From 8eee90fd9ac2eae47418005c5e213ccd4b72b50d Mon Sep 17 00:00:00 2001
From: Pavol Rusnak <pavol@rusnak.io>
Date: Sun, 29 Sep 2019 08:46:21 +0000
Subject: [PATCH] crypto: sync base58.c with upstream

---
 crypto/base58.c | 71 +++++++++++++++++++++++++------------------------
 1 file changed, 36 insertions(+), 35 deletions(-)

diff --git a/crypto/base58.c b/crypto/base58.c
index d3a1ddb7e..2d0fa514c 100644
--- a/crypto/base58.c
+++ b/crypto/base58.c
@@ -24,7 +24,6 @@
 #include "base58.h"
 #include <stdbool.h>
 #include <string.h>
-#include <sys/types.h>
 #include "memzero.h"
 #include "ripemd160.h"
 #include "sha2.h"
@@ -41,6 +40,12 @@ const int8_t b58digits_map[] = {
     49, 50, 51, 52, 53, 54, 55, 56, 57, -1, -1, -1, -1, -1,
 };
 
+typedef uint64_t b58_maxint_t;
+typedef uint32_t b58_almostmaxint_t;
+#define b58_almostmaxint_bits (sizeof(b58_almostmaxint_t) * 8)
+static const b58_almostmaxint_t b58_almostmaxint_mask =
+    ((((b58_maxint_t)1) << b58_almostmaxint_bits) - 1);
+
 bool b58tobin(void *bin, size_t *binszp, const char *b58) {
   size_t binsz = *binszp;
 
@@ -50,17 +55,18 @@ bool b58tobin(void *bin, size_t *binszp, const char *b58) {
 
   const unsigned char *b58u = (const unsigned char *)b58;
   unsigned char *binu = bin;
-  size_t outisz = (binsz + 3) / 4;
-  uint32_t outi[outisz];
-  uint64_t t;
-  uint32_t c;
+  size_t outisz =
+      (binsz + sizeof(b58_almostmaxint_t) - 1) / sizeof(b58_almostmaxint_t);
+  b58_almostmaxint_t outi[outisz];
+  b58_maxint_t t;
+  b58_almostmaxint_t c;
   size_t i, j;
-  uint8_t bytesleft = binsz % 4;
-  uint32_t zeromask = bytesleft ? (0xffffffff << (bytesleft * 8)) : 0;
+  uint8_t bytesleft = binsz % sizeof(b58_almostmaxint_t);
+  b58_almostmaxint_t zeromask =
+      bytesleft ? (b58_almostmaxint_mask << (bytesleft * 8)) : 0;
   unsigned zerocount = 0;
-  size_t b58sz;
 
-  b58sz = strlen(b58);
+  size_t b58sz = strlen(b58);
 
   memzero(outi, sizeof(outi));
 
@@ -76,9 +82,9 @@ bool b58tobin(void *bin, size_t *binszp, const char *b58) {
       return false;
     c = (unsigned)b58digits_map[b58u[i]];
     for (j = outisz; j--;) {
-      t = ((uint64_t)outi[j]) * 58 + c;
-      c = (t & 0x3f00000000) >> 32;
-      outi[j] = t & 0xffffffff;
+      t = ((b58_maxint_t)outi[j]) * 58 + c;
+      c = t >> b58_almostmaxint_bits;
+      outi[j] = t & b58_almostmaxint_mask;
     }
     if (c)
       // Output number too big (carry to the next int32)
@@ -89,26 +95,17 @@ bool b58tobin(void *bin, size_t *binszp, const char *b58) {
   }
 
   j = 0;
-  switch (bytesleft) {
-    case 3:
-      *(binu++) = (outi[0] & 0xff0000) >> 16;
-      //-fallthrough
-    case 2:
-      *(binu++) = (outi[0] & 0xff00) >> 8;
-      //-fallthrough
-    case 1:
-      *(binu++) = (outi[0] & 0xff);
-      ++j;
-      //-fallthrough
-    default:
-      break;
+  if (bytesleft) {
+    for (i = bytesleft; i > 0; --i) {
+      *(binu++) = (outi[0] >> (8 * (i - 1))) & 0xff;
+    }
+    ++j;
   }
 
   for (; j < outisz; ++j) {
-    *(binu++) = (outi[j] >> 0x18) & 0xff;
-    *(binu++) = (outi[j] >> 0x10) & 0xff;
-    *(binu++) = (outi[j] >> 8) & 0xff;
-    *(binu++) = (outi[j] >> 0) & 0xff;
+    for (i = sizeof(*outi); i > 0; --i) {
+      *(binu++) = (outi[j] >> (8 * (i - 1))) & 0xff;
+    }
   }
 
   // Count canonical base58 byte count
@@ -119,6 +116,7 @@ bool b58tobin(void *bin, size_t *binszp, const char *b58) {
         /* result too large */
         return false;
       }
+
       break;
     }
     --*binszp;
@@ -149,24 +147,28 @@ int b58check(const void *bin, size_t binsz, HasherType hasher_type,
 bool b58enc(char *b58, size_t *b58sz, const void *data, size_t binsz) {
   const uint8_t *bin = data;
   int carry;
-  ssize_t i, j, high, zcount = 0;
+  size_t i, j, high, zcount = 0;
   size_t size;
 
-  while (zcount < (ssize_t)binsz && !bin[zcount]) ++zcount;
+  while (zcount < binsz && !bin[zcount]) ++zcount;
 
   size = (binsz - zcount) * 138 / 100 + 1;
   uint8_t buf[size];
   memzero(buf, size);
 
-  for (i = zcount, high = size - 1; i < (ssize_t)binsz; ++i, high = j) {
+  for (i = zcount, high = size - 1; i < binsz; ++i, high = j) {
     for (carry = bin[i], j = size - 1; (j > high) || carry; --j) {
       carry += 256 * buf[j];
       buf[j] = carry % 58;
       carry /= 58;
+      if (!j) {
+        // Otherwise j wraps to maxint which is > high
+        break;
+      }
     }
   }
 
-  for (j = 0; j < (ssize_t)size && !buf[j]; ++j)
+  for (j = 0; j < size && !buf[j]; ++j)
     ;
 
   if (*b58sz <= zcount + size - j) {
@@ -175,8 +177,7 @@ bool b58enc(char *b58, size_t *b58sz, const void *data, size_t binsz) {
   }
 
   if (zcount) memset(b58, '1', zcount);
-  for (i = zcount; j < (ssize_t)size; ++i, ++j)
-    b58[i] = b58digits_ordered[buf[j]];
+  for (i = zcount; j < size; ++i, ++j) b58[i] = b58digits_ordered[buf[j]];
   b58[i] = '\0';
   *b58sz = i + 1;