45 lines
1.9 KiB
Diff
45 lines
1.9 KiB
Diff
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From 898fb884b706aaeb283de4812340bb0bde8476dc Mon Sep 17 00:00:00 2001
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From: Matt Caswell <matt@openssl.org>
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Date: Wed, 29 Nov 2017 14:04:01 +0000
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Subject: [PATCH] Don't allow read/write after fatal error
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OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state"
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mechanism. The intent was that if a fatal error occurred during a handshake
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then OpenSSL would move into the error state and would immediately fail if
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you attempted to continue the handshake. This works as designed for the
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explicit handshake functions (SSL_do_handshake(), SSL_accept() and
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SSL_connect()), however due to a bug it does not work correctly if
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SSL_read() or SSL_write() is called directly. In that scenario, if the
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handshake fails then a fatal error will be returned in the initial function
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call. If SSL_read()/SSL_write() is subsequently called by the application
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for the same SSL object then it will succeed and the data is passed without
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being decrypted/encrypted directly from the SSL/TLS record layer.
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In order to exploit this issue an attacker would have to trick an
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application into behaving incorrectly by issuing an SSL_read()/SSL_write()
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after having already received a fatal error.
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Thanks to David Benjamin (Google) for reporting this issue and suggesting
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this fix.
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CVE-2017-3737
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Reviewed-by: Rich Salz <rsalz@openssl.org>
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---
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ssl/ssl.h | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/Cryptlib/Include/openssl/ssl.h b/Cryptlib/Include/openssl/ssl.h
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index 90aeb0ce4e1..3cf96a239ba 100644
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--- a/Cryptlib/Include/openssl/ssl.h
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+++ b/Cryptlib/Include/openssl/ssl.h
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@@ -1727,7 +1727,7 @@ extern "C" {
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# define SSL_ST_BEFORE 0x4000
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# define SSL_ST_OK 0x03
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# define SSL_ST_RENEGOTIATE (0x04|SSL_ST_INIT)
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-# define SSL_ST_ERR 0x05
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+# define SSL_ST_ERR (0x05|SSL_ST_INIT)
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# define SSL_CB_LOOP 0x01
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# define SSL_CB_EXIT 0x02
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