[PATCH 08/22] gss_krb5: handle new context format from gssd

steved
2010-03-15T13:26:31Z

For encryption types other than DES, gssd sends down context information
in a new format. This new format includes the information needed to
support the new Kerberos GSS-API tokens defined in rfc4121.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
Signed-off-by: Steve Dickson <steved@redhat.com>
---
include/linux/sunrpc/gss_krb5.h | 19 +++
net/sunrpc/auth_gss/gss_krb5_mech.c | 237 ++++++++++++++++++++++++++++++++++-
2 files changed, 255 insertions(+), 1 deletions(-)

diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index b17a310..81d6fc2 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -77,16 +77,31 @@ struct gss_krb5_enctype {
struct xdr_netobj *out); /* complete key generation */
};

+/* krb5_ctx flags definitions */
+#define KRB5_CTX_FLAG_INITIATOR 0x00000001
+#define KRB5_CTX_FLAG_CFX 0x00000002
+#define KRB5_CTX_FLAG_ACCEPTOR_SUBKEY 0x00000004
+
struct krb5_ctx {
int initiate; /* 1 = initiating, 0 = accepting */
u32 enctype;
+ u32 flags;
struct gss_krb5_enctype *gk5e; /* enctype-specific info */
struct crypto_blkcipher *enc;
struct crypto_blkcipher *seq;
+ struct crypto_blkcipher *acceptor_enc;
+ struct crypto_blkcipher *initiator_enc;
u8 cksum[GSS_KRB5_MAX_KEYLEN];
s32 endtime;
u32 seq_send;
+ u64 seq_send64;
struct xdr_netobj mech_used;
+ u8 initiator_sign[GSS_KRB5_MAX_KEYLEN];
+ u8 acceptor_sign[GSS_KRB5_MAX_KEYLEN];
+ u8 initiator_seal[GSS_KRB5_MAX_KEYLEN];
+ u8 acceptor_seal[GSS_KRB5_MAX_KEYLEN];
+ u8 initiator_integ[GSS_KRB5_MAX_KEYLEN];
+ u8 acceptor_integ[GSS_KRB5_MAX_KEYLEN];
};

extern spinlock_t krb5_seq_lock;
@@ -151,6 +166,10 @@ enum seal_alg {
#define ENCTYPE_DES3_CBC_RAW 0x0006 /* DES-3 cbc mode raw */
#define ENCTYPE_DES_HMAC_SHA1 0x0008
#define ENCTYPE_DES3_CBC_SHA1 0x0010
+#define ENCTYPE_AES128_CTS_HMAC_SHA1_96 0x0011
+#define ENCTYPE_AES256_CTS_HMAC_SHA1_96 0x0012
+#define ENCTYPE_ARCFOUR_HMAC 0x0017
+#define ENCTYPE_ARCFOUR_HMAC_EXP 0x0018
#define ENCTYPE_UNKNOWN 0x01ff

/*
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index 81e90aa..838b1dd 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -48,6 +48,8 @@
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif

+static struct gss_api_mech gss_kerberos_mech; /* forward declaration */
+
static struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
/*
* DES (All DES enctypes are mapped to the same gss functionality)
@@ -253,6 +255,237 @@ out_err:
return PTR_ERR(p);
}

+struct crypto_blkcipher *
+context_v2_alloc_cipher(struct krb5_ctx *ctx, u8 *key)
+{
+ struct crypto_blkcipher *cp;
+
+ cp = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name,
+ 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(cp)) {
+ printk("gss_kerberos_mech: unable to initialize "
+ "crypto algorithm %s\n", ctx->gk5e->encrypt_name);
+ return NULL;
+ }
+ if (crypto_blkcipher_setkey(cp, key, ctx->gk5e->keylength)) {
+ printk("gss_kerberos_mech: error setting key for "
+ "crypto algorithm %s\n", ctx->gk5e->encrypt_name);
+ crypto_free_blkcipher(cp);
+ return NULL;
+ }
+ return cp;
+}
+
+static inline void
+set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
+{
+ cdata[0] = (usage>>24)&0xff;
+ cdata[1] = (usage>>16)&0xff;
+ cdata[2] = (usage>>8)&0xff;
+ cdata[3] = usage&0xff;
+ cdata[4] = seed;
+}
+
+static int
+context_derive_keys_des3(struct krb5_ctx *ctx, u8 *rawkey, u32 keylen)
+{
+ struct xdr_netobj c, keyin, keyout;
+ u8 cdata[GSS_KRB5_K5CLENGTH];
+ u32 err;
+
+ c.len = GSS_KRB5_K5CLENGTH;
+ c.data = cdata;
+
+ keyin.data = rawkey;
+ keyin.len = keylen;
+ keyout.len = keylen;
+
+ /* seq uses the raw key */
+ ctx->seq = context_v2_alloc_cipher(ctx, rawkey);
+ if (ctx->seq == NULL)
+ goto out_err;
+
+ ctx->enc = context_v2_alloc_cipher(ctx, rawkey);
+ if (ctx->enc == NULL)
+ goto out_free_seq;
+
+ /* derive cksum */
+ set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
+ keyout.data = ctx->cksum;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving cksum key\n",
+ __func__, err);
+ goto out_free_enc;
+ }
+
+ return 0;
+
+out_free_enc:
+ crypto_free_blkcipher(ctx->enc);
+out_free_seq:
+ crypto_free_blkcipher(ctx->seq);
+out_err:
+ return -EINVAL;
+}
+
+static int
+context_derive_keys_new(struct krb5_ctx *ctx, u8 *rawkey, u32 keylen)
+{
+ struct xdr_netobj c, keyin, keyout;
+ u8 cdata[GSS_KRB5_K5CLENGTH];
+ u32 err;
+
+ c.len = GSS_KRB5_K5CLENGTH;
+ c.data = cdata;
+
+ keyin.data = rawkey;
+ keyin.len = keylen;
+ keyout.len = keylen;
+
+ /* initiator seal encryption */
+ set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
+ keyout.data = ctx->initiator_seal;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving initiator_seal key\n",
+ __func__, err);
+ goto out_err;
+ }
+ ctx->initiator_enc = context_v2_alloc_cipher(ctx, ctx->initiator_seal);
+ if (ctx->initiator_enc == NULL)
+ goto out_err;
+
+ /* acceptor seal encryption */
+ set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
+ keyout.data = ctx->acceptor_seal;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving acceptor_seal key\n",
+ __func__, err);
+ goto out_free_initiator_enc;
+ }
+ ctx->acceptor_enc = context_v2_alloc_cipher(ctx, ctx->acceptor_seal);
+ if (ctx->acceptor_enc == NULL)
+ goto out_free_initiator_enc;
+
+ /* initiator sign checksum */
+ set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
+ keyout.data = ctx->initiator_sign;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving initiator_sign key\n",
+ __func__, err);
+ goto out_free_acceptor_enc;
+ }
+
+ /* acceptor sign checksum */
+ set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
+ keyout.data = ctx->acceptor_sign;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving acceptor_sign key\n",
+ __func__, err);
+ goto out_free_acceptor_enc;
+ }
+
+ /* initiator seal integrity */
+ set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
+ keyout.data = ctx->initiator_integ;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving initiator_integ key\n",
+ __func__, err);
+ goto out_free_acceptor_enc;
+ }
+
+ /* acceptor seal integrity */
+ set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
+ keyout.data = ctx->acceptor_integ;
+ err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c);
+ if (err) {
+ dprintk("%s: Error %d deriving acceptor_integ key\n",
+ __func__, err);
+ goto out_free_acceptor_enc;
+ }
+
+ return 0;
+
+out_free_acceptor_enc:
+ crypto_free_blkcipher(ctx->acceptor_enc);
+out_free_initiator_enc:
+ crypto_free_blkcipher(ctx->initiator_enc);
+out_err:
+ return -EINVAL;
+}
+
+static int
+gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx)
+{
+ u8 rawkey[GSS_KRB5_MAX_KEYLEN];
+ int keylen;
+
+ p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
+ if (IS_ERR(p))
+ goto out_err;
+ ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
+
+ p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
+ if (IS_ERR(p))
+ goto out_err;
+ p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
+ if (IS_ERR(p))
+ goto out_err;
+ /* set seq_send for use by "older" enctypes */
+ ctx->seq_send = ctx->seq_send64;
+ if (ctx->seq_send64 != ctx->seq_send) {
+ dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
+ (long unsigned)ctx->seq_send64, ctx->seq_send);
+ goto out_err;
+ }
+ p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
+ if (IS_ERR(p))
+ goto out_err;
+ ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
+ if (ctx->gk5e == NULL) {
+ printk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
+ ctx->enctype);
+ p = ERR_PTR(-EINVAL);
+ goto out_err;
+ }
+ keylen = ctx->gk5e->keylength;
+
+ p = simple_get_bytes(p, end, rawkey, keylen);
+ if (IS_ERR(p))
+ goto out_err;
+
+ if (p != end) {
+ p = ERR_PTR(-EINVAL);
+ goto out_err;
+ }
+
+ ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
+ gss_kerberos_mech.gm_oid.len, GFP_KERNEL);
+ if (unlikely(ctx->mech_used.data == NULL)) {
+ p = ERR_PTR(-ENOMEM);
+ goto out_err;
+ }
+ ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
+
+ switch (ctx->enctype) {
+ case ENCTYPE_DES3_CBC_RAW:
+ return context_derive_keys_des3(ctx, rawkey, keylen);
+ case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
+ case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
+ return context_derive_keys_new(ctx, rawkey, keylen);
+ default:
+ return -EINVAL;
+ }
+
+out_err:
+ return PTR_ERR(p);
+}
+
static int
gss_import_sec_context_kerberos(const void *p, size_t len,
struct gss_ctx *ctx_id)
@@ -269,7 +502,7 @@ gss_import_sec_context_kerberos(const void *p, size_t len,
if (len == 85)
ret = gss_import_v1_context(p, end, ctx);
else
- ret = -EINVAL;
+ ret = gss_import_v2_context(p, end, ctx);

if (ret == 0)
ctx_id->internal_ctx_id = ctx;
@@ -286,6 +519,8 @@ gss_delete_sec_context_kerberos(void *internal_ctx) {

crypto_free_blkcipher(kctx->seq);
crypto_free_blkcipher(kctx->enc);
+ crypto_free_blkcipher(kctx->acceptor_enc);
+ crypto_free_blkcipher(kctx->initiator_enc);
kfree(kctx->mech_used.data);
kfree(kctx);
}
--
1.6.6.1