[PATCH] crypto: user - re-add size check for CRYPTO_MSG_GETALG

[Mathias Krause <minipli@googlemail.com>]

Commit 9aa867e46565 ("crypto: user - Add CRYPTO_MSG_DELRNG")
accidentally removed the minimum size check for CRYPTO_MSG_GETALG
netlink messages. This allows userland to send a truncated
CRYPTO_MSG_GETALG message as short as a netlink header only making
crypto_report() operate on uninitialized memory by accessing data
beyond the end of the netlink message.

Fix this be re-adding the minimum required size of CRYPTO_MSG_GETALG
messages to the crypto_msg_min[] array.

Fixes: 9aa867e46565 ("crypto: user - Add CRYPTO_MSG_DELRNG")
Cc: stable@vger.kernel.org	# v4.2
Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
---
This should go on top of crypto-2.6/master.

 crypto/crypto_user.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/crypto/crypto_user.c b/crypto/crypto_user.c
index 43fe85f20d57..7097a3395b25 100644
--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -455,6 +455,7 @@ static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 	[CRYPTO_MSG_NEWALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_DELALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_UPDATEALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
+	[CRYPTO_MSG_GETALG	- CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 	[CRYPTO_MSG_DELRNG	- CRYPTO_MSG_BASE] = 0,
 };
 
-- 
1.7.10.4