From f461b7692546127f58140be8eb97b750d4dc3134 Mon Sep 17 00:00:00 2001
From: Pieter Wuille <pieter.wuille@gmail.com>
Date: Fri, 5 Dec 2014 18:13:28 +0100
Subject: [PATCH] Allocate precomputation arrays on the heap

---
 src/ecmult_impl.h | 3 ++-
 src/group_impl.h  | 6 ++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h
index 445b815..690d525 100644
--- a/src/ecmult_impl.h
+++ b/src/ecmult_impl.h
@@ -43,13 +43,14 @@ static void secp256k1_ecmult_table_precomp_gej_var(secp256k1_gej_t *pre, const s
 
 static void secp256k1_ecmult_table_precomp_ge_var(secp256k1_ge_t *pre, const secp256k1_gej_t *a, int w) {
     const int table_size = 1 << (w-2);
-    secp256k1_gej_t prej[table_size];
+    secp256k1_gej_t *prej = malloc(sizeof(secp256k1_gej_t) * table_size);
     prej[0] = *a;
     secp256k1_gej_t d; secp256k1_gej_double_var(&d, a);
     for (int i=1; i<table_size; i++) {
         secp256k1_gej_add_var(&prej[i], &d, &prej[i-1]);
     }
     secp256k1_ge_set_all_gej_var(table_size, pre, prej);
+    free(prej);
 }
 
 /** The number of entries a table with precomputed multiples needs to have. */
diff --git a/src/group_impl.h b/src/group_impl.h
index cbd0d8c..a8d0cb2 100644
--- a/src/group_impl.h
+++ b/src/group_impl.h
@@ -85,15 +85,16 @@ static void secp256k1_ge_set_gej_var(secp256k1_ge_t *r, secp256k1_gej_t *a) {
 
 static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t r[len], const secp256k1_gej_t a[len]) {
     size_t count = 0;
-    secp256k1_fe_t az[len];
+    secp256k1_fe_t *az = malloc(sizeof(secp256k1_fe_t) * len);
     for (size_t i=0; i<len; i++) {
         if (!a[i].infinity) {
             az[count++] = a[i].z;
         }
     }
 
-    secp256k1_fe_t azi[count];
+    secp256k1_fe_t *azi = malloc(sizeof(secp256k1_fe_t) * count);
     secp256k1_fe_inv_all_var(count, azi, az);
+    free(az);
 
     count = 0;
     for (size_t i=0; i<len; i++) {
@@ -106,6 +107,7 @@ static void secp256k1_ge_set_all_gej_var(size_t len, secp256k1_ge_t r[len], cons
             secp256k1_fe_mul(&r[i].y, &a[i].y, &zi3);
         }
     }
+    free(azi);
 }
 
 static void secp256k1_gej_set_infinity(secp256k1_gej_t *r) {