[PATCH 02/18] SUNRPC: Add crypto/krb5 enctype lookup to krb5_ctx

[Chuck Lever <cel@kernel.org>]

From: Chuck Lever <chuck.lever@oracle.com>

Each krb5_ctx currently points to a gss_krb5_enctype, the
rpcsec_gss_krb5 module's own enctype descriptor. To begin
using the common crypto/krb5 library, store a pointer to the
corresponding struct krb5_enctype (from <crypto/krb5.h>) as
well.

The lookup is performed in gss_import_v2_context() immediately
after the existing gss_krb5_lookup_enctype() call. If
crypto_krb5_find_enctype() cannot find a matching enctype the
context import fails, ensuring the module never operates with
a partially-initialized krb5_ctx.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/auth_gss/gss_krb5_internal.h | 3 +++
 net/sunrpc/auth_gss/gss_krb5_mech.c     | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/net/sunrpc/auth_gss/gss_krb5_internal.h b/net/sunrpc/auth_gss/gss_krb5_internal.h
index 8769e9e705bf..11402c3b4972 100644
--- a/net/sunrpc/auth_gss/gss_krb5_internal.h
+++ b/net/sunrpc/auth_gss/gss_krb5_internal.h
@@ -8,6 +8,8 @@
 #ifndef _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H
 #define _NET_SUNRPC_AUTH_GSS_KRB5_INTERNAL_H
 
+#include <crypto/krb5.h>
+
 /*
  * The RFCs often specify payload lengths in bits. This helper
  * converts a specified bit-length to the number of octets/bytes.
@@ -62,6 +64,7 @@ struct krb5_ctx {
 	u32			enctype;
 	u32			flags;
 	const struct gss_krb5_enctype *gk5e; /* enctype-specific info */
+	const struct krb5_enctype *krb5e; /* crypto/krb5 enctype */
 	struct crypto_sync_skcipher *enc;
 	struct crypto_sync_skcipher *seq;
 	struct crypto_sync_skcipher *acceptor_enc;
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index 6db64a9111a9..060d8fc4358e 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -432,6 +432,13 @@ gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
 		p = ERR_PTR(-EINVAL);
 		goto out_err;
 	}
+	ctx->krb5e = crypto_krb5_find_enctype(ctx->enctype);
+	if (!ctx->krb5e) {
+		dprintk("gss_kerberos_mech: crypto/krb5 missing enctype %u\n",
+			ctx->enctype);
+		p = ERR_PTR(-EINVAL);
+		goto out_err;
+	}
 	keylen = ctx->gk5e->keylength;
 
 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);

-- 
2.53.0