73 lines
2.2 KiB
Diff
73 lines
2.2 KiB
Diff
From 45f235c116d4deab95c576aff77fe46d609f8553 Mon Sep 17 00:00:00 2001
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From: Tony Cook <tony@develop-help.com>
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Date: Mon, 15 Apr 2019 15:23:32 +1000
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Subject: [PATCH] (perl #17844) don't update SvCUR until after we've done
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moving
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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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SvCUR() before the SvGROW() calls could result in reading beyond the
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end of a buffer.
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It wasn't a problem in the normal case, since sv_grow() just calls
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realloc() which has its own notion of how big the memory block is, but
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if the SV is SvOOK() sv_backoff() tries to move SvCUR()+1 bytes, which
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might be larger than the currently allocated size of the PV.
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Signed-off-by: Petr Písař <ppisar@redhat.com>
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---
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doop.c | 2 +-
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t/op/bop.t | 11 ++++++++++-
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2 files changed, 11 insertions(+), 2 deletions(-)
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diff --git a/doop.c b/doop.c
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index 88220092c3..c9c953212e 100644
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--- a/doop.c
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+++ b/doop.c
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@@ -1087,7 +1087,6 @@ Perl_do_vop(pTHX_ I32 optype, SV *sv, SV *left, SV *right)
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lsave = lc;
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rsave = rc;
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- SvCUR_set(sv, len);
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(void)SvPOK_only(sv);
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if (SvOK(sv) || SvTYPE(sv) > SVt_PVMG) {
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dc = SvPV_force_nomg_nolen(sv);
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@@ -1103,6 +1102,7 @@ Perl_do_vop(pTHX_ I32 optype, SV *sv, SV *left, SV *right)
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sv_usepvn_flags(sv, dc, needlen, SV_HAS_TRAILING_NUL);
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dc = SvPVX(sv); /* sv_usepvn() calls Renew() */
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}
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+ SvCUR_set(sv, len);
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if (len >= sizeof(long)*4 &&
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!(PTR2nat(dc) % sizeof(long)) &&
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diff --git a/t/op/bop.t b/t/op/bop.t
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index eecd90387f..07f057d0a9 100644
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--- a/t/op/bop.t
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+++ b/t/op/bop.t
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@@ -18,7 +18,7 @@ BEGIN {
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# If you find tests are failing, please try adding names to tests to track
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# down where the failure is, and supply your new names as a patch.
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# (Just-in-time test naming)
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-plan tests => 501;
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+plan tests => 502;
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# numerics
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ok ((0xdead & 0xbeef) == 0x9ead);
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@@ -669,3 +669,12 @@ foreach my $op_info ([and => "&"], [or => "|"], [xor => "^"]) {
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like $@, $expected, $description;
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}
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}
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+
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+{
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+ # perl #17844 - only visible with valgrind/ASAN
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+ fresh_perl_is(<<'EOS',
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+formline X000n^\\0,\\0^\\0for\0,0..10
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+EOS
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+ '',
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+ {}, "[perl #17844] access beyond end of block");
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+}
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--
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2.25.4
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