53 lines
1.9 KiB
Diff
53 lines
1.9 KiB
Diff
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From 7402016d87474403eea5c52dc2c071f68cbbe25c Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?=C3=86var=20Arnfj=C3=B6r=C3=B0=20Bjarmason?= <avar@cpan.org>
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Date: Tue, 13 Dec 2011 14:43:12 +0000
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Subject: [PATCH] [RT #78266] Don't leak memory when accessing named captures
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that didn't match
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Since 5.10 (probably 44a2ac759e) named captures have been leaking
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memory when they're used, don't actually match, but are later
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accessed. E.g.:
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$ perl -wle 'for (1..10_000_000) { if ("foo" =~ /(foo|(?<capture>bar))?/) { my $capture = $+{capture} } } system "ps -o rss $$"'
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RSS
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238524
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Here we match the "foo" branch of our regex, but since we've used a
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name capture we'll end up running the code in
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Perl_reg_named_buff_fetch, which allocates a newSVsv(&PL_sv_undef) but
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never uses it unless it's trying to return an array.
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Just change that code not to allocate scalars we don't plan to
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return. With this fix we don't leak any memory since there's nothing
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to leak anymore.
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$ ./perl -Ilib -wle 'for (1..10_000_000) { if ("foo" =~ /(foo|(?<capture>bar))?/) { my $capture = $+{capture} } } system "ps -o rss $$"'
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RSS
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3528
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This reverts commit b28f4af8cf94eb18c0cfde71e9625081912499a8 ("Fix
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allocating something in the first place is a better solution than
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allocating it, not using it, and then freeing it.
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Petr Pisar: perldelta and wrong fix (commit b28f4af8cf) removed.
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---
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regcomp.c | 7 ++-----
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diff --git a/regcomp.c b/regcomp.c
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index 9e9fac4..56b2b9c 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -5409,7 +5409,8 @@ Perl_reg_named_buff_fetch(pTHX_ REGEXP * const r, SV * const namesv,
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if (!retarray)
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return ret;
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} else {
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- ret = newSVsv(&PL_sv_undef);
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+ if (retarray)
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+ ret = newSVsv(&PL_sv_undef);
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}
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if (retarray)
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av_push(retarray, ret);
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--
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1.7.7.4
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