/* rsa_pss.c */
-/* Written by Dr Stephen N Henson (shenson@bigfoot.com) for the OpenSSL
+/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
* project 2005.
*/
/* ====================================================================
#include <openssl/rand.h>
#include <openssl/sha.h>
-const static unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
+static const unsigned char zeroes[] = {0,0,0,0,0,0,0,0};
+
+#if defined(_MSC_VER) && defined(_ARM_)
+#pragma optimize("g", off)
+#endif
int RSA_verify_PKCS1_PSS(RSA *rsa, const unsigned char *mHash,
const EVP_MD *Hash, const unsigned char *EM, int sLen)
{
int i;
int ret = 0;
- int hLen, maskedDBLen, emBits, emLen;
+ int hLen, maskedDBLen, MSBits, emLen;
const unsigned char *H;
unsigned char *DB = NULL;
EVP_MD_CTX ctx;
unsigned char H_[EVP_MAX_MD_SIZE];
- emBits = BN_num_bits(rsa->n) - 1;
- emLen = (emBits + 7) >> 3;
- hLen = EVP_MD_size(Hash);
- if (emLen < (hLen + sLen + 2))
+
+ hLen = M_EVP_MD_size(Hash);
+ /*
+ * Negative sLen has special meanings:
+ * -1 sLen == hLen
+ * -2 salt length is autorecovered from signature
+ * -N reserved
+ */
+ if (sLen == -1) sLen = hLen;
+ else if (sLen == -2) sLen = -2;
+ else if (sLen < -2)
{
- RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
goto err;
}
- if (EM[emLen - 1] != 0xbc)
+
+ MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
+ emLen = RSA_size(rsa);
+ if (EM[0] & (0xFF << MSBits))
{
- RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
goto err;
}
- if (EM[0] & (0xFF << (emBits & 0x7)))
+ if (MSBits == 0)
{
- RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_FIRST_OCTET_INVALID);
+ EM++;
+ emLen--;
+ }
+ if (emLen < (hLen + sLen + 2)) /* sLen can be small negative */
+ {
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_DATA_TOO_LARGE);
+ goto err;
+ }
+ if (EM[emLen - 1] != 0xbc)
+ {
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_LAST_OCTET_INVALID);
goto err;
}
maskedDBLen = emLen - hLen - 1;
PKCS1_MGF1(DB, maskedDBLen, H, hLen, Hash);
for (i = 0; i < maskedDBLen; i++)
DB[i] ^= EM[i];
- DB[0] &= 0xFF >> (8 - (emBits & 0x7));
- for (i = 0; i < (emLen - hLen - sLen - 2); i++)
+ if (MSBits)
+ DB[0] &= 0xFF >> (8 - MSBits);
+ for (i = 0; DB[i] == 0 && i < (maskedDBLen-1); i++) ;
+ if (DB[i++] != 0x1)
{
- if (DB[i] != 0)
- {
- RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS,
- RSA_R_ZERO_CHECK_FAILED);
- goto err;
- }
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_RECOVERY_FAILED);
+ goto err;
}
- if (DB[i] != 0x1)
+ if (sLen >= 0 && (maskedDBLen - i) != sLen)
{
- RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_ONE_CHECK_FAILED);
+ RSAerr(RSA_F_RSA_VERIFY_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
goto err;
}
EVP_MD_CTX_init(&ctx);
EVP_DigestInit_ex(&ctx, Hash, NULL);
EVP_DigestUpdate(&ctx, zeroes, sizeof zeroes);
EVP_DigestUpdate(&ctx, mHash, hLen);
- if (sLen)
- EVP_DigestUpdate(&ctx, DB + maskedDBLen - sLen, sLen);
+ if (maskedDBLen - i)
+ EVP_DigestUpdate(&ctx, DB + i, maskedDBLen - i);
EVP_DigestFinal(&ctx, H_, NULL);
EVP_MD_CTX_cleanup(&ctx);
if (memcmp(H_, H, hLen))
{
int i;
int ret = 0;
- int hLen, maskedDBLen, emBits, emLen;
+ int hLen, maskedDBLen, MSBits, emLen;
unsigned char *H, *salt = NULL, *p;
EVP_MD_CTX ctx;
- emBits = BN_num_bits(rsa->n) - 1;
- emLen = (emBits + 7) >> 3;
- hLen = EVP_MD_size(Hash);
- if (sLen < 0)
- sLen = 0;
- if (emLen < (hLen + sLen + 2))
+
+ hLen = M_EVP_MD_size(Hash);
+ /*
+ * Negative sLen has special meanings:
+ * -1 sLen == hLen
+ * -2 salt length is maximized
+ * -N reserved
+ */
+ if (sLen == -1) sLen = hLen;
+ else if (sLen == -2) sLen = -2;
+ else if (sLen < -2)
+ {
+ RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS, RSA_R_SLEN_CHECK_FAILED);
+ goto err;
+ }
+
+ MSBits = (BN_num_bits(rsa->n) - 1) & 0x7;
+ emLen = RSA_size(rsa);
+ if (MSBits == 0)
+ {
+ *EM++ = 0;
+ emLen--;
+ }
+ if (sLen == -2)
+ {
+ sLen = emLen - hLen - 2;
+ }
+ else if (emLen < (hLen + sLen + 2))
{
RSAerr(RSA_F_RSA_PADDING_ADD_PKCS1_PSS,
RSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE);
for (i = 0; i < sLen; i++)
*p++ ^= salt[i];
}
- EM[0] &= 0xFF >> (8 - (emBits & 0x7));
+ if (MSBits)
+ EM[0] &= 0xFF >> (8 - MSBits);
/* H is already in place so just set final 0xbc */
return ret;
}
+
+#if defined(_MSC_VER)
+#pragma optimize("",on)
+#endif