Fix stack manipulation when a lexical subroutine is defined in a do block in as a member of an iteration list

This commit is contained in:
Petr Písař 2018-01-09 17:46:34 +01:00
parent 04fb749292
commit acce317536
2 changed files with 113 additions and 0 deletions

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@ -0,0 +1,105 @@
From 695d6585affc8f13711f013329fb4810ab89d833 Mon Sep 17 00:00:00 2001
From: Father Chrysostomos <sprout@cpan.org>
Date: Tue, 14 Nov 2017 18:55:55 -0800
Subject: [PATCH] [perl #132442] Fix stack with do {my sub l; 1}
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
A block in perl usually compiles to a leave op with an enter inside
it, followed by the statements:
leave
enter
nextstate
... expr ...
nextstate
... expr ...
If a block contains only one statement, and that statement is suffic-
iently innocuous, then the enter/leave pair to create the scope at run
time get skipped, and instead we have a simple scope op which is not
even executed:
scope
ex-nextstate
... expr ...
The nextstate in this case also gets nulled.
In the case of do { my sub l; 1 } we were getting a variation of the
latter, that looked like this:
scope
introcv
clonecv
nextstate
... expr ...
The problem here is that nextstate resets the stack, even though a new
scope has not been pushed, so we end up with all existing stack items
from the *outer* scope getting clobbered.
One can have fun with this and erase everything pushed on to the stack
so far in a given statement:
$ ./perl -le 'print join "-", 1..10, do {my sub l; ","}, 11..20'
11,12,13,14,15,16,17,18,19,20
Here I replaced the first argument to join() from within the do{}
block, after having cleared the stack.
Why was the op tree was getting muddled up like this? The my sub
declaration does not immediately add any ops to the op tree; those ops
get added when the current scope finishing compiling, since those ops
must be inserted at the beginning of the block.
I have not fully looked into the order that things happen, and why the
nextstate op does not get nulled; but it did not matter, because of
the simple fix: Treat lexical sub declarations as not innocuous by
setting the HINT_BLOCK_SCOPE flag when a lexical sub is declared.
Thus, we end up with an enter/leave pair, which creates a
proper scope.
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
op.c | 2 ++
t/op/lexsub.t | 5 ++++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/op.c b/op.c
index 8fa5aad876..c617ad2a00 100644
--- a/op.c
+++ b/op.c
@@ -9243,6 +9243,8 @@ Perl_newMYSUB(pTHX_ I32 floor, OP *o, OP *proto, OP *attrs, OP *block)
PERL_ARGS_ASSERT_NEWMYSUB;
+ PL_hints |= HINT_BLOCK_SCOPE;
+
/* Find the pad slot for storing the new sub.
We cannot use PL_comppad, as it is the pad owned by the new sub. We
need to look in CvOUTSIDE and find the pad belonging to the enclos-
diff --git a/t/op/lexsub.t b/t/op/lexsub.t
index 3fa17acdda..f085cd97e8 100644
--- a/t/op/lexsub.t
+++ b/t/op/lexsub.t
@@ -7,7 +7,7 @@ BEGIN {
*bar::is = *is;
*bar::like = *like;
}
-plan 149;
+plan 150;
# -------------------- our -------------------- #
@@ -957,3 +957,6 @@ like runperl(
{
my sub h; sub{my $x; sub{h}}
}
+
+is join("-", qw(aa bb), do { my sub lleexx; 123 }, qw(cc dd)),
+ "aa-bb-123-cc-dd", 'do { my sub...} in a list [perl #132442]';
--
2.13.6

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@ -233,6 +233,10 @@ Patch68: perl-5.26.1-Fix-deparsing-of-transliterations-with-unprintable-c
# in upstream after 5.27.5
Patch69: perl-5.26.1-fix-do-dir-returning-no.patch
# Fix stack manipulation when a lexical subroutine is defined in a do block in
# a member of an iteration list, RT#132442, in upstream after 5.27.5
Patch70: perl-5.27.5-perl-132442-Fix-stack-with-do-my-sub-l-1.patch
# Link XS modules to libperl.so with EU::CBuilder on Linux, bug #960048
Patch200: perl-5.16.3-Link-XS-modules-to-libperl.so-with-EU-CBuilder-on-Li.patch
@ -2817,6 +2821,7 @@ Perl extension for Version Objects
%patch67 -p1
%patch68 -p1
%patch69 -p1
%patch70 -p1
%patch200 -p1
%patch201 -p1
@ -2860,6 +2865,7 @@ perl -x patchlevel.h \
'Fedora Patch67: Fix a crash when untying an object witout a stash' \
'Fedora Patch68: Fix deparsing of transliterations with unprintable characters (RT#132405)' \
'Fedora Patch69: Fix error reporting on do() on a directory (RT#125774)' \
'Fedora Patch70: Fix stack manipulation when a lexical subroutine is defined in a do block in a member of an iteration list (RT#132442)' \
'Fedora Patch200: Link XS modules to libperl.so with EU::CBuilder on Linux' \
'Fedora Patch201: Link XS modules to libperl.so with EU::MM on Linux' \
%{nil}
@ -5156,6 +5162,8 @@ popd
- Fix a crash when untying an object witout a stash
- Fix deparsing of transliterations with unprintable characters (RT#132405)
- Fix error reporting on do() on a directory (RT#125774)
- Fix stack manipulation when a lexical subroutine is defined in a do block in
a member of an iteration list (RT#132442)
* Mon Sep 25 2017 Jitka Plesnikova <jplesnik@redhat.com> - 4:5.26.1-401
- Update perl(:MODULE_COMPAT)