SUNRPC: Hoist KDF into struct gss_krb5_enctype

Each Kerberos enctype can have a different KDF. Refactor the key
derivation path to support different KDFs for the enctypes
introduced in subsequent patches.

In particular, expose the key derivation function in struct
gss_krb5_enctype instead of the enctype's preferred random-to-key
function. The latter is usually the identity function and is only
ever called during key derivation, so have each KDF call it
directly.

A couple of extra clean-ups:
- Deduplicate the set_cdata() helper
- Have ->derive_key return negative errnos, in accordance with usual
  kernel coding conventions

This patch is a little bigger than I'd like, but these are all
mechanical changes and they are all to the same areas of code. No
behavior change is intended.

Tested-by: Scott Mayhew <smayhew@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

1 files changed, 5 insertions, 20 deletions

diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index 85fce36c242d..04addef79177 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -70,9 +70,11 @@ struct gss_krb5_enctype {
 	const u32		keybytes;	/* raw key len, in bytes */
 	const u32		keylength;	/* final key len, in bytes */
 	int (*import_ctx)(struct krb5_ctx *ctx, gfp_t gfp_mask);
-	u32 (*mk_key) (const struct gss_krb5_enctype *gk5e,
-		       struct xdr_netobj *in,
-		       struct xdr_netobj *out);	/* complete key generation */
+	int (*derive_key)(const struct gss_krb5_enctype *gk5e,
+			  const struct xdr_netobj *in,
+			  struct xdr_netobj *out,
+			  const struct xdr_netobj *label,
+			  gfp_t gfp_mask);
 	u32 (*encrypt)(struct krb5_ctx *kctx, u32 offset,
 			struct xdr_buf *buf, struct page **pages);
 	u32 (*decrypt)(struct krb5_ctx *kctx, u32 offset, u32 len,
@@ -257,21 +259,4 @@ krb5_get_seq_num(struct krb5_ctx *kctx,
 int
 xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen);
 
-u32
-krb5_derive_key(const struct gss_krb5_enctype *gk5e,
-		const struct xdr_netobj *inkey,
-		struct xdr_netobj *outkey,
-		const struct xdr_netobj *in_constant,
-		gfp_t gfp_mask);
-
-u32
-gss_krb5_des3_make_key(const struct gss_krb5_enctype *gk5e,
-		       struct xdr_netobj *randombits,
-		       struct xdr_netobj *key);
-
-u32
-gss_krb5_aes_make_key(const struct gss_krb5_enctype *gk5e,
-		      struct xdr_netobj *randombits,
-		      struct xdr_netobj *key);
-
 #endif /* _LINUX_SUNRPC_GSS_KRB5_H */