' => {},
+# 'c' => []
# );
#$b{'a'}[1] = \%b;
-#$b{'a'}[2] = $b{'c'};
#$b{'b'} = \%b;
+#$b{'c'} = $b{'a'}[2];
#$a = $b{'a'};
EOT
@@ -163,15 +166,15 @@
#$a = [
# 1,
# {
-# 'c' => [],
# 'a' => [],
-# 'b' => {}
+# 'b' => {},
+# 'c' => []
# },
# []
#];
-#$a->[1]{'c'} = [EMAIL PROTECTED];
#$a->[1]{'a'} = $a;
#$a->[1]{'b'} = $a->[1];
+#$a->[1]{'c'} = [EMAIL PROTECTED];
#$a->[2] = [EMAIL PROTECTED];
#$b = $a->[1];
EOT
@@ -199,12 +202,12 @@
# 1,
# #1
# {
+# a => $a,
+# b => $a->[1],
# c => [
# #0
# 'c'
-# ],
-# a => $a,
-# b => $a->[1]
+# ]
# },
# #2
# $a->[1]{c}
@@ -224,11 +227,11 @@
#$VAR1 = [
# 1,
# {
+# 'a' => [],
+# 'b' => {},
# 'c' => [
# 'c'
-# ],
-# 'a' => [],
-# 'b' => {}
+# ]
# },
# []
#];
@@ -246,11 +249,11 @@
#[
# 1,
# {
+# a => $VAR1,
+# b => $VAR1->[1],
# c => [
# 'c'
-# ],
-# a => $VAR1,
-# b => $VAR1->[1]
+# ]
# },
# $VAR1->[1]{c}
#]
@@ -269,8 +272,8 @@
##
$WANT = <<'EOT';
#$VAR1 = {
-# "reftest" => \\1,
-# "abc\0'\efg" => "mno\0"
+# "abc\0'\efg" => "mno\0",
+# "reftest" => \\1
#};
EOT
@@ -284,8 +287,8 @@
$WANT = <<"EOT";
#\$VAR1 = {
-# 'reftest' => \\\\1,
-# 'abc\0\\'\efg' => 'mno\0'
+# 'abc\0\\'\efg' => 'mno\0',
+# 'reftest' => \\\\1
#};
EOT
@@ -320,15 +323,15 @@
# do{my $o},
# #2
# {
-# 'c' => [],
# 'a' => 1,
# 'b' => do{my $o},
+# 'c' => [],
# 'd' => {}
# }
# ];
#*::foo{ARRAY}->[1] = $foo;
-#*::foo{ARRAY}->[2]{'c'} = *::foo{ARRAY};
#*::foo{ARRAY}->[2]{'b'} = *::foo{SCALAR};
+#*::foo{ARRAY}->[2]{'c'} = *::foo{ARRAY};
#*::foo{ARRAY}->[2]{'d'} = *::foo{ARRAY}->[2];
#*::foo = *::foo{ARRAY}->[2];
[EMAIL PROTECTED] = @{*::foo{ARRAY}};
@@ -349,15 +352,15 @@
# -10,
# do{my $o},
# {
-# 'c' => [],
# 'a' => 1,
# 'b' => do{my $o},
+# 'c' => [],
# 'd' => {}
# }
#];
#*::foo{ARRAY}->[1] = $foo;
-#*::foo{ARRAY}->[2]{'c'} = *::foo{ARRAY};
#*::foo{ARRAY}->[2]{'b'} = *::foo{SCALAR};
+#*::foo{ARRAY}->[2]{'c'} = *::foo{ARRAY};
#*::foo{ARRAY}->[2]{'d'} = *::foo{ARRAY}->[2];
#*::foo = *::foo{ARRAY}->[2];
#$bar = *::foo{ARRAY};
@@ -379,13 +382,13 @@
#*::foo = \5;
#*::foo = [EMAIL PROTECTED];
#*::foo = {
-# 'c' => [],
# 'a' => 1,
# 'b' => do{my $o},
+# 'c' => [],
# 'd' => {}
#};
-#*::foo{HASH}->{'c'} = [EMAIL PROTECTED];
#*::foo{HASH}->{'b'} = *::foo{SCALAR};
+#*::foo{HASH}->{'c'} = [EMAIL PROTECTED];
#*::foo{HASH}->{'d'} = *::foo{HASH};
#$bar[2] = *::foo{HASH};
#%baz = %{*::foo{HASH}};
@@ -406,13 +409,13 @@
#*::foo = \5;
#*::foo = $bar;
#*::foo = {
-# 'c' => [],
# 'a' => 1,
# 'b' => do{my $o},
+# 'c' => [],
# 'd' => {}
#};
-#*::foo{HASH}->{'c'} = $bar;
#*::foo{HASH}->{'b'} = *::foo{SCALAR};
+#*::foo{HASH}->{'c'} = $bar;
#*::foo{HASH}->{'d'} = *::foo{HASH};
#$bar->[2] = *::foo{HASH};
#$baz = *::foo{HASH};
@@ -430,9 +433,9 @@
# -10,
# $foo,
# {
-# c => [EMAIL PROTECTED],
# a => 1,
# b => \5,
+# c => [EMAIL PROTECTED],
# d => $bar[2]
# }
#);
@@ -452,9 +455,9 @@
# -10,
# $foo,
# {
-# c => $bar,
# a => 1,
# b => \5,
+# c => $bar,
# d => $bar->[2]
# }
#];
@@ -483,8 +486,8 @@
##
$WANT = <<'EOT';
#%kennels = (
-# Second => \'Wags',
-# First => \'Fido'
+# First => \'Fido',
+# Second => \'Wags'
#);
[EMAIL PROTECTED] = (
# ${$kennels{First}},
@@ -522,8 +525,8 @@
##
$WANT = <<'EOT';
#%kennels = (
-# Second => \'Wags',
-# First => \'Fido'
+# First => \'Fido',
+# Second => \'Wags'
#);
[EMAIL PROTECTED] = (
# ${$kennels{First}},
@@ -546,8 +549,8 @@
# 'Fido',
# 'Wags',
# {
-# Second => \$dogs[1],
-# First => \$dogs[0]
+# First => \$dogs[0],
+# Second => \$dogs[1]
# }
#);
#%kennels = %{$dogs[2]};
@@ -581,13 +584,13 @@
# 'Fido',
# 'Wags',
# {
-# Second => \'Wags',
-# First => \'Fido'
+# First => \'Fido',
+# Second => \'Wags'
# }
#);
#%kennels = (
-# Second => \'Wags',
-# First => \'Fido'
+# First => \'Fido',
+# Second => \'Wags'
#);
EOT
@@ -833,7 +836,6 @@
{
$i = 0;
$a = { map { ("$_$_$_", ++$i) } 'I'..'Q' };
- local $Data::Dumper::Sortkeys = 1;
############# 193
##
==== //depot/maint-5.8/perl/hv.h#5 (text) ====
Index: perl/hv.h
--- perl/hv.h#4~19400~ Sun May 4 01:29:43 2003
+++ perl/hv.h Wed Jun 25 22:36:41 2003
@@ -56,13 +56,20 @@
* (a) the hashed data being interpreted as "unsigned char" (new since 5.8,
* a "char" can be either signed or signed, depending on the compiler)
* (b) catering for old code that uses a "char"
+ * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
+ * to avoid "algorithmic complexity attacks".
*/
+#if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
+# define PERL_HASH_SEED PL_hash_seed
+#else
+# define PERL_HASH_SEED 0
+#endif
#define PERL_HASH(hash,str,len) \
STMT_START { \
register const char *s_PeRlHaSh_tmp = str; \
register const unsigned char *s_PeRlHaSh = (const unsigned char
*)s_PeRlHaSh_tmp; \
register I32 i_PeRlHaSh = len; \
- register U32 hash_PeRlHaSh = 0; \
+ register U32 hash_PeRlHaSh = PERL_HASH_SEED; \
while (i_PeRlHaSh--) { \
hash_PeRlHaSh += *s_PeRlHaSh++; \
hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
==== //depot/maint-5.8/perl/intrpvar.h#18 (text) ====
Index: perl/intrpvar.h
--- perl/intrpvar.h#17~19745~ Wed Jun 11 23:35:47 2003
+++ perl/intrpvar.h Wed Jun 25 22:36:41 2003
@@ -556,6 +556,8 @@
PERLVARI(Ippid, IV, 0)
#endif
+PERLVARI(Ihash_seed, UV, 0) /* Hash initializer */
+
/* New variables must be added to the very end, before this comment,
* for binary compatibility (the offsets of the old members must not change).
* (Don't forget to add your variable also to perl_clone()!)
==== //depot/maint-5.8/perl/lib/Thread/Semaphore.pm#2 (text) ====
Index: perl/lib/Thread/Semaphore.pm
--- perl/lib/Thread/Semaphore.pm#1~17645~ Fri Jul 19 12:29:57 2002
+++ perl/lib/Thread/Semaphore.pm Wed Jun 25 22:36:41 2003
@@ -12,14 +12,14 @@
use Thread::Semaphore;
my $s = new Thread::Semaphore;
- $s->up; # Also known as the semaphore V -operation.
+ $s->down; # Also known as the semaphore P operation.
# The guarded section is here
- $s->down; # Also known as the semaphore P -operation.
+ $s->up; # Also known as the semaphore V operation.
# The default semaphore value is 1.
my $s = new Thread::Semaphore($initial_value);
+ $s->down($down_value);
$s->up($up_value);
- $s->down($up_value);
=head1 DESCRIPTION
@@ -29,7 +29,7 @@
Semaphores don't limit their values to zero or one, so they can be used to
control access to some resource that there may be more than one of. (For
-example, filehandles). Increment and decrement amounts aren't fixed at one
+example, filehandles.) Increment and decrement amounts aren't fixed at one
either, so threads can reserve or return multiple resources at once.
=head1 FUNCTIONS AND METHODS
@@ -53,6 +53,10 @@
count is equal to or larger than the amount you're C<down>ing the
semaphore's count by.
+This is the semaphore "P operation" (the name derives from the Dutch
+word "pak", which means "capture" -- the semaphore operations were
+named by the late Dijkstra, who was Dutch).
+
=item up
=item up NUMBER
@@ -61,6 +65,9 @@
or by one if no number has been specified. This will unblock any thread blocked
trying to C<down> the semaphore if the C<up> raises the semaphore count
above the amount that the C<down>s are trying to decrement it by.
+
+This is the semaphore "V operation" (the name derives from the Dutch
+word "vrij", which means "release").
=back
==== //depot/maint-5.8/perl/opcode.h#5 (text+w) ====
Index: perl/opcode.h
--- perl/opcode.h#4~19400~ Sun May 4 01:29:43 2003
+++ perl/opcode.h Wed Jun 25 22:36:41 2003
@@ -21,10 +21,10 @@
START_EXTERN_C
-#define OP_NAME(o) (o->op_type == OP_CUSTOM ? custom_op_name(o) : \
- PL_op_name[o->op_type])
-#define OP_DESC(o) (o->op_type == OP_CUSTOM ? custom_op_desc(o) : \
- PL_op_desc[o->op_type])
+#define OP_NAME(o) ((o)->op_type == OP_CUSTOM ? custom_op_name(o) : \
+ PL_op_name[(o)->op_type])
+#define OP_DESC(o) ((o)->op_type == OP_CUSTOM ? custom_op_desc(o) : \
+ PL_op_desc[(o)->op_type])
#ifndef DOINIT
EXT char *PL_op_name[];
==== //depot/maint-5.8/perl/opcode.pl#9 (xtext) ====
Index: perl/opcode.pl
--- perl/opcode.pl#8~19400~ Sun May 4 01:29:43 2003
+++ perl/opcode.pl Wed Jun 25 22:36:41 2003
@@ -90,10 +90,10 @@
START_EXTERN_C
-#define OP_NAME(o) (o->op_type == OP_CUSTOM ? custom_op_name(o) : \\
- PL_op_name[o->op_type])
-#define OP_DESC(o) (o->op_type == OP_CUSTOM ? custom_op_desc(o) : \\
- PL_op_desc[o->op_type])
+#define OP_NAME(o) ((o)->op_type == OP_CUSTOM ? custom_op_name(o) : \\
+ PL_op_name[(o)->op_type])
+#define OP_DESC(o) ((o)->op_type == OP_CUSTOM ? custom_op_desc(o) : \\
+ PL_op_desc[(o)->op_type])
#ifndef DOINIT
EXT char *PL_op_name[];
==== //depot/maint-5.8/perl/perl.c#36 (text) ====
Index: perl/perl.c
--- perl/perl.c#35~19844~ Sun Jun 22 12:38:58 2003
+++ perl/perl.c Wed Jun 25 22:36:41 2003
@@ -316,6 +316,33 @@
PL_stashcache = newHV();
+#if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
+ /* [perl #22371] Algorimic Complexity Attack on Perl 5.6.1, 5.8.0 */
+ {
+ char *s = PerlEnv_getenv("PERL_HASH_SEED");
+ if (s)
+ while (isSPACE(*s)) s++;
+ if (s && isDIGIT(*s))
+ PL_hash_seed = (UV)atoi(s);
+#ifndef USE_HASH_SEED_EXPLICIT
+ else {
+ /* Compute a random seed */
+ (void)seedDrand01((Rand_seed_t)seed());
+ PL_srand_called = TRUE;
+ PL_hash_seed = (UV)(Drand01() * (NV)UV_MAX);
+#if RANDBITS < (UVSIZE * 8)
+ {
+ int skip = (UVSIZE * 8) - RANDBITS;
+ PL_hash_seed >>= skip;
+ /* The low bits might need extra help. */
+ PL_hash_seed += (UV)(Drand01() * ((1 << skip) - 1));
+ }
+#endif /* RANDBITS < (UVSIZE * 8) */
+ }
+#endif /* USE_HASH_SEED_EXPLICIT */
+ }
+#endif /* #if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) */
+
ENTER;
}
==== //depot/maint-5.8/perl/perl.h#34 (text) ====
Index: perl/perl.h
--- perl/perl.h#33~19844~ Sun Jun 22 12:38:58 2003
+++ perl/perl.h Wed Jun 25 22:36:41 2003
@@ -2302,6 +2302,12 @@
#if !defined(OS2) && !defined(MACOS_TRADITIONAL)
# include "iperlsys.h"
#endif
+
+/* [perl #22371] Algorimic Complexity Attack on Perl 5.6.1, 5.8.0 */
+#if !defined(NO_HASH_SEED) && !defined(USE_HASH_SEED) &&
!defined(USE_HASH_SEED_EXPLICIT)
+# define USE_HASH_SEED
+#endif
+
#include "regexp.h"
#include "sv.h"
#include "util.h"
==== //depot/maint-5.8/perl/perlapi.h#18 (text+w) ====
Index: perl/perlapi.h
--- perl/perlapi.h#17~19745~ Wed Jun 11 23:35:47 2003
+++ perl/perlapi.h Wed Jun 25 22:36:41 2003
@@ -274,6 +274,8 @@
#define PL_glob_index (*Perl_Iglob_index_ptr(aTHX))
#undef PL_globalstash
#define PL_globalstash (*Perl_Iglobalstash_ptr(aTHX))
+#undef PL_hash_seed
+#define PL_hash_seed (*Perl_Ihash_seed_ptr(aTHX))
#undef PL_he_arenaroot
#define PL_he_arenaroot (*Perl_Ihe_arenaroot_ptr(aTHX))
#undef PL_he_root
==== //depot/maint-5.8/perl/pod/perlfunc.pod#25 (text) ====
Index: perl/pod/perlfunc.pod
--- perl/pod/perlfunc.pod#24~19803~ Mon Jun 16 22:18:41 2003
+++ perl/pod/perlfunc.pod Wed Jun 25 22:36:41 2003
@@ -1267,9 +1267,12 @@
element in the hash.
Entries are returned in an apparently random order. The actual random
-order is subject to change in future versions of perl, but it is guaranteed
-to be in the same order as either the C<keys> or C<values> function
-would produce on the same (unmodified) hash.
+order is subject to change in future versions of perl, but it is
+guaranteed to be in the same order as either the C<keys> or C<values>
+function would produce on the same (unmodified) hash. Since Perl
+5.8.1 the ordering is different even between different runs of Perl
+because of security reasons (see L<perlsec/"Algorithmic Complexity
+Attacks".)
When the hash is entirely read, a null array is returned in list context
(which when assigned produces a false (C<0>) value), and C<undef> in
@@ -2314,13 +2317,19 @@
=item keys HASH
-Returns a list consisting of all the keys of the named hash. (In
-scalar context, returns the number of keys.) The keys are returned in
-an apparently random order. The actual random order is subject to
-change in future versions of perl, but it is guaranteed to be the same
-order as either the C<values> or C<each> function produces (given
-that the hash has not been modified). As a side effect, it resets
-HASH's iterator.
+Returns a list consisting of all the keys of the named hash.
+(In scalar context, returns the number of keys.)
+
+The keys are returned in an apparently random order. The actual
+random order is subject to change in future versions of perl, but it
+is guaranteed to be the same order as either the C<values> or C<each>
+function produces (given that the hash has not been modified).
+Since Perl 5.8.1 the ordering is different even between different
+runs of Perl because of security reasons (see L<perlsec/"Algorithmic
+Complexity Attacks".)
+
+As a side effect, calling keys() resets the HASH's internal iterator,
+see L</each>.
Here is yet another way to print your environment:
@@ -6206,12 +6215,19 @@
=item values HASH
-Returns a list consisting of all the values of the named hash. (In a
-scalar context, returns the number of values.) The values are
-returned in an apparently random order. The actual random order is
-subject to change in future versions of perl, but it is guaranteed to
-be the same order as either the C<keys> or C<each> function would
-produce on the same (unmodified) hash.
+Returns a list consisting of all the values of the named hash.
+(In a scalar context, returns the number of values.)
+
+The values are returned in an apparently random order. The actual
+random order is subject to change in future versions of perl, but it
+is guaranteed to be the same order as either the C<keys> or C<each>
+function would produce on the same (unmodified) hash. Since Perl
+5.8.1 the ordering is different even between different runs of Perl
+because of security reasons (see L<perlsec/"Algorithmic Complexity
+Attacks".)
+
+As a side effect, calling values() resets the HASH's internal iterator,
+see L</each>.
Note that the values are not copied, which means modifying them will
modify the contents of the hash:
@@ -6219,7 +6235,6 @@
for (values %hash) { s/foo/bar/g } # modifies %hash values
for (@hash{keys %hash}) { s/foo/bar/g } # same
-As a side effect, calling values() resets the HASH's internal iterator.
See also C<keys>, C<each>, and C<sort>.
=item vec EXPR,OFFSET,BITS
==== //depot/maint-5.8/perl/pod/perlrun.pod#21 (text) ====
Index: perl/pod/perlrun.pod
--- perl/pod/perlrun.pod#20~19759~ Fri Jun 13 00:22:57 2003
+++ perl/pod/perlrun.pod Wed Jun 25 22:36:41 2003
@@ -1099,6 +1099,26 @@
If using the C<encoding> pragma without an explicit encoding name, the
PERL_ENCODING environment variable is consulted for an encoding name.
+=item PERL_HASH_SEED
+
+(Since Perl 5.8.1.)
+
+Used to randomise Perl's internal hash function. To emulate the
+pre-5.8.1 behaviour, set to an integer (zero means exactly the same
+order as 5.8.0). "Pre-5.8.1" means, among other things, that hash
+keys will be ordered the same between different runs of Perl.
+
+The default behaviour is to randomise unless the PERL_HASH_SEED is set.
+If Perl has been compiled with the -DUSE_HASH_SEED_EXPLICIT the default
+behaviour is B<not> to randomise unless the PERL_HASH_SEED is set.
+
+If PERL_HASH_SEED is unset or set to a non-numeric string, Perl uses
+the pseudorandom seed supplied by the operating system and libraries.
+If unset, each different run of Perl will have different ordering of
+the outputs of keys(), values, and each().
+
+See L<perlsec/"Algorithmic Complexity Attacks"> for more information.
+
=item PERL_ROOT (specific to the VMS port)
A translation concealed rooted logical name that contains perl and the
==== //depot/maint-5.8/perl/pod/perlsec.pod#4 (text) ====
Index: perl/pod/perlsec.pod
--- perl/pod/perlsec.pod#3~18257~ Sat Dec 7 14:38:49 2002
+++ perl/pod/perlsec.pod Wed Jun 25 22:36:41 2003
@@ -386,6 +386,62 @@
L<perlunicode> for details, and L<perlunicode/"Security Implications
of Unicode"> for security implications in particular.
+=head2 Algorithmic Complexity Attacks
+
+Certain internal algorithms used in the implementation of Perl can
+be attacked by choosing the input carefully to consume large amounts
+of either time or space or both. This can lead into the so-called
+I<Denial of Service> (DoS) attacks.
+
+=over 4
+
+=item *
+
+Hash Function - the algorithm used to "order" hash elements has been
+changed several times during the development of Perl, mainly to be
+reasonably fast. In Perl 5.8.1 also the security aspect was taken
+into account.
+
+In Perls before 5.8.1 one could rather easily generate data that as
+hash keys would cause Perl to consume large amounts of time because
+internal structure of hashes would badly degenerate. In Perl 5.8.1
+the hash function is randomly perturbed by a pseudorandom seed which
+makes generating such naughty hash keys harder.
+See L<perlrun/PERL_HASH_SEED> for more information.
+
+The random perturbation is done by default but if one wants for some
+reason emulate the old behaviour one can set the environment variable
+PERL_HASH_SEED to zero (or any other integer). One possible reason
+for wanting to emulate the old behaviour is that in the new behaviour
+consecutive runs of Perl will order hash keys differently, which may
+confuse some applications (like Data::Dumper: the outputs of two
+different runs are no more identical).
+
+=item *
+
+Regular expressions - Perl's regular expression engine is so called
+NFA (Non-Finite Automaton), which among other things means that it can
+rather easily consume large amounts of both time and space if the
+regular expression may match in several ways. Careful crafting of the
+regular expressions can help but quite often there really isn't much
+one can do (the book "Mastering Regular Expressions" is required
+reading, see L<perlfaq2>). Running out of space manifests itself by
+Perl running out of memory.
+
+=item *
+
+Sorting - the quicksort algorithm used in Perls before 5.8.0 to
+implement the sort() function is very easy to trick into misbehaving
+so that it consumes a lot of time. Nothing more is required than
+resorting a list already sorted. Starting from Perl 5.8.0 a different
+sorting algorithm, mergesort, is used. Mergesort is insensitive to
+its input data, so it cannot be similarly fooled.
+
+=back
+
+See L<http://www.cs.rice.edu/~scrosby/hash/> for more information,
+and any computer science text book on the algorithmic complexity.
+
=head1 SEE ALSO
L<perlrun> for its description of cleaning up environment variables.
==== //depot/maint-5.8/perl/pp_ctl.c#29 (text) ====
Index: perl/pp_ctl.c
--- perl/pp_ctl.c#28~19823~ Thu Jun 19 07:51:22 2003
+++ perl/pp_ctl.c Wed Jun 25 22:36:41 2003
@@ -2796,8 +2796,7 @@
else
sv_setpv(ERRSV,"");
if (yyparse() || PL_error_count || !PL_eval_root) {
- SV **newsp;
- I32 gimme;
+ SV **newsp; /* Used by POPBLOCK. */
PERL_CONTEXT *cx;
I32 optype = 0; /* Might be reset by POPEVAL. */
STRLEN n_a;
@@ -2847,7 +2846,16 @@
*startop = PL_eval_root;
} else
SAVEFREEOP(PL_eval_root);
- if (gimme & G_VOID)
+
+ /* Set the context for this new optree.
+ * If the last op is an OP_REQUIRE, force scalar context.
+ * Otherwise, propagate the context from the eval(). */
+ if (PL_eval_root->op_type == OP_LEAVEEVAL
+ && cUNOPx(PL_eval_root)->op_first->op_type == OP_LINESEQ
+ && cLISTOPx(cUNOPx(PL_eval_root)->op_first)->op_last->op_type
+ == OP_REQUIRE)
+ scalar(PL_eval_root);
+ else if (gimme & G_VOID)
scalarvoid(PL_eval_root);
else if (gimme & G_ARRAY)
list(PL_eval_root);
==== //depot/maint-5.8/perl/sv.c#55 (text) ====
Index: perl/sv.c
--- perl/sv.c#54~19850~ Tue Jun 24 11:49:22 2003
+++ perl/sv.c Wed Jun 25 22:36:41 2003
@@ -10972,6 +10972,7 @@
PL_glob_index = proto_perl->Iglob_index;
PL_srand_called = proto_perl->Isrand_called;
+ PL_hash_seed = proto_perl->Ihash_seed;
PL_uudmap['M'] = 0; /* reinits on demand */
PL_bitcount = Nullch; /* reinits on demand */
==== //depot/maint-5.8/perl/t/comp/require.t#4 (xtext) ====
Index: perl/t/comp/require.t
--- perl/t/comp/require.t#3~19803~ Mon Jun 16 22:18:41 2003
+++ perl/t/comp/require.t Wed Jun 25 22:36:41 2003
@@ -11,7 +11,7 @@
my $Is_EBCDIC = (ord('A') == 193) ? 1 : 0;
my $Is_UTF8 = (${^OPEN} || "") =~ /:utf8/;
-my $total_tests = 29;
+my $total_tests = 30;
if ($Is_EBCDIC || $Is_UTF8) { $total_tests = 26; }
print "1..$total_tests\n";
@@ -134,8 +134,7 @@
write_file('bleah.pm', <<'**BLEAH**'
print "not " if !defined wantarray || wantarray ne '';
-my $TODO = $i == 23 ? " # TODO bug #21742" : "";
-print "ok $i - require() context$TODO\n";
+print "ok $i - require() context\n";
1;
**BLEAH**
);
@@ -143,6 +142,7 @@
$foo = eval q{require bleah}; delete $INC{"bleah.pm"}; ++$::i;
@foo = eval q{require bleah}; delete $INC{"bleah.pm"}; ++$::i;
eval q{require bleah}; delete $INC{"bleah.pm"}; ++$::i;
+ eval q{$_=$_+2;require bleah}; delete $INC{"bleah.pm"}; ++$::i;
$foo = eval {require bleah}; delete $INC{"bleah.pm"}; ++$::i;
@foo = eval {require bleah}; delete $INC{"bleah.pm"}; ++$::i;
eval {require bleah};
End of Patch.
