[PATCH net v2] esp: select CRYPTO_SEQIV when useful

[Eric Biggers <ebiggers@kernel.org>]

From: Eric Biggers <ebiggers@google.com>

CRYPTO_CTR no longer selects CRYPTO_SEQIV, which breaks IPsec for users
who need any of the algorithms that use seqiv.  These users now would
need to explicitly enable CRYPTO_SEQIV.

There doesn't seem to be a clear rule on what algorithms the IPsec
options (INET_ESP and INET6_ESP) actually select, as apparently none is
*always* required.  They currently select just a particular subset,
along with CRYPTO_ECHAINIV which is the other IV generator template.

As a compromise between too many and too few selections, select
CRYPTO_SEQIV if either CRYPTO_CTR or CRYPTO_CHACHA20POLY1305 is enabled.
These are the algorithms that can use seqiv for IPsec.  (Note: GCM and
CCM can too, but those both use CTR.)

Fixes: f23efcbcc523 ("crypto: ctr - no longer needs CRYPTO_SEQIV")
Cc: Corentin Labbe <clabbe@baylibre.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---

v2: added the 'if' condition and updated commit message

 net/ipv4/Kconfig | 1 +
 net/ipv6/Kconfig | 1 +
 2 files changed, 2 insertions(+)

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index 23ba5045e3d3..6520b30883cf 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -361,6 +361,7 @@ config INET_ESP
 	select CRYPTO_SHA1
 	select CRYPTO_DES
 	select CRYPTO_ECHAINIV
+	select CRYPTO_SEQIV if CRYPTO_CTR || CRYPTO_CHACHA20POLY1305
 	---help---
 	  Support for IPsec ESP.
 
diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 4f03aece2980..c78adb0f5339 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -70,6 +70,7 @@ config INET6_ESP
 	select CRYPTO_SHA1
 	select CRYPTO_DES
 	select CRYPTO_ECHAINIV
+	select CRYPTO_SEQIV if CRYPTO_CTR || CRYPTO_CHACHA20POLY1305
 	---help---
 	  Support for IPsec ESP.
 
-- 
2.27.0.278.ge193c7cf3a9-goog