gss_krb5: handle new context format from gssd

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>

3 files changed, 258 insertions, 4 deletions

diff --git a/include/linux/sunrpc/gss_krb5.h b/include/linux/sunrpc/gss_krb5.h
index d31ba0304d18..04d5279f17df 100644
--- a/include/linux/sunrpc/gss_krb5.h
+++ b/include/linux/sunrpc/gss_krb5.h
@@ -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);
diff --git a/net/sunrpc/auth_gss/gss_krb5_keys.c b/net/sunrpc/auth_gss/gss_krb5_keys.c
index 832ce901bf68..253b4149584a 100644
--- a/net/sunrpc/auth_gss/gss_krb5_keys.c
+++ b/net/sunrpc/auth_gss/gss_krb5_keys.c
@@ -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)
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index fdf0eb2057ab..8b612e733563 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 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);
 }