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70 lines
2.5 KiB
70 lines
2.5 KiB
5 years ago
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From 42e9b60980bb8e29e76629e14c6aa945194c0647 Mon Sep 17 00:00:00 2001
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From: Hugo van der Sanden <hv@crypt.org>
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Date: Wed, 5 Oct 2016 02:20:26 +0100
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Subject: [PATCH] [perl #129061] CURLYX nodes can be studied more than once
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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study_chunk() for CURLYX is used to set flags on the linked WHILEM
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node to say it is the whilem_c'th of whilem_seen. However it assumes
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each CURLYX can be studied only once, which is not the case - there
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are various cases such as GOSUB which call study_chunk() recursively
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on already-visited parts of the program.
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Storing the wrong index can cause the super-linear cache handling in
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regmatch() to read/write the byte after the end of poscache.
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Also reported in [perl #129281].
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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regcomp.c | 12 +++++++++---
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t/re/pat.t | 1 -
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2 files changed, 9 insertions(+), 4 deletions(-)
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diff --git a/regcomp.c b/regcomp.c
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index 850a6c1..48c8d8d 100644
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--- a/regcomp.c
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+++ b/regcomp.c
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@@ -5218,15 +5218,21 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
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However, this time it's not a subexpression
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we care about, but the expression itself. */
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&& (maxcount == REG_INFTY)
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- && data && ++data->whilem_c < 16) {
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+ && data) {
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/* This stays as CURLYX, we can put the count/of pair. */
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/* Find WHILEM (as in regexec.c) */
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regnode *nxt = oscan + NEXT_OFF(oscan);
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if (OP(PREVOPER(nxt)) == NOTHING) /* LONGJMP */
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nxt += ARG(nxt);
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- PREVOPER(nxt)->flags = (U8)(data->whilem_c
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- | (RExC_whilem_seen << 4)); /* On WHILEM */
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+ nxt = PREVOPER(nxt);
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+ if (nxt->flags & 0xf) {
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+ /* we've already set whilem count on this node */
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+ } else if (++data->whilem_c < 16) {
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+ assert(data->whilem_c <= RExC_whilem_seen);
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+ nxt->flags = (U8)(data->whilem_c
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+ | (RExC_whilem_seen << 4)); /* On WHILEM */
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+ }
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}
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if (data && fl & (SF_HAS_PAR|SF_IN_PAR))
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pars++;
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diff --git a/t/re/pat.t b/t/re/pat.t
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index ecd3af1..16bfc8e 100644
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--- a/t/re/pat.t
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+++ b/t/re/pat.t
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@@ -1909,7 +1909,6 @@ EOP
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}
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{
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# [perl #129281] buffer write overflow, detected by ASAN, valgrind
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- local $::TODO = "whilem_c bumped too much";
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fresh_perl_is('/0(?0)|^*0(?0)|^*(^*())0|/', '', {}, "don't bump whilem_c too much");
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}
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} # End of sub run_tests
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--
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2.7.4
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