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Report information
Id: 126193
Status: resolved
Priority: 0/
Queue: perl5

Owner: Nobody
Requestors: brian.carpenter [at] gmail.com
dcollinsn [at] gmail.com
Cc:
AdminCc:

Operating System: (no value)
PatchStatus: (no value)
Severity: low
Type: unknown
Perl Version: (no value)
Fixed In: (no value)

Attachments
0001-perl-126193-don-t-use-a-trash-SV-if-no-indexes-are-p.patch



Subject: Assertion failed: Perl_sv_2iv_flags (sv.c:2435)
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Fuzzing perl v5.23.4 (v5.23.3-7-ge120c24) with AFL found the following assertion failure: perl -e '{$0{@{[()[[]=~m[@]]*0]}}}{}' perl: sv.c:2435: Perl_sv_2iv_flags: Assertion `((svtype)((sv)->sv_flags & 0xff)) != SVt_PVAV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVHV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVFM' failed. Aborted Program received signal SIGABRT, Aborted. 0x00007ffff6d90165 in *__GI_raise (sig=<optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 64 ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or directory. (gdb) bt #0 0x00007ffff6d90165 in *__GI_raise (sig=<optimized out>) at ../nptl/sysdeps/unix/sysv/linux/raise.c:64 #1 0x00007ffff6d933e0 in *__GI_abort () at abort.c:92 #2 0x00007ffff6d89311 in *__GI___assert_fail ( assertion=0xf7a7f0 "((svtype)((sv)->sv_flags & 0xff)) != SVt_PVAV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVHV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVFM", file=<optimized out>, line=2435, function=0xf8f8b0 "Perl_sv_2iv_flags") at assert.c:81 #3 0x0000000000a1d511 in Perl_sv_2iv_flags () at sv.c:2434 #4 0x0000000000ae6886 in Perl_pp_lslice () at pp.c:5112 #5 0x00000000007e523f in Perl_runops_debug () at dump.c:2224 #6 0x0000000000545b99 in perl_run () at perl.c:2456 #7 0x000000000042c988 in main () at perlmain.c:116 Script doesn't appear to affect v5.21.7 (v5.21.6-602-ge9d2bd8) in any way.
Subject: Segmentation fault / assert fail in Perl_sv_2iv_flags
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Greetings Porters, I have compiled bleadperl with the afl-gcc compiler using: ./Configure -Dusedevel -Dprefix='/usr/local/perl-afl' -Dcc='ccache afl-gcc' -Duselongdouble -Duse64bitall -Doptimize=-g -Uversiononly -Uman1dir -Uman3dir -des AFL_HARDEN=1 make && make test And then fuzzed the resulting binary using: AFL_NO_VAR_CHECK=1 afl-fuzz -i in -o out bin/perl @@ After reducing testcases using `afl-tmin` and performing additional minimization by hand, I have located the following testcase that triggers a segmentation fault in the perl interpreter. The testcase is the file: ($0[(((0/[(())])[()]))]) On standard perls, this results in a SIGSEGV. In debugging perls, this results in the following output: perl: sv.c:2435: Perl_sv_2iv_flags: Assertion `((svtype)((sv)->sv_flags & 0xff)) != SVt_PVAV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVHV && ((svtype)((sv)->sv_flags & 0xff)) != SVt_PVFM' failed. Aborted **GDB** (gdb) run Starting program: /home/dcollins/perl/perl -e \(\$0\[\(\(\(0/\[\(\(\)\)\]\)\[\(\)\]\)\)\]\) [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". Program received signal SIGSEGV, Segmentation fault. 0x0000000000aeb260 in Perl_grok_number_flags (pv=0x0, len=18446744073709551615, valuep=0x7fffffffe370, flags=0) at numeric.c:857 857 while (s < send && isSPACE(*s)) (gdb) bt #0 0x0000000000aeb260 in Perl_grok_number_flags (pv=0x0, len=18446744073709551615, valuep=0x7fffffffe370, flags=0) at numeric.c:857 #1 0x00000000007fc884 in Perl_sv_2iv_flags (sv=0xe7a8e8, flags=-1, flags@entry=2) at sv.c:2467 #2 0x000000000087dbfa in Perl_pp_lslice () at pp.c:5113 #3 0x000000000076c45b in Perl_runops_standard () at run.c:41 #4 0x00000000004ee9af in S_run_body (oldscope=1) at perl.c:2456 #5 perl_run (my_perl=<optimized out>) at perl.c:2379 #6 0x00000000004261c8 in main (argc=3, argv=0x7fffffffe648, env=0x7fffffffe668) at perlmain.c:116 (gdb) info locals s = 0x0 send = 0xffffffffffffffff <error: Cannot access memory at address 0xffffffffffffffff> d = 0xe6b1f8 "\001" numtype = 0 **VALGRIND** ==6349== Memcheck, a memory error detector ==6349== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al. ==6349== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info ==6349== Command: /home/dcollins/perl/perl -e ($0[(((0/[(())])[()]))]) ==6349== ==6349== Invalid read of size 1 ==6349== at 0xAEB260: Perl_grok_number_flags (numeric.c:857) ==6349== by 0x7FC883: Perl_sv_2iv_flags (sv.c:2467) ==6349== by 0x87DBF9: Perl_pp_lslice (pp.c:5113) ==6349== by 0x76C45A: Perl_runops_standard (run.c:41) ==6349== by 0x4EE9AE: S_run_body (perl.c:2456) ==6349== by 0x4EE9AE: perl_run (perl.c:2379) ==6349== by 0x4261C7: main (perlmain.c:116) ==6349== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==6349== ==6349== ==6349== Process terminating with default action of signal 11 (SIGSEGV) ==6349== Access not within mapped region at address 0x0 ==6349== at 0xAEB260: Perl_grok_number_flags (numeric.c:857) ==6349== by 0x7FC883: Perl_sv_2iv_flags (sv.c:2467) ==6349== by 0x87DBF9: Perl_pp_lslice (pp.c:5113) ==6349== by 0x76C45A: Perl_runops_standard (run.c:41) ==6349== by 0x4EE9AE: S_run_body (perl.c:2456) ==6349== by 0x4EE9AE: perl_run (perl.c:2379) ==6349== by 0x4261C7: main (perlmain.c:116) ==6349== If you believe this happened as a result of a stack ==6349== overflow in your program's main thread (unlikely but ==6349== possible), you can try to increase the size of the ==6349== main thread stack using the --main-stacksize= flag. ==6349== The main thread stack size used in this run was 8388608. ==6349== ==6349== HEAP SUMMARY: ==6349== in use at exit: 113,814 bytes in 537 blocks ==6349== total heap usage: 634 allocs, 97 frees, 128,928 bytes allocated ==6349== ==6349== LEAK SUMMARY: ==6349== definitely lost: 176 bytes in 1 blocks ==6349== indirectly lost: 1,993 bytes in 20 blocks ==6349== possibly lost: 0 bytes in 0 blocks ==6349== still reachable: 111,645 bytes in 516 blocks ==6349== suppressed: 0 bytes in 0 blocks ==6349== Rerun with --leak-check=full to see details of leaked memory ==6349== ==6349== For counts of detected and suppressed errors, rerun with: -v ==6349== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0) Segmentation fault **PERL -V** Summary of my perl5 (revision 5 version 23 subversion 4) configuration: Commit id: 94757bf7ac8451b3588578f287f9c511a04011bf Platform: osname=linux, osvers=3.16.0-4-amd64, archname=x86_64-linux-ld uname='linux nightshade64 3.16.0-4-amd64 #1 smp debian 3.16.7-ckt11-1+deb8u4 (2015-09-19) x86_64 gnulinux ' config_args='-Dusedevel -Dprefix=/usr/local/perl-afl -Dcc=ccache afl-gcc -Duselongdouble -Duse64bitall -Doptimize=-g -Uversiononly -Uman1dir -Uman3dir -DDEBUGGING -DPERL_POISON -des' hint=recommended, useposix=true, d_sigaction=define useithreads=undef, usemultiplicity=undef use64bitint=define, use64bitall=define, uselongdouble=define usemymalloc=n, bincompat5005=undef Compiler: cc='ccache afl-gcc', ccflags ='-fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64', optimize='-g', cppflags='-fwrapv -DDEBUGGING -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include' ccversion='', gccversion='4.9.2', 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='long double', nvsize=16, Off_t='off_t', lseeksize=8 alignbytes=16, prototype=define Linker and Libraries: ld='ccache afl-gcc', ldflags =' -fstack-protector-strong -L/usr/local/lib' libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/4.9/include-fixed /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-2.19.so, so=so, useshrplib=false, libperl=libperl.a gnulibc_version='2.19' Dynamic Linking: dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E' cccdlflags='-fPIC', lddlflags='-shared -g -L/usr/local/lib -fstack-protector-strong' Characteristics of this binary (from libperl): Compile-time options: HAS_TIMES PERLIO_LAYERS PERL_COPY_ON_WRITE PERL_DONT_CREATE_GVSV PERL_HASH_FUNC_ONE_AT_A_TIME_HARD PERL_MALLOC_WRAP PERL_PRESERVE_IVUV PERL_USE_DEVEL USE_64_BIT_ALL USE_64_BIT_INT USE_LARGE_FILES USE_LOCALE USE_LOCALE_COLLATE USE_LOCALE_CTYPE USE_LOCALE_NUMERIC USE_LOCALE_TIME USE_LONG_DOUBLE USE_PERLIO USE_PERL_ATOF Built under linux Compiled at Oct 2 2015 22:37:40 @INC: /usr/local/perl-afl/lib/site_perl/5.23.4/x86_64-linux-ld /usr/local/perl-afl/lib/site_perl/5.23.4 /usr/local/perl-afl/lib/5.23.4/x86_64-linux-ld /usr/local/perl-afl/lib/5.23.4 .
Date: Mon, 12 Oct 2015 13:36:45 +0200
From: Victor ADAM <victor [...] drawall.cc>
Subject: Re: [perl #126274] Segmentation fault / assert fail in Perl_sv_2iv_flags
To: perlbug-followup [...] perl.org
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I performed some additional reduction by hand. The following causes the same error (SIGSEGV with identical backtrace): $0[()[()]]
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On Mon Oct 12 04:37:26 2015, victor@drawall.cc wrote: Show quoted text
> I performed some additional reduction by hand. The following causes > the same error (SIGSEGV with identical backtrace): > > $0[()[()]] >
Probably a dupe of https://rt.perl.org/Ticket/Display.html?id=126193.
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On Mon Oct 12 11:52:59 2015, brian.carpenter@gmail.com wrote: Show quoted text
> On Mon Oct 12 04:37:26 2015, victor@drawall.cc wrote:
> > I performed some additional reduction by hand. The following causes > > the same error (SIGSEGV with identical backtrace): > > > > $0[()[()]] > >
> > Probably a dupe of https://rt.perl.org/Ticket/Display.html?id=126193.
Looks like it to me, so I've merged them. The attached patch fixes the problem for me. Tony
Subject: 0001-perl-126193-don-t-use-a-trash-SV-if-no-indexes-are-p.patch
From c902887933f2025fd547357674c2699a1a95c96f Mon Sep 17 00:00:00 2001 From: Tony Cook <tony@develop-help.com> Date: Wed, 11 Nov 2015 15:57:09 +1100 Subject: [perl #126193] don't use a trash SV if no indexes are provided to pp_lslice --- pp.c | 23 ++++++++++++++--------- t/op/list.t | 5 ++++- 2 files changed, 18 insertions(+), 10 deletions(-) diff --git a/pp.c b/pp.c index 35a5f26..7301d8b 100644 --- a/pp.c +++ b/pp.c @@ -5268,15 +5268,20 @@ PP(pp_lslice) SV **lelem; if (GIMME_V != G_ARRAY) { - I32 ix = SvIV(*lastlelem); - if (ix < 0) - ix += max; - if (ix < 0 || ix >= max) - *firstlelem = &PL_sv_undef; - else - *firstlelem = firstrelem[ix]; - SP = firstlelem; - RETURN; + if (lastlelem < firstlelem) { + *firstlelem = &PL_sv_undef; + } + else { + I32 ix = SvIV(*lastlelem); + if (ix < 0) + ix += max; + if (ix < 0 || ix >= max) + *firstlelem = &PL_sv_undef; + else + *firstlelem = firstrelem[ix]; + } + SP = firstlelem; + RETURN; } if (max == 0) { diff --git a/t/op/list.t b/t/op/list.t index c7056d0..9fe00a4 100644 --- a/t/op/list.t +++ b/t/op/list.t @@ -6,7 +6,7 @@ BEGIN { require "./test.pl"; } -plan( tests => 69 ); +plan( tests => 70 ); @foo = (1, 2, 3, 4); cmp_ok($foo[0], '==', 1, 'first elem'); @@ -217,3 +217,6 @@ sub empty {} tie $t, ""; () = (empty(), ($t)x10); # empty() since sub calls usually result in copies is(tied($t)->{fetched}, undef, 'assignment to empty list makes no copies'); + +# this was passing a trash SV at the top of the stack to SvIV() +ok(($0[()[()]],1), "[perl #126193] list slice with zero indexes"); -- 2.1.4
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On Tue Nov 10 20:59:32 2015, tonyc wrote: Show quoted text
> On Mon Oct 12 11:52:59 2015, brian.carpenter@gmail.com wrote:
> > On Mon Oct 12 04:37:26 2015, victor@drawall.cc wrote:
> > > I performed some additional reduction by hand. The following causes > > > the same error (SIGSEGV with identical backtrace): > > > > > > $0[()[()]] > > >
> > > > Probably a dupe of https://rt.perl.org/Ticket/Display.html?id=126193.
> > Looks like it to me, so I've merged them. > > The attached patch fixes the problem for me.
Applied as 9e59c36b452568c56b99957f02b853c42e280f8a. Tony
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Thank you for submitting this report. You have helped make Perl better. With the release of Perl 5.24.0 on May 9, 2016, this and 149 other issues have been resolved. Perl 5.24.0 may be downloaded via https://metacpan.org/release/RJBS/perl-5.24.0


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