path: root/main/botan/CVE-2021-24115.patch

From 8f7846f60b2bee43990a27f4e725980742bbb48f Mon Sep 17 00:00:00 2001
From: Jack Lloyd <jack@randombit.net>
Date: Tue, 15 Dec 2020 06:59:08 -0500
Subject: [PATCH] Backport of #2543 to release-2

---
 src/lib/codec/base32/base32.cpp | 167 ++++++++++++++++---------------
 src/lib/codec/base58/base58.cpp | 129 +++++++++++++-----------
 src/lib/codec/base64/base64.cpp | 172 ++++++++++++++++++--------------
 src/lib/codec/hex/hex.cpp       | 107 ++++++++++----------
 src/lib/utils/ct_utils.h        |  24 +++++
 5 files changed, 332 insertions(+), 267 deletions(-)

diff --git a/src/lib/codec/base32/base32.cpp b/src/lib/codec/base32/base32.cpp
index fc9883c86..224dae991 100644
--- a/src/lib/codec/base32/base32.cpp
+++ b/src/lib/codec/base32/base32.cpp
@@ -1,7 +1,7 @@
 /*
 * Base32 Encoding and Decoding
 * (C) 2018 Erwan Chaussy
-* (C) 2018 Jack Lloyd
+* (C) 2018,2020 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -9,6 +9,7 @@
 #include <botan/base32.h>
 #include <botan/internal/codec_base.h>
 #include <botan/internal/rounding.h>
+#include <botan/internal/ct_utils.h>
 
 namespace Botan {
 
@@ -58,45 +59,11 @@ class Base32 final
          return (round_up(input_length, m_encoding_bytes_out) * m_encoding_bytes_in) / m_encoding_bytes_out;
          }
 
-      static void encode(char out[8], const uint8_t in[5]) noexcept
-         {
-         out[0] = Base32::m_bin_to_base32[(in[0] & 0xF8) >> 3];
-         out[1] = Base32::m_bin_to_base32[((in[0] & 0x07) << 2) | (in[1] >> 6)];
-         out[2] = Base32::m_bin_to_base32[((in[1] & 0x3E) >> 1)];
-         out[3] = Base32::m_bin_to_base32[((in[1] & 0x01) << 4) | (in[2] >> 4)];
-         out[4] = Base32::m_bin_to_base32[((in[2] & 0x0F) << 1) | (in[3] >> 7)];
-         out[5] = Base32::m_bin_to_base32[((in[3] & 0x7C) >> 2)];
-         out[6] = Base32::m_bin_to_base32[((in[3] & 0x03) << 3) | (in[4] >> 5)];
-         out[7] = Base32::m_bin_to_base32[in[4] & 0x1F];
-         }
+      static void encode(char out[8], const uint8_t in[5]) noexcept;
 
-      static inline uint8_t lookup_binary_value(char input) noexcept
-         {
-         return Base32::m_base32_to_bin[static_cast<uint8_t>(input)];
-         }
+      static uint8_t lookup_binary_value(char input) noexcept;
 
-      static inline bool check_bad_char(uint8_t bin, char input, bool ignore_ws)
-         {
-         if(bin <= 0x1F)
-            {
-            return true;
-            }
-         else if(!(bin == 0x81 || (bin == 0x80 && ignore_ws)))
-            {
-            std::string bad_char(1, input);
-            if(bad_char == "\t")
-               { bad_char = "\\t"; }
-            else if(bad_char == "\n")
-               { bad_char = "\\n"; }
-            else if(bad_char == "\r")
-               { bad_char = "\\r"; }
-
-            throw Invalid_Argument(
-               std::string("base32_decode: invalid base32 character '") +
-               bad_char + "'");
-            }
-         return false;
-         }
+      static bool check_bad_char(uint8_t bin, char input, bool ignore_ws);
 
       static void decode(uint8_t* out_ptr, const uint8_t decode_buf[8])
          {
@@ -116,55 +83,97 @@ class Base32 final
       static const size_t m_encoding_bits = 5;
       static const size_t m_remaining_bits_before_padding = 6;
 
-
       static const size_t m_encoding_bytes_in = 5;
       static const size_t m_encoding_bytes_out = 8;
+   };
 
+namespace {
 
-      static const uint8_t m_bin_to_base32[32];
-      static const uint8_t m_base32_to_bin[256];
-   };
+char lookup_base32_char(uint8_t x)
+   {
+   BOTAN_DEBUG_ASSERT(x < 32);
+
+   const auto in_AZ = CT::Mask<uint8_t>::is_lt(x, 26);
+
+   const char c_AZ = 'A' + x;
+   const char c_27 = '2' + (x - 26);
+
+   return in_AZ.select(c_AZ, c_27);
+   }
+
+}
 
-const uint8_t Base32::m_bin_to_base32[32] =
+//static
+void Base32::encode(char out[8], const uint8_t in[5]) noexcept
    {
-   'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
-   'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
-   '2', '3', '4', '5', '6', '7'
-   };
+   const uint8_t b0 = (in[0] & 0xF8) >> 3;
+   const uint8_t b1 = ((in[0] & 0x07) << 2) | (in[1] >> 6);
+   const uint8_t b2 = ((in[1] & 0x3E) >> 1);
+   const uint8_t b3 = ((in[1] & 0x01) << 4) | (in[2] >> 4);
+   const uint8_t b4 = ((in[2] & 0x0F) << 1) | (in[3] >> 7);
+   const uint8_t b5 = ((in[3] & 0x7C) >> 2);
+   const uint8_t b6 = ((in[3] & 0x03) << 3) | (in[4] >> 5);
+   const uint8_t b7 = in[4] & 0x1F;
+
+   out[0] = lookup_base32_char(b0);
+   out[1] = lookup_base32_char(b1);
+   out[2] = lookup_base32_char(b2);
+   out[3] = lookup_base32_char(b3);
+   out[4] = lookup_base32_char(b4);
+   out[5] = lookup_base32_char(b5);
+   out[6] = lookup_base32_char(b6);
+   out[7] = lookup_base32_char(b7);
+   }
 
-/*
-* base32 Decoder Lookup Table
-* Warning: assumes ASCII encodings
-*/
-const uint8_t Base32::m_base32_to_bin[256] =
+//static
+uint8_t Base32::lookup_binary_value(char input) noexcept
    {
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80,
-   0x80, 0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0x81, 0xFF, 0xFF, 0xFF, 0x00, 0x01, 0x02, 0x03, 0x04,
-   0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
-   0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
-   0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
-   };
+   const uint8_t c = static_cast<uint8_t>(input);
+
+   const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('Z'));
+   const auto is_decimal     = CT::Mask<uint8_t>::is_within_range(c, uint8_t('2'), uint8_t('7'));
+
+   const auto is_equal       = CT::Mask<uint8_t>::is_equal(c, uint8_t('='));
+   const auto is_whitespace  = CT::Mask<uint8_t>::is_any_of(c, {
+         uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
+      });
+
+   const uint8_t c_upper = c - uint8_t('A');
+   const uint8_t c_decim = c - uint8_t('2') + 26;
+
+   uint8_t ret = 0xFF; // default value
+
+   ret = is_alpha_upper.select(c_upper, ret);
+   ret = is_decimal.select(c_decim, ret);
+   ret = is_equal.select(0x81, ret);
+   ret = is_whitespace.select(0x80, ret);
+
+   return ret;
+   }
+
+//static
+bool Base32::check_bad_char(uint8_t bin, char input, bool ignore_ws)
+   {
+   if(bin <= 0x1F)
+      {
+      return true;
+      }
+   else if(!(bin == 0x81 || (bin == 0x80 && ignore_ws)))
+      {
+      std::string bad_char(1, input);
+      if(bad_char == "\t")
+         { bad_char = "\\t"; }
+      else if(bad_char == "\n")
+         { bad_char = "\\n"; }
+      else if(bad_char == "\r")
+         { bad_char = "\\r"; }
+
+      throw Invalid_Argument(
+         std::string("base32_decode: invalid base32 character '") +
+         bad_char + "'");
+      }
+   return false;
+   }
 
 }
 
diff --git a/src/lib/codec/base58/base58.cpp b/src/lib/codec/base58/base58.cpp
index 5aa9441d3..a6d509012 100644
--- a/src/lib/codec/base58/base58.cpp
+++ b/src/lib/codec/base58/base58.cpp
@@ -1,5 +1,5 @@
 /*
-* (C) 2018 Jack Lloyd
+* (C) 2018,2020 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -9,6 +9,7 @@
 #include <botan/bigint.h>
 #include <botan/divide.h>
 #include <botan/loadstor.h>
+#include <botan/internal/ct_utils.h>
 #include <botan/hash.h>
 
 namespace Botan {
@@ -30,73 +31,52 @@ uint32_t sha256_d_checksum(const uint8_t input[], size_t input_length)
    return load_be<uint32_t>(checksum.data(), 0);
    }
 
-class Character_Table
+char lookup_base58_char(uint8_t x)
    {
-   public:
-      // This must be a literal constant
-      Character_Table(const char* alphabet) :
-         m_alphabet(alphabet)
-         {
-         const size_t alpha_len = std::strlen(alphabet);
-
-         // 128 or up would flow into 0x80 invalid bit
-         if(alpha_len == 0 || alpha_len >= 128)
-            throw Invalid_Argument("Bad Character_Table string");
-
-         m_alphabet_len = static_cast<uint8_t>(alpha_len);
-
-         set_mem(m_tab, 256, 0x80);
-
-         for(size_t i = 0; m_alphabet[i]; ++i)
-            {
-            const uint8_t b = static_cast<uint8_t>(m_alphabet[i]);
-            BOTAN_ASSERT(m_tab[b] == 0x80, "No duplicate chars");
-            m_tab[b] = static_cast<uint8_t>(i);
-            }
-         }
-
-      uint8_t radix() const { return m_alphabet_len; }
-
-      char operator[](size_t i) const
-         {
-         BOTAN_ASSERT(i < m_alphabet_len, "Character in range");
-         return m_alphabet[i];
-         }
-
-      uint8_t code_for(char c) const
-         {
-         return m_tab[static_cast<uint8_t>(c)];
-         }
-
-   private:
-      const char* m_alphabet;
-      uint8_t m_alphabet_len;
-      uint8_t m_tab[256];
-   };
-
-static const Character_Table& BASE58_ALPHA()
-   {
-   static const Character_Table base58_alpha("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz");
-   return base58_alpha;
+   // "123456789 ABCDEFGH JKLMN PQRSTUVWXYZ abcdefghijk mnopqrstuvwxyz"
+   BOTAN_DEBUG_ASSERT(x < 58);
+
+   const auto is_dec_19      = CT::Mask<uint8_t>::is_lte(x, 8);
+   const auto is_alpha_AH    = CT::Mask<uint8_t>::is_within_range(x, 9, 16);
+   const auto is_alpha_JN    = CT::Mask<uint8_t>::is_within_range(x, 17, 21);
+   const auto is_alpha_PZ    = CT::Mask<uint8_t>::is_within_range(x, 22, 32);
+   const auto is_alpha_ak    = CT::Mask<uint8_t>::is_within_range(x, 33, 43);
+   // otherwise in 'm'-'z'
+
+   const char c_19 = '1' + x;
+   const char c_AH = 'A' + (x - 9);
+   const char c_JN = 'J' + (x - 17);
+   const char c_PZ = 'P' + (x - 22);
+   const char c_ak = 'a' + (x - 33);
+   const char c_mz = 'm' + (x - 44);
+
+   char ret = c_mz;
+   ret = is_dec_19.select(c_19, ret);
+   ret = is_alpha_AH.select(c_AH, ret);
+   ret = is_alpha_JN.select(c_JN, ret);
+   ret = is_alpha_PZ.select(c_PZ, ret);
+   ret = is_alpha_ak.select(c_ak, ret);
+
+   return ret;
    }
 
 std::string base58_encode(BigInt v, size_t leading_zeros)
    {
-   const auto base58 = BASE58_ALPHA();
+   const uint8_t radix = 58;
 
    std::string result;
    BigInt q;
-   uint8_t r;
 
    while(v.is_nonzero())
       {
-      ct_divide_u8(v, base58.radix(), q, r);
-      result.push_back(base58[r]);
+      uint8_t r;
+      ct_divide_u8(v, radix, q, r);
+      result.push_back(lookup_base58_char(r));
       v.swap(q);
       }
 
    for(size_t i = 0; i != leading_zeros; ++i)
-      result.push_back(base58[0]);
+      result.push_back('1'); // 'zero' byte
 
    return std::string(result.rbegin(), result.rend());
    }
@@ -112,6 +92,39 @@ size_t count_leading_zeros(const T input[], size_t input_length, Z zero)
    return leading_zeros;
    }
 
+uint8_t base58_value_of(char input)
+   {
+   // "123456789 ABCDEFGH JKLMN PQRSTUVWXYZ abcdefghijk mnopqrstuvwxyz"
+
+   const uint8_t c = static_cast<uint8_t>(input);
+
+   const auto is_dec_19      = CT::Mask<uint8_t>::is_within_range(c, uint8_t('1'), uint8_t('9'));
+   const auto is_alpha_AH    = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('H'));
+   const auto is_alpha_JN    = CT::Mask<uint8_t>::is_within_range(c, uint8_t('J'), uint8_t('N'));
+   const auto is_alpha_PZ    = CT::Mask<uint8_t>::is_within_range(c, uint8_t('P'), uint8_t('Z'));
+
+   const auto is_alpha_ak    = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('k'));
+   const auto is_alpha_mz    = CT::Mask<uint8_t>::is_within_range(c, uint8_t('m'), uint8_t('z'));
+
+   const uint8_t c_dec_19 = c - uint8_t('1');
+   const uint8_t c_AH     = c - uint8_t('A') + 9;
+   const uint8_t c_JN     = c - uint8_t('J') + 17;
+   const uint8_t c_PZ     = c - uint8_t('P') + 22;
+
+   const uint8_t c_ak     = c - uint8_t('a') + 33;
+   const uint8_t c_mz     = c - uint8_t('m') + 44;
+
+   uint8_t ret = 0xFF; // default value
+
+   ret = is_dec_19.select(c_dec_19, ret);
+   ret = is_alpha_AH.select(c_AH, ret);
+   ret = is_alpha_JN.select(c_JN, ret);
+   ret = is_alpha_PZ.select(c_PZ, ret);
+   ret = is_alpha_ak.select(c_ak, ret);
+   ret = is_alpha_mz.select(c_mz, ret);
+   return ret;
+   }
+
 }
 
 std::string base58_encode(const uint8_t input[], size_t input_length)
@@ -130,9 +143,7 @@ std::string base58_check_encode(const uint8_t input[], size_t input_length)
 
 std::vector<uint8_t> base58_decode(const char input[], size_t input_length)
    {
-   const auto base58 = BASE58_ALPHA();
-
-   const size_t leading_zeros = count_leading_zeros(input, input_length, base58[0]);
+   const size_t leading_zeros = count_leading_zeros(input, input_length, '1');
 
    BigInt v;
 
@@ -143,12 +154,12 @@ std::vector<uint8_t> base58_decode(const char input[], size_t input_length)
       if(c == ' ' || c == '\n')
          continue;
 
-      const size_t idx = base58.code_for(c);
+      const uint8_t idx = base58_value_of(c);
 
-      if(idx == 0x80)
+      if(idx == 0xFF)
          throw Decoding_Error("Invalid base58");
 
-      v *= base58.radix();
+      v *= 58;
       v += idx;
       }
 
diff --git a/src/lib/codec/base64/base64.cpp b/src/lib/codec/base64/base64.cpp
index b4f78bca0..bb286cc6e 100644
--- a/src/lib/codec/base64/base64.cpp
+++ b/src/lib/codec/base64/base64.cpp
@@ -1,6 +1,6 @@
 /*
 * Base64 Encoding and Decoding
-* (C) 2010,2015 Jack Lloyd
+* (C) 2010,2015,2020 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -9,6 +9,7 @@
 #include <botan/internal/codec_base.h>
 #include <botan/exceptn.h>
 #include <botan/internal/rounding.h>
+#include <botan/internal/ct_utils.h>
 
 namespace Botan {
 
@@ -58,41 +59,11 @@ class Base64 final
          return (round_up(input_length, m_encoding_bytes_out) * m_encoding_bytes_in) / m_encoding_bytes_out;
          }
 
-      static void encode(char out[8], const uint8_t in[5]) noexcept
-         {
-         out[0] = Base64::m_bin_to_base64[(in[0] & 0xFC) >> 2];
-         out[1] = Base64::m_bin_to_base64[((in[0] & 0x03) << 4) | (in[1] >> 4)];
-         out[2] = Base64::m_bin_to_base64[((in[1] & 0x0F) << 2) | (in[2] >> 6)];
-         out[3] = Base64::m_bin_to_base64[in[2] & 0x3F];
-         }
+      static void encode(char out[8], const uint8_t in[5]) noexcept;
 
-      static inline uint8_t lookup_binary_value(char input) noexcept
-         {
-         return Base64::m_base64_to_bin[static_cast<uint8_t>(input)];
-         }
+      static uint8_t lookup_binary_value(char input) noexcept;
 
-      static inline bool check_bad_char(uint8_t bin, char input, bool ignore_ws)
-         {
-         if(bin <= 0x3F)
-            {
-            return true;
-            }
-         else if(!(bin == 0x81 || (bin == 0x80 && ignore_ws)))
-            {
-            std::string bad_char(1, input);
-            if(bad_char == "\t")
-               { bad_char = "\\t"; }
-            else if(bad_char == "\n")
-               { bad_char = "\\n"; }
-            else if(bad_char == "\r")
-               { bad_char = "\\r"; }
-
-            throw Invalid_Argument(
-               std::string("base64_decode: invalid base64 character '") +
-               bad_char + "'");
-            }
-         return false;
-         }
+      static bool check_bad_char(uint8_t bin, char input, bool ignore_ws);
 
       static void decode(uint8_t* out_ptr, const uint8_t decode_buf[4])
          {
@@ -110,57 +81,104 @@ class Base64 final
       static const size_t m_encoding_bits = 6;
       static const size_t m_remaining_bits_before_padding = 8;
 
-
       static const size_t m_encoding_bytes_in = 3;
       static const size_t m_encoding_bytes_out = 4;
+   };
 
+char lookup_base64_char(uint8_t x)
+   {
+   BOTAN_DEBUG_ASSERT(x < 64);
+
+   const auto in_az = CT::Mask<uint8_t>::is_within_range(x, 26, 51);
+   const auto in_09 = CT::Mask<uint8_t>::is_within_range(x, 52, 61);
+   const auto eq_plus = CT::Mask<uint8_t>::is_equal(x, 62);
+   const auto eq_slash = CT::Mask<uint8_t>::is_equal(x, 63);
+
+   const char c_AZ = 'A' + x;
+   const char c_az = 'a' + (x - 26);
+   const char c_09 = '0' + (x - 2*26);
+   const char c_plus = '+';
+   const char c_slash = '/';
+
+   char ret = c_AZ;
+   ret = in_az.select(c_az, ret);
+   ret = in_09.select(c_09, ret);
+   ret = eq_plus.select(c_plus, ret);
+   ret = eq_slash.select(c_slash, ret);
+
+   return ret;
+   }
 
-      static const uint8_t m_bin_to_base64[64];
-      static const uint8_t m_base64_to_bin[256];
-   };
+//static
+void Base64::encode(char out[8], const uint8_t in[5]) noexcept
+   {
+   const uint8_t b0 = (in[0] & 0xFC) >> 2;
+   const uint8_t b1 = ((in[0] & 0x03) << 4) | (in[1] >> 4);
+   const uint8_t b2 = ((in[1] & 0x0F) << 2) | (in[2] >> 6);
+   const uint8_t b3 = in[2] & 0x3F;
+   out[0] = lookup_base64_char(b0);
+   out[1] = lookup_base64_char(b1);
+   out[2] = lookup_base64_char(b2);
+   out[3] = lookup_base64_char(b3);
+   }
 
-const uint8_t Base64::m_bin_to_base64[64] =
+//static
+uint8_t Base64::lookup_binary_value(char input) noexcept
    {
-   'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
-   'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
-   'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
-   'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
-   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
-   };
+   const uint8_t c = static_cast<uint8_t>(input);
+   const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('Z'));
+   const auto is_alpha_lower = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('z'));
+   const auto is_decimal     = CT::Mask<uint8_t>::is_within_range(c, uint8_t('0'), uint8_t('9'));
+
+   const auto is_plus        = CT::Mask<uint8_t>::is_equal(c, uint8_t('+'));
+   const auto is_slash       = CT::Mask<uint8_t>::is_equal(c, uint8_t('/'));
+   const auto is_equal       = CT::Mask<uint8_t>::is_equal(c, uint8_t('='));
+
+   const auto is_whitespace  = CT::Mask<uint8_t>::is_any_of(c, {
+         uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
+      });
+
+   const uint8_t c_upper = c - uint8_t('A');
+   const uint8_t c_lower = c - uint8_t('a') + 26;
+   const uint8_t c_decim = c - uint8_t('0') + 2*26;
+
+   uint8_t ret = 0xFF; // default value
+
+   ret = is_alpha_upper.select(c_upper, ret);
+   ret = is_alpha_lower.select(c_lower, ret);
+   ret = is_decimal.select(c_decim, ret);
+   ret = is_plus.select(62, ret);
+   ret = is_slash.select(63, ret);
+   ret = is_equal.select(0x81, ret);
+   ret = is_whitespace.select(0x80, ret);
+
+   return ret;
+   }
 
-/*
-* base64 Decoder Lookup Table
-* Warning: assumes ASCII encodings
-*/
-const uint8_t Base64::m_base64_to_bin[256] =
+//static
+bool Base64::check_bad_char(uint8_t bin, char input, bool ignore_ws)
    {
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80,
-   0x80, 0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0x3E, 0xFF, 0xFF, 0xFF, 0x3F, 0x34, 0x35,
-   0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0xFF, 0xFF,
-   0xFF, 0x81, 0xFF, 0xFF, 0xFF, 0x00, 0x01, 0x02, 0x03, 0x04,
-   0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
-   0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
-   0x19, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x1A, 0x1B, 0x1C,
-   0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26,
-   0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, 0x30,
-   0x31, 0x32, 0x33, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-   0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF
-   };
+   if(bin <= 0x3F)
+      {
+      return true;
+      }
+   else if(!(bin == 0x81 || (bin == 0x80 && ignore_ws)))
+      {
+      std::string bad_char(1, input);
+      if(bad_char == "\t")
+         { bad_char = "\\t"; }
+      else if(bad_char == "\n")
+         { bad_char = "\\n"; }
+      else if(bad_char == "\r")
+         { bad_char = "\\r"; }
+
+      throw Invalid_Argument(
+         std::string("base64_decode: invalid base64 character '") +
+         bad_char + "'");
+      }
+   return false;
+   }
+
 }
 
 size_t base64_encode(char out[],
diff --git a/src/lib/codec/hex/hex.cpp b/src/lib/codec/hex/hex.cpp
index 6bbd7c28e..1ae21f398 100644
--- a/src/lib/codec/hex/hex.cpp
+++ b/src/lib/codec/hex/hex.cpp
@@ -1,6 +1,6 @@
 /*
 * Hex Encoding and Decoding
-* (C) 2010 Jack Lloyd
+* (C) 2010,2020 Jack Lloyd
 *
 * Botan is released under the Simplified BSD License (see license.txt)
 */
@@ -8,29 +8,38 @@
 #include <botan/hex.h>
 #include <botan/mem_ops.h>
 #include <botan/exceptn.h>
+#include <botan/internal/ct_utils.h>
 
 namespace Botan {
 
+namespace {
+
+char hex_encode_nibble(uint8_t n, bool uppercase)
+   {
+   BOTAN_DEBUG_ASSERT(n <= 15);
+
+   const auto in_09 = CT::Mask<uint8_t>::is_lt(n, 10);
+
+   const char c_09 = n + '0';
+   const char c_af = n + (uppercase ? 'A' : 'a') - 10;
+
+   return in_09.select(c_09, c_af);
+   }
+
+}
+
 void hex_encode(char output[],
                 const uint8_t input[],
                 size_t input_length,
                 bool uppercase)
    {
-   static const uint8_t BIN_TO_HEX_UPPER[16] = {
-      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-      'A', 'B', 'C', 'D', 'E', 'F' };
-
-   static const uint8_t BIN_TO_HEX_LOWER[16] = {
-      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
-      'a', 'b', 'c', 'd', 'e', 'f' };
-
-   const uint8_t* tbl = uppercase ? BIN_TO_HEX_UPPER : BIN_TO_HEX_LOWER;
-
    for(size_t i = 0; i != input_length; ++i)
       {
-      uint8_t x = input[i];
-      output[2*i  ] = tbl[(x >> 4) & 0x0F];
-      output[2*i+1] = tbl[(x     ) & 0x0F];
+      const uint8_t n0 = (input[i] >> 4) & 0xF;
+      const uint8_t n1 = (input[i]     ) & 0xF;
+
+      output[2*i  ] = hex_encode_nibble(n0, uppercase);
+      output[2*i+1] = hex_encode_nibble(n1, uppercase);
       }
    }
 
@@ -46,49 +55,43 @@ std::string hex_encode(const uint8_t input[],
    return output;
    }
 
+namespace {
+
+uint8_t hex_char_to_bin(char input)
+   {
+   const uint8_t c = static_cast<uint8_t>(input);
+
+   const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('F'));
+   const auto is_alpha_lower = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('f'));
+   const auto is_decimal     = CT::Mask<uint8_t>::is_within_range(c, uint8_t('0'), uint8_t('9'));
+
+   const auto is_whitespace  = CT::Mask<uint8_t>::is_any_of(c, {
+         uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
+      });
+
+   const uint8_t c_upper = c - uint8_t('A') + 10;
+   const uint8_t c_lower = c - uint8_t('a') + 10;
+   const uint8_t c_decim = c - uint8_t('0');
+
+   uint8_t ret = 0xFF; // default value
+
+   ret = is_alpha_upper.select(c_upper, ret);
+   ret = is_alpha_lower.select(c_lower, ret);
+   ret = is_decimal.select(c_decim, ret);
+   ret = is_whitespace.select(0x80, ret);
+
+   return ret;
+   }
+
+}
+
+
 size_t hex_decode(uint8_t output[],
                   const char input[],
                   size_t input_length,
                   size_t& input_consumed,
                   bool ignore_ws)
    {
-   /*
-   * Mapping of hex characters to either their binary equivalent
-   * or to an error code.
-   *  If valid hex (0-9 A-F a-f), the value.
-   *  If whitespace, then 0x80
-   *  Otherwise 0xFF
-   * Warning: this table assumes ASCII character encodings
-   */
-
-   static const uint8_t HEX_TO_BIN[256] = {
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x80,
-      0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0x80, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00, 0x01,
-      0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
-      0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x0A, 0x0B, 0x0C,
-      0x0D, 0x0E, 0x0F, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
-      0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
-
    uint8_t* out_ptr = output;
    bool top_nibble = true;
 
@@ -96,7 +99,7 @@ size_t hex_decode(uint8_t output[],
 
    for(size_t i = 0; i != input_length; ++i)
       {
-      const uint8_t bin = HEX_TO_BIN[static_cast<uint8_t>(input[i])];
+      const uint8_t bin = hex_char_to_bin(input[i]);
 
       if(bin >= 0x10)
          {
diff --git a/src/lib/utils/ct_utils.h b/src/lib/utils/ct_utils.h
index 17737a97c..f2e745293 100644
--- a/src/lib/utils/ct_utils.h
+++ b/src/lib/utils/ct_utils.h
@@ -183,6 +183,30 @@ class Mask
          return ~Mask<T>::is_lt(x, y);
          }
 
+      static Mask<T> is_within_range(T v, T l, T u)
+         {
+         //return Mask<T>::is_gte(v, l) & Mask<T>::is_lte(v, u);
+
+         const T v_lt_l = v^((v^l) | ((v-l)^v));
+         const T v_gt_u = u^((u^v) | ((u-v)^u));
+         const T either = v_lt_l | v_gt_u;
+         return ~Mask<T>(expand_top_bit(either));
+         }
+
+      static Mask<T> is_any_of(T v, std::initializer_list<T> accepted)
+         {
+         T accept = 0;
+
+         for(auto a: accepted)
+            {
+            const T diff = a ^ v;
+            const T eq_zero = ~diff & (diff - 1);
+            accept |= eq_zero;
+            }
+
+         return Mask<T>(expand_top_bit(accept));
+         }
+
       /**
       * AND-combine two masks
       */
-- 
2.31.1