57 lines
2.4 KiB
Diff
57 lines
2.4 KiB
Diff
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From f4cd5e29bc15621f2ab8fc5d7de0e68e62d43999 Mon Sep 17 00:00:00 2001
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From: Hugo van der Sanden <hv@crypt.org>
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Date: Tue, 15 Sep 2020 14:02:54 +0100
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Subject: [PATCH] [gh18096] assume worst-case for GOSUBs we don't analyse
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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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During study_chunk, under various conditions we avoid recursing into
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a GOSUB. But we must avoid giving the enclosing scope the idea that
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this GOSUB would match only an empty string, since that could trigger
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wrong optimizations (eg CURLYX => CURLYM in the ticket).
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So we mark the construct as infinite, as in the code branch where we
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_do_ recurse into it.
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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regcomp.c | 7 ++++++-
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t/re/re_tests | 2 ++
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2 files changed, 8 insertions(+), 1 deletion(-)
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diff --git a/regcomp.c b/regcomp.c
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index 124ea5b90b..fae3f8079d 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -5212,7 +5212,12 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
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* might result in a minlen of 1 and not of 4,
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* but this doesn't make us mismatch, just try a bit
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* harder than we should.
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- * */
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+ *
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+ * However we must assume this GOSUB is infinite, to
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+ * avoid wrongly applying other optimizations in the
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+ * enclosing scope - see GH 18096, for example.
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+ */
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+ is_inf = is_inf_internal = 1;
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scan= regnext(scan);
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continue;
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}
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diff --git a/t/re/re_tests b/t/re/re_tests
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index 554a7004a2..ab5a0d8012 100644
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--- a/t/re/re_tests
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+++ b/t/re/re_tests
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@@ -2023,6 +2023,8 @@ AB\s+\x{100} AB \x{100}X y - -
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/(?iaax:A? \K +)/ African_Feh c - \\K + is forbidden - matches null string many times in regex
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/(?iaa:A?\K+)/ African_Feh c - \\K+ is forbidden - matches null string many times in regex
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/(?iaa:A?\K*)/ African_Feh c - \\K* is forbidden - matches null string many times in regex
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+^((\w|<(\s)*(?1)(?3)*>)(?:(?3)*\+(?3)*(?2))*)(?3)*\+ a + b + <c + d> y $1 a + b # [GH #18096]
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+^((\w|<(\s)*(?1)(?3)*>)(?:(?3)*\+(?3)*(?2))*)(?3)*\+ a + <b> + c y $1 a + <b> # [GH #18096]
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# Keep these lines at the end of the file
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# pat string y/n/etc expr expected-expr skip-reason comment
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# vim: softtabstop=0 noexpandtab
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--
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2.25.4
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