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>
This commit is contained in:
Kevin Coffman 2010-03-17 13:02:46 -04:00 committed by Trond Myklebust
parent 4fc4c3ce0d
commit 725f2865d4
4 changed files with 66 additions and 5 deletions

View file

@ -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 @@ enum seal_alg {
#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 @@ s32
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);