79 lines
2.3 KiB
Diff
79 lines
2.3 KiB
Diff
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From 0d468aacfc2c14b904896d9d7ee2cd07bf7c6004 Mon Sep 17 00:00:00 2001
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From: akallabeth <akallabeth@posteo.net>
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Date: Tue, 19 May 2020 07:41:14 +0200
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Subject: [PATCH] Fixed GHSL-2020-102 heap overflow
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(cherry picked from commit 197b16cc15a12813c2e4fa2d6ae9cd9c4a57e581)
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---
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libfreerdp/crypto/crypto.c | 41 ++++++++++++++++++++++++++++----------
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1 file changed, 30 insertions(+), 11 deletions(-)
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diff --git a/libfreerdp/crypto/crypto.c b/libfreerdp/crypto/crypto.c
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index 39875f74d..10d430a82 100644
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--- a/libfreerdp/crypto/crypto.c
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+++ b/libfreerdp/crypto/crypto.c
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@@ -96,13 +96,24 @@ exit:
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static int crypto_rsa_common(const BYTE* input, int length, UINT32 key_length, const BYTE* modulus,
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const BYTE* exponent, int exponent_size, BYTE* output)
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{
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- BN_CTX* ctx;
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+ BN_CTX* ctx = NULL;
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int output_length = -1;
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- BYTE* input_reverse;
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- BYTE* modulus_reverse;
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- BYTE* exponent_reverse;
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- BIGNUM* mod, *exp, *x, *y;
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- input_reverse = (BYTE*) malloc(2 * key_length + exponent_size);
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+ BYTE* input_reverse = NULL;
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+ BYTE* modulus_reverse = NULL;
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+ BYTE* exponent_reverse = NULL;
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+ BIGNUM* mod = NULL;
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+ BIGNUM* exp = NULL;
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+ BIGNUM* x = NULL;
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+ BIGNUM* y = NULL;
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+ size_t bufferSize = 2 * key_length + exponent_size;
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+
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+ if (!input || (length < 0) || (exponent_size < 0) || !modulus || !exponent || !output)
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+ return -1;
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+
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+ if (length > bufferSize)
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+ bufferSize = length;
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+
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+ input_reverse = (BYTE*)calloc(bufferSize, 1);
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if (!input_reverse)
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return -1;
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@@ -131,16 +142,24 @@ static int crypto_rsa_common(const BYTE* input, int length, UINT32 key_length, c
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if (!(y = BN_new()))
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goto fail_bn_y;
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- BN_bin2bn(modulus_reverse, key_length, mod);
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- BN_bin2bn(exponent_reverse, exponent_size, exp);
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- BN_bin2bn(input_reverse, length, x);
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- BN_mod_exp(y, x, exp, mod, ctx);
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+ if (!BN_bin2bn(modulus_reverse, key_length, mod))
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+ goto fail;
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+
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+ if (!BN_bin2bn(exponent_reverse, exponent_size, exp))
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+ goto fail;
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+ if (!BN_bin2bn(input_reverse, length, x))
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+ goto fail;
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+ if (BN_mod_exp(y, x, exp, mod, ctx) != 1)
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+ goto fail;
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output_length = BN_bn2bin(y, output);
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+ if (output_length < 0)
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+ goto fail;
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crypto_reverse(output, output_length);
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- if (output_length < (int) key_length)
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+ if (output_length < key_length)
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memset(output + output_length, 0, key_length - output_length);
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+fail:
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BN_free(y);
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fail_bn_y:
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BN_clear_free(x);
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--
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2.26.2
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