File 1312-erts-Fix-potential-integer-overflow-in-EST... of Package erlang

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File 1312-erts-Fix-potential-integer-overflow-in-ESTACK.patch of Package erlang (Revision 66a224e208ffe9ee89602bad56a74dfa)

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From d26eff597c5f4a9a79055e85b8d59fa5f7ca4698 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Fri, 12 Nov 2021 14:00:44 +0100
Subject: [PATCH 2/2] erts: Fix potential integer overflow in ESTACK

If ESTACK_RESERVE is called with a large enough N then
the subtraction would overflow and the stack would not
be grown as it should. As far as I can tell this is never
done so this fix is to protect against future use.
---
 erts/emulator/beam/global.h | 30 +++++++++++-------------------
 1 file changed, 11 insertions(+), 19 deletions(-)

diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index 3eb0225b4e..9176309e42 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -443,28 +443,29 @@ do {						\
 
 #define ESTACK_IS_STATIC(s) ((s).start == ESTK_DEF_STACK(s))
 
+#define ESTACK_RESERVE(s, push_cnt)             \
+do {					        \
+    if ((s).end - (s).sp < (Sint)(push_cnt)) {	\
+	erl_grow_estack(&(s), (push_cnt));	\
+    }					        \
+} while(0)
+
 #define ESTACK_PUSH(s, x)			\
 do {						\
-    if ((s).sp == (s).end) {			\
-	erl_grow_estack(&(s), 1); 		\
-    }						\
+    ESTACK_RESERVE(s, 1);                       \
     *(s).sp++ = (x);				\
 } while(0)
 
 #define ESTACK_PUSH2(s, x, y)			\
 do {						\
-    if ((s).sp > (s).end - 2) {			\
-	erl_grow_estack(&(s), 2);		\
-    }						\
+    ESTACK_RESERVE(s, 2);                       \
     *(s).sp++ = (x);				\
     *(s).sp++ = (y);				\
 } while(0)
 
 #define ESTACK_PUSH3(s, x, y, z)		\
 do {						\
-    if ((s).sp > (s).end - 3) {			\
-	erl_grow_estack(&s, 3); 		\
-    }						\
+    ESTACK_RESERVE(s, 3);                       \
     *(s).sp++ = (x);				\
     *(s).sp++ = (y);				\
     *(s).sp++ = (z);				\
@@ -472,22 +473,13 @@ do {						\
 
 #define ESTACK_PUSH4(s, E1, E2, E3, E4)		\
 do {						\
-    if ((s).sp > (s).end - 4) {			\
-	erl_grow_estack(&s, 4);                 \
-    }						\
+    ESTACK_RESERVE(s, 4);                       \
     *(s).sp++ = (E1);				\
     *(s).sp++ = (E2);				\
     *(s).sp++ = (E3);				\
     *(s).sp++ = (E4);				\
 } while(0)
 
-#define ESTACK_RESERVE(s, push_cnt)             \
-do {					        \
-    if ((s).sp > (s).end - (push_cnt)) {	\
-	erl_grow_estack(&(s), (push_cnt));	\
-    }					        \
-} while(0)
-
 /* Must be preceded by ESTACK_RESERVE */
 #define ESTACK_FAST_PUSH(s, x)				\
 do {							\
-- 
2.31.1

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File 1312-erts-Fix-potential-integer-overflow-in-ESTACK.patch of Package erlang (Revision 66a224e208ffe9ee89602bad56a74dfa)

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