perl/perl-5.26.0-don-t-call-Perl_fbm_instr-with-negative-length.patch

117 lines
3.8 KiB
Diff

From 10e784017784a8c1b1835b04026f8948eb502e50 Mon Sep 17 00:00:00 2001
From: David Mitchell <davem@iabyn.com>
Date: Fri, 16 Jun 2017 15:46:19 +0100
Subject: [PATCH] don't call Perl_fbm_instr() with negative length
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Ported to 5.26.0:
commit bb152a4b442f7718fd37d32cc558be675e8ae1ae
Author: David Mitchell <davem@iabyn.com>
Date: Fri Jun 16 15:46:19 2017 +0100
don't call Perl_fbm_instr() with negative length
RT #131575
re_intuit_start() could calculate a maximum end position less than the
current start position. This used to get rejected by fbm_intr(), until
v5.23.3-110-g147f21b, which made fbm_intr() faster and removed unnecessary
checks.
This commits fixes re_intuit_start(), and adds an assert to fbm_intr().
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
regexec.c | 17 +++++++++++------
t/re/pat.t | 13 ++++++++++++-
util.c | 2 ++
3 files changed, 25 insertions(+), 7 deletions(-)
diff --git a/regexec.c b/regexec.c
index 35b88d7..4e82bc2 100644
--- a/regexec.c
+++ b/regexec.c
@@ -126,13 +126,16 @@ static const char* const non_utf8_target_but_utf8_required
(U8*)(off >= 0 ? reginfo->strend : reginfo->strbeg)) \
: (U8*)(pos + off))
-#define HOPBACKc(pos, off) \
- (char*)(reginfo->is_utf8_target \
- ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(reginfo->strbeg)) \
- : (pos - off >= reginfo->strbeg) \
- ? (U8*)pos - off \
+/* like HOPMAYBE3 but backwards. lim must be +ve. Returns NULL on overshoot */
+#define HOPBACK3(pos, off, lim) \
+ (reginfo->is_utf8_target \
+ ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(lim)) \
+ : (pos - off >= lim) \
+ ? (U8*)pos - off \
: NULL)
+#define HOPBACKc(pos, off) ((char*)HOPBACK3(pos, off, reginfo->strbeg))
+
#define HOP3(pos,off,lim) (reginfo->is_utf8_target ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
#define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
@@ -884,7 +887,9 @@ Perl_re_intuit_start(pTHX_
(IV)prog->check_end_shift);
});
- end_point = HOP3(strend, -end_shift, strbeg);
+ end_point = HOPBACK3(strend, end_shift, rx_origin);
+ if (!end_point)
+ goto fail_finish;
start_point = HOPMAYBE3(rx_origin, start_shift, end_point);
if (!start_point)
goto fail_finish;
diff --git a/t/re/pat.t b/t/re/pat.t
index 16bfc8e..2510eab 100644
--- a/t/re/pat.t
+++ b/t/re/pat.t
@@ -23,7 +23,7 @@ BEGIN {
skip_all('no re module') unless defined &DynaLoader::boot_DynaLoader;
skip_all_without_unicode_tables();
-plan tests => 837; # Update this when adding/deleting tests.
+plan tests => 838; # Update this when adding/deleting tests.
run_tests() unless caller;
@@ -1911,6 +1911,17 @@ EOP
# [perl #129281] buffer write overflow, detected by ASAN, valgrind
fresh_perl_is('/0(?0)|^*0(?0)|^*(^*())0|/', '', {}, "don't bump whilem_c too much");
}
+
+ {
+ # RT #131575 intuit skipping back from the end to find the highest
+ # possible start point, was potentially hopping back beyond pos()
+ # and crashing by calling fbm_instr with a negative length
+
+ my $text = "=t=\x{5000}";
+ pos($text) = 3;
+ ok(scalar($text !~ m{(~*=[a-z]=)}g), "RT #131575");
+ }
+
} # End of sub run_tests
1;
diff --git a/util.c b/util.c
index f1b92a9..69763bc 100644
--- a/util.c
+++ b/util.c
@@ -816,6 +816,8 @@ Perl_fbm_instr(pTHX_ unsigned char *big, unsigned char *bigend, SV *littlestr, U
PERL_ARGS_ASSERT_FBM_INSTR;
+ assert(bigend >= big);
+
if ((STRLEN)(bigend - big) < littlelen) {
if ( tail
&& ((STRLEN)(bigend - big) == littlelen - 1)
--
2.9.4