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gss_krb5: handle new context format from gssd
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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>
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Kevin Coffman authored and Trond Myklebust committed May 14, 2010
1 parent 4891f2d commit 47d8480
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Showing 3 changed files with 258 additions and 4 deletions.
23 changes: 21 additions & 2 deletions include/linux/sunrpc/gss_krb5.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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

/*
Expand Down Expand Up @@ -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);
2 changes: 1 addition & 1 deletion net/sunrpc/auth_gss/gss_krb5_keys.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down
237 changes: 236 additions & 1 deletion net/sunrpc/auth_gss/gss_krb5_mech.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand Down Expand Up @@ -247,6 +249,237 @@ gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
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)
Expand All @@ -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;
Expand All @@ -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);
}
Expand Down

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