--- /dev/null
+From f17fed5006177dce8ac48229c424a2da0d6ba492 Mon Sep 17 00:00:00 2001
+From: Tony Cook <tony@develop-help.com>
+Date: Tue, 8 Aug 2017 09:32:58 +1000
+Subject: [PATCH] (perl #131844) fix various space calculation issues in
+ pp_pack.c
+
+- for the originally reported case, if the start/cur pointer is in the
+ top 75% of the address space the add (cur) + glen addition would
+ overflow, resulting in the condition failing incorrectly.
+
+- the addition of the existing space used to the space needed could
+ overflow, resulting in too small an allocation and a buffer overflow.
+
+- the scaling for UTF8 could overflow.
+
+- the multiply to calculate the space needed for many items could
+ overflow.
+
+For the first case, do a space calculation without making new pointers.
+
+For the other cases, detect the overflow and croak if there's an
+overflow.
+
+Originally this used Size_t_MAX as the maximum size of a memory
+allocation, but for -DDEBUGGING builds realloc() throws a panic for
+allocations over half the address space in size, changing the error
+reported for the allocation.
+
+For non-DEBUGGING builds the Size_t_MAX limit has the small chance
+of finding a system that has 3GB of contiguous space available, and
+allocating that space, which could be a denial of servce in some cases.
+
+Unfortunately changing the limit to half the address space means that
+the exact case with the original issue can no longer occur, so the
+test is no longer testing against the address + length issue that
+caused the original problem, since the allocation is failing earlier.
+
+One option would be to change the test so the size request by pack is
+just under 2GB, but this has a higher (but still low) probability that
+the system has the address space available, and will actually try to
+allocate the memory, so let's not do that.
+
+Note: changed
+plan tests => 14713;
+to
+plan tests => 14712;
+in a/t/op/pack.t
+to apply this patch on perl 5.24.1.
+
+CVE: CVE-2018-6913
+Upstream-Status: Backport [https://perl5.git.perl.org/perl.git/commitdiff/f17fed5006177dce8ac48229c424a2da0d6ba492]
+
+Signed-off-by: Jagadeesh Krishnanjanappa <jkrishnanjanappa@mvista.com>
+---
+ pp_pack.c | 25 +++++++++++++++++++++----
+ t/op/pack.t | 24 +++++++++++++++++++++++-
+ 2 files changed, 44 insertions(+), 5 deletions(-)
+
+diff --git a/pp_pack.c b/pp_pack.c
+index 8937d6d715..5e9cc64301 100644
+--- a/pp_pack.c
++++ b/pp_pack.c
+@@ -357,11 +357,28 @@ STMT_START { \
+ } \
+ } STMT_END
+
++#define SAFE_UTF8_EXPAND(var) \
++STMT_START { \
++ if ((var) > SSize_t_MAX / UTF8_EXPAND) \
++ Perl_croak(aTHX_ "%s", "Out of memory during pack()"); \
++ (var) = (var) * UTF8_EXPAND; \
++} STMT_END
++
++#define GROWING2(utf8, cat, start, cur, item_size, item_count) \
++STMT_START { \
++ if (SSize_t_MAX / (item_size) < (item_count)) \
++ Perl_croak(aTHX_ "%s", "Out of memory during pack()"); \
++ GROWING((utf8), (cat), (start), (cur), (item_size) * (item_count)); \
++} STMT_END
++
+ #define GROWING(utf8, cat, start, cur, in_len) \
+ STMT_START { \
+ STRLEN glen = (in_len); \
+- if (utf8) glen *= UTF8_EXPAND; \
+- if ((cur) + glen >= (start) + SvLEN(cat)) { \
++ STRLEN catcur = (STRLEN)((cur) - (start)); \
++ if (utf8) SAFE_UTF8_EXPAND(glen); \
++ if (SSize_t_MAX - glen < catcur) \
++ Perl_croak(aTHX_ "%s", "Out of memory during pack()"); \
++ if (catcur + glen >= SvLEN(cat)) { \
+ (start) = sv_exp_grow(cat, glen); \
+ (cur) = (start) + SvCUR(cat); \
+ } \
+@@ -372,7 +389,7 @@ STMT_START { \
+ STMT_START { \
+ const STRLEN glen = (in_len); \
+ STRLEN gl = glen; \
+- if (utf8) gl *= UTF8_EXPAND; \
++ if (utf8) SAFE_UTF8_EXPAND(gl); \
+ if ((cur) + gl >= (start) + SvLEN(cat)) { \
+ *cur = '\0'; \
+ SvCUR_set((cat), (cur) - (start)); \
+@@ -2126,7 +2143,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* sym
+ if (props && !(props & PACK_SIZE_UNPREDICTABLE)) {
+ /* We can process this letter. */
+ STRLEN size = props & PACK_SIZE_MASK;
+- GROWING(utf8, cat, start, cur, (STRLEN) len * size);
++ GROWING2(utf8, cat, start, cur, size, (STRLEN)len);
+ }
+ }
+
+diff --git a/t/op/pack.t b/t/op/pack.t
+index 664aaaf1b0..cf0e286509 100644
+--- a/t/op/pack.t
++++ b/t/op/pack.t
+@@ -12,7 +12,7 @@ my $no_endianness = $] > 5.009 ? '' :
+ my $no_signedness = $] > 5.009 ? '' :
+ "Signed/unsigned pack modifiers not available on this perl";
+
+-plan tests => 14712;
++plan tests => 14717;
+
+ use strict;
+ use warnings qw(FATAL all);
+@@ -2044,3 +2044,25 @@ ok(1, "argument underflow did not crash"
+ is(pack("H40", $up_nul), $twenty_nuls,
+ "check pack H zero fills (utf8 source)");
+ }
++
++SKIP:
++{
++ # [perl #131844] pointer addition overflow
++ $Config{ptrsize} == 4
++ or skip "[perl #131844] need 32-bit build for this test", 4;
++ # prevent ASAN just crashing on the allocation failure
++ local $ENV{ASAN_OPTIONS} = $ENV{ASAN_OPTIONS};
++ $ENV{ASAN_OPTIONS} .= ",allocator_may_return_null=1";
++ fresh_perl_like('pack "f999999999"', qr/Out of memory during pack/, { stderr => 1 },
++ "pointer addition overflow");
++
++ # integer (STRLEN) overflow from addition of glen to current length
++ fresh_perl_like('pack "c10f1073741823"', qr/Out of memory during pack/, { stderr => 1 },
++ "integer overflow calculating allocation (addition)");
++
++ fresh_perl_like('pack "W10f536870913", 256', qr/Out of memory during pack/, { stderr => 1 },
++ "integer overflow calculating allocation (utf8)");
++
++ fresh_perl_like('pack "c10f1073741824"', qr/Out of memory during pack/, { stderr => 1 },
++ "integer overflow calculating allocation (multiply)");
++}
+--
+2.15.1-424-g9478a660812
+
