109 lines
2.9 KiB
Diff
109 lines
2.9 KiB
Diff
From 85df897fcfe76250deecfdeb239ba1e4279d8532 Mon Sep 17 00:00:00 2001
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From: David Mitchell <davem@iabyn.com>
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Date: Tue, 26 Mar 2019 11:04:07 +0000
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Subject: [PATCH] avoid leak with local $h{foo}, $a[n]
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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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When SAVEt_DELETE / SAVEt_ADELETE deletes a hash/array entry on scope
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exit, they also decrement the refcount of the hash/array, and for the
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hash, also free the saved key.
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However, if the call to hv_delete() or av_delete() dies (e.g. when
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calling a tied DELETE method) then the hash/array and key will leak
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because leave_scope() calls av/hv_delete(), *then* does the
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SvREFCNT_dec() etc.
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The fix is to push new FREEPV/FREESV actions just before calling
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av/hv_delete().
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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scope.c | 17 ++++++++++++++---
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t/op/tie.t | 37 +++++++++++++++++++++++++++++++++++++
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2 files changed, 51 insertions(+), 3 deletions(-)
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diff --git a/scope.c b/scope.c
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index 83a7b76893..3e4ee4344b 100644
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--- a/scope.c
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+++ b/scope.c
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@@ -1253,15 +1253,26 @@ Perl_leave_scope(pTHX_ I32 base)
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case SAVEt_DELETE:
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a0 = ap[0]; a1 = ap[1]; a2 = ap[2];
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+ /* hv_delete could die, so free the key and SvREFCNT_dec the
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+ * hv by pushing new save actions
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+ */
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+ /* ap[0] is the key */
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+ ap[1].any_uv = SAVEt_FREEPV; /* was len */
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+ /* ap[2] is the hv */
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+ ap[3].any_uv = SAVEt_FREESV; /* was SAVEt_DELETE */
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+ PL_savestack_ix += 4;
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(void)hv_delete(a2.any_hv, a0.any_pv, a1.any_i32, G_DISCARD);
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- SvREFCNT_dec(a2.any_hv);
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- Safefree(a0.any_ptr);
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break;
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case SAVEt_ADELETE:
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a0 = ap[0]; a1 = ap[1];
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+ /* av_delete could die, so SvREFCNT_dec the av by pushing a
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+ * new save action
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+ */
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+ ap[0].any_av = a1.any_av;
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+ ap[1].any_uv = SAVEt_FREESV;
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+ PL_savestack_ix += 2;
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(void)av_delete(a1.any_av, a0.any_iv, G_DISCARD);
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- SvREFCNT_dec(a1.any_av);
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break;
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case SAVEt_DESTRUCTOR_X:
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diff --git a/t/op/tie.t b/t/op/tie.t
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index a2d771a009..bfcafce87a 100644
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--- a/t/op/tie.t
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+++ b/t/op/tie.t
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@@ -1585,3 +1585,40 @@ print "[$x][$f][$n][$s]\n";
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EXPECT
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[3][1][3][0]
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[0][2][3][0]
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+########
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+# dying while doing a SAVEt_DELETE dureing scope exit leaked a copy of the
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+# key. Give ASan something to play with
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+sub TIEHASH { bless({}, $_[0]) }
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+sub EXISTS { 0 }
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+sub DELETE { die; }
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+sub DESTROY { print "destroy\n"; }
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+
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+eval {
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+ my %h;
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+ tie %h, "main";
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+ local $h{foo};
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+ print "leaving\n";
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+};
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+print "left\n";
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+EXPECT
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+leaving
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+destroy
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+left
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+########
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+# ditto for SAVEt_DELETE with an array
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+sub TIEARRAY { bless({}, $_[0]) }
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+sub EXISTS { 0 }
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+sub DELETE { die; }
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+sub DESTROY { print "destroy\n"; }
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+
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+eval {
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+ my @a;
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+ tie @a, "main";
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+ delete local $a[0];
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+ print "leaving\n";
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+};
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+print "left\n";
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+EXPECT
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+leaving
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+destroy
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+left
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--
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2.20.1
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