[PATCH 4.6 16/31] crypto: user - re-add size check for CRYPTO_MSG_GETALG

[Greg Kroah-Hartman]

4.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

commit 055ddaace03580455a7b7dbea8e93d62acee61fc upstream.

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")
Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Cc: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/crypto/crypto_user.c
+++ b/crypto/crypto_user.c
@@ -455,6 +455,7 @@ static const int crypto_msg_min[CRYPTO_N
 	[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,
 };