[perl #130648] regcomp.c:6195: voidS_pat_upgrade_to_utf8(RExC_state_t *const, char **, STRLEN *, int): Assertion`*(d - 1) == ')'' failed

# New Ticket Created by  Sergey Aleynikov 
# Please include the string:  [perl #130648]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=130648 >


This is a bug report for perl from sergey.aleynikov@gmail.com,
generated with the help of perlbug 1.40 running under perl 5.25.9.


-----------------------------------------------------------------
[Please describe your issue here]

While fuzzing perl v5.25.9-35-g32207c637b built with afl and run
under libdislocator, I found the following 16-bytes program

hexdump -C 0042
00000000  6d 27 5c 34 30 30 28 3f  7b 3c 3c 7d 29 0a 0a 27  |m'\400(?{<<})..'|
00000010

to cause an assertion failure. It crashes on perls dating back to at
least 5.8.8, albeit with different messages. GDB info about the crash
location:

(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58
#1  0x00007f0dbddc740a in __GI_abort () at abort.c:89
#2  0x00007f0dbddbee47 in __assert_fail_base (fmt=<optimized out>,
assertion=assertion@entry=0x7f0dbf4ab3ac "*(d - 1) == ')'",
    file=file@entry=0x7f0dbf4a9198 "regcomp.c", line=line@entry=6195,
    function=function@entry=0x7f0dbf4b2500 <__PRETTY_FUNCTION__.16556>
"S_pat_upgrade_to_utf8") at assert.c:92
#3  0x00007f0dbddbeef2 in __GI___assert_fail (assertion=0x7f0dbf4ab3ac
"*(d - 1) == ')'", file=0x7f0dbf4a9198 "regcomp.c", line=6195,
    function=0x7f0dbf4b2500 <__PRETTY_FUNCTION__.16556>
"S_pat_upgrade_to_utf8") at assert.c:101
#4  0x00007f0dbf1ec789 in S_pat_upgrade_to_utf8
(pRExC_state=0x7fff4cce2030, pat_p=0x7fff4cce1cb8,
plen_p=0x7fff4cce1cb0, num_code_blocks=1)
    at regcomp.c:6195
#5  0x00007f0dbf1f1c7d in Perl_re_op_compile (patternp=0x0,
pat_count=3, expr=0x7f0dc1237bd8, eng=0x7f0dbf735540
<PL_core_reg_engine>, old_re=0x0,
    is_bare_re=0x0, orig_rx_flags=0, pm_flags=0) at regcomp.c:7106
#6  0x00007f0dbf112952 in Perl_pmruntime (o=0x7f0dc1237c18,
expr=0x7f0dc1238078, repl=0x0, flags=1, floor=0) at op.c:5882
#7  0x00007f0dbf1c3ecc in Perl_yyparse (gramtype=258) at perly.y:1204
#8  0x00007f0dbf142b1a in S_parse_body (env=0x0, xsinit=0x7f0dbf0fdf98
<xs_init>) at perl.c:2376
#9  0x00007f0dbf140e7f in perl_parse (my_perl=0x7f0dc1215010,
xsinit=0x7f0dbf0fdf98 <xs_init>, argc=3, argv=0x7fff4cce2b88, env=0x0)
at perl.c:1691
#10 0x00007f0dbf0fded6 in main (argc=3, argv=0x7fff4cce2b88,
env=0x7fff4cce2ba8) at perlmain.c:121
(gdb) f 4
#4  0x00007f0dbf1ec789 in S_pat_upgrade_to_utf8
(pRExC_state=0x7fff4cce2030, pat_p=0x7fff4cce1cb8,
plen_p=0x7fff4cce1cb0, num_code_blocks=1)
    at regcomp.c:6195
6195                    assert(*(d - 1) == ')');
(gdb) p *(d-1)
$1 = 10 '\n'

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=medium
---
Site configuration information for perl 5.25.9:

Configured by root at Sat Jan 14 02:25:05 MSK 2017.

Summary of my perl5 (revision 5 version 25 subversion 9) configuration:
  Commit id: cbe2fc5001aa59cdc73e04cc35e097a2ecfbeec0
  Platform:
    osname=linux
    osvers=3.16.0-4-amd64
    archname=x86_64-linux
    uname='linux dorothy 3.16.0-4-amd64 #1 smp debian 3.16.36-1+deb8u2
(2016-10-19) x86_64 gnulinux '
    config_args='-des -Dusedevel -DDEBUGGING -Dcc=afl-clang-fast
-Doptimize=-O0 -g -ggdb3'
    hint=recommended
    useposix=true
    d_sigaction=define
    useithreads=undef
    usemultiplicity=undef
    use64bitint=define
    use64bitall=define
    uselongdouble=undef
    usemymalloc=n
    bincompat5005=undef
  Compiler:
    cc='afl-clang-fast'
    ccflags ='-DDEBUGGING -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
    optimize='-O0 -g -ggdb3'
    cppflags='-DDEBUGGING -fno-strict-aliasing -pipe
-fstack-protector-strong -I/usr/local/include'
    ccversion=''
    gccversion='4.2.1 Compatible Clang 3.9.1 (tags/RELEASE_391/rc2)'
    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='afl-clang-fast'
    ldflags =' -fstack-protector-strong -L/usr/local/lib'
    libpth=/usr/local/lib /usr/lib/llvm-3.9/bin/../lib/clang/3.9.1/lib
/usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu
/lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib
    libs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
    libc=libc-2.24.so
    so=so
    useshrplib=false
    libperl=libperl.a
    gnulibc_version='2.24'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs
    dlext=so
    d_dlsymun=undef
    ccdlflags='-Wl,-E'
    cccdlflags='-fPIC'
    lddlflags='-shared -O0 -g -ggdb3 -L/usr/local/lib -fstack-protector-strong'


---
@INC for perl 5.25.9:
    lib
    /usr/local/lib/perl5/site_perl/5.25.9/x86_64-linux
    /usr/local/lib/perl5/site_perl/5.25.9
    /usr/local/lib/perl5/5.25.9/x86_64-linux
    /usr/local/lib/perl5/5.25.9

---
Environment for perl 5.25.9:
    HOME=/home/afl
    LANG=en_US.UTF-8
    LANGUAGE=en_US:en
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/afl/perlbrew/bin:/home/afl/perlbrew/perls/perl-5.22.1/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games
    PERLBREW_BASHRC_VERSION=0.78
    PERLBREW_HOME=/home/afl/.perlbrew
    PERLBREW_MANPATH=/home/afl/perlbrew/perls/perl-5.22.1/man
    PERLBREW_PATH=/home/afl/perlbrew/bin:/home/afl/perlbrew/perls/perl-5.22.1/bin
    PERLBREW_PERL=perl-5.22.1
    PERLBREW_ROOT=/home/afl/perlbrew
    PERLBREW_VERSION=0.78
    PERL_BADLANG (unset)
    SHELL=/usr/bin/zsh

• [perl #130648] regcomp.c:6195: voidS_pat_upgrade_to_utf8(RExC_state_t *const, char **, STRLEN *, int): Assertion`*(d - 1) == ')'' failed by Sergey Aleynikov