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pkcs7: refactoring PKCS7_VerifySignedData to reduce stack usage: ~ 50 bytes + 8 * sizeof(mp_int) bytes moved to the heap.

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--- variable key moved to the heap (more than 8 * sizeof(mp_int) bytes saved)
--- variable digest moved to the heap (50 bytes saved)
This commit is contained in:
Moisés Guimarães 2014-06-13 15:39:18 -03:00
parent 60b2495f47
commit eacff3ba83
1 changed files with 57 additions and 16 deletions
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73
ctaocrypt/src/pkcs7.c
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@ -791,11 +791,6 @@ int PKCS7_VerifySignedData(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz)
return ASN_PARSE_E;
if (length > 0) {
RsaKey key;
word32 scratch = 0;
int plainSz = 0;
byte digest[MAX_SEQ_SZ+MAX_ALGO_SZ+MAX_OCTET_STR_SZ+SHA_DIGEST_SIZE];
/* Get the sequence of the first signerInfo */
if (GetSequence(pkiMsg, &idx, &length, pkiMsgSz) < 0)
return ASN_PARSE_E;
@ -854,21 +849,67 @@ int PKCS7_VerifySignedData(PKCS7* pkcs7, byte* pkiMsg, word32 pkiMsgSz)
idx += length;
}
XMEMSET(digest, 0, sizeof(digest));
pkcs7->content = content;
pkcs7->contentSz = contentSz;
ret = InitRsaKey(&key, NULL);
if (ret != 0) return ret;
if (RsaPublicKeyDecode(pkcs7->publicKey, &scratch, &key,
pkcs7->publicKeySz) < 0) {
CYASSL_MSG("ASN RSA key decode error");
return PUBLIC_KEY_E;
{
word32 scratch = 0;
int plainSz = 0;
int digestSz = MAX_SEQ_SZ + MAX_ALGO_SZ +
MAX_OCTET_STR_SZ + SHA_DIGEST_SIZE;
#ifdef CYASSL_SMALL_STACK
byte* digest;
RsaKey* key;
digest = (byte*)XMALLOC(digestSz, NULL, DYNAMIC_TYPE_TMP_BUFFER);
if (digest == NULL)
return MEMORY_E;
key = (RsaKey*)XMALLOC(sizeof(RsaKey), NULL,
DYNAMIC_TYPE_TMP_BUFFER);
if (key == NULL) {
XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
return MEMORY_E;
}
#else
byte digest[digestSz];
RsaKey stack_key;
RsaKey* key = &stack_key;
#endif
XMEMSET(digest, 0, digestSz);
ret = InitRsaKey(key, NULL);
if (ret != 0) {
#ifdef CYASSL_SMALL_STACK
XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(key, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return ret;
}
if (RsaPublicKeyDecode(pkcs7->publicKey, &scratch, key,
pkcs7->publicKeySz) < 0) {
CYASSL_MSG("ASN RSA key decode error");
#ifdef CYASSL_SMALL_STACK
XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(key, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
return PUBLIC_KEY_E;
}
plainSz = RsaSSL_Verify(sig, sigSz, digest, digestSz, key);
FreeRsaKey(key);
#ifdef CYASSL_SMALL_STACK
XFREE(digest, NULL, DYNAMIC_TYPE_TMP_BUFFER);
XFREE(key, NULL, DYNAMIC_TYPE_TMP_BUFFER);
#endif
if (plainSz < 0)
return plainSz;
}
plainSz = RsaSSL_Verify(sig, sigSz, digest, sizeof(digest), &key);
FreeRsaKey(&key);
if (plainSz < 0)
return plainSz;
}
return 0;