From 72d4d098b0dbb10d3904868acc11c97acafa8d80 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Stefan=20S=C3=B8rensen?= Date: Tue, 3 Jul 2018 09:48:10 +0200 Subject: [PATCH] dropbear: Disable legacy/insecure options MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Dropbear by default enables a number of algorithms that are now considered insecure and should only be used when legacy support is required: 3DES encryption Blowfish encryption SHA1-96 message integrity CBC encryption mode DSA public keys Diffie-Hellman Group1 key exchange So disable them by default, but add a config option for bringing them back. Furthermore the Blowfish legacy algorithm is unconditionally disabled Signed-off-by: Stefan Sørensen Reviewed-by: Baruch Siach Reviewed-by: Thomas De Schampheleire Signed-off-by: Thomas Petazzoni --- package/dropbear/Config.in | 10 ++++++++++ package/dropbear/dropbear.mk | 12 +++++++++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/package/dropbear/Config.in b/package/dropbear/Config.in index 5d6b83b6d1..62f77bad9d 100644 --- a/package/dropbear/Config.in +++ b/package/dropbear/Config.in @@ -56,4 +56,14 @@ config BR2_PACKAGE_DROPBEAR_LASTLOG Enable logging of dropbear access to lastlog. Notice that Buildroot does not generate lastlog by default. +config BR2_PACKAGE_DROPBEAR_LEGACY_CRYPTO + bool "enable legacy crypto" + help + Enable legacy and possibly insecure algorithms: + 3DES encryption + SHA1-96 message integrity + CBC encryption mode + DSA public keys + Diffie-Hellman Group1 key exchange + endif diff --git a/package/dropbear/dropbear.mk b/package/dropbear/dropbear.mk index bb902bc7ce..7b1468cfb1 100644 --- a/package/dropbear/dropbear.mk +++ b/package/dropbear/dropbear.mk @@ -56,13 +56,23 @@ endef DROPBEAR_POST_EXTRACT_HOOKS += DROPBEAR_SVR_PASSWORD_AUTH endif +define DROPBEAR_DISABLE_LEGACY_CRYPTO + echo '#define DROPBEAR_3DES 0' >> $(@D)/localoptions.h + echo '#define DROPBEAR_ENABLE_CBC_MODE 0' >> $(@D)/localoptions.h + echo '#define DROPBEAR_SHA1_96_HMAC 0' >> $(@D)/localoptions.h + echo '#define DROPBEAR_DSS 0' >> $(@D)/localoptions.h + echo '#define DROPBEAR_DH_GROUP1 0' >> $(@D)/localoptions.h +endef +ifneq ($(BR2_PACKAGE_DROPBEAR_LEGACY_CRYPTO),y) +DROPBEAR_POST_EXTRACT_HOOKS += DROPBEAR_DISABLE_LEGACY_CRYPTO +endif + define DROPBEAR_ENABLE_REVERSE_DNS echo '#define DO_HOST_LOOKUP 1' >> $(@D)/localoptions.h endef define DROPBEAR_BUILD_FEATURED echo '#define DROPBEAR_SMALL_CODE 0' >> $(@D)/localoptions.h - echo '#define DROPBEAR_BLOWFISH 1' >> $(@D)/localoptions.h echo '#define DROPBEAR_TWOFISH128 1' >> $(@D)/localoptions.h echo '#define DROPBEAR_TWOFISH256 1' >> $(@D)/localoptions.h endef -- 2.30.2