Skip Menu |
Report information
Id: 126319
Status: resolved
Priority: 0/
Queue: perl5

Owner: Nobody
Requestors: 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)



Subject: Segmentation fault in Perl_sv_catpvn_flags
Download (untitled) / with headers
text/plain 9.5k
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: /\b{sb}\b{wb}//b{}//>s>>>g>>0 The fuzzer seems to have started from the testcase in [perl #126260], but is does not appear to be at all related - that is a regexp related bug, while this bug is occurring in sv.c. **GDB** (gdb) run Starting program: /usr/local/perl-afl/bin/perl allcrash/f4i000027 [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. 0x00007ffff6df5b9c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) bt #0 0x00007ffff6df5b9c in ?? () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00000000009f5567 in memmove (__len=18446744073709551615, __src=0x1213001, __dest=<optimized out>) at /usr/include/x86_64-linux-gnu/bits/string3.h:57 #2 Perl_sv_catpvn_flags (dsv=0x12056a0, sstr=0x1213001 "", slen=18446744073709551615, flags=16384) at sv.c:5370 #3 0x000000000090410e in Perl_pp_subst () at pp_hot.c:3055 #4 0x00000000007dec7f in Perl_runops_debug () at dump.c:2224 #5 0x0000000000544469 in S_run_body (oldscope=1) at perl.c:2456 #6 perl_run (my_perl=<optimized out>) at perl.c:2379 #7 0x000000000042c6f8 in main (argc=2, argv=0x7fffffffe348, env=0x7fffffffe360) at perlmain.c:116 **VALGRIND** ==19889== Memcheck, a memory error detector ==19889== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al. ==19889== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info ==19889== Command: ../bin/perl allcrash/f4i000027 ==19889== ==19889== Invalid write of size 8 ==19889== at 0x4C2C04B: memcpy@GLIBC_2.2.5 (vg_replace_strmem.c:1017) ==19889== by 0x9F5566: memmove (string3.h:57) ==19889== by 0x9F5566: Perl_sv_catpvn_flags (sv.c:5370) ==19889== by 0x90410D: Perl_pp_subst (pp_hot.c:3055) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== Address 0x5f814c8 is 8 bytes inside a block of size 10 alloc'd ==19889== at 0x4C27C0F: malloc (vg_replace_malloc.c:299) ==19889== by 0x7EFD6C: Perl_safesysmalloc (util.c:153) ==19889== by 0x98BD5F: Perl_sv_grow (sv.c:1624) ==19889== by 0x9BBDBB: Perl_sv_setpvn (sv.c:4849) ==19889== by 0x9BD012: Perl_newSVpvn_flags (sv.c:9085) ==19889== by 0x901BF4: Perl_pp_subst (pp_hot.c:3001) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== ==19889== Invalid read of size 8 ==19889== at 0x4C2C048: memcpy@GLIBC_2.2.5 (vg_replace_strmem.c:1017) ==19889== by 0x9F5566: memmove (string3.h:57) ==19889== by 0x9F5566: Perl_sv_catpvn_flags (sv.c:5370) ==19889== by 0x90410D: Perl_pp_subst (pp_hot.c:3055) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== Address 0x5f81420 is 6 bytes after a block of size 10 alloc'd ==19889== at 0x4C27C0F: malloc (vg_replace_malloc.c:299) ==19889== by 0x7EFD6C: Perl_safesysmalloc (util.c:153) ==19889== by 0x98BD5F: Perl_sv_grow (sv.c:1624) ==19889== by 0x9EA7D7: Perl_sv_pvn_force_flags (sv.c:9871) ==19889== by 0x901316: Perl_pp_subst (pp_hot.c:2991) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== ==19889== Invalid read of size 8 ==19889== at 0x4C2C056: memcpy@GLIBC_2.2.5 (vg_replace_strmem.c:1017) ==19889== by 0x9F5566: memmove (string3.h:57) ==19889== by 0x9F5566: Perl_sv_catpvn_flags (sv.c:5370) ==19889== by 0x90410D: Perl_pp_subst (pp_hot.c:3055) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== Address 0x5f81428 is 14 bytes after a block of size 10 alloc'd ==19889== at 0x4C27C0F: malloc (vg_replace_malloc.c:299) ==19889== by 0x7EFD6C: Perl_safesysmalloc (util.c:153) ==19889== by 0x98BD5F: Perl_sv_grow (sv.c:1624) ==19889== by 0x9EA7D7: Perl_sv_pvn_force_flags (sv.c:9871) ==19889== by 0x901316: Perl_pp_subst (pp_hot.c:2991) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== ==19889== ==19889== Process terminating with default action of signal 11 (SIGSEGV) ==19889== Access not within mapped region at address 0x6350000 ==19889== at 0x4C2C04B: memcpy@GLIBC_2.2.5 (vg_replace_strmem.c:1017) ==19889== by 0x9F5566: memmove (string3.h:57) ==19889== by 0x9F5566: Perl_sv_catpvn_flags (sv.c:5370) ==19889== by 0x90410D: Perl_pp_subst (pp_hot.c:3055) ==19889== by 0x7DEC7E: Perl_runops_debug (dump.c:2224) ==19889== by 0x544468: S_run_body (perl.c:2456) ==19889== by 0x544468: perl_run (perl.c:2379) ==19889== by 0x42C6F7: main (perlmain.c:116) ==19889== If you believe this happened as a result of a stack ==19889== overflow in your program's main thread (unlikely but ==19889== possible), you can try to increase the size of the ==19889== main thread stack using the --main-stacksize= flag. ==19889== The main thread stack size used in this run was 8388608. ==19889== ==19889== HEAP SUMMARY: ==19889== in use at exit: 122,132 bytes in 648 blocks ==19889== total heap usage: 783 allocs, 135 frees, 148,398 bytes allocated ==19889== ==19889== LEAK SUMMARY: ==19889== definitely lost: 328 bytes in 1 blocks ==19889== indirectly lost: 2,631 bytes in 39 blocks ==19889== possibly lost: 0 bytes in 0 blocks ==19889== still reachable: 119,173 bytes in 608 blocks ==19889== suppressed: 0 bytes in 0 blocks ==19889== Rerun with --leak-check=full to see details of leaked memory ==19889== ==19889== For counts of detected and suppressed errors, rerun with: -v ==19889== ERROR SUMMARY: 998087 errors from 3 contexts (suppressed: 0 from 0) **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: DEBUGGING 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 Sep 30 2015 16:39:59 @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 .
RT-Send-CC: perl5-porters [...] perl.org
Download (untitled) / with headers
text/plain 1.2k
On Sat Oct 10 14:20:55 2015, dcollinsn@gmail.com wrote: Show quoted text
> 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: > > /\b{sb}\b{wb}//b{}//>s>>>g>>0 > > The fuzzer seems to have started from the testcase in [perl #126260], > but is does not appear to be at all related - that is a regexp related > bug, while this bug is occurring in sv.c.
This can be simplified: tony@mars:.../git/perl$ ./perl -e '/\b{wb}/; s///g' Segmentation fault tony@mars:.../git/perl$ ./perl -e '/\b{sb}/; s///g' Segmentation fault tony@mars:.../git/perl$ ./perl -e '/\b{gcb}/; s///g' Segmentation fault tony@mars:.../git/perl$ ./perl -e '/\b/; s///g' tony@mars:.../git/perl$ Looking at it further. Tony
RT-Send-CC: perl5-porters [...] perl.org
Download (untitled) / with headers
text/plain 187b
This is now fixed in blead by commit f0bd363c36d925d8d3dfe3b68715763c850b171a Thank you for spotting this. It led to me finding several more bugs with this feature. -- Karl Williamson
From: Karl Williamson <public [...] khwilliamson.com>
To: perlbug-followup [...] perl.org
CC: perl5-porters [...] perl.org
Subject: Re: [perl #126319] Segmentation fault in Perl_sv_catpvn_flags
Date: Mon, 19 Oct 2015 13:05:33 -0600
Download (untitled) / with headers
text/plain 621b
On 10/19/2015 12:52 PM, Karl Williamson via RT wrote: Show quoted text
> This is now fixed in blead by commit > f0bd363c36d925d8d3dfe3b68715763c850b171a > > Thank you for spotting this. It led to me finding several more bugs with this feature. >
I meant to include text, but forgot, in the final commit message talking about how these bugs cancelled each other out except in rare cases, so that everything passed the extensive test suite furnished by Unicode, until I started fixing things. The commit message for 139a998acd6eae73587ff4f048925394f73682d9 also was supposed to have said the TODOs were instituted 6 commits earlier.
Download (untitled) / with headers
text/plain 252b
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


This service is sponsored and maintained by Best Practical Solutions and runs on Perl.org infrastructure.

For issues related to this RT instance (aka "perlbug"), please contact perlbug-admin at perl.org