[OE-core][zeus][PATCH] openssl: fix CVE-2020-1967

[OE-core][zeus][PATCH] openssl: fix CVE-2020-1967

[ZhangXiao]

Server or client applications that call the SSL_check_chain()
function during or after a TLS 1.3 handshake may crash due to
a NULL pointer dereference as a result of incorrect handling of
the "signature_algorithms_cert" TLS extension.

The crash occurs if an invalid or unrecognised signature
algorithm is received from the peer. This could be exploited
by a malicious peer in a Denial of Service attack.

Signed-off-by: Zhang Xiao <xiao.zhang@windriver.com>
---
 .../openssl/openssl/CVE-2020-1967.patch       | 53 +++++++++++++++++++
 .../openssl/openssl_1.1.1d.bb                 |  1 +
 2 files changed, 54 insertions(+)
 create mode 100644 meta/recipes-connectivity/openssl/openssl/CVE-2020-1967.patch

diff --git a/meta/recipes-connectivity/openssl/openssl/CVE-2020-1967.patch b/meta/recipes-connectivity/openssl/openssl/CVE-2020-1967.patch
new file mode 100644
index 0000000000..dfe8ed1332
--- /dev/null
+++ b/meta/recipes-connectivity/openssl/openssl/CVE-2020-1967.patch
@@ -0,0 +1,53 @@
+From 27b06c515c0a7e14853f84be85fb70c4450a6925 Mon Sep 17 00:00:00 2001
+From: Benjamin Kaduk <kaduk@mit.edu>
+Date: Fri, 10 Apr 2020 12:27:28 -0700
+Subject: [PATCH] Fix NULL dereference in SSL_check_chain() for TLS 1.3
+
+commit eb563247aef3e83dda7679c43f9649270462e5b1 upstream
+git://git.openssl.org/openssl.git
+
+In the tls1_check_sig_alg() helper function, we loop through the list of
+"signature_algorithms_cert" values received from the client and attempt
+to look up each one in turn in our internal table that maps wire
+codepoint to string-form name, digest and/or signature NID, etc., in
+order to compare the signature scheme from the peer's list against what
+is used to sign the certificates in the certificate chain we're
+checking.  Unfortunately, when the peer sends a value that we don't
+support, the lookup returns NULL, but we unconditionally dereference the
+lookup result for the comparison, leading to an application crash
+triggerable by an unauthenticated client.
+
+Since we will not be able to say anything about algorithms we don't
+recognize, treat NULL return from lookup as "does not match".
+
+We currently only apply the "signature_algorithm_cert" checks on TLS 1.3
+connections, so previous TLS versions are unaffected.  SSL_check_chain()
+is not called directly from libssl, but may be used by the application
+inside a callback (e.g., client_hello or cert callback) to verify that a
+candidate certificate chain will be acceptable to the client.
+
+CVE-2020-1967
+Upstream-Status: Backport
+
+Reviewed-by: Matt Caswell <matt@openssl.org>
+Signed-off-by: Zhang Xiao <xiao.zhang@windriver.com>
+---
+ ssl/t1_lib.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
+index b482019..5287d10 100644
+--- a/ssl/t1_lib.c
++++ b/ssl/t1_lib.c
+@@ -2099,7 +2099,7 @@ static int tls1_check_sig_alg(SSL *s, X509 *x, int default_nid)
+         sigalg = use_pc_sigalgs
+                  ? tls1_lookup_sigalg(s->s3->tmp.peer_cert_sigalgs[i])
+                  : s->shared_sigalgs[i];
+-        if (sig_nid == sigalg->sigandhash)
++        if (sigalg != NULL && sig_nid == sigalg->sigandhash)
+             return 1;
+     }
+     return 0;
+-- 
+2.23.0
+
diff --git a/meta/recipes-connectivity/openssl/openssl_1.1.1d.bb b/meta/recipes-connectivity/openssl/openssl_1.1.1d.bb
index 169824a8be..1bf7073127 100644
--- a/meta/recipes-connectivity/openssl/openssl_1.1.1d.bb
+++ b/meta/recipes-connectivity/openssl/openssl_1.1.1d.bb
@@ -18,6 +18,7 @@ SRC_URI = "http://www.openssl.org/source/openssl-${PV}.tar.gz \
            file://afalg.patch \
            file://CVE-2019-1551.patch \
            file://reproducible.patch \
+           file://CVE-2020-1967.patch \
            "
 
 SRC_URI_append_class-nativesdk = " \
-- 
2.23.0

✗ patchtest: failure for openssl: fix CVE-2020-1967

[Patchwork]

== Series Details ==

Series: openssl: fix CVE-2020-1967
Revision: 1
URL   : https://patchwork.openembedded.org/series/23836/
State : failure

== Summary ==


Thank you for submitting this patch series to OpenEmbedded Core. This is
an automated response. Several tests have been executed on the proposed
series by patchtest resulting in the following failures:



* Patch            [zeus] openssl: fix CVE-2020-1967
 Issue             Missing or incorrectly formatted CVE tag in included patch file [test_cve_tag_format] 
  Suggested fix    Correct or include the CVE tag on cve patch with format: "CVE: CVE-YYYY-XXXX"



If you believe any of these test results are incorrect, please reply to the
mailing list (openembedded-core@lists.openembedded.org) raising your concerns.
Otherwise we would appreciate you correcting the issues and submitting a new
version of the patchset if applicable. Please ensure you add/increment the
version number when sending the new version (i.e. [PATCH] -> [PATCH v2] ->
[PATCH v3] -> ...).

---
Guidelines:     https://www.openembedded.org/wiki/Commit_Patch_Message_Guidelines
Test framework: http://git.yoctoproject.org/cgit/cgit.cgi/patchtest
Test suite:     http://git.yoctoproject.org/cgit/cgit.cgi/patchtest-oe