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keys: fixing DeriveKeys:

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--- variables md5InputSz, shaInputSz and keyDataSz removed

keys: refactoring MakeSslMasterSecret to reduce stack usage:
--- variable shaOutput moved to the heap (20 bytes saved)
--- variable md5Input moved to the heap (532 bytes saved)
--- variable shaInput moved to the heap (579 bytes saved)
--- variable md5 moved to the heap (sizeof(Md5) saved)
--- variable sha moved to the heap (sizeof(Sha) saved)
This commit is contained in:
Moisés Guimarães
2014-08-11 14:17:44 -07:00
parent cc6b11c95b
commit 1a8d06a0e3
1 changed files with 105 additions and 64 deletions
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103
src/keys.c
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@ -2240,10 +2240,6 @@ int DeriveKeys(CYASSL* ssl)
int rounds = (length + MD5_DIGEST_SIZE - 1 ) / MD5_DIGEST_SIZE, i;
int ret = 0;
word32 md5InputSz = SECRET_LEN + SHA_DIGEST_SIZE;
word32 shaInputSz = KEY_PREFIX + SECRET_LEN + 2 * RAN_LEN;
word32 keyDataSz = KEY_PREFIX * MD5_DIGEST_SIZE; /* max size */
#ifdef CYASSL_SMALL_STACK
byte* shaOutput;
byte* md5Input;
@ -2253,9 +2249,9 @@ int DeriveKeys(CYASSL* ssl)
Sha* sha;
#else
byte shaOutput[SHA_DIGEST_SIZE];
byte md5Input[md5InputSz];
byte shaInput[shaInputSz];
byte keyData[keyDataSz];
byte md5Input[SECRET_LEN + SHA_DIGEST_SIZE];
byte shaInput[KEY_PREFIX + SECRET_LEN + 2 * RAN_LEN];
byte keyData[KEY_PREFIX * MD5_DIGEST_SIZE];
Md5 md5[1];
Sha sha[1];
#endif
@ -2263,9 +2259,12 @@ int DeriveKeys(CYASSL* ssl)
#ifdef CYASSL_SMALL_STACK
shaOutput = (byte*)XMALLOC(SHA_DIGEST_SIZE,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
md5Input = (byte*)XMALLOC(md5InputSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
shaInput = (byte*)XMALLOC(shaInputSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
keyData = (byte*)XMALLOC(keyDataSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
md5Input = (byte*)XMALLOC(SECRET_LEN + SHA_DIGEST_SIZE,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
shaInput = (byte*)XMALLOC(KEY_PREFIX + SECRET_LEN + 2 * RAN_LEN,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
keyData = (byte*)XMALLOC(KEY_PREFIX * MD5_DIGEST_SIZE,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
md5 = (Md5*)XMALLOC(sizeof(Md5), NULL, DYNAMIC_TYPE_TMP_BUFFER);
sha = (Sha*)XMALLOC(sizeof(Sha), NULL, DYNAMIC_TYPE_TMP_BUFFER);
@ -2304,11 +2303,12 @@ int DeriveKeys(CYASSL* ssl)
idx += RAN_LEN;
XMEMCPY(shaInput + idx, ssl->arrays->clientRandom, RAN_LEN);
ShaUpdate(sha, shaInput, shaInputSz - KEY_PREFIX + j);
ShaUpdate(sha, shaInput, (KEY_PREFIX + SECRET_LEN + 2 * RAN_LEN)
- KEY_PREFIX + j);
ShaFinal(sha, shaOutput);
XMEMCPY(md5Input + SECRET_LEN, shaOutput, SHA_DIGEST_SIZE);
Md5Update(md5, md5Input, md5InputSz);
Md5Update(md5, md5Input, SECRET_LEN + SHA_DIGEST_SIZE);
Md5Final(md5, keyData + i * MD5_DIGEST_SIZE);
}
@ -2350,15 +2350,23 @@ static int CleanPreMaster(CYASSL* ssl)
/* Create and store the master secret see page 32, 6.1 */
static int MakeSslMasterSecret(CYASSL* ssl)
{
byte shaOutput[SHA_DIGEST_SIZE];
byte md5Input[ENCRYPT_LEN + SHA_DIGEST_SIZE];
byte shaInput[PREFIX + ENCRYPT_LEN + 2 * RAN_LEN];
int i, ret;
word32 idx;
word32 pmsSz = ssl->arrays->preMasterSz;
Md5 md5;
Sha sha;
#ifdef CYASSL_SMALL_STACK
byte* shaOutput;
byte* md5Input;
byte* shaInput;
Md5* md5;
Sha* sha;
#else
byte shaOutput[SHA_DIGEST_SIZE];
byte md5Input[ENCRYPT_LEN + SHA_DIGEST_SIZE];
byte shaInput[PREFIX + ENCRYPT_LEN + 2 * RAN_LEN];
Md5 md5[1];
Sha sha[1];
#endif
#ifdef SHOW_SECRETS
{
@ -2370,17 +2378,40 @@ static int MakeSslMasterSecret(CYASSL* ssl)
}
#endif
InitMd5(&md5);
ret = InitSha(&sha);
if (ret != 0)
return ret;
#ifdef CYASSL_SMALL_STACK
shaOutput = (byte*)XMALLOC(SHA_DIGEST_SIZE,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
md5Input = (byte*)XMALLOC(ENCRYPT_LEN + SHA_DIGEST_SIZE,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
shaInput = (byte*)XMALLOC(PREFIX + ENCRYPT_LEN + 2 * RAN_LEN,
NULL, DYNAMIC_TYPE_TMP_BUFFER);
md5 = (Md5*)XMALLOC(sizeof(Md5), NULL, DYNAMIC_TYPE_TMP_BUFFER);
sha = (Sha*)XMALLOC(sizeof(Sha), NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (shaOutput == NULL || md5Input == NULL || shaInput == NULL ||
md5 == NULL || sha == NULL) {
if (shaOutput) XFREE(shaOutput, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (md5Input) XFREE(md5Input, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (shaInput) XFREE(shaInput, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (md5) XFREE(md5, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (sha) XFREE(sha, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return MEMORY_E;
}
#endif
InitMd5(md5);
ret = InitSha(sha);
if (ret == 0) {
XMEMCPY(md5Input, ssl->arrays->preMasterSecret, pmsSz);
for (i = 0; i < MASTER_ROUNDS; ++i) {
byte prefix[KEY_PREFIX]; /* only need PREFIX bytes but static */
if (!SetPrefix(prefix, i)) { /* analysis thinks will overrun */
return PREFIX_ERROR;
ret = PREFIX_ERROR;
break;
}
idx = 0;
@ -2393,14 +2424,14 @@ static int MakeSslMasterSecret(CYASSL* ssl)
idx += RAN_LEN;
XMEMCPY(shaInput + idx, ssl->arrays->serverRandom, RAN_LEN);
idx += RAN_LEN;
ShaUpdate(&sha, shaInput, idx);
ShaFinal(&sha, shaOutput);
ShaUpdate(sha, shaInput, idx);
ShaFinal(sha, shaOutput);
idx = pmsSz; /* preSz */
XMEMCPY(md5Input + idx, shaOutput, SHA_DIGEST_SIZE);
idx += SHA_DIGEST_SIZE;
Md5Update(&md5, md5Input, idx);
Md5Final(&md5, &ssl->arrays->masterSecret[i * MD5_DIGEST_SIZE]);
Md5Update(md5, md5Input, idx);
Md5Final(md5, &ssl->arrays->masterSecret[i * MD5_DIGEST_SIZE]);
}
#ifdef SHOW_SECRETS
@ -2413,14 +2444,24 @@ static int MakeSslMasterSecret(CYASSL* ssl)
}
#endif
if (ret == 0)
ret = DeriveKeys(ssl);
if (ret != 0) {
/* always try to clean PreMaster */
CleanPreMaster(ssl);
return ret;
}
return CleanPreMaster(ssl);
#ifdef CYASSL_SMALL_STACK
XFREE(shaOutput, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(md5Input, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(shaInput, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(md5, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(sha, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
if (ret == 0)
ret = CleanPreMaster(ssl);
else
CleanPreMaster(ssl);
return ret;
}
#endif