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Changed AesGcmEncrypt and Decrypt to allow the same pointer to write and read buffers.

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This commit is contained in:
John Safranek 2012-06-26 09:29:48 -07:00
parent 918ea3a074
commit 737cd127e8
1 changed files with 14 additions and 12 deletions
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26
ctaocrypt/src/aes.c
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@ -1551,6 +1551,7 @@ void AesGcmEncrypt(Aes* aes, byte* out, const byte* in, word32 sz,
byte* c = out;
byte h[AES_BLOCK_SIZE];
byte ctr[AES_BLOCK_SIZE];
byte scratch[AES_BLOCK_SIZE];
CYASSL_ENTER("AesGcmEncrypt");
@ -1565,19 +1566,18 @@ void AesGcmEncrypt(Aes* aes, byte* out, const byte* in, word32 sz,
while (blocks--) {
IncrementGcmCounter(ctr);
AesEncrypt(aes, ctr, c);
xorbuf(c, p, AES_BLOCK_SIZE);
AesEncrypt(aes, ctr, scratch);
xorbuf(scratch, p, AES_BLOCK_SIZE);
XMEMCPY(c, scratch, AES_BLOCK_SIZE);
p += AES_BLOCK_SIZE;
c += AES_BLOCK_SIZE;
}
if (partial != 0) {
byte cPartial[AES_BLOCK_SIZE];
IncrementGcmCounter(ctr);
AesEncrypt(aes, ctr, cPartial);
XMEMCPY(c, cPartial, partial);
xorbuf(c, p, partial);
AesEncrypt(aes, ctr, scratch);
xorbuf(scratch, p, partial);
XMEMCPY(c, scratch, partial);
}
GHASH(h, authIn, authInSz, out, sz, authTag, authTagSz);
InitGcmCounter(ctr);
@ -1596,6 +1596,7 @@ int AesGcmDecrypt(Aes* aes, byte* out, const byte* in, word32 sz,
byte* p = out;
byte h[AES_BLOCK_SIZE];
byte ctr[AES_BLOCK_SIZE];
byte scratch[AES_BLOCK_SIZE];
CYASSL_ENTER("AesGcmDecrypt");
@ -1624,8 +1625,9 @@ int AesGcmDecrypt(Aes* aes, byte* out, const byte* in, word32 sz,
while (blocks--) {
IncrementGcmCounter(ctr);
AesEncrypt(aes, ctr, p);
xorbuf(p, c, AES_BLOCK_SIZE);
AesEncrypt(aes, ctr, scratch);
xorbuf(scratch, c, AES_BLOCK_SIZE);
XMEMCPY(p, scratch, AES_BLOCK_SIZE);
p += AES_BLOCK_SIZE;
c += AES_BLOCK_SIZE;
@ -1634,9 +1636,9 @@ int AesGcmDecrypt(Aes* aes, byte* out, const byte* in, word32 sz,
byte pPartial[AES_BLOCK_SIZE];
IncrementGcmCounter(ctr);
AesEncrypt(aes, ctr, pPartial);
XMEMCPY(p, pPartial, partial);
xorbuf(p, c, partial);
AesEncrypt(aes, ctr, scratch);
xorbuf(scratch, c, partial);
XMEMCPY(p, scratch, partial);
}
return 0;