[RFC PATCH 1/2] crypto: Allow working with key references

[Richard Weinberger]

Some crypto accelerators allow working with secure or hidden keys.
This keys are not exposed to Linux nor main memory. To use them
for a crypto operation they are referenced with a device specific id.

This patch adds a new flag, CRYPTO_TFM_REQ_REF_KEY.
If this flag is set, crypto drivers should tread the key as
specified via setkey as reference and not as regular key.
Since we reuse the key data structure such a reference is limited
by the key size of the chiper and is chip specific.

TODO: If the cipher implementation or the driver does not
support reference keys, we need a way to detect this an fail
upon setkey.
How should the driver indicate that it supports this feature?

Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
 include/linux/crypto.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index f2565a103158..737ea00e026b 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -121,6 +121,7 @@
 #define CRYPTO_TFM_REQ_FORBID_WEAK_KEYS	0x00000100
 #define CRYPTO_TFM_REQ_MAY_SLEEP	0x00000200
 #define CRYPTO_TFM_REQ_MAY_BACKLOG	0x00000400
+#define CRYPTO_TFM_REQ_REF_KEY		0x00000800
 #define CRYPTO_TFM_RES_WEAK_KEY		0x00100000
 #define CRYPTO_TFM_RES_BAD_KEY_LEN   	0x00200000
 #define CRYPTO_TFM_RES_BAD_KEY_SCHED 	0x00400000
-- 
2.16.4