security/keys: make BIG_KEYS dependent on stdrng.

Since BIG_KEYS can't be compiled as module it requires one of the "stdrng"
providers to be compiled into kernel. Otherwise big_key_crypto_init() fails
on crypto_alloc_rng step and next dereference of big_key_skcipher (e.g. in
big_key_preparse()) results in a NULL pointer dereference.

Fixes: 13100a72f40f5748a04017e0ab3df4cf27c809ef ('Security: Keys: Big keys stored encrypted')
Signed-off-by: Artem Savkov <asavkov@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Stephan Mueller <smueller@chronox.de>
cc: Kirill Marinushkin <k.marinushkin@gmail.com>
cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>

diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index f826e87..d942c7c 100644 (file)
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -41,7 +41,7 @@ config BIG_KEYS
        bool "Large payload keys"
        depends on KEYS
        depends on TMPFS
        bool "Large payload keys"
        depends on KEYS
        depends on TMPFS

-       select CRYPTO
+       depends on (CRYPTO_ANSI_CPRNG = y || CRYPTO_DRBG = y)

        select CRYPTO_AES
        select CRYPTO_ECB
        select CRYPTO_RNG
        select CRYPTO_AES
        select CRYPTO_ECB
        select CRYPTO_RNG