gnu: gnutls: Fix CVE-2021-20231 and CVE-2021-20232.

* gnu/packages/patches/gnutls-CVE-2021-20231.patch,
gnu/packages/patches/gnutls-CVE-2021-20232.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/tls.scm (gnutls)[replacement]: New field.
(gnutls/fixed): New variable.
(guile2.2-gnutls): Use package/inherit.

3 files changed, 134 insertions, 3 deletions

diff --git a/gnu/packages/patches/gnutls-CVE-2021-20231.patch b/gnu/packages/patches/gnutls-CVE-2021-20231.patch
new file mode 100644
index 0000000000..5186522eee
--- /dev/null
+++ b/gnu/packages/patches/gnutls-CVE-2021-20231.patch
@@ -0,0 +1,62 @@
+From 15beb4b193b2714d88107e7dffca781798684e7e Mon Sep 17 00:00:00 2001
+From: Daiki Ueno <ueno@gnu.org>
+Date: Fri, 29 Jan 2021 14:06:05 +0100
+Subject: [PATCH 1/2] key_share: avoid use-after-free around realloc
+
+Signed-off-by: Daiki Ueno <ueno@gnu.org>
+---
+ lib/ext/key_share.c | 12 +++++-------
+ 1 file changed, 5 insertions(+), 7 deletions(-)
+
+diff --git a/lib/ext/key_share.c b/lib/ext/key_share.c
+index ab8abf8fe..a8c4bb5cf 100644
+--- a/lib/ext/key_share.c
++++ b/lib/ext/key_share.c
+@@ -664,14 +664,14 @@ key_share_send_params(gnutls_session_t session,
+ {
+ 	unsigned i;
+ 	int ret;
+-	unsigned char *lengthp;
+-	unsigned int cur_length;
+ 	unsigned int generated = 0;
+ 	const gnutls_group_entry_st *group;
+ 	const version_entry_st *ver;
+ 
+ 	/* this extension is only being sent on client side */
+ 	if (session->security_parameters.entity == GNUTLS_CLIENT) {
++		unsigned int length_pos;
++
+ 		ver = _gnutls_version_max(session);
+ 		if (unlikely(ver == NULL || ver->key_shares == 0))
+ 			return 0;
+@@ -679,16 +679,13 @@ key_share_send_params(gnutls_session_t session,
+ 		if (!have_creds_for_tls13(session))
+ 			return 0;
+ 
+-		/* write the total length later */
+-		lengthp = &extdata->data[extdata->length];
++		length_pos = extdata->length;
+ 
+ 		ret =
+ 		    _gnutls_buffer_append_prefix(extdata, 16, 0);
+ 		if (ret < 0)
+ 			return gnutls_assert_val(ret);
+ 
+-		cur_length = extdata->length;
+-
+ 		if (session->internals.hsk_flags & HSK_HRR_RECEIVED) { /* we know the group */
+ 			group = get_group(session);
+ 			if (unlikely(group == NULL))
+@@ -736,7 +733,8 @@ key_share_send_params(gnutls_session_t session,
+ 		}
+ 
+ 		/* copy actual length */
+-		_gnutls_write_uint16(extdata->length - cur_length, lengthp);
++		_gnutls_write_uint16(extdata->length - length_pos - 2,
++				     &extdata->data[length_pos]);
+ 
+ 	} else { /* server */
+ 		ver = get_version(session);
+-- 
+2.30.2
+
diff --git a/gnu/packages/patches/gnutls-CVE-2021-20232.patch b/gnu/packages/patches/gnutls-CVE-2021-20232.patch
new file mode 100644
index 0000000000..dc3a0be690
--- /dev/null
+++ b/gnu/packages/patches/gnutls-CVE-2021-20232.patch
@@ -0,0 +1,60 @@
+From 75a937d97f4fefc6f9b08e3791f151445f551cb3 Mon Sep 17 00:00:00 2001
+From: Daiki Ueno <ueno@gnu.org>
+Date: Fri, 29 Jan 2021 14:06:23 +0100
+Subject: [PATCH 2/2] pre_shared_key: avoid use-after-free around realloc
+
+Signed-off-by: Daiki Ueno <ueno@gnu.org>
+---
+ lib/ext/pre_shared_key.c | 15 ++++++++++++---
+ 1 file changed, 12 insertions(+), 3 deletions(-)
+
+diff --git a/lib/ext/pre_shared_key.c b/lib/ext/pre_shared_key.c
+index a042c6488..380bf39ed 100644
+--- a/lib/ext/pre_shared_key.c
++++ b/lib/ext/pre_shared_key.c
+@@ -267,7 +267,7 @@ client_send_params(gnutls_session_t session,
+ 	size_t spos;
+ 	gnutls_datum_t username = {NULL, 0};
+ 	gnutls_datum_t user_key = {NULL, 0}, rkey = {NULL, 0};
+-	gnutls_datum_t client_hello;
++	unsigned client_hello_len;
+ 	unsigned next_idx;
+ 	const mac_entry_st *prf_res = NULL;
+ 	const mac_entry_st *prf_psk = NULL;
+@@ -428,8 +428,7 @@ client_send_params(gnutls_session_t session,
+ 	assert(extdata->length >= sizeof(mbuffer_st));
+ 	assert(ext_offset >= (ssize_t)sizeof(mbuffer_st));
+ 	ext_offset -= sizeof(mbuffer_st);
+-	client_hello.data = extdata->data+sizeof(mbuffer_st);
+-	client_hello.size = extdata->length-sizeof(mbuffer_st);
++	client_hello_len = extdata->length-sizeof(mbuffer_st);
+ 
+ 	next_idx = 0;
+ 
+@@ -440,6 +439,11 @@ client_send_params(gnutls_session_t session,
+ 	}
+ 
+ 	if (prf_res && rkey.size > 0) {
++		gnutls_datum_t client_hello;
++
++		client_hello.data = extdata->data+sizeof(mbuffer_st);
++		client_hello.size = client_hello_len;
++
+ 		ret = compute_psk_binder(session, prf_res,
+ 					 binders_len, binders_pos,
+ 					 ext_offset, &rkey, &client_hello, 1,
+@@ -474,6 +478,11 @@ client_send_params(gnutls_session_t session,
+ 	}
+ 
+ 	if (prf_psk && user_key.size > 0 && info) {
++		gnutls_datum_t client_hello;
++
++		client_hello.data = extdata->data+sizeof(mbuffer_st);
++		client_hello.size = client_hello_len;
++
+ 		ret = compute_psk_binder(session, prf_psk,
+ 					 binders_len, binders_pos,
+ 					 ext_offset, &user_key, &client_hello, 0,
+-- 
+2.30.2
+
diff --git a/gnu/packages/tls.scm b/gnu/packages/tls.scm
index e0741ad310..e8e1350e29 100644
--- a/gnu/packages/tls.scm
+++ b/gnu/packages/tls.scm
@@ -1,6 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
-;;; Copyright © 2014, 2015, 2016, 2017, 2018 Mark H Weaver <mhw@netris.org>
+;;; Copyright © 2014, 2015, 2016, 2017, 2018, 2021 Mark H Weaver <mhw@netris.org>
 ;;; Copyright © 2014 Ian Denhardt <ian@zenhack.net>
 ;;; Copyright © 2013, 2015 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2015 David Thompson <davet@gnu.org>
@@ -165,6 +165,7 @@ living in the same process.")
   (package
     (name "gnutls")
     (version "3.6.15")
+    (replacement gnutls/fixed)
     (source (origin
               (method url-fetch)
               ;; Note: Releases are no longer on ftp.gnu.org since the
@@ -256,6 +257,15 @@ required structures.")
     (properties '((ftp-server . "ftp.gnutls.org")
                   (ftp-directory . "/gcrypt/gnutls")))))
 
+(define gnutls/fixed
+  (package
+    (inherit gnutls)
+    (source (origin
+              (inherit (package-source gnutls))
+              (patches (append (search-patches "gnutls-CVE-2021-20231.patch"
+                                               "gnutls-CVE-2021-20232.patch")
+                               (origin-patches (package-source gnutls))))))))
+
 (define-public gnutls/guile-2.0
   ;; GnuTLS for Guile 2.0.
   (package/inherit gnutls
@@ -274,8 +284,7 @@ required structures.")
               ,@(package-inputs gnutls)))))
 
 (define-public guile2.2-gnutls
-  (package
-    (inherit gnutls)
+  (package/inherit gnutls
     (name "guile2.2-gnutls")
     (inputs `(("guile" ,guile-2.2)
               ,@(alist-delete "guile"