185 lines
7.1 KiB
Diff
185 lines
7.1 KiB
Diff
From f1e1b256c5c1773d90e828cca6323c53fa23391b Mon Sep 17 00:00:00 2001
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From: Yves Orton <demerphq@gmail.com>
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Date: Tue, 25 Jun 2013 21:01:27 +0200
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Subject: [PATCH] Fix rules for parsing numeric escapes in regexes
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Commit 726ee55d introduced better handling of things like \87 in a
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regex, but as an unfortunate side effect broke latex2html.
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The rules for handling backslashes in regexen are a bit arcane.
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Anything starting with \0 is octal.
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The sequences \1 through \9 are always backrefs.
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Any other sequence is interpreted as a decimal, and if there
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are that many capture buffers defined in the pattern at that point
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then the sequence is a backreference. If however it is larger
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than the number of buffers the sequence is treated as an octal digit.
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A consequence of this is that \118 could be a backreference to
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the 118th capture buffer, or it could be the string "\11" . "8". In
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other words depending on the context we might even use a different
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number of digits for the escape!
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This also left an awkward edge case, of multi digit sequences
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starting with 8 or 9 like m/\87/ which would result in us parsing
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as though we had seen /87/ (iow a null byte at the start) or worse
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like /\x{00}87/ which is clearly wrong.
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This patches fixes the cases where the capture buffers are defined,
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and causes things like the \87 or \97 to throw the same error that
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/\8/ would. One might argue we should complain about an illegal
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octal sequence, but this seems more consistent with an error like
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/\9/ and IMO will be less surprising in an error message.
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This patch includes exhaustive tests of patterns of the form
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/(a)\1/, /((a))\2/ etc, so that we dont break this again if we
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change the logic more.
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---
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regcomp.c | 31 ++++++++++++++++++++++---------
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t/re/pat.t | 19 ++++++++++++++++++-
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t/re/re_tests | 7 +++----
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t/re/reg_mesg.t | 6 +++---
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4 files changed, 46 insertions(+), 17 deletions(-)
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diff --git a/regcomp.c b/regcomp.c
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index c7f8885..d01f62a 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -10706,7 +10706,7 @@ tryagain:
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if (num < 1)
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vFAIL("Reference to nonexistent or unclosed group");
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}
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- if (!isg && num > 9 && num >= RExC_npar)
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+ if (!isg && num > 9 && num >= RExC_npar && *RExC_parse != '8' && *RExC_parse != '9')
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/* Probably a character specified in octal, e.g. \35 */
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goto defchar;
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else {
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@@ -10983,10 +10983,28 @@ tryagain:
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p++;
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ender = grok_bslash_c(*p++, UTF, SIZE_ONLY);
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break;
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- case '0': case '1': case '2': case '3':case '4':
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+ case '8': case '9': /* must be a backreference */
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+ --p;
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+ goto loopdone;
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+ case '1': case '2': case '3':case '4':
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case '5': case '6': case '7':
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- if (*p == '0' ||
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- (isDIGIT(p[1]) && atoi(p) >= RExC_npar))
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+ /* When we parse backslash escapes there is ambiguity between
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+ * backreferences and octal escapes. Any escape from \1 - \9 is
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+ * a backreference, any multi-digit escape which does not start with
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+ * 0 and which when evaluated as decimal could refer to an already
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+ * parsed capture buffer is a backslash. Anything else is octal.
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+ *
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+ * Note this implies that \118 could be interpreted as 118 OR as
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+ * "\11" . "8" depending on whether there were 118 capture buffers
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+ * defined already in the pattern.
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+ */
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+ if ( !isDIGIT(p[1]) || atoi(p) <= RExC_npar )
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+ { /* Not to be treated as an octal constant, go
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+ find backref */
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+ --p;
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+ goto loopdone;
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+ }
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+ case '0':
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{
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I32 flags = PERL_SCAN_SILENT_ILLDIGIT;
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STRLEN numlen = 3;
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@@ -11005,11 +11023,6 @@ tryagain:
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form_short_octal_warning(p, numlen));
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}
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}
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- else { /* Not to be treated as an octal constant, go
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- find backref */
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- --p;
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- goto loopdone;
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- }
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if (PL_encoding && ender < 0x100)
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goto recode_encoding;
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break;
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diff --git a/t/re/pat.t b/t/re/pat.t
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index bdfea87..99d719d 100644
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--- a/t/re/pat.t
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+++ b/t/re/pat.t
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@@ -20,7 +20,7 @@ BEGIN {
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require './test.pl';
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}
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-plan tests => 472; # Update this when adding/deleting tests.
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+plan tests => 572; # Update this when adding/deleting tests.
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run_tests() unless caller;
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@@ -1363,6 +1363,23 @@ EOP
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is ($s, 'XXcdXXX&', 'RT #119125 with /x');
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}
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+ {
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+ # if we have 87 capture buffers defined then \87 should refer to the 87th.
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+ # test that this is true for 1..100
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+ my $str= "aa";
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+ for my $i (1..100) {
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+ my $pat= "a";
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+ $pat= "($pat)" for 1 .. $i;
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+ $pat.="\\$i";
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+ eval {
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+ ok($str=~/$pat/,"\\$i works with $i buffers");
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+ 1;
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+ } or do {
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+ ok(0,"\\$i works with $i buffers");
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+ };
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+ }
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+ }
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+
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} # End of sub run_tests
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1;
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diff --git a/t/re/re_tests b/t/re/re_tests
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index b3231c2..9a24360 100644
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--- a/t/re/re_tests
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+++ b/t/re/re_tests
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@@ -1487,10 +1487,9 @@ abc\N{def - c - \\N{NAME} must be resolved by the lexer
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[a\o{1000}] \x{200} y $& \x{200}
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# The below were inserting a NULL
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-\87 87 y $& 87
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-a\87 a87 y $& a87
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-a\97 a97 y $& a97
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-
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+\87 87 c - Reference to nonexistent group in regex
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+a\87 a87 c - Reference to nonexistent group in regex
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+a\97 a97 c - Reference to nonexistent group in regex
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# The below was inserting a NULL into the character class.
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[\8\9] \000 Sn - -
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diff --git a/t/re/reg_mesg.t b/t/re/reg_mesg.t
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index b8098fd..56c7b55 100644
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--- a/t/re/reg_mesg.t
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+++ b/t/re/reg_mesg.t
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@@ -177,6 +177,9 @@ my @death =
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'm/[\o]/' => 'Missing braces on \o{} {#} m/[\o{#}]/',
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'm/[\o{}]/' => 'Number with no digits {#} m/[\o{}{#}]/',
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'm/(?^-i:foo)/' => 'Sequence (?^-...) not recognized {#} m/(?^-{#}i:foo)/',
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+ 'm/\87/' => 'Reference to nonexistent group {#} m/\87{#}/',
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+ 'm/a\87/' => 'Reference to nonexistent group {#} m/a\87{#}/',
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+ 'm/a\97/' => 'Reference to nonexistent group {#} m/a\97{#}/',
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);
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# Tests involving a user-defined charnames translator are in pat_advanced.t
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@@ -203,9 +206,6 @@ my @warning = (
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'/\018/' => '\'\018\' resolved to \'\o{1}8\' {#} m/\018{#}/',
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'/[\08]/' => '\'\08\' resolved to \'\o{0}8\' {#} m/[\08{#}]/',
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'/[\018]/' => '\'\018\' resolved to \'\o{1}8\' {#} m/[\018{#}]/',
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- '/\87/' => 'Unrecognized escape \8 passed through {#} m/\8{#}7/',
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- '/a\87/' => 'Unrecognized escape \8 passed through {#} m/a\8{#}7/',
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- '/a\97/' => 'Unrecognized escape \9 passed through {#} m/a\9{#}7/',
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'/(?=a)*/' => '(?=a)* matches null string many times {#} m/(?=a)*{#}/',
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'my $x = \'\m\'; qr/a$x/' => 'Unrecognized escape \m passed through {#} m/a\m{#}/',
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'/\q/' => 'Unrecognized escape \q passed through {#} m/\q{#}/',
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--
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1.8.3.1
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