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106 lines
4.3 KiB
106 lines
4.3 KiB
From dc1f8f6b581a8e4efbb782398ab3e7c3a52b062f Mon Sep 17 00:00:00 2001
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From: Karl Williamson <khw@cpan.org>
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Date: Tue, 8 May 2018 12:13:18 -0600
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Subject: [PATCH] PATCH: [perl #133185] Infinite loop in qr//
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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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This loop was inadvertently introduced as part of patches to fix
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(perl #132227 CVE-2018-6797] heap-buffer-overflow". The commit in 5.27
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responsible was f8fb8615ddc5a80e3bbd4386a8914497f921b62d.
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To be vulnerable, the pattern must start out as /d (hence no use 5.012
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or higher), and then there must be something that implicitly forces /u
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(which the \pp does in the test case added by this patch), and then
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(?aa), and then the code point \xDF. (German Sharp S). The /i must be
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in effect by the time the DF is encountered, but it needn't come in the
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(?aa) which the test does.
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The problem is that the conditional that is testing that we switched
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away from /d rules is assuming that this happened during the
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construction of the current EXACTFish node. The comments I wrote
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indicate this assumption. But this example shows that the switch can
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come before this node started getting constructed, and so it loops.
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The patch explicitly saves the state at the beginning of this node's
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construction, and only retries if it changed during that construction.
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Therefore the next time through, it will see that it hasn't changed
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since the previous time, and won't loop.
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Petr Písař: Ported to 5.26.2 from:
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commit 0b9cb33b146b3eb55634853f883a880771dd1413
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Author: Karl Williamson <khw@cpan.org>
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Date: Tue May 8 12:13:18 2018 -0600
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PATCH: [perl #133185] Infinite loop in qr//
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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regcomp.c | 10 +++++++++-
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t/re/speed.t | 5 ++++-
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2 files changed, 13 insertions(+), 2 deletions(-)
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diff --git a/regcomp.c b/regcomp.c
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index 845e660..18fa465 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -13100,6 +13100,10 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
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bool maybe_exactfu = PASS2
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&& (node_type == EXACTF || node_type == EXACTFL);
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+ /* To see if RExC_uni_semantics changes during parsing of the node.
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+ * */
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+ bool uni_semantics_at_node_start;
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+
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/* If a folding node contains only code points that don't
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* participate in folds, it can be changed into an EXACT node,
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* which allows the optimizer more things to look for */
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@@ -13147,6 +13151,8 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
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|| UTF8_IS_INVARIANT(UCHARAT(RExC_parse))
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|| UTF8_IS_START(UCHARAT(RExC_parse)));
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+ uni_semantics_at_node_start = RExC_uni_semantics;
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+
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/* Here, we have a literal character. Find the maximal string of
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* them in the input that we can fit into a single EXACTish node.
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* We quit at the first non-literal or when the node gets full */
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@@ -13550,7 +13556,9 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)
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* didn't think it needed to reparse. But this
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* sharp s now does indicate the need for
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* reparsing. */
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- if (RExC_uni_semantics) {
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+ if ( uni_semantics_at_node_start
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+ != RExC_uni_semantics)
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+ {
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p = oldp;
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goto loopdone;
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}
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diff --git a/t/re/speed.t b/t/re/speed.t
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index 4a4830f..9a57de1 100644
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--- a/t/re/speed.t
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+++ b/t/re/speed.t
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@@ -24,7 +24,7 @@ BEGIN {
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skip_all('no re module') unless defined &DynaLoader::boot_DynaLoader;
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skip_all_without_unicode_tables();
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-plan tests => 58; #** update watchdog timeouts proportionally when adding tests
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+plan tests => 59; #** update watchdog timeouts proportionally when adding tests
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use strict;
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use warnings;
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@@ -156,6 +156,9 @@ PROG
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ok( $elapsed <= 1, "should not COW on long string with substr and m//g");
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}
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+ # [perl #133185] Infinite loop
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+ like("!\xdf", eval 'qr/\pp(?aai)\xdf/',
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+ 'Compiling qr/\pp(?aai)\xdf/ doesn\'t loop');
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} # End of sub run_tests
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--
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2.14.3
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