gss_krb5: Introduce encryption type framework
Make the client and server code consistent regarding the extra buffer
space made available for the auth code when wrapping data.
Add some comments/documentation about the available buffer space
in the xdr_buf head and tail when gss_wrap is called.
Add a compile-time check to make sure we are not exceeding the available
buffer space.
Add a central function to shift head data.
Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index e7bbdba..31bb8a5 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -40,6 +40,12 @@
#include <linux/sunrpc/gss_err.h>
#include <linux/sunrpc/gss_asn1.h>
+/* Maximum checksum function output for the supported crypto algorithms */
+#define GSS_KRB5_MAX_CKSUM_LEN (20)
+
+/* Maximum blocksize for the supported crypto algorithms */
+#define GSS_KRB5_MAX_BLOCKSIZE (16)
+
struct krb5_ctx {
int initiate; /* 1 = initiating, 0 = accepting */
struct crypto_blkcipher *enc;
@@ -113,6 +119,22 @@
#define ENCTYPE_DES3_CBC_SHA1 0x0010
#define ENCTYPE_UNKNOWN 0x01ff
+/*
+ * This compile-time check verifies that we will not exceed the
+ * slack space allotted by the client and server auth_gss code
+ * before they call gss_wrap().
+ */
+#define GSS_KRB5_MAX_SLACK_NEEDED \
+ (GSS_KRB5_TOK_HDR_LEN /* gss token header */ \
+ + GSS_KRB5_MAX_CKSUM_LEN /* gss token checksum */ \
+ + GSS_KRB5_MAX_BLOCKSIZE /* confounder */ \
+ + GSS_KRB5_MAX_BLOCKSIZE /* possible padding */ \
+ + GSS_KRB5_TOK_HDR_LEN /* encrypted hdr in v2 token */\
+ + GSS_KRB5_MAX_CKSUM_LEN /* encryption hmac */ \
+ + 4 + 4 /* RPC verifier */ \
+ + GSS_KRB5_TOK_HDR_LEN \
+ + GSS_KRB5_MAX_CKSUM_LEN)
+
s32
make_checksum(char *, char *header, int hdrlen, struct xdr_buf *body,
int body_offset, struct xdr_netobj *cksum);
@@ -157,3 +179,6 @@
krb5_get_seq_num(struct crypto_blkcipher *key,
unsigned char *cksum,
unsigned char *buf, int *direction, u32 *seqnum);
+
+int
+xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen);