60 lines
2.0 KiB
Diff
60 lines
2.0 KiB
Diff
From 75bb5aa48dfcf930533cd069393fc8a45e4ece18 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 12:31:57 +0000
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Subject: [PATCH] fix leak in cloned regexes.
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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 a regex is cloned for a new thread, the string buffer (which holds
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the text of the original pattern) wasn't being freed because SvLEN was
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being set to 0.
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For example:
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use threads;
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my $r = qr/abc/;
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threads->new( sub { 1; })->join;
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In the new thread, $r is cloned but when the thread exits, the string
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buffer holding "(?^:abc)" was leaking.
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This was broken by v5.27.2-30-gdf6b4bd565.
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The problem was that in the cloned SV, the buffer was copied, but the
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SvLEN(sv) was left set at zero, which along with the SVf_FAKE, mader it
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look like the buffer was alien and so not freed.
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SvLEN was 0 in the parent thread's $r, since $r and its compile-time
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prototype share the same string buffer (so only the original SV has
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SvLEN > 0 - all the copies - within the same thread - have mother_re
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pointing to the original).
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When REs are cloned into another thread, mother_re isn't preserved,
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so each RE has its own copy of the buffer.
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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regcomp.c | 5 +++++
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1 file changed, 5 insertions(+)
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diff --git a/regcomp.c b/regcomp.c
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index 547b9113e3..15783541a4 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -20956,6 +20956,11 @@ Perl_re_dup_guts(pTHX_ const REGEXP *sstr, REGEXP *dstr, CLONE_PARAMS *param)
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2: something we no longer hold a reference on
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so we need to copy it locally. */
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RX_WRAPPED(dstr) = SAVEPVN(RX_WRAPPED_const(sstr), SvCUR(sstr)+1);
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+ /* set malloced length to a non-zero value so it will be freed
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+ * (otherwise in combination with SVf_FAKE it looks like an alien
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+ * buffer). It doesn't have to be the actual malloced size, since it
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+ * should never be grown */
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+ SvLEN_set(dstr, SvCUR(sstr)+1);
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ret->mother_re = NULL;
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}
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#endif /* PERL_IN_XSUB_RE */
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--
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2.20.1
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