48 lines
1.7 KiB
Diff
48 lines
1.7 KiB
Diff
From fb9fa6b51defd48157eeb207f52181f735d96148 Mon Sep 17 00:00:00 2001
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From: Peter Kaestle <peter.kaestle@nokia.com>
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Date: Mon, 15 Mar 2021 13:19:56 +0100
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Subject: [PATCH] ssl sigalg extension: fix NULL pointer dereference
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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As the variable peer_sigalgslen is not cleared on ssl rehandshake, it's
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possible to crash an openssl tls secured server remotely by sending a
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manipulated hello message in a rehandshake.
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On such a manipulated rehandshake, tls1_set_shared_sigalgs() calls
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tls12_shared_sigalgs() with the peer_sigalgslen of the previous
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handshake, while the peer_sigalgs has been freed.
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As a result tls12_shared_sigalgs() walks over the available
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peer_sigalgs and tries to access data of a NULL pointer.
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This issue was introduced by c589c34e61 (Add support for the TLS 1.3
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signature_algorithms_cert extension, 2018-01-11).
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Signed-off-by: Peter Kästle <peter.kaestle@nokia.com>
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Signed-off-by: Samuel Sapalski <samuel.sapalski@nokia.com>
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CVE-2021-3449
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CLA: trivial
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Reviewed-by: Tomas Mraz <tomas@openssl.org>
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Reviewed-by: Paul Dale <pauli@openssl.org>
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Reviewed-by: Matt Caswell <matt@openssl.org>
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---
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ssl/statem/extensions.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
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index b055935d697b..4aed508d0f03 100644
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--- a/ssl/statem/extensions.c
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+++ b/ssl/statem/extensions.c
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@@ -1139,6 +1139,7 @@ static int init_sig_algs(SSL *s, unsigned int context)
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/* Clear any signature algorithms extension received */
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OPENSSL_free(s->s3->tmp.peer_sigalgs);
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s->s3->tmp.peer_sigalgs = NULL;
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+ s->s3->tmp.peer_sigalgslen = 0;
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return 1;
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}
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