From 6552f55f78145c603da8c08e867606a83f433616 Mon Sep 17 00:00:00 2001
From: Daniel Mendler <mail@daniel-mendler.de>
Date: Mon, 20 May 2019 08:38:25 +0200
Subject: [PATCH] handle EOF condition in mp_fread, fix #163

---
 bn_mp_fread.c   | 25 ++++++++++++++-----------
 tommath_class.h |  2 +-
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/bn_mp_fread.c b/bn_mp_fread.c
index bbb59a5a2..04a13168d 100644
--- a/bn_mp_fread.c
+++ b/bn_mp_fread.c
@@ -9,14 +9,9 @@ mp_err mp_fread(mp_int *a, int radix, FILE *stream)
 {
    mp_err err;
    mp_sign neg;
-   int ch, y;
-   unsigned pos;
-
-   /* clear a */
-   mp_zero(a);
 
    /* if first digit is - then set negative */
-   ch = fgetc(stream);
+   int ch = fgetc(stream);
    if (ch == (int)'-') {
       neg = MP_NEG;
       ch = fgetc(stream);
@@ -24,8 +19,17 @@ mp_err mp_fread(mp_int *a, int radix, FILE *stream)
       neg = MP_ZPOS;
    }
 
-   for (;;) {
-      pos = (unsigned)(ch - (int)'(');
+   /* no digits, return error */
+   if (ch == EOF) {
+      return MP_ERR;
+   }
+
+   /* clear a */
+   mp_zero(a);
+
+   do {
+      int y;
+      unsigned pos = (unsigned)(ch - (int)'(');
       if (mp_s_rmap_reverse_sz < pos) {
          break;
       }
@@ -43,10 +47,9 @@ mp_err mp_fread(mp_int *a, int radix, FILE *stream)
       if ((err = mp_add_d(a, (mp_digit)y, a)) != MP_OKAY) {
          return err;
       }
+   } while ((ch = fgetc(stream)) != EOF);
 
-      ch = fgetc(stream);
-   }
-   if (mp_cmp_d(a, 0uL) != MP_EQ) {
+   if (!mp_iszero(a)) {
       a->sign = neg;
    }
 
diff --git a/tommath_class.h b/tommath_class.h
index f102f1c51..d51c7f8b7 100644
--- a/tommath_class.h
+++ b/tommath_class.h
@@ -398,7 +398,7 @@
 #   define BN_MP_ZERO_C
 #   define BN_MP_MUL_D_C
 #   define BN_MP_ADD_D_C
-#   define BN_MP_CMP_D_C
+#   define BN_MP_ISZERO_C
 #endif
 
 #if defined(BN_MP_FWRITE_C)