1 files changed, 109 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pk_pad/eme_pkcs1/eme_pkcs.cpp b/comm/third_party/botan/src/lib/pk_pad/eme_pkcs1/eme_pkcs.cpp
new file mode 100644
index 0000000000..eac3da5d9a
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pk_pad/eme_pkcs1/eme_pkcs.cpp
@@ -0,0 +1,109 @@
+/*
+* PKCS #1 v1.5 Type 2 (encryption) padding
+* (C) 1999-2007,2015,2016 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/eme_pkcs.h>
+#include <botan/exceptn.h>
+#include <botan/rng.h>
+#include <botan/internal/ct_utils.h>
+
+namespace Botan {
+
+/*
+* PKCS1 Pad Operation
+*/
+secure_vector<uint8_t> EME_PKCS1v15::pad(const uint8_t in[], size_t inlen,
+                                     size_t key_length,
+                                     RandomNumberGenerator& rng) const
+   {
+   key_length /= 8;
+
+   if(inlen > maximum_input_size(key_length * 8))
+      {
+      throw Invalid_Argument("PKCS1: Input is too large");
+      }
+
+   secure_vector<uint8_t> out(key_length);
+
+   out[0] = 0x02;
+   rng.randomize(out.data() + 1, (key_length - inlen - 2));
+
+   for(size_t j = 1; j != key_length - inlen - 1; ++j)
+      {
+      if(out[j] == 0)
+         {
+         out[j] = rng.next_nonzero_byte();
+         }
+      }
+
+   buffer_insert(out, key_length - inlen, in, inlen);
+
+   return out;
+   }
+
+/*
+* PKCS1 Unpad Operation
+*/
+secure_vector<uint8_t> EME_PKCS1v15::unpad(uint8_t& valid_mask,
+                                        const uint8_t in[], size_t inlen) const
+   {
+   /*
+   * RSA decryption pads the ciphertext up to the modulus size, so this only
+   * occurs with very (!) small keys, or when fuzzing.
+   *
+   * 11 bytes == 00,02 + 8 bytes mandatory padding + 00
+   */
+   if(inlen < 11)
+      {
+      valid_mask = false;
+      return secure_vector<uint8_t>();
+      }
+
+   CT::poison(in, inlen);
+
+   CT::Mask<uint8_t> bad_input_m = CT::Mask<uint8_t>::cleared();
+   CT::Mask<uint8_t> seen_zero_m = CT::Mask<uint8_t>::cleared();
+   size_t delim_idx = 2; // initial 0002
+
+   bad_input_m |= ~CT::Mask<uint8_t>::is_equal(in[0], 0);
+   bad_input_m |= ~CT::Mask<uint8_t>::is_equal(in[1], 2);
+
+   for(size_t i = 2; i < inlen; ++i)
+      {
+      const auto is_zero_m = CT::Mask<uint8_t>::is_zero(in[i]);
+      delim_idx += seen_zero_m.if_not_set_return(1);
+      seen_zero_m |= is_zero_m;
+      }
+
+   // no zero delim -> bad padding
+   bad_input_m |= ~seen_zero_m;
+   /*
+   delim indicates < 8 bytes padding -> bad padding
+
+   We require 11 here because we are counting also the 00 delim byte
+   */
+   bad_input_m |= CT::Mask<uint8_t>(CT::Mask<size_t>::is_lt(delim_idx, 11));
+
+   valid_mask = (~bad_input_m).unpoisoned_value();
+   const secure_vector<uint8_t> output = CT::copy_output(bad_input_m, in, inlen, delim_idx);
+
+   CT::unpoison(in, inlen);
+
+   return output;
+   }
+
+/*
+* Return the max input size for a given key size
+*/
+size_t EME_PKCS1v15::maximum_input_size(size_t keybits) const
+   {
+   if(keybits / 8 > 10)
+      return ((keybits / 8) - 10);
+   else
+      return 0;
+   }
+
+}