gss_krb5: handle new context format from gssd
authorKevin Coffman <kwc@citi.umich.edu>
Wed, 17 Mar 2010 17:02:54 +0000 (13:02 -0400)
committerTrond Myklebust <Trond.Myklebust@netapp.com>
Fri, 14 May 2010 19:09:17 +0000 (15:09 -0400)
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>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
include/linux/sunrpc/gss_krb5.h
net/sunrpc/auth_gss/gss_krb5_keys.c
net/sunrpc/auth_gss/gss_krb5_mech.c

index d31ba03..04d5279 100644 (file)
@@ -72,21 +72,36 @@ struct gss_krb5_enctype {
        u32 (*decrypt) (struct crypto_blkcipher *tfm,
                        void *iv, void *in, void *out,
                        int length);            /* decryption function */
-       u32 (*mk_key) (struct gss_krb5_enctype *gk5e,
+       u32 (*mk_key) (const struct gss_krb5_enctype *gk5e,
                       struct xdr_netobj *in,
                       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;
        const 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
 
 /*
@@ -238,7 +257,7 @@ int
 xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen);
 
 u32
-krb5_derive_key(struct gss_krb5_enctype *gk5e,
+krb5_derive_key(const struct gss_krb5_enctype *gk5e,
                const struct xdr_netobj *inkey,
                struct xdr_netobj *outkey,
                const struct xdr_netobj *in_constant);
index 832ce90..253b414 100644 (file)
@@ -147,7 +147,7 @@ static void krb5_nfold(u32 inbits, const u8 *in,
  * Taken from MIT Kerberos and modified.
  */
 
-u32 krb5_derive_key(struct gss_krb5_enctype *gk5e,
+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)
index fdf0eb2..8b612e7 100644 (file)
@@ -48,6 +48,8 @@
 # define RPCDBG_FACILITY       RPCDBG_AUTH
 #endif
 
+static struct gss_api_mech gss_kerberos_mech;  /* forward declaration */
+
 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
        /*
         * DES (All DES enctypes are mapped to the same gss functionality)
@@ -247,6 +249,237 @@ 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)) {
+               dprintk("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)) {
+               dprintk("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) {
+               dprintk("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)
@@ -262,7 +495,7 @@ 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;
@@ -279,6 +512,8 @@ 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);
 }