sv.c:2612: Perl_sv_2nv_flags: Assertion `SvTYPE(sv) != SVt_PVAV && SvTYPE(sv) != SVt_PVHV && SvTYPE(sv) != SVt_PVFM' failed

[p5pRT]

Migrated from rt.perl.org#130669 (status was 'open')

Searchable as RT130669$

[p5pRT]

From @dur-randir

Created by @dur-randir

While fuzzing perl v5.25.8-216-gfbceb79751 built with afl and run
under libdislocator, I found the following program

printf my(%c)​:_

to cause an assertion failure, even when run under -c for a syntax
check. This is a regression between v5.14.0 and v5.16.0,
bisect points to

69974ce is the first bad commit
commit 69974ce
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Dec 31 23​:24​:57 2011 -0800

  [perl #103492] Give lvalue cx to (s)printf args

  Or potential lvalue context, like function calls.

  The %n format code’s existence renders these two very much like func-
  tion calls, as they can modify their arguments.

  This allows sprintf("...%n", substr ...) to work.

GDB info about the crash location​:

(gdb) bt
#0 __GI_raise (sig=sig@​entry=6) at ../sysdeps/unix/sysv/linux/raise.c​:58
#1 0x00007f27fd71c40a in __GI_abort () at abort.c​:89
#2 0x00007f27fd713e47 in __assert_fail_base (fmt=<optimized out>,
assertion=assertion@​entry=0x7f27feda5f70 "(o->op_flags & OPf_WANT) !=
OPf_WANT_VOID",
  file=file@​entry=0x7f27feda452e "op.c", line=line@​entry=2877,
function=function@​entry=0x7f27fedaaab0 <__PRETTY_FUNCTION__.15847>
"Perl_op_lvalue_flags")
  at assert.c​:92
#3 0x00007f27fd713ef2 in __GI___assert_fail (assertion=0x7f27feda5f70
"(o->op_flags & OPf_WANT) != OPf_WANT_VOID", file=0x7f27feda452e
"op.c", line=2877,
  function=0x7f27fedaaab0 <__PRETTY_FUNCTION__.15847>
"Perl_op_lvalue_flags") at assert.c​:101
#4 0x00007f27fea5b5e7 in Perl_op_lvalue_flags (o=0x7f27fff48a30,
type=239, flags=0) at op.c​:2877
#5 0x00007f27fea59c9b in S_modkids (o=0x7f27fff47350, type=239) at op.c​:2369
#6 0x00007f27fea80ffa in Perl_ck_listiob (o=0x7f27fff47350) at op.c​:10468
#7 0x00007f27fea63357 in Perl_op_convert_list (type=239, flags=0,
o=0x7f27fff47350) at op.c​:4802
#8 0x00007f27feb16156 in Perl_yyparse (gramtype=258) at perly.y​:883
#9 0x00007f27fea9733a in S_parse_body (env=0x0, xsinit=0x7f27fea52de8
<xs_init>) at perl.c​:2376
#10 0x00007f27fea9569f in perl_parse (my_perl=0x7f27fff26010,
xsinit=0x7f27fea52de8 <xs_init>, argc=3, argv=0x7fffbd27a108, env=0x0)
at perl.c​:1691
#11 0x00007f27fea52d26 in main (argc=3, argv=0x7fffbd27a108,
env=0x7fffbd27a128) at perlmain.c​:121

Perl Info

Flags:
    category=core
    severity=low

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

[p5pRT]

From @dur-randir

Created by @dur-randir

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

$INC{'attributes.pm'} = 1, eval q!-my(%c)​:_!

to cause an assertion failure. GDB info about the crash location​:

(gdb) bt
#0 __GI_raise (sig=sig@​entry=6) at ../sysdeps/unix/sysv/linux/raise.c​:58
#1 0x00007f6cdecf840a in __GI_abort () at abort.c​:89
#2 0x00007f6cdecefe47 in __assert_fail_base (fmt=<optimized out>,
  assertion=assertion@​entry=0x7f6ce0bc1910 "SvTYPE(sv) != SVt_PVAV
&& SvTYPE(sv) != SVt_PVHV && SvTYPE(sv) != SVt_PVFM",
  file=file@​entry=0x7f6ce0bc0196 "sv.c", line=line@​entry=2612,
function=function@​entry=0x7f6ce0bce860 <__PRETTY_FUNCTION__.16836>
"Perl_sv_2nv_flags")
  at assert.c​:92
#3 0x00007f6cdecefef2 in __GI___assert_fail (
  assertion=assertion@​entry=0x7f6ce0bc1910 "SvTYPE(sv) != SVt_PVAV
&& SvTYPE(sv) != SVt_PVHV && SvTYPE(sv) != SVt_PVFM",
  file=file@​entry=0x7f6ce0bc0196 "sv.c", line=line@​entry=2612,
function=function@​entry=0x7f6ce0bce860 <__PRETTY_FUNCTION__.16836>
"Perl_sv_2nv_flags")
  at assert.c​:101
#4 0x00007f6ce059dac3 in Perl_sv_2nv_flags
(sv=sv@​entry=0x7f6ce26db6d0, flags=flags@​entry=0) at sv.c​:2611
#5 0x00007f6ce06d6f1a in Perl_pp_negate () at pp.c​:2584
#6 0x00007f6ce03f45a3 in Perl_runops_debug () at dump.c​:2444
#7 0x00007f6ce01502b5 in S_run_body (oldscope=1) at perl.c​:2528
#8 perl_run (my_perl=<optimized out>) at perl.c​:2451
#9 0x00007f6ce003b814 in main (argc=<optimized out>, argv=<optimized
out>, env=<optimized out>) at perlmain.c​:123

Perl Info

Flags:
    category=core
    severity=low

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

[p5pRT]

From @iabyn

On Sun, Jan 29, 2017 at 07​:26​:25AM -0800, Sergey Aleynikov wrote​:

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

$INC{'attributes.pm'} = 1, eval q!-my(%c)​:_!

to cause an assertion failure. GDB info about the crash location​:

This can be simplified to

  package Foo;
  use attributes;
  sub MODIFY_HASH_ATTRIBUTES { () }

  -(my %c : someattr);

The problem is that

  my %c : someattr;

gets compiled as

  my %c;
  attributes->import('Foo', \%c, 'someattr);

but the code which injects all those extra entersub etc ops doesn't seem
to be able to cope with that code not being in void context. So

  -(my %c : someattr);

gets compiled as something a bit like

  -( my %c, attributes->import('Foo', \%c, 'someattr));

except that the first padhv[%c] is compiled in void rather than scalar context,
which causes the HV to be pushed on the stack rather than its key count.

I'm not sure whether the attribute-handling code in op.c should be fixed
to handle non-void context, or whether lexical var attributes should be
illegal in non-void context. I suspect the former.

--
Never do today what you can put off till tomorrow.

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

From @tonycoz

On Sun, 22 Jan 2017 14​:53​:01 -0800, randir wrote​:

While fuzzing perl v5.25.8-216-gfbceb79751 built with afl and run
under libdislocator, I found the following program

printf my(%c)​:_

to cause an assertion failure, even when run under -c for a syntax
check. This is a regression between v5.14.0 and v5.16.0,
bisect points to

69974ce is the first bad commit
commit 69974ce
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Dec 31 23​:24​:57 2011 -0800

This might be related to 130669.

Tony

[p5pRT]

The RT System itself - Status changed from 'new' to 'open'

[p5pRT]

From @iabyn

On Tue, Feb 28, 2017 at 07​:35​:52PM -0800, Tony Cook via RT wrote​:

On Sun, 22 Jan 2017 14​:53​:01 -0800, randir wrote​:

While fuzzing perl v5.25.8-216-gfbceb79751 built with afl and run
under libdislocator, I found the following program

printf my(%c)​:_

to cause an assertion failure, even when run under -c for a syntax
check. This is a regression between v5.14.0 and v5.16.0,
bisect points to

69974ce is the first bad commit
commit 69974ce
Author​: Father Chrysostomos <sprout@​cpan.org>
Date​: Sat Dec 31 23​:24​:57 2011 -0800

This might be related to 130669.

Yes, it looks to be the same underlying issue. I'll merge the tickets.

--
print+qq&$}$"$/$s$,$a$d$g$s$@​$.$q$,$​:$.$q$^$,$@​$a$$;$.$q$m&if+map{m,^\d{0\,},,${$​::{$'}}=chr($"+=$&amp;||1)}q&10m22,42}6​:17a22.3@​3;^2dg3q/s"&=~m*\d\*.*g