110 lines
3.0 KiB
Diff
110 lines
3.0 KiB
Diff
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From 1385ac98c5f75358978bb05c2d6c4134413cf689 Mon Sep 17 00:00:00 2001
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From: David Mitchell <davem@iabyn.com>
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Date: Fri, 22 Mar 2019 17:38:48 +0000
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Subject: [PATCH] avoid leak assigning regexp to non-COW string
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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In something like
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$s = substr(.....); # $s now a non-COW SvPOK() SV
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$r = qr/..../;
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$s = $$r;
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$s's previous string buffer would leak when an SVt_REGEXP type SV is
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assigned to it.
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Worse, if $s was an SVt_PVPV, it would fail an assert on debugging
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builds.
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The fix is to make sure any remaining stringy stuff is cleaned up
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before copying the REGEXP.
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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regcomp.c | 16 ++++++++++++++++
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t/op/qr.t | 34 +++++++++++++++++++++++++++++++++-
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2 files changed, 49 insertions(+), 1 deletion(-)
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diff --git a/regcomp.c b/regcomp.c
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index 15783541a4..e13da83673 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -20665,7 +20665,23 @@ Perl_reg_temp_copy(pTHX_ REGEXP *dsv, REGEXP *ssv)
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if (!dsv)
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dsv = (REGEXP*) newSV_type(SVt_REGEXP);
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else {
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+ assert(SvTYPE(dsv) == SVt_REGEXP || (SvTYPE(dsv) == SVt_PVLV));
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+
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+ /* our only valid caller, sv_setsv_flags(), should have done
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+ * a SV_CHECK_THINKFIRST_COW_DROP() by now */
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+ assert(!SvOOK(dsv));
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+ assert(!SvIsCOW(dsv));
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+ assert(!SvROK(dsv));
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+
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+ if (SvPVX_const(dsv)) {
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+ if (SvLEN(dsv))
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+ Safefree(SvPVX(dsv));
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+ SvPVX(dsv) = NULL;
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+ }
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+ SvLEN_set(dsv, 0);
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+ SvCUR_set(dsv, 0);
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SvOK_off((SV *)dsv);
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+
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if (islv) {
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/* For PVLVs, the head (sv_any) points to an XPVLV, while
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* the LV's xpvlenu_rx will point to a regexp body, which
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diff --git a/t/op/qr.t b/t/op/qr.t
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index 32b9e3b23b..e03a465430 100644
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--- a/t/op/qr.t
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+++ b/t/op/qr.t
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@@ -7,7 +7,7 @@ BEGIN {
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require './test.pl';
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}
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-plan(tests => 34);
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+plan(tests => 37);
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sub r {
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return qr/Good/;
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@@ -135,3 +135,35 @@ sub {
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};
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}
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pass("PVLV-as-REGEXP double-free of PVX");
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+
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+# a non-cow SVPV leaked it's string buffer when a REGEXP was assigned to
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+# it. Give valgrind/ASan something to work on
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+{
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+ my $s = substr("ab",0,1); # generate a non-COW string
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+ my $r1 = qr/x/;
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+ $s = $$r1; # make sure "a" isn't leaked
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+ pass("REGEXP leak");
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+
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+ my $dest = 0;
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+ sub Foo99::DESTROY { $dest++ }
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+
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+ # ditto but make sure we don't leak a reference
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+ {
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+ my $ref = bless [], "Foo99";
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+ my $r2 = qr/x/;
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+ $ref = $$r2;
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+ }
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+ is($dest, 1, "REGEXP RV leak");
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+
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+ # and worse, assigning a REGEXP to an PVLV that had a string value
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+ # caused an assert failure. Same code, but using $_[0] which is an
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+ # lvalue, rather than $s.
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+
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+ my %h;
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+ sub {
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+ $_[0] = substr("ab",0,1); # generate a non-COW string
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+ my $r = qr/x/;
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+ $_[0] = $$r; # make sure "a" isn't leaked
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+ }->($h{foo}); # passes PVLV to sub
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+ is($h{foo}, "(?^:x)", "REGEXP PVLV leak");
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+}
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--
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2.20.1
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