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Fix a buffer overread when handling a scope error in qr/\(?{/

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This commit is contained in:
Petr Písař 2019-04-05 15:59:12 +02:00
parent 243ad0ccb9
commit 7d3f0728cf
2 changed files with 129 additions and 0 deletions
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122
perl-5.29.8-handle-scope-error-in-qr.patch Normal file
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@ -0,0 +1,122 @@
From 170c919fc4986a85062e9292e4cfed24771d2224 Mon Sep 17 00:00:00 2001
From: David Mitchell <davem@iabyn.com>
Date: Tue, 19 Mar 2019 10:58:46 +0000
Subject: [PATCH] handle scope error in qr/\(?{/
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
RT #133879
In this code:
BEGIN {$^H = 0x10000 }; # HINT_NEW_RE
qr/\(?{/
When the toker sees the 'qr', it looks ahead and thinks that the
pattern *might* contain code blocks, so creates a new anon sub to wrap
compilation of the pattern in (so that any code blocks get compiled as
part of the anon sub rather than the main body of the code).
Normally at the end of parsing the qr construct, the parser notes that
no code blocks were found, and throws the unneeded CV away and
restores the old PL_compcv (via a LEAVE_SCOPE). This false positive is
normal and is expected in the relevant code paths.
However, setting the HINT_NEW_RE (which indicates that
overload::constant is present for qr// but with no overloaded function
actually present) causes an error to be raised. The parser does error
recovery and continues.
However, v5.25.9-148-g7c44985626 added a test to not bother compiling a
pattern if the parser is in an errored state, which again is fine,
except it turns out that if this branch is taken, it skips the 'restore
the old PL_compcv' code, leading to the wrong value for PL_compcv when
ops are freed.
The fix is simple: move the "skip if errored" test to after PL_compcv
has been restored.
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
op.c | 20 ++++++++++++++------
t/re/reg_eval_scope.t | 14 +++++++++++++-
2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/op.c b/op.c
index 1f7ae3e610..afee9fcf02 100644
--- a/op.c
+++ b/op.c
@@ -7082,11 +7082,6 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, OP *repl, UV flags, I32 floor)
rx_flags |= RXf_SPLIT;
}
- /* Skip compiling if parser found an error for this pattern */
- if (pm->op_pmflags & PMf_HAS_ERROR) {
- return o;
- }
-
if (!has_code || !eng->op_comp) {
/* compile-time simple constant pattern */
@@ -7123,6 +7118,11 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, OP *repl, UV flags, I32 floor)
pm->op_pmflags &= ~PMf_HAS_CV;
}
+ /* Skip compiling if parser found an error for this pattern */
+ if (pm->op_pmflags & PMf_HAS_ERROR) {
+ return o;
+ }
+
PM_SETRE(pm,
eng->op_comp
? eng->op_comp(aTHX_ NULL, 0, expr, eng, NULL, NULL,
@@ -7134,7 +7134,15 @@ Perl_pmruntime(pTHX_ OP *o, OP *expr, OP *repl, UV flags, I32 floor)
}
else {
/* compile-time pattern that includes literal code blocks */
- REGEXP* re = eng->op_comp(aTHX_ NULL, 0, expr, eng, NULL, NULL,
+
+ REGEXP* re;
+
+ /* Skip compiling if parser found an error for this pattern */
+ if (pm->op_pmflags & PMf_HAS_ERROR) {
+ return o;
+ }
+
+ re = eng->op_comp(aTHX_ NULL, 0, expr, eng, NULL, NULL,
rx_flags,
(pm->op_pmflags |
((PL_hints & HINT_RE_EVAL) ? PMf_USE_RE_EVAL : 0))
diff --git a/t/re/reg_eval_scope.t b/t/re/reg_eval_scope.t
index 25b90b6482..3bf937d251 100644
--- a/t/re/reg_eval_scope.t
+++ b/t/re/reg_eval_scope.t
@@ -12,7 +12,7 @@ BEGIN {
}
}
-plan 48;
+plan 49;
fresh_perl_is <<'CODE', '781745', {}, '(?{}) has its own lexical scope';
my $x = 7; my $a = 4; my $b = 5;
@@ -371,3 +371,15 @@ SKIP: {
f3();
is ($s, \&f3, '__SUB__ qr multi');
}
+
+# RT #133879
+# ensure scope is properly restored when there's an error compiling a
+# "looks a bit like it has (?{}) but doesn't" qr//
+
+fresh_perl_like <<'CODE',
+ BEGIN {$^H = 0x10000 }; # HINT_NEW_RE
+ qr/\(?{/
+CODE
+ qr/Constant\(qq\) unknown/,
+ { stderr => 1 },
+ 'qr/\(?{';
--
2.20.1

7
perl.spec
View File

@ -264,6 +264,10 @@ Patch55: perl-5.29.8-perl-133778-adjust-MARK-if-we-extend-the-stack-in-pp
Patch56: perl-5.28.1-fix-leak-when-compiling-typed-hash-deref.patch
Patch57: perl-5.29.8-fix-blead-on-non-threaded-builds.patch
# Fix a buffer overread when handling a scope error in qr/\(?{/, RT#133879,
# in upstream after 5.29.8
Patch58: perl-5.29.8-handle-scope-error-in-qr.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
@ -2877,6 +2881,7 @@ Perl extension for Version Objects
%patch55 -p1
%patch56 -p1
%patch57 -p1
%patch58 -p1
%patch200 -p1
%patch201 -p1
@ -2926,6 +2931,7 @@ perl -x patchlevel.h \
'Fedora Patch54: Fix a race when loading XS modules' \
'Fedora Patch55: Fix extending a stack in Perl parser (RT#133778)' \
'Fedora Patch56: Fix a leak when compiling a typed hash dereference' \
'Fedora Patch58: Fix a buffer overread when handling a scope error in qr/\(?{/ (RT#133879)' \
'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}
@ -5216,6 +5222,7 @@ popd
%changelog
* Fri Apr 05 2019 Petr Pisar <ppisar@redhat.com> - 4:5.28.1-435
- Fix a leak when compiling a typed hash dereference
- Fix a buffer overread when handling a scope error in qr/\(?{/ (RT#133879)
* Tue Mar 05 2019 Björn Esser <besser82@fedoraproject.org> - 4:5.28.1-434
- Add explicit Requires: libxcrypt-devel to devel sub-package (bug #1666098)