Fix crash and latest update.
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+19
-16
@@ -1,5 +1,5 @@
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/*
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* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
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* Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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@@ -55,7 +55,7 @@ int RSA_padding_add_SSLv23(unsigned char *to, int tlen,
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/*
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* Copy of RSA_padding_check_PKCS1_type_2 with a twist that rejects padding
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* if nul delimiter is preceded by 8 consecutive 0x03 bytes. It also
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* if nul delimiter is not preceded by 8 consecutive 0x03 bytes. It also
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* preserves error code reporting for backward compatibility.
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*/
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int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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@@ -67,7 +67,10 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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unsigned int good, found_zero_byte, mask, threes_in_row;
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int zero_index = 0, msg_index, mlen = -1, err;
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if (flen < 10) {
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if (tlen <= 0 || flen <= 0)
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return -1;
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if (flen > num || num < 11) {
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RSAerr(RSA_F_RSA_PADDING_CHECK_SSLV23, RSA_R_DATA_TOO_SMALL);
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return -1;
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}
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@@ -89,10 +92,9 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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from -= 1 & mask;
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*--em = *from & mask;
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}
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from = em;
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good = constant_time_is_zero(from[0]);
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good &= constant_time_eq(from[1], 2);
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good = constant_time_is_zero(em[0]);
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good &= constant_time_eq(em[1], 2);
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err = constant_time_select_int(good, 0, RSA_R_BLOCK_TYPE_IS_NOT_02);
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mask = ~good;
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@@ -100,18 +102,18 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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found_zero_byte = 0;
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threes_in_row = 0;
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for (i = 2; i < num; i++) {
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unsigned int equals0 = constant_time_is_zero(from[i]);
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unsigned int equals0 = constant_time_is_zero(em[i]);
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zero_index = constant_time_select_int(~found_zero_byte & equals0,
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i, zero_index);
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found_zero_byte |= equals0;
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threes_in_row += 1 & ~found_zero_byte;
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threes_in_row &= found_zero_byte | constant_time_eq(from[i], 3);
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threes_in_row &= found_zero_byte | constant_time_eq(em[i], 3);
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}
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/*
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* PS must be at least 8 bytes long, and it starts two bytes into |from|.
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* PS must be at least 8 bytes long, and it starts two bytes into |em|.
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* If we never found a 0-byte, then |zero_index| is 0 and the check
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* also fails.
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*/
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@@ -120,7 +122,7 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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RSA_R_NULL_BEFORE_BLOCK_MISSING);
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mask = ~good;
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good &= constant_time_lt(threes_in_row, 8);
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good &= constant_time_ge(threes_in_row, 8);
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err = constant_time_select_int(mask | good, err,
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RSA_R_SSLV3_ROLLBACK_ATTACK);
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mask = ~good;
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@@ -148,15 +150,16 @@ int RSA_padding_check_SSLv23(unsigned char *to, int tlen,
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* should be noted that failure is indistinguishable from normal
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* operation if |tlen| is fixed by protocol.
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*/
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tlen = constant_time_select_int(constant_time_lt(num, tlen), num, tlen);
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tlen = constant_time_select_int(constant_time_lt(num - 11, tlen),
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num - 11, tlen);
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msg_index = constant_time_select_int(good, msg_index, num - tlen);
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mlen = num - msg_index;
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for (from += msg_index, mask = good, i = 0; i < tlen; i++) {
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unsigned int equals = constant_time_eq(i, mlen);
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for (mask = good, i = 0; i < tlen; i++) {
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unsigned int equals = constant_time_eq(msg_index, num);
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from -= tlen & equals; /* if (i == mlen) rewind */
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mask &= mask ^ equals; /* if (i == mlen) mask = 0 */
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to[i] = constant_time_select_8(mask, from[i], to[i]);
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msg_index -= tlen & equals; /* rewind at EOF */
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mask &= ~equals; /* mask = 0 at EOF */
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to[i] = constant_time_select_8(mask, em[msg_index++], to[i]);
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}
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OPENSSL_clear_free(em, num);
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