From eecc44dab8ad98246b2c4dbedf977113f1874f77 Mon Sep 17 00:00:00 2001
From: Nick Mathewson <nickm@torproject.org>
Date: Thu, 7 Feb 2008 16:10:33 +0000
Subject:  r17963@catbus:  nickm | 2008-02-07 10:14:25 -0500  Be more thorough
 about memory poisoning and clearing.  Add an in-place version of aes_crypt in
 order to remove a memcpy from relay_crypt_one_payload.

svn:r13414
---
 src/common/aes.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

(limited to 'src/common/aes.c')

diff --git a/src/common/aes.c b/src/common/aes.c
index 6dc4896988..cd8317dd11 100644
--- a/src/common/aes.c
+++ b/src/common/aes.c
@@ -289,7 +289,7 @@ aes_crypt(aes_cnt_cipher_t *cipher, const char *input, size_t len,
    * of alignmement, using a bigger buffer, and so on. Not till after 0.1.2.x,
    * though. */
   int c = cipher->pos;
-  if (!len) return;
+  if (PREDICT_UNLIKELY(!len)) return;
 
   while (1) {
     do {
@@ -312,6 +312,42 @@ aes_crypt(aes_cnt_cipher_t *cipher, const char *input, size_t len,
   }
 }
 
+/** Encrypt <b>len</b> bytes from <b>input</b>, storing the results in place.
+ * Uses the key in <b>cipher</b>, and advances the counter by <b>len</b> bytes
+ * as it encrypts.
+ */
+void
+aes_crypt_inplace(aes_cnt_cipher_t *cipher, char *data, size_t len)
+{
+
+  /* XXXX This function is up to 5% of our runtime in some profiles;
+   * we should look into unrolling some of the loops; taking advantage
+   * of alignmement, using a bigger buffer, and so on. Not till after 0.1.2.x,
+   * though. */
+  int c = cipher->pos;
+  if (PREDICT_UNLIKELY(!len)) return;
+
+  while (1) {
+    do {
+      if (len-- == 0) { cipher->pos = c; return; }
+      *(data++) ^= cipher->buf[c];
+    } while (++c != 16);
+    cipher->pos = c = 0;
+    if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 0))) {
+      if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 1))) {
+        if (PREDICT_UNLIKELY(! ++COUNTER(cipher, 2))) {
+          ++COUNTER(cipher, 3);
+          UPDATE_CTR_BUF(cipher, 3);
+        }
+        UPDATE_CTR_BUF(cipher, 2);
+      }
+      UPDATE_CTR_BUF(cipher, 1);
+    }
+    UPDATE_CTR_BUF(cipher, 0);
+    _aes_fill_buf(cipher);
+  }
+}
+
 /** Reset the 128-bit counter of <b>cipher</b> to the 16-bit big-endian value
  * in <b>iv</b>. */
 void
-- 
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