Assertion failure in S_regmatch (regexec.c: 6493)

[p5pRT]

Migrated from rt.perl.org#134083 (status was 'new')

Searchable as RT134083$

[p5pRT]

From @dur-randir

Created by @dur-randir

While fuzzing perl v5.29.10-23-g7c0d7520a3 built with afl and run
under libdislocator, I found the following program

use utf8;
eval"\320\200 f'\r\r0'=~'\\R??\r0'"

to cause an assertion failure

perl​: regexec.c​:6493​: S_regmatch​: Assertion `n == REG_INFTY ||
locinput == li' failed.

GDB stack trace is following

#0 __GI_raise (sig=sig@​entry=6) at ../sysdeps/unix/sysv/linux/raise.c​:50
#1 0x00007ffff7c48535 in __GI_abort () at abort.c​:79
#2 0x00007ffff7c4840f in __assert_fail_base (fmt=0x7ffff7daaee0
"%s%s%s​:%u​: %s%sAssertion `%s' failed.\n%n",
  assertion=0x555555796fc0 "n == REG_INFTY || locinput == li",
file=0x555555795f88 "regexec.c", line=6493, function=<optimized out>)
at assert.c​:92
#3 0x00007ffff7c560f2 in __GI___assert_fail
(assertion=assertion@​entry=0x555555796fc0 "n == REG_INFTY || locinput
== li",
  file=file@​entry=0x555555795f88 "regexec.c", line=line@​entry=6493,
function=function@​entry=0x555555798b08 <__PRETTY_FUNCTION__.14818>
"S_regmatch")
  at assert.c​:101
#4 0x000055555570670c in S_regmatch (prog=<optimized out>,
startpos=0x555555a00a10 "\r\r0", reginfo=0x7fffffffddb0) at
regexec.c​:6493
#5 S_regtry (reginfo=reginfo@​entry=0x7fffffffddb0,
startposp=startposp@​entry=0x7fffffffdd98) at regexec.c​:3200
#6 0x0000555555711530 in Perl_regexec_flags (rx=0x5555559f4c20,
stringarg=0x555555a00a10 "\r\r0", strend=0x555555a00a13 "",
strbeg=0x555555a00a10 "\r\r0",
  minend=<optimized out>, sv=0x5555559f4b60, data=0x0, flags=97) at
regexec.c​:2917
#7 0x0000555555656e29 in Perl_pp_match () at pp_hot.c​:1446
#8 0x000055555562aa8a in Perl_runops_debug () at dump.c​:2427
#9 0x00005555555ae109 in S_run_body (oldscope=1) at perl.c​:2456
#10 perl_run (my_perl=<optimized out>) at perl.c​:2372
#11 0x0000555555582b1f in main (argc=<optimized out>, argv=<optimized
out>, env=<optimized out>) at perlmain.c​:114

This is a regression between 5.18 and 5.20, bisect points to

commit b24b43f (HEAD, refs/bisect/bad)
Author​: Karl Williamson <public@​khwilliamson.com>
Date​: Mon Jan 6 13​:41​:46 2014 -0700

  IDStart and IDCont no longer go out to disk

  These are the base names for various macros used in parsing identifiers.
  Prior to this patch, parsing a code point above Latin1 caused loading
  disk files. This patch causes all the information to be compiled into
  the Perl binary.

Perl Info

Flags:
    category=core
    severity=medium

Site configuration information for perl 5.29.9:

Configured by dur-randir at Wed Feb 27 14:51:01 MSK 2019.

Summary of my perl5 (revision 5 version 29 subversion 9) configuration:
  Commit id: c1e47bad34ce1d9c84ed57c9b8978bcbd5a02e98
  Platform:
    osname=darwin
    osvers=13.4.0
    archname=darwin-thread-multi-2level
    uname='darwin isengard.local 13.4.0 darwin kernel version 13.4.0:
mon jan 11 18:17:34 pst 2016; root:xnu-2422.115.15~1release_x86_64
x86_64 '
    config_args='-de -Dusedevel -DDEBUGGING -Dusethreads'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=define
    usemultiplicity=define
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    default_inc_excludes_dot=define
    bincompat5005=undef
  Compiler:
    cc='cc'
    ccflags ='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.9
-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include -DPERL_USE_SAFE_PUTENV'
    optimize='-O3 -g'
    cppflags='-fno-common -DPERL_DARWIN -mmacosx-version-min=10.9
-DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector
-I/usr/local/include'
    ccversion=''
    gccversion='4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.56)'
    gccosandvers=''
    intsize=4
    longsize=8
    ptrsize=8
    doublesize=8
    byteorder=12345678
    doublekind=3
    d_longlong=define
    longlongsize=8
    d_longdbl=define
    longdblsize=16
    longdblkind=3
    ivtype='long'
    ivsize=8
    nvtype='double'
    nvsize=8
    Off_t='off_t'
    lseeksize=8
    alignbytes=8
    prototype=define
  Linker and Libraries:
    ld='cc'
    ldflags =' -mmacosx-version-min=10.9 -fstack-protector -L/usr/local/lib'
    libpth=/usr/local/lib
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.0/lib
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib
/usr/lib
    libs=-lpthread -lgdbm -ldbm -ldl -lm -lutil -lc
    perllibs=-lpthread -ldl -lm -lutil -lc
    libc=
    so=dylib
    useshrplib=false
    libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=bundle
    d_dlsymun=undef
    ccdlflags=' '
    cccdlflags=' '
    lddlflags=' -mmacosx-version-min=10.9 -bundle -undefined
dynamic_lookup -L/usr/local/lib -fstack-protector'



@INC for perl 5.29.9:
    lib
    /usr/local/lib/perl5/site_perl/5.29.9/darwin-thread-multi-2level
    /usr/local/lib/perl5/site_perl/5.29.9
    /usr/local/lib/perl5/5.29.9/darwin-thread-multi-2level
    /usr/local/lib/perl5/5.29.9


Environment for perl 5.29.9:
    DYLD_LIBRARY_PATH (unset)
    HOME=/Users/dur-randir
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/Users/dur-randir/perlbrew/bin:/Users/dur-randir/perlbrew/perls/perl-5.22.1/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/texbin
    PERLBREW_HOME=/Users/dur-randir/.perlbrew
    PERLBREW_MANPATH=/Users/dur-randir/perlbrew/perls/perl-5.22.1/man
    PERLBREW_PATH=/Users/dur-randir/perlbrew/bin:/Users/dur-randir/perlbrew/perls/perl-5.22.1/bin
    PERLBREW_PERL=perl-5.22.1
    PERLBREW_ROOT=/Users/dur-randir/perlbrew
    PERLBREW_SHELLRC_VERSION=0.84
    PERLBREW_VERSION=0.84
    PERL_BADLANG (unset)
    SHELL=/usr/local/bin/zsh