From beba892bc0d4e4ded4d667ab1d2a94f4d75109a9 Mon Sep 17 00:00:00 2001
From: czurnieden <czurnieden@gmx.de>
Date: Tue, 9 May 2023 17:17:12 +0200
Subject: [PATCH] Fix possible integer overflow

[fsumsal] Slightly altered to make it work with libtommath-1.1.0

---
 bn_mp_2expt.c                | 4 ++++
 bn_mp_grow.c                 | 4 ++++
 bn_mp_init_size.c            | 5 +++++
 bn_mp_mul_2d.c               | 4 ++++
 bn_s_mp_mul_digs.c           | 4 ++++
 bn_s_mp_mul_high_digs.c      | 4 ++++
 8 files changed, 33 insertions(+)

diff --git a/bn_mp_2expt.c b/bn_mp_2expt.c
index 0ae3df1bf..23de0c3c5 100644
--- a/bn_mp_2expt.c
+++ b/bn_mp_2expt.c
@@ -12,6 +12,10 @@ mp_err mp_2expt(mp_int *a, int b)
 {
    int     res;
 
+   if (b < 0) {
+      return MP_VAL;
+   }
+
    /* zero a as per default */
    mp_zero(a);
 
diff --git a/bn_mp_grow.c b/bn_mp_grow.c
index 9e904c547..2b1682651 100644
--- a/bn_mp_grow.c
+++ b/bn_mp_grow.c
@@ -9,6 +9,10 @@ mp_err mp_grow(mp_int *a, int size)
    int     i;
    mp_digit *tmp;
 
+   if (size < 0) {
+      return MP_VAL;
+   }
+
    /* if the alloc size is smaller alloc more ram */
    if (a->alloc < size) {
       /* ensure there are always at least MP_PREC digits extra on top */
diff --git a/bn_mp_init_size.c b/bn_mp_init_size.c
index d62268721..99573833f 100644
--- a/bn_mp_init_size.c
+++ b/bn_mp_init_size.c
@@ -6,6 +6,10 @@
 {
    int x;
 
+   if (size < 0) {
+      return MP_VAL;
+   }
+
    /* pad size so there are always extra digits */
    size += (MP_PREC * 2) - (size % MP_PREC);
 
diff --git a/bn_mp_mul_2d.c b/bn_mp_mul_2d.c
index 87354de20..bfeaf2eb2 100644
--- a/bn_mp_mul_2d.c
+++ b/bn_mp_mul_2d.c
@@ -9,6 +9,10 @@ mp_err mp_mul_2d(const mp_int *a, int b, mp_int *c)
    mp_digit d;
    int      res;
 
+   if (b < 0) {
+      return MP_VAL;
+   }
+
    /* copy */
    if (a != c) {
       if ((res = mp_copy(a, c)) != MP_OKAY) {
diff --git a/bn_s_mp_mul_digs.c b/bn_s_mp_mul_digs.c
index 64509d4cb..3682b4980 100644
--- a/bn_s_mp_mul_digs.c
+++ b/bn_s_mp_mul_digs.c
@@ -16,6 +16,10 @@ mp_err s_mp_mul_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
    mp_word r;
    mp_digit tmpx, *tmpt, *tmpy;
 
+   if (digs < 0) {
+      return MP_VAL;
+   }
+
    /* can we use the fast multiplier? */
    if ((digs < (int)MP_WARRAY) &&
        (MIN(a->used, b->used) <
diff --git a/bn_s_mp_mul_high_digs.c b/bn_s_mp_mul_high_digs.c
index 2bb2a5098..c9dd355f8 100644
--- a/bn_s_mp_mul_high_digs.c
+++ b/bn_s_mp_mul_high_digs.c
@@ -15,6 +15,10 @@ mp_err s_mp_mul_high_digs(const mp_int *a, const mp_int *b, mp_int *c, int digs)
    mp_word r;
    mp_digit tmpx, *tmpt, *tmpy;
 
+   if (digs < 0) {
+      return MP_VAL;
+   }
+
    /* can we use the fast multiplier? */
 #ifdef BN_FAST_S_MP_MUL_HIGH_DIGS_C
    if (((a->used + b->used + 1) < (int)MP_WARRAY)