Re: [ptxdist] [APPLIED] dropbear: Rework key exchange algorithm options

[Michael Olbrich <m.olbrich@pengutronix.de>]

Thanks, applied as 91608613316a0031ec4a9581f762160a99239ce2.

Michael

[sent from post-receive hook]

On Fri, 29 Jul 2022 08:23:34 +0200, Alexander Dahl <ada@thorsis.com> wrote:
> The options for diffie-hellman key exchange were mixed up with message
> integrity hmacs.
> 
> Signed-off-by: Alexander Dahl <ada@thorsis.com>
> Message-Id: <20220704121831.23787-7-ada@thorsis.com>
> Signed-off-by: Michael Olbrich <m.olbrich@pengutronix.de>
> 
> diff --git a/rules/dropbear.in b/rules/dropbear.in
> index 33e8500a93ee..a64b2306a64a 100644
> --- a/rules/dropbear.in
> +++ b/rules/dropbear.in
> @@ -279,7 +279,30 @@ config DROPBEAR_ED25519
>  	  Public keys are 256 bits long and signatures are 512 bits
>  	  long.
>  
> -comment "Key exchange algorithm ---"
> +comment "Key exchange algorithm, at least one required ---"
> +
> +config DROPBEAR_DH_GROUP14_SHA256
> +	bool
> +	prompt "group14_sha256"
> +	default y
> +	help
> +	  2048 bit, sha2-256.
> +	  group14 is supported by most implementations.
> +
> +config DROPBEAR_DH_GROUP14_SHA1
> +	bool
> +	prompt "group14_sha1"
> +	help
> +	  2048 bit, sha1.
> +	  group14 is supported by most implementations.
> +
> +config DROPBEAR_DH_GROUP16
> +	bool
> +	prompt "group16"
> +	help
> +	  4096 bit, sha2-512.
> +	  group16 provides a greater strength level but is slower and
> +	  increases binary size.
>  
>  config DROPBEAR_ECDH
>  	bool
> @@ -287,16 +310,32 @@ config DROPBEAR_ECDH
>  	help
>  	  ECDH stands for Elliptic Curve Diffie-Hellman.
>  
> +	  Small systems should generally include either curve25519 or
> +	  ecdh for performance.
> +
>  config DROPBEAR_CURVE25519
>  	bool
> -	prompt "curve25519-donna"
> +	prompt "curve25519"
>  	help
> -	  Enable curve25519-donna for key exchange.
> +	  Enable curve25519 for key exchange.
>  	  This is another elliptic curve method with good security properties.
>  	  This algorithm does not rely on NIST-based curves
>  	  and gives us more security confidence against a possible
>  	  backdoor in nistp-256 curve.
>  
> +	  Small systems should generally include either curve25519 or
> +	  ecdh for performance.
> +
> +config DROPBEAR_DH_GROUP1
> +	bool
> +	prompt "group1 (legacy, client only)"
> +	help
> +	  1024 bit, sha1.
> +	  This is too small for security though is necessary if you need
> +	  compatibility with some implementations such as Dropbear
> +	  versions < 0.53.
> +	  Client only!
> +
>  comment "Authentication types, at least one required --- RFC Draft requires pubkey auth"
>  
>  config DROPBEAR_PASSWD
> diff --git a/rules/dropbear.make b/rules/dropbear.make
> index 7653cf3e57cc..e86b8bf43803 100644
> --- a/rules/dropbear.make
> +++ b/rules/dropbear.make
> @@ -157,13 +157,9 @@ endif
>  ifdef PTXCONF_DROPBEAR_SHA1
>  	@echo "ptxdist: enabling sha1"
>  	@echo "#define DROPBEAR_SHA1_HMAC 1" >> $(DROPBEAR_LOCALOPTIONS)
> -	@echo "#define DROPBEAR_DH_GROUP1 1" >> $(DROPBEAR_LOCALOPTIONS)
> -	@echo "#define DROPBEAR_DH_GROUP14_SHA1 1" >> $(DROPBEAR_LOCALOPTIONS)
>  else
>  	@echo "ptxdist: disabling sha1"
>  	@echo "#define DROPBEAR_SHA1_HMAC 0" >> $(DROPBEAR_LOCALOPTIONS)
> -	@echo "#define DROPBEAR_DH_GROUP1 0" >> $(DROPBEAR_LOCALOPTIONS)
> -	@echo "#define DROPBEAR_DH_GROUP14_SHA1 0" >> $(DROPBEAR_LOCALOPTIONS)
>  endif
>  
>  ifdef PTXCONF_DROPBEAR_SHA1_96
> @@ -223,6 +219,30 @@ endif
>  	@echo "#define DROPBEAR_SK_ED25519 0" >> $(DROPBEAR_LOCALOPTIONS)
>  
>  # key exchange algorithm
> +ifdef PTXCONF_DROPBEAR_DH_GROUP14_SHA256
> +	@echo "ptxdist: enabling dh_group14_sha256"
> +	@echo "#define DROPBEAR_DH_GROUP14_SHA256 1" >> $(DROPBEAR_LOCALOPTIONS)
> +else
> +	@echo "ptxdist: disabling dh_group14_sha256"
> +	@echo "#define DROPBEAR_DH_GROUP14_SHA256 0" >> $(DROPBEAR_LOCALOPTIONS)
> +endif
> +
> +ifdef PTXCONF_DROPBEAR_DH_GROUP14_SHA1
> +	@echo "ptxdist: enabling dh_group14_sha1"
> +	@echo "#define DROPBEAR_DH_GROUP14_SHA1 1" >> $(DROPBEAR_LOCALOPTIONS)
> +else
> +	@echo "ptxdist: disabling dh_group14_sha1"
> +	@echo "#define DROPBEAR_DH_GROUP14_SHA1 0" >> $(DROPBEAR_LOCALOPTIONS)
> +endif
> +
> +ifdef PTXCONF_DROPBEAR_DH_GROUP16
> +	@echo "ptxdist: enabling dh_group16"
> +	@echo "#define DROPBEAR_DH_GROUP16 1" >> $(DROPBEAR_LOCALOPTIONS)
> +else
> +	@echo "ptxdist: disabling dh_group16"
> +	@echo "#define DROPBEAR_DH_GROUP16 0" >> $(DROPBEAR_LOCALOPTIONS)
> +endif
> +
>  ifdef PTXCONF_DROPBEAR_ECDH
>  	@echo "ptxdist: enabling ecdh"
>  	@echo "#define DROPBEAR_ECDH 1" >> $(DROPBEAR_LOCALOPTIONS)
> @@ -239,6 +259,14 @@ else
>  	@echo "#define DROPBEAR_CURVE25519 0" >> $(DROPBEAR_LOCALOPTIONS)
>  endif
>  
> +ifdef PTXCONF_DROPBEAR_DH_GROUP1
> +	@echo "ptxdist: enabling dh_group1"
> +	@echo "#define DROPBEAR_DH_GROUP1 1" >> $(DROPBEAR_LOCALOPTIONS)
> +else
> +	@echo "ptxdist: disabling dh_group1"
> +	@echo "#define DROPBEAR_DH_GROUP1 0" >> $(DROPBEAR_LOCALOPTIONS)
> +endif
> +
>  # authentication types
>  ifdef PTXCONF_DROPBEAR_PASSWD
>  	@echo "ptxdist: enabling passwd"