This patch results in the t/re/pat.t ptest failing.

Is this a real issue?

Steve

On Tue, Aug 18, 2020, 4:06 AM Lee Chee Yang <[email protected]> wrote:

> From: Lee Chee Yang <[email protected]>
>
> Minor changes to the test cases count in the .patch file to make it
> align with current version, so the fixes can be apply.
> Changes apply to line:
>
> https://github.com/perl/perl5/commit/66bbb51b93253a3f87d11c2695cfb7bdb782184a#diff-e31ddd69cf47acf02911647c691a0283L28
>
> Signed-off-by: Lee Chee Yang <[email protected]>
> ---
>  .../perl/files/CVE-2020-12723.patch           | 302 ++++++++++++++++++
>  meta/recipes-devtools/perl/perl_5.30.1.bb     |   1 +
>  2 files changed, 303 insertions(+)
>  create mode 100644 meta/recipes-devtools/perl/files/CVE-2020-12723.patch
>
> diff --git a/meta/recipes-devtools/perl/files/CVE-2020-12723.patch
> b/meta/recipes-devtools/perl/files/CVE-2020-12723.patch
> new file mode 100644
> index 0000000000..ad195cffab
> --- /dev/null
> +++ b/meta/recipes-devtools/perl/files/CVE-2020-12723.patch
> @@ -0,0 +1,302 @@
> +From da9ec461e22915ccabb06785bf39ec34577ada12 Mon Sep 17 00:00:00 2001
> +From: Hugo van der Sanden <[email protected]>
> +Date: Sat, 11 Apr 2020 14:10:24 +0100
> +Subject: [PATCH] study_chunk: avoid mutating regexp program within GOSUB
> +
> +gh16947 and gh17743: studying GOSUB may restudy in an inner call
> +(via a mix of recursion and enframing) something that an outer call
> +is in the middle of looking at.  Let the outer frame deal with it.
> +
> +(CVE-2020-12723)
> +
> +(cherry picked from commit c4033e740bd18d9fbe3456a9db2ec2053cdc5271)
> +
> +Upstream-Status: Backport [
> https://github.com/perl/perl5/commit/66bbb51b93253a3f87d11c2695cfb7bdb782184a
> ]
> +CVE: CVE-2020-12723
> +Signed-off-by: Chee Yang Lee <[email protected]>
> +
> +---
> + embed.fnc  |  2 +-
> + embed.h    |  2 +-
> + proto.h    |  2 +-
> + regcomp.c  | 54 +++++++++++++++++++++++++++++++++++-------------------
> + t/re/pat.t | 26 +++++++++++++++++++++++++-
> + 5 files changed, 63 insertions(+), 23 deletions(-)
> +
> +diff --git a/embed.fnc b/embed.fnc
> +index f45c127..eff4a50 100644
> +--- a/embed.fnc
> ++++ b/embed.fnc
> +@@ -2480,7 +2480,7 @@ Es       |SSize_t|study_chunk    |NN RExC_state_t
> *pRExC_state \
> +                               |NULLOK struct scan_data_t *data \
> +                                 |I32 stopparen|U32 recursed_depth \
> +                               |NULLOK regnode_ssc *and_withp \
> +-                              |U32 flags|U32 depth
> ++                              |U32 flags|U32 depth|bool was_mutate_ok
> + Es    |void   |rck_elide_nothing|NN regnode *node
> + EsR   |SV *   |get_ANYOFM_contents|NN const regnode * n
> + EsRn  |U32    |add_data       |NN RExC_state_t* const pRExC_state \
> +diff --git a/embed.h b/embed.h
> +index 356a8b9..5346ec5 100644
> +--- a/embed.h
> ++++ b/embed.h
> +@@ -1239,7 +1239,7 @@
> + #define ssc_is_cp_posixl_init S_ssc_is_cp_posixl_init
> + #define ssc_or(a,b,c)         S_ssc_or(aTHX_ a,b,c)
> + #define ssc_union(a,b,c)      S_ssc_union(aTHX_ a,b,c)
> +-#define study_chunk(a,b,c,d,e,f,g,h,i,j,k)    S_study_chunk(aTHX_
> a,b,c,d,e,f,g,h,i,j,k)
> ++#define study_chunk(a,b,c,d,e,f,g,h,i,j,k,l)  S_study_chunk(aTHX_
> a,b,c,d,e,f,g,h,i,j,k,l)
> + #  endif
> + #  if defined(PERL_IN_REGCOMP_C) || defined (PERL_IN_DUMP_C)
> + #define _invlist_dump(a,b,c,d)        Perl__invlist_dump(aTHX_ a,b,c,d)
> +diff --git a/proto.h b/proto.h
> +index 91530b1..1bda01f 100644
> +--- a/proto.h
> ++++ b/proto.h
> +@@ -5655,7 +5655,7 @@ PERL_STATIC_INLINE void  S_ssc_union(pTHX_
> regnode_ssc *ssc, SV* const invlist, c
> + #define PERL_ARGS_ASSERT_SSC_UNION    \
> +       assert(ssc); assert(invlist)
> + #endif
> +-STATIC SSize_t        S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp, SSize_t *minlenp, SSize_t *deltap, regnode *last, struct
> scan_data_t *data, I32 stopparen, U32 recursed_depth, regnode_ssc
> *and_withp, U32 flags, U32 depth);
> ++STATIC SSize_t        S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp, SSize_t *minlenp, SSize_t *deltap, regnode *last, struct
> scan_data_t *data, I32 stopparen, U32 recursed_depth, regnode_ssc
> *and_withp, U32 flags, U32 depth, bool was_mutate_ok);
> + #define PERL_ARGS_ASSERT_STUDY_CHUNK  \
> +       assert(pRExC_state); assert(scanp); assert(minlenp);
> assert(deltap); assert(last)
> + #endif
> +diff --git a/regcomp.c b/regcomp.c
> +index 5a9adee..8d7df1f 100644
> +--- a/regcomp.c
> ++++ b/regcomp.c
> +@@ -106,6 +106,7 @@ typedef struct scan_frame {
> +     regnode *next_regnode;      /* next node to process when last is
> reached */
> +     U32 prev_recursed_depth;
> +     I32 stopparen;              /* what stopparen do we use */
> ++    bool in_gosub;              /* this or an outer frame is for GOSUB */
> +
> +     struct scan_frame *this_prev_frame; /* this previous frame */
> +     struct scan_frame *prev_frame;      /* previous frame */
> +@@ -4466,7 +4467,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                       I32 stopparen,
> +                         U32 recursed_depth,
> +                       regnode_ssc *and_withp,
> +-                      U32 flags, U32 depth)
> ++                      U32 flags, U32 depth, bool was_mutate_ok)
> +                       /* scanp: Start here (read-write). */
> +                       /* deltap: Write maxlen-minlen here. */
> +                       /* last: Stop before this one. */
> +@@ -4545,6 +4546,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                                    node length to get a real minimum
> (because
> +                                    the folded version may be shorter) */
> +       bool unfolded_multi_char = FALSE;
> ++        /* avoid mutating ops if we are anywhere within the recursed or
> ++         * enframed handling for a GOSUB: the outermost level will
> handle it.
> ++         */
> ++        bool mutate_ok = was_mutate_ok && !(frame && frame->in_gosub);
> +       /* Peephole optimizer: */
> +         DEBUG_STUDYDATA("Peep", data, depth, is_inf);
> +         DEBUG_PEEP("Peep", scan, depth, flags);
> +@@ -4555,7 +4560,8 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +          * parsing code, as each (?:..) is handled by a different
> invocation of
> +          * reg() -- Yves
> +          */
> +-        JOIN_EXACT(scan,&min_subtract, &unfolded_multi_char, 0);
> ++        if (mutate_ok)
> ++            JOIN_EXACT(scan,&min_subtract, &unfolded_multi_char, 0);
> +
> +         /* Follow the next-chain of the current node and optimize
> +            away all the NOTHINGs from it.
> +@@ -4587,7 +4593,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +             /* DEFINEP study_chunk() recursion */
> +             (void)study_chunk(pRExC_state, &scan, &minlen,
> +                               &deltanext, next, &data_fake, stopparen,
> +-                              recursed_depth, NULL, f, depth+1);
> ++                              recursed_depth, NULL, f, depth+1,
> mutate_ok);
> +
> +             scan = next;
> +         } else
> +@@ -4655,7 +4661,8 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                     /* recurse study_chunk() for each BRANCH in an
> alternation */
> +                   minnext = study_chunk(pRExC_state, &scan, minlenp,
> +                                       &deltanext, next, &data_fake,
> stopparen,
> +-                                      recursed_depth, NULL, f, depth+1);
> ++                                      recursed_depth, NULL, f, depth+1,
> ++                                      mutate_ok);
> +
> +                   if (min1 > minnext)
> +                       min1 = minnext;
> +@@ -4722,9 +4729,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                   }
> +               }
> +
> +-                if (PERL_ENABLE_TRIE_OPTIMISATION &&
> +-                        OP( startbranch ) == BRANCH )
> +-                {
> ++                if (PERL_ENABLE_TRIE_OPTIMISATION
> ++                    && OP(startbranch) == BRANCH
> ++                    && mutate_ok
> ++                ) {
> +               /* demq.
> +
> +                    Assuming this was/is a branch we are dealing with:
> 'scan'
> +@@ -5179,6 +5187,9 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                 newframe->stopparen = stopparen;
> +                 newframe->prev_recursed_depth = recursed_depth;
> +                 newframe->this_prev_frame= frame;
> ++                newframe->in_gosub = (
> ++                    (frame && frame->in_gosub) || OP(scan) == GOSUB
> ++                );
> +
> +                 DEBUG_STUDYDATA("frame-new", data, depth, is_inf);
> +                 DEBUG_PEEP("fnew", scan, depth, flags);
> +@@ -5336,7 +5347,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +
> +                 /* This temporary node can now be turned into EXACTFU,
> and
> +                  * must, as regexec.c doesn't handle it */
> +-                if (OP(next) == EXACTFU_S_EDGE) {
> ++                if (OP(next) == EXACTFU_S_EDGE && mutate_ok) {
> +                     OP(next) = EXACTFU;
> +                 }
> +
> +@@ -5344,8 +5355,9 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                     &&   isALPHA_A(* STRING(next))
> +                     && (         OP(next) == EXACTFAA
> +                         || (     OP(next) == EXACTFU
> +-                            && ! HAS_NONLATIN1_SIMPLE_FOLD_CLOSURE(*
> STRING(next)))))
> +-                {
> ++                            && ! HAS_NONLATIN1_SIMPLE_FOLD_CLOSURE(*
> STRING(next))))
> ++                    &&   mutate_ok
> ++                ) {
> +                     /* These differ in just one bit */
> +                     U8 mask = ~ ('A' ^ 'a');
> +
> +@@ -5432,7 +5444,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                                   (mincount == 0
> +                                    ? (f & ~SCF_DO_SUBSTR)
> +                                    : f)
> +-                                  ,depth+1);
> ++                                  , depth+1, mutate_ok);
> +
> +               if (flags & SCF_DO_STCLASS)
> +                   data->start_class = oclass;
> +@@ -5498,7 +5510,9 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +               if (  OP(oscan) == CURLYX && data
> +                     && data->flags & SF_IN_PAR
> +                     && !(data->flags & SF_HAS_EVAL)
> +-                    && !deltanext && minnext == 1 ) {
> ++                    && !deltanext && minnext == 1
> ++                      && mutate_ok
> ++                ) {
> +                   /* Try to optimize to CURLYN.  */
> +                   regnode *nxt = NEXTOPER(oscan) + EXTRA_STEP_2ARGS;
> +                   regnode * const nxt1 = nxt;
> +@@ -5548,10 +5562,10 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                     && !(data->flags & SF_HAS_EVAL)
> +                     && !deltanext     /* atom is fixed width */
> +                     && minnext != 0   /* CURLYM can't handle zero width
> */
> +-
> +                          /* Nor characters whose fold at run-time may be
> +                           * multi-character */
> +                       && ! (RExC_seen & REG_UNFOLDED_MULTI_SEEN)
> ++                      && mutate_ok
> +               ) {
> +                   /* XXXX How to optimize if data == 0? */
> +                   /* Optimize to a simpler form.  */
> +@@ -5604,7 +5618,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state,
> regnode **scanp,
> +                         /* recurse study_chunk() on optimised CURLYX =>
> CURLYM */
> +                       study_chunk(pRExC_state, &nxt1, minlenp,
> &deltanext, nxt,
> +                                     NULL, stopparen, recursed_depth,
> NULL, 0,
> +-                                    depth+1);
> ++                                    depth+1, mutate_ok);
> +                   }
> +                   else
> +                       oscan->flags = 0;
> +@@ -6009,7 +6023,8 @@ Perl_re_printf( aTHX_  "LHS=%" UVuf " RHS=%" UVuf
> "\n",
> +                 /* recurse study_chunk() for lookahead body */
> +                 minnext = study_chunk(pRExC_state, &nscan, minlenp,
> &deltanext,
> +                                       last, &data_fake, stopparen,
> +-                                      recursed_depth, NULL, f, depth+1);
> ++                                      recursed_depth, NULL, f, depth+1,
> ++                                      mutate_ok);
> +                 if (scan->flags) {
> +                     if (   deltanext < 0
> +                         || deltanext > (I32) U8_MAX
> +@@ -6114,7 +6129,7 @@ Perl_re_printf( aTHX_  "LHS=%" UVuf " RHS=%" UVuf
> "\n",
> +                 *minnextp = study_chunk(pRExC_state, &nscan, minnextp,
> +                                         &deltanext, last, &data_fake,
> +                                         stopparen, recursed_depth, NULL,
> +-                                        f, depth+1);
> ++                                        f, depth+1, mutate_ok);
> +                 if (scan->flags) {
> +                     assert(0);  /* This code has never been tested since
> this
> +                                    is normally not compiled */
> +@@ -6282,7 +6297,8 @@ Perl_re_printf( aTHX_  "LHS=%" UVuf " RHS=%" UVuf
> "\n",
> +                         /* optimise study_chunk() for TRIE */
> +                         minnext = study_chunk(pRExC_state, &scan,
> minlenp,
> +                             &deltanext, (regnode *)nextbranch,
> &data_fake,
> +-                            stopparen, recursed_depth, NULL, f, depth+1);
> ++                            stopparen, recursed_depth, NULL, f, depth+1,
> ++                            mutate_ok);
> +                     }
> +                     if (nextbranch && PL_regkind[OP(nextbranch)]==BRANCH)
> +                         nextbranch= regnext((regnode*)nextbranch);
> +@@ -8075,7 +8091,7 @@ Perl_re_op_compile(pTHX_ SV ** const patternp, int
> pat_count,
> +             &data, -1, 0, NULL,
> +             SCF_DO_SUBSTR | SCF_WHILEM_VISITED_POS | stclass_flag
> +                           | (restudied ? SCF_TRIE_DOING_RESTUDY : 0),
> +-            0);
> ++            0, TRUE);
> +
> +
> +         CHECK_RESTUDY_GOTO_butfirst(LEAVE_with_name("study_chunk"));
> +@@ -8204,7 +8220,7 @@ Perl_re_op_compile(pTHX_ SV ** const patternp, int
> pat_count,
> +             SCF_DO_STCLASS_AND|SCF_WHILEM_VISITED_POS|(restudied
> +                                                       ?
> SCF_TRIE_DOING_RESTUDY
> +                                                       : 0),
> +-            0);
> ++            0, TRUE);
> +
> +         CHECK_RESTUDY_GOTO_butfirst(NOOP);
> +
> +diff --git a/t/re/pat.t b/t/re/pat.t
> +index 6a868f4..2869b58 100644
> +--- a/t/re/pat.t
> ++++ b/t/re/pat.t
> +@@ -25,7 +25,7 @@ BEGIN {
> + skip_all('no re module') unless defined &DynaLoader::boot_DynaLoader;
> + skip_all_without_unicode_tables();
> +
> +-plan tests => 864;  # Update this when adding/deleting tests.
> ++plan tests => 873;  # Update this when adding/deleting tests.
> +
> + run_tests() unless caller;
> +
> +@@ -2115,6 +2115,30 @@ x{0c!}\;\;îçÿ   /0f/! F   /;îçÿù\Q    x ÿÿÿÿ   ù
>   `x{0c!} ;   ù\Q
> +         like(runperl(prog => "$s", stderr => 1), qr/Unmatched \(/);
> +    }
> +
> ++    # gh16947: test regexp corruption (GOSUB)
> ++    {
> ++        fresh_perl_is(q{
> ++            'xy' =~ /x(?0)|x(?|y|y)/ && print 'ok'
> ++        }, 'ok', {}, 'gh16947: test regexp corruption (GOSUB)');
> ++    }
> ++    # gh16947: test fix doesn't break SUSPEND
> ++    {
> ++        fresh_perl_is(q{ 'sx' =~ m{ss++}i; print 'ok' },
> ++                'ok', {}, "gh16947: test fix doesn't break SUSPEND");
> ++    }
> ++
> ++    # gh17743: more regexp corruption via GOSUB
> ++    {
> ++        fresh_perl_is(q{
> ++            "0" =~ /((0(?0)|000(?|0000|0000)(?0))|)/; print "ok"
> ++        }, 'ok', {}, 'gh17743: test regexp corruption (1)');
> ++
> ++        fresh_perl_is(q{
> ++            "000000000000" =~
> /(0(())(0((?0)())|000(?|\x{ef}\x{bf}\x{bd}|\x{ef}\x{bf}\x{bd}))|)/;
> ++            print "ok"
> ++        }, 'ok', {}, 'gh17743: test regexp corruption (2)');
> ++    }
> ++
> + } # End of sub run_tests
> +
> + 1;
> diff --git a/meta/recipes-devtools/perl/perl_5.30.1.bb
> b/meta/recipes-devtools/perl/perl_5.30.1.bb
> index 47b2f9ca65..b53aff1216 100644
> --- a/meta/recipes-devtools/perl/perl_5.30.1.bb
> +++ b/meta/recipes-devtools/perl/perl_5.30.1.bb
> @@ -27,6 +27,7 @@ SRC_URI = "
> https://www.cpan.org/src/5.0/perl-${PV}.tar.gz;name=perl \
>             file://CVE-2020-10543.patch \
>             file://CVE-2020-10878_1.patch \
>             file://CVE-2020-10878_2.patch \
> +           file://CVE-2020-12723.patch \
>             "
>  SRC_URI_append_class-native = " \
>             file://perl-configpm-switch.patch \
> --
> 2.17.1
>
> 
>
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