openssl: disable digests by default, misc fixes

Openssh uses digest contexts across forks, which is not supported by the
/dev/crypto engine.  The speed of digests is usually not worth enabling
them anyway.  This changes the default of the DIGESTS option to NONE, so
the user still has the option to enable them.

Added another patch related to the use of encryption contexts across
forks, that ignores a failure to close a previous open session when
reinitializing a context, instead of failing the reinitialization.

Added a link to the Cryptographic Hardware Accelerators document to the
engine pacakges description, to provide more detailed instructions to
configure the engines.

Revert the removal of the OPENSSL_ENGINE_CRYPTO symbol, currently used
by openssh.  There is an open PR to update openssh; when merged, this
symbol can be safely removed.

Signed-off-by: Eneas U de Queiroz <[email protected]>
Signed-off-by: Hans Dedecker <[email protected]> [refresh patches]

package/libs/openssl/Config.in

@@ -269,7 +269,13 @@ config OPENSSL_ENGINE_BUILTIN_AFALG
 	select PACKAGE_libopenssl-conf
 	help
 		This enables use of hardware acceleration through the
-		AF_ALG kenrel interface.
+		AF_ALG kernel interface.
+
+config OPENSSL_ENGINE_CRYPTO
+	# This symbol is deprecated.  Currently it is used by the openssh package.
+	# Once openwrt/packages#8272 is merged, this can be safely removed.
+	bool
+	default OPENSSL_ENGINE_BUILTIN_DEVCRYPTO || PACKAGE_libopenssl-devcrypto
 
 config OPENSSL_ENGINE_BUILTIN_DEVCRYPTO
 	bool
@@ -279,6 +285,9 @@ config OPENSSL_ENGINE_BUILTIN_DEVCRYPTO
 	help
 		This enables use of hardware acceleration through OpenBSD
 		Cryptodev API (/dev/crypto) interface.
+		Even though configuration is not strictly needed, it is worth seeing
+		https://openwrt.org/docs/techref/hardware/cryptographic.hardware.accelerators
+		for information on how to configure the engine.
 
 config OPENSSL_ENGINE_BUILTIN_PADLOCK
 	bool

package/libs/openssl/Makefile

@@ -11,7 +11,7 @@ PKG_NAME:=openssl
 PKG_BASE:=1.1.1
 PKG_BUGFIX:=b
 PKG_VERSION:=$(PKG_BASE)$(PKG_BUGFIX)
-PKG_RELEASE:=2
+PKG_RELEASE:=3
 PKG_USE_MIPS16:=0
 ENGINES_DIR=engines-1.1
 
@@ -147,6 +147,7 @@ This package adds an engine that enables hardware acceleration
 through the AF_ALG kernel interface.
 To use it, you need to configure the engine in /etc/ssl/openssl.cnf
 See https://www.openssl.org/docs/man1.1.1/man5/config.html#Engine-Configuration-Module
+and https://openwrt.org/docs/techref/hardware/cryptographic.hardware.accelerators
 The engine_id is "afalg"
 endef
 
@@ -163,6 +164,7 @@ This package adds an engine that enables hardware acceleration
 through the /dev/crypto kernel interface.
 To use it, you need to configure the engine in /etc/ssl/openssl.cnf
 See https://www.openssl.org/docs/man1.1.1/man5/config.html#Engine-Configuration-Module
+and https://openwrt.org/docs/techref/hardware/cryptographic.hardware.accelerators
 The engine_id is "devcrypto"
 endef
 
@@ -178,6 +180,7 @@ define Package/libopenssl-padlock/description
 This package adds an engine that enables VIA Padlock hardware acceleration.
 To use it, you need to configure it in /etc/ssl/openssl.cnf.
 See https://www.openssl.org/docs/man1.1.1/man5/config.html#Engine-Configuration-Module
+and https://openwrt.org/docs/techref/hardware/cryptographic.hardware.accelerators
 The engine_id is "padlock"
 endef
 

package/libs/openssl/patches/500-e_devcrypto-default-to-not-use-digests-in-engine.patch

@@ -0,0 +1,41 @@
+From 5d3be6bc8ed7d73ab2c4d389fb0f0a03dacd04b1 Mon Sep 17 00:00:00 2001
+From: Eneas U de Queiroz <[email protected]>
+Date: Mon, 11 Mar 2019 09:29:13 -0300
+Subject: [PATCH] e_devcrypto: default to not use digests in engine
+
+Digests are almost always slower when using /dev/crypto because of the
+cost of the context switches.  Only for large blocks it is worth it.
+
+Also, when forking, the open context structures are duplicated, but the
+internal kernel sessions are still shared between forks, which means an
+update/close operation in one fork affects all processes using that
+session.
+
+This affects digests, especially for HMAC, where the session with the
+key hash is used as a source for subsequent operations.  At least one
+popular application does this across a fork.  Disabling digests by
+default will mitigate the problem, while still allowing the user to
+turn them on if it is safe and fast enough.
+
+Signed-off-by: Eneas U de Queiroz <[email protected]>
+
+--- a/engines/e_devcrypto.c
++++ b/engines/e_devcrypto.c
+@@ -854,7 +854,7 @@ static void prepare_digest_methods(void)
+     for (i = 0, known_digest_nids_amount = 0; i < OSSL_NELEM(digest_data);
+          i++) {
+ 
+-        selected_digests[i] = 1;
++        selected_digests[i] = 0;
+ 
+         /*
+          * Check that the digest is usable
+@@ -1074,7 +1074,7 @@ static const ENGINE_CMD_DEFN devcrypto_c
+ #ifdef IMPLEMENT_DIGEST
+    {DEVCRYPTO_CMD_DIGESTS,
+     "DIGESTS",
+-    "either ALL, NONE, or a comma-separated list of digests to enable [default=ALL]",
++    "either ALL, NONE, or a comma-separated list of digests to enable [default=NONE]",
+     ENGINE_CMD_FLAG_STRING},
+ #endif
+ 

package/libs/openssl/patches/510-e_devcrypto-ignore-error-when-closing-session.patch

@@ -0,0 +1,24 @@
+From b6e6d157367bae91a8015434769572e430257d40 Mon Sep 17 00:00:00 2001
+From: Eneas U de Queiroz <[email protected]>
+Date: Mon, 11 Mar 2019 10:15:14 -0300
+Subject: [PATCH] e_devcrypto: ignore error when closing session
+
+In cipher_init, ignore an eventual error when closing the previous
+session.  It may have been closed by another process after a fork.
+
+Signed-off-by: Eneas U de Queiroz <[email protected]>
+
+--- a/engines/e_devcrypto.c
++++ b/engines/e_devcrypto.c
+@@ -197,9 +197,8 @@ static int cipher_init(EVP_CIPHER_CTX *c
+         get_cipher_data(EVP_CIPHER_CTX_nid(ctx));
+ 
+     /* cleanup a previous session */
+-    if (cipher_ctx->sess.ses != 0 &&
+-        clean_devcrypto_session(&cipher_ctx->sess) == 0)
+-        return 0;
++    if (cipher_ctx->sess.ses != 0)
++        clean_devcrypto_session(&cipher_ctx->sess);
+ 
+     cipher_ctx->sess.cipher = cipher_d->devcryptoid;
+     cipher_ctx->sess.keylen = cipher_d->keylen;