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[CVE-2018-18314] Heap-based buffer overflow in S_regatom #16041

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p5pRT opened this issue Jun 25, 2017 · 20 comments

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@p5pRT p5pRT commented Jun 25, 2017

Migrated from rt.perl.org#131649 (status was 'resolved')

Searchable as RT131649$

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@p5pRT p5pRT commented Jun 25, 2017

From @jwilk

Consider the following Perl program​:

m/(?[(?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/;
__END__

This is what happens when I run it​:

  The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[ <-- HERE (?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
  The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[(?s​:(?[ <-- HERE [x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
  panic​: reg_node overrun trying to emit 0, 8677794>=8677790 at test line 1.

Valgrind says it's a heap-based buffer overflow​:

  Invalid write of size 1
  at 0x80EE11B​: S_regatom (regcomp.c​:13490)
  by 0x80E6A9D​: S_regpiece (regcomp.c​:11669)
  by 0x80E6872​: S_regbranch (regcomp.c​:11594)
  by 0x80E58D4​: S_reg (regcomp.c​:11332)
  by 0x80D85AF​: Perl_re_op_compile (regcomp.c​:7309)
  by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
  by 0x80C2417​: Perl_yyparse (perly.y​:1204)
  by 0x8086637​: S_parse_body (perl.c​:2377)
  by 0x808578B​: perl_parse (perl.c​:1692)
  by 0x8061751​: main (perlmain.c​:121)
  Address 0x428e698 is 0 bytes after a block of size 160 alloc'd
  at 0x402A1CC​: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
  by 0x81082BC​: Perl_safesysmalloc (util.c​:153)
  by 0x80D7E43​: Perl_re_op_compile (regcomp.c​:7155)
  by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
  by 0x80C2417​: Perl_yyparse (perly.y​:1204)
  by 0x8086637​: S_parse_body (perl.c​:2377)
  by 0x808578B​: perl_parse (perl.c​:1692)
  by 0x8061751​: main (perlmain.c​:121)

$ perl -V
Summary of my perl5 (revision 5 version 26 subversion 0) configuration​:
  Commit id​: 95388f2
  Platform​:
  osname=linux
  osvers=3.16.0-4-686-pae
  archname=i686-linux
  uname='linux dirac 3.16.0-4-686-pae #1 smp debian 3.16.43-2 (2017-04-30) i686 gnulinux '
  config_args='-Dcc=gcc -d'
  hint=previous
  useposix=true
  d_sigaction=define
  useithreads=undef
  usemultiplicity=undef
  use64bitint=undef
  use64bitall=undef
  uselongdouble=undef
  usemymalloc=n
  default_inc_excludes_dot=define
  bincompat5005=undef
  Compiler​:
  cc='gcc'
  ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
  optimize='-g'
  cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
  ccversion=''
  gccversion='4.9.2'
  gccosandvers=''
  intsize=4
  longsize=4
  ptrsize=4
  doublesize=8
  byteorder=1234
  doublekind=3
  d_longlong=define
  longlongsize=8
  d_longdbl=define
  longdblsize=12
  longdblkind=3
  ivtype='long'
  ivsize=4
  nvtype='double'
  nvsize=8
  Off_t='off_t'
  lseeksize=8
  alignbytes=4
  prototype=define
  Linker and Libraries​:
  ld='cc'
  ldflags =' -fstack-protector-strong -L/usr/local/lib'
  libpth=/usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /lib/i386-linux-gnu /lib/../lib /usr/lib/i386-linux-gnu /usr/lib/../lib /lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/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 -O2 -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_OP_PARENT
  PERL_PRESERVE_IVUV
  USE_LARGE_FILES
  USE_LOCALE
  USE_LOCALE_COLLATE
  USE_LOCALE_CTYPE
  USE_LOCALE_NUMERIC
  USE_LOCALE_TIME
  USE_PERLIO
  USE_PERL_ATOF
  Built under linux
  Compiled at Jun 21 2017 19​:00​:20
  @​INC​:
  /usr/local/lib/perl5/site_perl/5.26.0/i686-linux
  /usr/local/lib/perl5/site_perl/5.26.0
  /usr/local/lib/perl5/5.26.0/i686-linux
  /usr/local/lib/perl5/5.26.0

--
Jakub Wilk

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@p5pRT p5pRT commented Jun 26, 2017

From @demerphq

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Cheers,
Yves

On 25 June 2017 at 04​:40, Jakub Wilk <perl5-security-report@​perl.org> wrote​:

# New Ticket Created by Jakub Wilk
# Please include the string​: [perl #131649]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=131649 >

Consider the following Perl program​:

m/(?[(?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/;
__END__

This is what happens when I run it​:

The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[ <-- HERE (?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[(?s​:(?[ <-- HERE [x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
panic​: reg_node overrun trying to emit 0, 8677794>=8677790 at test line 1.

Valgrind says it's a heap-based buffer overflow​:

Invalid write of size 1
at 0x80EE11B​: S_regatom (regcomp.c​:13490)
by 0x80E6A9D​: S_regpiece (regcomp.c​:11669)
by 0x80E6872​: S_regbranch (regcomp.c​:11594)
by 0x80E58D4​: S_reg (regcomp.c​:11332)
by 0x80D85AF​: Perl_re_op_compile (regcomp.c​:7309)
by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
by 0x80C2417​: Perl_yyparse (perly.y​:1204)
by 0x8086637​: S_parse_body (perl.c​:2377)
by 0x808578B​: perl_parse (perl.c​:1692)
by 0x8061751​: main (perlmain.c​:121)
Address 0x428e698 is 0 bytes after a block of size 160 alloc'd
at 0x402A1CC​: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
by 0x81082BC​: Perl_safesysmalloc (util.c​:153)
by 0x80D7E43​: Perl_re_op_compile (regcomp.c​:7155)
by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
by 0x80C2417​: Perl_yyparse (perly.y​:1204)
by 0x8086637​: S_parse_body (perl.c​:2377)
by 0x808578B​: perl_parse (perl.c​:1692)
by 0x8061751​: main (perlmain.c​:121)

$ perl -V
Summary of my perl5 (revision 5 version 26 subversion 0) configuration​:
Commit id​: 95388f2
Platform​:
osname=linux
osvers=3.16.0-4-686-pae
archname=i686-linux
uname='linux dirac 3.16.0-4-686-pae #1 smp debian 3.16.43-2 (2017-04-30) i686 gnulinux '
config_args='-Dcc=gcc -d'
hint=previous
useposix=true
d_sigaction=define
useithreads=undef
usemultiplicity=undef
use64bitint=undef
use64bitall=undef
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler​:
cc='gcc'
ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
optimize='-g'
cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
ccversion=''
gccversion='4.9.2'
gccosandvers=''
intsize=4
longsize=4
ptrsize=4
doublesize=8
byteorder=1234
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=12
longdblkind=3
ivtype='long'
ivsize=4
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=4
prototype=define
Linker and Libraries​:
ld='cc'
ldflags =' -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /lib/i386-linux-gnu /lib/../lib /usr/lib/i386-linux-gnu /usr/lib/../lib /lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/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 -O2 -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_OP_PARENT
PERL_PRESERVE_IVUV
USE_LARGE_FILES
USE_LOCALE
USE_LOCALE_COLLATE
USE_LOCALE_CTYPE
USE_LOCALE_NUMERIC
USE_LOCALE_TIME
USE_PERLIO
USE_PERL_ATOF
Built under linux
Compiled at Jun 21 2017 19​:00​:20
@​INC​:
/usr/local/lib/perl5/site_perl/5.26.0/i686-linux
/usr/local/lib/perl5/site_perl/5.26.0
/usr/local/lib/perl5/5.26.0/i686-linux
/usr/local/lib/perl5/5.26.0

--
Jakub Wilk

--
perl -Mre=debug -e "/just|another|perl|hacker/"

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@p5pRT p5pRT commented Jun 26, 2017

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

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@p5pRT p5pRT commented Jul 2, 2017

From @khwilliamson

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like the
rest of regcomp. It looks like it was my naivete showing up in the
initial design. I would have to refamiliarize myself with the code to
be able to carefully evaluate your patch (that wouldn't take too long),
but I suspect that there are other glitches awaiting if we don't fold
the passes together. That makes it easy to keep them in sync as well.

Cheers,
Yves

On 25 June 2017 at 04​:40, Jakub Wilk <perl5-security-report@​perl.org> wrote​:

# New Ticket Created by Jakub Wilk
# Please include the string​: [perl #131649]
# in the subject line of all future correspondence about this issue.
# <URL​: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=131649 >

Consider the following Perl program​:

m/(?[(?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/;
__END__

This is what happens when I run it​:

The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[ <-- HERE (?s​:(?[[x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
The regex_sets feature is experimental in regex; marked by <-- HERE in m/(?[(?s​:(?[ <-- HERE [x]][xx]xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx])/ at test line 1.
panic​: reg_node overrun trying to emit 0, 8677794>=8677790 at test line 1.

Valgrind says it's a heap-based buffer overflow​:

Invalid write of size 1
at 0x80EE11B​: S_regatom (regcomp.c​:13490)
by 0x80E6A9D​: S_regpiece (regcomp.c​:11669)
by 0x80E6872​: S_regbranch (regcomp.c​:11594)
by 0x80E58D4​: S_reg (regcomp.c​:11332)
by 0x80D85AF​: Perl_re_op_compile (regcomp.c​:7309)
by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
by 0x80C2417​: Perl_yyparse (perly.y​:1204)
by 0x8086637​: S_parse_body (perl.c​:2377)
by 0x808578B​: perl_parse (perl.c​:1692)
by 0x8061751​: main (perlmain.c​:121)
Address 0x428e698 is 0 bytes after a block of size 160 alloc'd
at 0x402A1CC​: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
by 0x81082BC​: Perl_safesysmalloc (util.c​:153)
by 0x80D7E43​: Perl_re_op_compile (regcomp.c​:7155)
by 0x806D7DF​: Perl_pmruntime (op.c​:5882)
by 0x80C2417​: Perl_yyparse (perly.y​:1204)
by 0x8086637​: S_parse_body (perl.c​:2377)
by 0x808578B​: perl_parse (perl.c​:1692)
by 0x8061751​: main (perlmain.c​:121)

$ perl -V
Summary of my perl5 (revision 5 version 26 subversion 0) configuration​:
Commit id​: 95388f2
Platform​:
osname=linux
osvers=3.16.0-4-686-pae
archname=i686-linux
uname='linux dirac 3.16.0-4-686-pae #1 smp debian 3.16.43-2 (2017-04-30) i686 gnulinux '
config_args='-Dcc=gcc -d'
hint=previous
useposix=true
d_sigaction=define
useithreads=undef
usemultiplicity=undef
use64bitint=undef
use64bitall=undef
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler​:
cc='gcc'
ccflags ='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -D_FORTIFY_SOURCE=2'
optimize='-g'
cppflags='-fwrapv -fno-strict-aliasing -pipe -fstack-protector-strong -I/usr/local/include'
ccversion=''
gccversion='4.9.2'
gccosandvers=''
intsize=4
longsize=4
ptrsize=4
doublesize=8
byteorder=1234
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=12
longdblkind=3
ivtype='long'
ivsize=4
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=4
prototype=define
Linker and Libraries​:
ld='cc'
ldflags =' -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /lib/i386-linux-gnu /lib/../lib /usr/lib/i386-linux-gnu /usr/lib/../lib /lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/lib /usr/local/lib /usr/lib/gcc/i586-linux-gnu/4.9/include-fixed /usr/include/i386-linux-gnu /usr/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 -O2 -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_OP_PARENT
PERL_PRESERVE_IVUV
USE_LARGE_FILES
USE_LOCALE
USE_LOCALE_COLLATE
USE_LOCALE_CTYPE
USE_LOCALE_NUMERIC
USE_LOCALE_TIME
USE_PERLIO
USE_PERL_ATOF
Built under linux
Compiled at Jun 21 2017 19​:00​:20
@​INC​:
/usr/local/lib/perl5/site_perl/5.26.0/i686-linux
/usr/local/lib/perl5/site_perl/5.26.0
/usr/local/lib/perl5/5.26.0/i686-linux
/usr/local/lib/perl5/5.26.0

--
Jakub Wilk

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@p5pRT p5pRT commented Jul 2, 2017

From @demerphq

On 2 July 2017 at 06​:03, Karl Williamson <public@​khwilliamson.com> wrote​:

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like the rest
of regcomp. It looks like it was my naivete showing up in the initial
design. I would have to refamiliarize myself with the code to be able to
carefully evaluate your patch (that wouldn't take too long), but I suspect
that there are other glitches awaiting if we don't fold the passes together.
That makes it easy to keep them in sync as well.

I think we should formally define the grammar before we touch the
code. Once we have a formal definition the rest should flow easily. We
have something like the following unreduced grammar.

extended_regexp​: '(?[' eclass_expr '])'
binop​: '+' | '-' | ...
simple_charclass_def​: ....
escape_class​: '\\s' | ...
eclass_expr​: escape_class
  | '[' simple_charclass_def ']'
  | '(' eclass_expr ')'
  | eclass_expr op exclass_expr
  | '!' eclass_expr
  | '(?' modifiers '​:' extended_regexp ')'

Personally I think it is odd we only allow extended regexps to
embedded in one another when they are wrapped in '(?...​:)' style
brackets that have modifiers. To fix that I think we should add

  | extended_regexp

to the eclass_expr production. In other words

/(?[ (?[ (?[ (?[ [x] ]) ]) ]) ])/

should be legal. We shouldn't have to write

/(?s​:(?[ (?s​:(?[ (?s​:(?[ (?s​:(?[ [x] ])) ])) ])) ]))/

for instance, and if we allow

/(?[ (?s​:(?[ ... ])) ])/

we should allow

/(?[ (?​:(?[ ... ])) ])/

and

/(?[ (?​: (?[ ... ]) ) ])/

and etc... (note the whitespace)

I think once we have a proper definition of the grammar allowed inside
of an extended regex it should be easy to fix the code or prove it
correct.

Yves

--
perl -Mre=debug -e "/just|another|perl|hacker/"

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@p5pRT p5pRT commented Nov 29, 2017

From @iabyn

On Sun, Jul 02, 2017 at 12​:17​:39PM +0200, demerphq wrote​:

On 2 July 2017 at 06​:03, Karl Williamson <public@​khwilliamson.com> wrote​:

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like the rest
of regcomp. It looks like it was my naivete showing up in the initial
design. I would have to refamiliarize myself with the code to be able to
carefully evaluate your patch (that wouldn't take too long), but I suspect
that there are other glitches awaiting if we don't fold the passes together.
That makes it easy to keep them in sync as well.

I think we should formally define the grammar before we touch the
code. Once we have a formal definition the rest should flow easily. We
have something like the following unreduced grammar.

extended_regexp​: '(?[' eclass_expr '])'
binop​: '+' | '-' | ...
simple_charclass_def​: ....
escape_class​: '\\s' | ...
eclass_expr​: escape_class
| '[' simple_charclass_def ']'
| '(' eclass_expr ')'
| eclass_expr op exclass_expr
| '!' eclass_expr
| '(?' modifiers '​:' extended_regexp ')'

Personally I think it is odd we only allow extended regexps to
embedded in one another when they are wrapped in '(?...​:)' style
brackets that have modifiers. To fix that I think we should add

               | extended\_regexp

to the eclass_expr production. In other words

/(?[ (?[ (?[ (?[ [x] ]) ]) ]) ])/

should be legal. We shouldn't have to write

/(?s​:(?[ (?s​:(?[ (?s​:(?[ (?s​:(?[ [x] ])) ])) ])) ]))/

for instance, and if we allow

/(?[ (?s​:(?[ ... ])) ])/

we should allow

/(?[ (?​:(?[ ... ])) ])/

and

/(?[ (?​: (?[ ... ]) ) ])/

and etc... (note the whitespace)

I think once we have a proper definition of the grammar allowed inside
of an extended regex it should be easy to fix the code or prove it
correct.

Has there been any progress on this issue?

--
Justice is when you get what you deserve.
Law is when you get what you pay for.

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@p5pRT p5pRT commented Nov 29, 2017

From @demerphq

On 29 November 2017 at 09​:58, Dave Mitchell <davem@​iabyn.com> wrote​:

On Sun, Jul 02, 2017 at 12​:17​:39PM +0200, demerphq wrote​:

On 2 July 2017 at 06​:03, Karl Williamson <public@​khwilliamson.com> wrote​:

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like the rest
of regcomp. It looks like it was my naivete showing up in the initial
design. I would have to refamiliarize myself with the code to be able to
carefully evaluate your patch (that wouldn't take too long), but I suspect
that there are other glitches awaiting if we don't fold the passes together.
That makes it easy to keep them in sync as well.

I think we should formally define the grammar before we touch the
code. Once we have a formal definition the rest should flow easily. We
have something like the following unreduced grammar.

extended_regexp​: '(?[' eclass_expr '])'
binop​: '+' | '-' | ...
simple_charclass_def​: ....
escape_class​: '\\s' | ...
eclass_expr​: escape_class
| '[' simple_charclass_def ']'
| '(' eclass_expr ')'
| eclass_expr op exclass_expr
| '!' eclass_expr
| '(?' modifiers '​:' extended_regexp ')'

Personally I think it is odd we only allow extended regexps to
embedded in one another when they are wrapped in '(?...​:)' style
brackets that have modifiers. To fix that I think we should add

               | extended\_regexp

to the eclass_expr production. In other words

/(?[ (?[ (?[ (?[ [x] ]) ]) ]) ])/

should be legal. We shouldn't have to write

/(?s​:(?[ (?s​:(?[ (?s​:(?[ (?s​:(?[ [x] ])) ])) ])) ]))/

for instance, and if we allow

/(?[ (?s​:(?[ ... ])) ])/

we should allow

/(?[ (?​:(?[ ... ])) ])/

and

/(?[ (?​: (?[ ... ]) ) ])/

and etc... (note the whitespace)

I think once we have a proper definition of the grammar allowed inside
of an extended regex it should be easy to fix the code or prove it
correct.

Has there been any progress on this issue?

I am waiting on Karl to reply. As far as I know my patch does fix the issue.

Yves

--
perl -Mre=debug -e "/just|another|perl|hacker/"

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@p5pRT p5pRT commented Nov 29, 2017

From @khwilliamson

On 11/29/2017 02​:46 AM, demerphq wrote​:

On 29 November 2017 at 09​:58, Dave Mitchell <davem@​iabyn.com> wrote​:

On Sun, Jul 02, 2017 at 12​:17​:39PM +0200, demerphq wrote​:

On 2 July 2017 at 06​:03, Karl Williamson <public@​khwilliamson.com> wrote​:

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses quite
different and separate code for the sizing pass and the actual code
generation pass, and the difference in the parsing rules means that
things would cause an assertion failure in the second pass are not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like the rest
of regcomp. It looks like it was my naivete showing up in the initial
design. I would have to refamiliarize myself with the code to be able to
carefully evaluate your patch (that wouldn't take too long), but I suspect
that there are other glitches awaiting if we don't fold the passes together.
That makes it easy to keep them in sync as well.

I think we should formally define the grammar before we touch the
code. Once we have a formal definition the rest should flow easily. We
have something like the following unreduced grammar.

extended_regexp​: '(?[' eclass_expr '])'
binop​: '+' | '-' | ...
simple_charclass_def​: ....
escape_class​: '\\s' | ...
eclass_expr​: escape_class
| '[' simple_charclass_def ']'
| '(' eclass_expr ')'
| eclass_expr op exclass_expr
| '!' eclass_expr
| '(?' modifiers '​:' extended_regexp ')'

Personally I think it is odd we only allow extended regexps to
embedded in one another when they are wrapped in '(?...​:)' style
brackets that have modifiers. To fix that I think we should add

                | extended\_regexp

to the eclass_expr production. In other words

/(?[ (?[ (?[ (?[ [x] ]) ]) ]) ])/

should be legal. We shouldn't have to write

/(?s​:(?[ (?s​:(?[ (?s​:(?[ (?s​:(?[ [x] ])) ])) ])) ]))/

for instance, and if we allow

/(?[ (?s​:(?[ ... ])) ])/

we should allow

/(?[ (?​:(?[ ... ])) ])/

and

/(?[ (?​: (?[ ... ]) ) ])/

and etc... (note the whitespace)

I think once we have a proper definition of the grammar allowed inside
of an extended regex it should be easy to fix the code or prove it
correct.

Has there been any progress on this issue?

I am waiting on Karl to reply. As far as I know my patch does fix the issue.

Yves

I think his patch solves the issue, but my writing a grammar comes after
the code freeze

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@p5pRT p5pRT commented Aug 21, 2018

From @tonycoz

On Wed, 29 Nov 2017 10​:53​:43 -0800, public@​khwilliamson.com wrote​:

On 11/29/2017 02​:46 AM, demerphq wrote​:

On 29 November 2017 at 09​:58, Dave Mitchell <davem@​iabyn.com> wrote​:

On Sun, Jul 02, 2017 at 12​:17​:39PM +0200, demerphq wrote​:

On 2 July 2017 at 06​:03, Karl Williamson <public@​khwilliamson.com>
wrote​:

On 06/26/2017 05​:42 AM, demerphq wrote​:

I have a patch for this in yves/fix_131649

The extended charclass parser is a bit unusual in that it uses
quite
different and separate code for the sizing pass and the actual
code
generation pass, and the difference in the parsing rules means
that
things would cause an assertion failure in the second pass are
not
caught as errors in the first pass.

My patch cleans up some of this logic and adds some trace, but it
needs some review by Karl.

Personally I would expect the first pass to use the same parsing
rules
as the second. I also was surprised to find that (?s​:(?[[x]])) is
allowed inside an extended regex, but (?[ [x] ]) is not. I
understand
the cause of the discrepancy, but it seems undesirable.

Maybe we should bite the bullet and fold the passes together, like
the rest
of regcomp. It looks like it was my naivete showing up in the
initial
design. I would have to refamiliarize myself with the code to be
able to
carefully evaluate your patch (that wouldn't take too long), but I
suspect
that there are other glitches awaiting if we don't fold the passes
together.
That makes it easy to keep them in sync as well.

I think we should formally define the grammar before we touch the
code. Once we have a formal definition the rest should flow easily.
We
have something like the following unreduced grammar.

extended_regexp​: '(?[' eclass_expr '])'
binop​: '+' | '-' | ...
simple_charclass_def​: ....
escape_class​: '\\s' | ...
eclass_expr​: escape_class
| '[' simple_charclass_def ']'
| '(' eclass_expr ')'
| eclass_expr op exclass_expr
| '!' eclass_expr
| '(?' modifiers '​:' extended_regexp ')'

Personally I think it is odd we only allow extended regexps to
embedded in one another when they are wrapped in '(?...​:)' style
brackets that have modifiers. To fix that I think we should add

| extended_regexp

to the eclass_expr production. In other words

/(?[ (?[ (?[ (?[ [x] ]) ]) ]) ])/

should be legal. We shouldn't have to write

/(?s​:(?[ (?s​:(?[ (?s​:(?[ (?s​:(?[ [x] ])) ])) ])) ]))/

for instance, and if we allow

/(?[ (?s​:(?[ ... ])) ])/

we should allow

/(?[ (?​:(?[ ... ])) ])/

and

/(?[ (?​: (?[ ... ]) ) ])/

and etc... (note the whitespace)

I think once we have a proper definition of the grammar allowed
inside
of an extended regex it should be easy to fix the code or prove it
correct.

Has there been any progress on this issue?

I am waiting on Karl to reply. As far as I know my patch does fix the
issue.

Yves

I think his patch solves the issue, but my writing a grammar comes
after
the code freeze

If I understand the issue, compiling an attacker controlled regexp can overflow a heap allocated buffer, making it a security issue.

I suspect, given it's a regexp compilation that an attacker has a lot of control over the data written beyond the end of the buffer.[1]

Tony

[1] which doesn't matter much, given attacks like the one you linked
  https://daniel.haxx.se/blog/2016/10/14/a-single-byte-write-opened-a-root-execution-exploit/

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@p5pRT p5pRT commented Sep 20, 2018

From @tonycoz

On Wed, 29 Nov 2017 10​:53​:43 -0800, public@​khwilliamson.com wrote​:

On 11/29/2017 02​:46 AM, demerphq wrote​:

I am waiting on Karl to reply. As far as I know my patch does fix the
issue.

Yves

I think his patch solves the issue, but my writing a grammar comes
after
the code freeze

Which patch?

I don't see a yves/fix_131649 branch anywhere.

Tony
Tony

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@p5pRT p5pRT commented Sep 24, 2018

From @tonycoz

I plan to request a CVE ID for this issue in the next couple of days.

If anyone has already requested an ID, please let me know.

Thanks,
Tony

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@p5pRT p5pRT commented Oct 2, 2018

From @tonycoz

On Wed, 19 Sep 2018 17​:37​:48 -0700, tonyc wrote​:

On Wed, 29 Nov 2017 10​:53​:43 -0800, public@​khwilliamson.com wrote​:

On 11/29/2017 02​:46 AM, demerphq wrote​:

I am waiting on Karl to reply. As far as I know my patch does fix the
issue.

Yves

I think his patch solves the issue, but my writing a grammar comes
after
the code freeze

Which patch?

I don't see a yves/fix_131649 branch anywhere.

It turns out this was fixed in 19a498a, which is included in 5.28.

This doesn't cherry-pick cleanly to 5.26, the attached is a merged cherry-pick of the fix.

Tony

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@p5pRT p5pRT commented Oct 2, 2018

From @tonycoz

0001-5.26-fix-131649-extended-charclass-can-trigger-assert.patch
From 926efad7572e351b649af3139c4ca53abe20f19b Mon Sep 17 00:00:00 2001
From: Yves Orton <demerphq@gmail.com>
Date: Mon, 26 Jun 2017 13:19:55 +0200
Subject: fix #131649 - extended charclass can trigger assert

The extended charclass parser makes some assumptions during the
first pass which are only true on well structured input, and it
does not properly catch various errors. later on the code assumes
that things the first pass will let through are valid, when in
fact they should trigger errors.

(cherry picked from commit 19a498a461d7c81ae3507c450953d1148efecf4f)
---
 pod/perldiag.pod        | 27 ++++++++++++++++++++++++++-
 pod/perlrecharclass.pod |  4 ++--
 regcomp.c               | 28 ++++++++++++++++++----------
 t/lib/warnings/regcomp  |  6 +++---
 t/re/reg_mesg.t         | 29 ++++++++++++++++-------------
 t/re/regex_sets.t       |  6 +++---
 6 files changed, 68 insertions(+), 32 deletions(-)

diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 106fe41121..c29925a2a4 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -5904,7 +5904,7 @@ yourself.
 a perl4 interpreter, especially if the next 2 tokens are "use strict"
 or "my $var" or "our $var".
 
-=item Syntax error in (?[...]) in regex m/%s/
+=item Syntax error in (?[...]) in regex; marked by <-- HERE in m/%s/
 
 (F) Perl could not figure out what you meant inside this construct; this
 notifies you that it is giving up trying.
@@ -6402,6 +6402,31 @@ to find out why that isn't happening.
 (F) The unexec() routine failed for some reason.  See your local FSF
 representative, who probably put it there in the first place.
 
+=item Unexpected ']' with no following ')' in (?[... in regex; marked by <-- HERE in m/%s/
+
+(F) While parsing an extended character class a ']' character was encountered
+at a point in the definition where the only legal use of ']' is to close the
+character class definition as part of a '])', you may have forgotten the close
+paren, or otherwise confused the parser.
+
+=item Expecting close paren for nested extended charclass in regex; marked by <-- HERE in m/%s/
+
+(F) While parsing a nested extended character class like:
+
+    (?[ ... (?flags:(?[ ... ])) ... ])
+                             ^
+
+we expected to see a close paren ')' (marked by ^) but did not.
+
+=item Expecting close paren for wrapper for nested extended charclass in regex; marked by <-- HERE in m/%s/
+
+(F) While parsing a nested extended character class like:
+
+    (?[ ... (?flags:(?[ ... ])) ... ])
+                              ^
+
+we expected to see a close paren ')' (marked by ^) but did not.
+
 =item Unexpected binary operator '%c' with no preceding operand in regex;
 marked by S<<-- HERE> in m/%s/
 
diff --git a/pod/perlrecharclass.pod b/pod/perlrecharclass.pod
index 79480e4131..8c008507d1 100644
--- a/pod/perlrecharclass.pod
+++ b/pod/perlrecharclass.pod
@@ -1128,8 +1128,8 @@ hence both of the following work:
 Any contained POSIX character classes, including things like C<\w> and C<\D>
 respect the C<E<sol>a> (and C<E<sol>aa>) modifiers.
 
-C<< (?[ ]) >> is a regex-compile-time construct.  Any attempt to use
-something which isn't knowable at the time the containing regular
+Note that C<< (?[ ]) >> is a regex-compile-time construct.  Any attempt
+to use something which isn't knowable at the time the containing regular
 expression is compiled is a fatal error.  In practice, this means
 just three limitations:
 
diff --git a/regcomp.c b/regcomp.c
index 2bee9d4460..5583b0a7bd 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -14823,8 +14823,9 @@ S_handle_regex_sets(pTHX_ RExC_state_t *pRExC_state, SV** return_invlist,
                                     TRUE /* Force /x */ );
 
             switch (*RExC_parse) {
-                case '?':
-                    if (RExC_parse[1] == '[') depth++, RExC_parse++;
+                case '(':
+                    if (RExC_parse[1] == '?' && RExC_parse[2] == '[')
+                        depth++, RExC_parse+=2;
                     /* FALLTHROUGH */
                 default:
                     break;
@@ -14881,9 +14882,9 @@ S_handle_regex_sets(pTHX_ RExC_state_t *pRExC_state, SV** return_invlist,
                 }
 
                 case ']':
-                    if (depth--) break;
-                    RExC_parse++;
-                    if (*RExC_parse == ')') {
+                    if (RExC_parse[1] == ')') {
+                        RExC_parse++;
+                        if (depth--) break;
                         node = reganode(pRExC_state, ANYOF, 0);
                         RExC_size += ANYOF_SKIP;
                         nextchar(pRExC_state);
@@ -14895,20 +14896,25 @@ S_handle_regex_sets(pTHX_ RExC_state_t *pRExC_state, SV** return_invlist,
 
                         return node;
                     }
-                    goto no_close;
+                    /* We output the messages even if warnings are off, because we'll fail
+                     * the very next thing, and these give a likely diagnosis for that */
+                    if (posix_warnings && av_tindex_skip_len_mg(posix_warnings) >= 0) {
+                        output_or_return_posix_warnings(pRExC_state, posix_warnings, NULL);
+                    }
+                    RExC_parse++;
+                    vFAIL("Unexpected ']' with no following ')' in (?[...");
             }
 
             RExC_parse += UTF ? UTF8SKIP(RExC_parse) : 1;
         }
 
-      no_close:
         /* We output the messages even if warnings are off, because we'll fail
          * the very next thing, and these give a likely diagnosis for that */
         if (posix_warnings && av_tindex_skip_len_mg(posix_warnings) >= 0) {
             output_or_return_posix_warnings(pRExC_state, posix_warnings, NULL);
         }
 
-        FAIL("Syntax error in (?[...])");
+        vFAIL("Syntax error in (?[...])");
     }
 
     /* Pass 2 only after this. */
@@ -15088,12 +15094,14 @@ redo_curchar:
                      * inversion list, and RExC_parse points to the trailing
                      * ']'; the next character should be the ')' */
                     RExC_parse++;
-                    assert(UCHARAT(RExC_parse) == ')');
+                    if (UCHARAT(RExC_parse) != ')')
+                        vFAIL("Expecting close paren for nested extended charclass");
 
                     /* Then the ')' matching the original '(' handled by this
                      * case: statement */
                     RExC_parse++;
-                    assert(UCHARAT(RExC_parse) == ')');
+                    if (UCHARAT(RExC_parse) != ')')
+                        vFAIL("Expecting close paren for wrapper for nested extended charclass");
 
                     RExC_parse++;
                     RExC_flags = save_flags;
diff --git a/t/lib/warnings/regcomp b/t/lib/warnings/regcomp
index 2b084c59b0..51ad57ccbe 100644
--- a/t/lib/warnings/regcomp
+++ b/t/lib/warnings/regcomp
@@ -59,21 +59,21 @@ Unmatched [ in regex; marked by <-- HERE in m/abc[ <-- HERE ���[.00./ at - line
 qr/(?[[[:word]]])/;
 EXPECT
 Assuming NOT a POSIX class since there is no terminating ':' in regex; marked by <-- HERE in m/(?[[[:word <-- HERE ]]])/ at - line 2.
-syntax error in (?[...]) in regex m/(?[[[:word]]])/ at - line 2.
+Unexpected ']' with no following ')' in (?[... in regex; marked by <-- HERE in m/(?[[[:word]] <-- HERE ])/ at - line 2.
 ########
 # NAME qr/(?[ [[:digit: ])/
 # OPTION fatal
 qr/(?[[[:digit: ])/;
 EXPECT
 Assuming NOT a POSIX class since no blanks are allowed in one in regex; marked by <-- HERE in m/(?[[[:digit: ] <-- HERE )/ at - line 2.
-syntax error in (?[...]) in regex m/(?[[[:digit: ])/ at - line 2.
+syntax error in (?[...]) in regex; marked by <-- HERE in m/(?[[[:digit: ]) <-- HERE / at - line 2.
 ########
 # NAME qr/(?[ [:digit: ])/
 # OPTION fatal
 qr/(?[[:digit: ])/
 EXPECT
 Assuming NOT a POSIX class since no blanks are allowed in one in regex; marked by <-- HERE in m/(?[[:digit: ] <-- HERE )/ at - line 2.
-syntax error in (?[...]) in regex m/(?[[:digit: ])/ at - line 2.
+syntax error in (?[...]) in regex; marked by <-- HERE in m/(?[[:digit: ]) <-- HERE / at - line 2.
 ########
 # NAME [perl #126141]
 # OPTION fatal
diff --git a/t/re/reg_mesg.t b/t/re/reg_mesg.t
index 39cfcf7df1..1b36d6df20 100644
--- a/t/re/reg_mesg.t
+++ b/t/re/reg_mesg.t
@@ -213,8 +213,9 @@ my @death =
  '/\b{gc}/' => "'gc' is an unknown bound type {#} m/\\b{gc{#}}/",
  '/\B{gc}/' => "'gc' is an unknown bound type {#} m/\\B{gc{#}}/",
 
- '/(?[[[::]]])/' => "Syntax error in (?[...]) in regex m/(?[[[::]]])/",
- '/(?[[[:w:]]])/' => "Syntax error in (?[...]) in regex m/(?[[[:w:]]])/",
+
+ '/(?[[[::]]])/' => "Unexpected ']' with no following ')' in (?[... {#} m/(?[[[::]]{#}])/",
+ '/(?[[[:w:]]])/' => "Unexpected ']' with no following ')' in (?[... {#} m/(?[[[:w:]]{#}])/",
  '/(?[[:w:]])/' => "",
  '/([.].*)[.]/'   => "",    # [perl #127582]
  '/[.].*[.]/'     => "",    # [perl #127604]
@@ -237,11 +238,12 @@ my @death =
  '/(?[ \p{foo} ])/' => 'Can\'t find Unicode property definition "foo" {#} m/(?[ \p{foo}{#} ])/',
  '/(?[ \p{ foo = bar } ])/' => 'Can\'t find Unicode property definition "foo = bar" {#} m/(?[ \p{ foo = bar }{#} ])/',
  '/(?[ \8 ])/' => 'Unrecognized escape \8 in character class {#} m/(?[ \8{#} ])/',
- '/(?[ \t ]/' => 'Syntax error in (?[...]) in regex m/(?[ \t ]/',
- '/(?[ [ \t ]/' => 'Syntax error in (?[...]) in regex m/(?[ [ \t ]/',
- '/(?[ \t ] ]/' => 'Syntax error in (?[...]) in regex m/(?[ \t ] ]/',
- '/(?[ [ ] ]/' => 'Syntax error in (?[...]) in regex m/(?[ [ ] ]/',
- '/(?[ \t + \e # This was supposed to be a comment ])/' => 'Syntax error in (?[...]) in regex m/(?[ \t + \e # This was supposed to be a comment ])/',
+ '/(?[ \t ]/' => "Unexpected ']' with no following ')' in (?[... {#} m/(?[ \\t ]{#}/",
+ '/(?[ [ \t ]/' => "Syntax error in (?[...]) {#} m/(?[ [ \\t ]{#}/",
+ '/(?[ \t ] ]/' => "Unexpected ']' with no following ')' in (?[... {#} m/(?[ \\t ]{#} ]/",
+ '/(?[ [ ] ]/' => "Syntax error in (?[...]) {#} m/(?[ [ ] ]{#}/",
+ '/(?[ \t + \e # This was supposed to be a comment ])/' =>
+    "Syntax error in (?[...]) {#} m/(?[ \\t + \\e # This was supposed to be a comment ]){#}/",
  '/(?[ ])/' => 'Incomplete expression within \'(?[ ])\' {#} m/(?[ {#}])/',
  'm/(?[[a-\d]])/' => 'False [] range "a-\d" {#} m/(?[[a-\d{#}]])/',
  'm/(?[[\w-x]])/' => 'False [] range "\w-" {#} m/(?[[\w-{#}x]])/',
@@ -427,10 +429,10 @@ my @death_utf8 = mark_as_utf8(
 
  '/���\p{}���/' => 'Empty \p{} {#} m/���\p{{#}}���/',
 
- '/���(?[[[:���]]])���/' => "Syntax error in (?[...]) in regex m/���(?[[[:���]]])���/",
- '/���(?[[[:���: ])���/' => "Syntax error in (?[...]) in regex m/���(?[[[:���: ])���/",
- '/���(?[[[::]]])���/' => "Syntax error in (?[...]) in regex m/���(?[[[::]]])���/",
- '/���(?[[[:���:]]])���/' => "Syntax error in (?[...]) in regex m/���(?[[[:���:]]])���/",
+ '/���(?[[[:���]]])���/' => "Unexpected ']' with no following ')' in (?[... {#} m/���(?[[[:���]]{#}])���/",
+ '/���(?[[[:���: ])���/' => "Syntax error in (?[...]) {#} m/���(?[[[:���: ])���{#}/",
+ '/���(?[[[::]]])���/' => "Unexpected ']' with no following ')' in (?[... {#} m/���(?[[[::]]{#}])���/",
+ '/���(?[[[:���:]]])���/' => "Unexpected ']' with no following ')' in (?[... {#} m/���(?[[[:���:]]{#}])���/",
  '/���(?[[:���:]])���/' => "",
  '/���(?[���])���/' =>  'Unexpected character {#} m/���(?[���{#}])���/',
  '/���(?[ + [���] ])/' => 'Unexpected binary operator \'+\' with no preceding operand {#} m/���(?[ +{#} [���] ])/',
@@ -443,8 +445,9 @@ my @death_utf8 = mark_as_utf8(
  '/(?[ \x{���} ])���/' => 'Non-hex character {#} m/(?[ \x{���{#}} ])���/',
  '/(?[ \p{���} ])/' => 'Can\'t find Unicode property definition "���" {#} m/(?[ \p{���}{#} ])/',
  '/(?[ \p{ ��� = bar } ])/' => 'Can\'t find Unicode property definition "��� = bar" {#} m/(?[ \p{ ��� = bar }{#} ])/',
- '/���(?[ \t ]/' => 'Syntax error in (?[...]) in regex m/���(?[ \t ]/',
- '/(?[ \t + \e # ��� This was supposed to be a comment ])/' => 'Syntax error in (?[...]) in regex m/(?[ \t + \e # ��� This was supposed to be a comment ])/',
+ '/���(?[ \t ]/' => "Unexpected ']' with no following ')' in (?[... {#} m/���(?[ \\t ]{#}/",
+ '/(?[ \t + \e # ��� This was supposed to be a comment ])/' =>
+    "Syntax error in (?[...]) {#} m/(?[ \\t + \\e # ��� This was supposed to be a comment ]){#}/",
  'm/(*���)���/' => q<Unknown verb pattern '���' {#} m/(*���){#}���/>,
  '/\c���/' => "Character following \"\\c\" must be printable ASCII",
  '/\b{���}/' => "'���' is an unknown bound type {#} m/\\b{���{#}}/",
diff --git a/t/re/regex_sets.t b/t/re/regex_sets.t
index 6a79f9d692..e9644bd4e6 100644
--- a/t/re/regex_sets.t
+++ b/t/re/regex_sets.t
@@ -158,13 +158,13 @@ for my $char ("��", "��", "��") {
 	eval { $_ = '/(?[(\c]) /'; qr/$_/ };
 	like($@, qr/^Syntax error/, '/(?[(\c]) / should not panic');
 	eval { $_ = '(?[\c#]' . "\n])"; qr/$_/ };
-	like($@, qr/^Syntax error/, '/(?[(\c]) / should not panic');
+	like($@, qr/^Unexpected/, '/(?[(\c]) / should not panic');
 	eval { $_ = '(?[(\c])'; qr/$_/ };
 	like($@, qr/^Syntax error/, '/(?[(\c])/ should be a syntax error');
 	eval { $_ = '(?[(\c]) ]\b'; qr/$_/ };
-	like($@, qr/^Syntax error/, '/(?[(\c]) ]\b/ should be a syntax error');
+	like($@, qr/^Unexpected/, '/(?[(\c]) ]\b/ should be a syntax error');
 	eval { $_ = '(?[\c[]](])'; qr/$_/ };
-	like($@, qr/^Syntax error/, '/(?[\c[]](])/ should be a syntax error');
+	like($@, qr/^Unexpected/, '/(?[\c[]](])/ should be a syntax error');
 	like("\c#", qr/(?[\c#])/, '\c# should match itself');
 	like("\c[", qr/(?[\c[])/, '\c[ should match itself');
 	like("\c\ ", qr/(?[\c\])/, '\c\ should match itself');
-- 
2.11.0

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@p5pRT p5pRT commented Oct 15, 2018

From @tonycoz

On Sun, 23 Sep 2018 23​:42​:36 -0700, tonyc wrote​:

I plan to request a CVE ID for this issue in the next couple of days.

This is CVE-2018-18314.

Tony

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@p5pRT p5pRT commented Oct 29, 2018

From @tonycoz

On Mon, Oct 01, 2018 at 05​:19​:54PM -0700, Tony Cook via RT wrote​:

On Wed, 19 Sep 2018 17​:37​:48 -0700, tonyc wrote​:

On Wed, 29 Nov 2017 10​:53​:43 -0800, public@​khwilliamson.com wrote​:

On 11/29/2017 02​:46 AM, demerphq wrote​:

I am waiting on Karl to reply. As far as I know my patch does fix the
issue.

Yves

I think his patch solves the issue, but my writing a grammar comes
after
the code freeze

Which patch?

I don't see a yves/fix_131649 branch anywhere.

It turns out this was fixed in 19a498a, which is included in 5.28.

This doesn't cherry-pick cleanly to 5.26, the attached is a merged cherry-pick of the fix.

And this was corrupted apparently at my end, turning all of the
non-UTF-8 bytes into the replacement character.

Attached a gzipped patch.

Tony

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@p5pRT p5pRT commented Oct 29, 2018

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@p5pRT p5pRT commented Nov 29, 2018

From @steve-m-hay

Moved to public queue with the release of 5.26.3.

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@p5pRT p5pRT commented Nov 29, 2018

From [Unknown Contact. See original ticket]

Moved to public queue with the release of 5.26.3.

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@p5pRT p5pRT commented Dec 2, 2018

From @khwilliamson

This has been fixed in blead and all maintenance releases, so resolving

A new ticket has been created to track creating a formal grammar for regex sets, mentioned originally in this ticket. The new ticket is

https://rt-archive.perl.org/perl5/Ticket/Display.html?id=133707

--
Karl Williamson

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@p5pRT p5pRT commented Dec 2, 2018

@khwilliamson - Status changed from 'open' to 'resolved'

@p5pRT p5pRT closed this Dec 2, 2018
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