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gss_krb5: add support for new token formats in rfc4121

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This is a step toward support for AES encryption types which are
required to use the new token formats defined in rfc4121.

Signed-off-by: Kevin Coffman <kwc@citi.umich.edu>
[SteveD: Fixed a typo in gss_verify_mic_v2()]
Signed-off-by: Steve Dickson <steved@redhat.com>
[Trond: Got rid of the TEST_ROTATE/TEST_EXTRA_COUNT crap]
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Kevin Coffman
2010-03-17 13:02:59 -04:00
committed by Trond Myklebust
parent c43abaedaf
commit de9c17eb4a
5 changed files with 406 additions and 0 deletions
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174
net/sunrpc/auth_gss/gss_krb5_wrap.c
View File

@@ -340,6 +340,174 @@ gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
return GSS_S_COMPLETE;
}
/*
* We cannot currently handle tokens with rotated data. We need a
* generalized routine to rotate the data in place. It is anticipated
* that we won't encounter rotated data in the general case.
*/
static u32
rotate_left(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, u16 rrc)
{
unsigned int realrrc = rrc % (buf->len - offset - GSS_KRB5_TOK_HDR_LEN);
if (realrrc == 0)
return 0;
dprintk("%s: cannot process token with rotated data: "
"rrc %u, realrrc %u\n", __func__, rrc, realrrc);
return 1;
}
static u32
gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
struct xdr_buf *buf, struct page **pages)
{
int blocksize;
u8 *ptr, *plainhdr;
s32 now;
u8 flags = 0x00;
__be16 *be16ptr, ec = 0;
__be64 *be64ptr;
u32 err;
dprintk("RPC: %s\n", __func__);
if (kctx->gk5e->encrypt_v2 == NULL)
return GSS_S_FAILURE;
/* make room for gss token header */
if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
return GSS_S_FAILURE;
/* construct gss token header */
ptr = plainhdr = buf->head[0].iov_base + offset;
*ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
*ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
/* We always do confidentiality in wrap tokens */
flags |= KG2_TOKEN_FLAG_SEALED;
*ptr++ = flags;
*ptr++ = 0xff;
be16ptr = (__be16 *)ptr;
blocksize = crypto_blkcipher_blocksize(kctx->acceptor_enc);
*be16ptr++ = cpu_to_be16(ec);
/* "inner" token header always uses 0 for RRC */
*be16ptr++ = cpu_to_be16(0);
be64ptr = (__be64 *)be16ptr;
spin_lock(&krb5_seq_lock);
*be64ptr = cpu_to_be64(kctx->seq_send64++);
spin_unlock(&krb5_seq_lock);
err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, ec, pages);
if (err)
return err;
now = get_seconds();
return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
}
static u32
gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
{
s32 now;
u64 seqnum;
u8 *ptr;
u8 flags = 0x00;
u16 ec, rrc;
int err;
u32 headskip, tailskip;
u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
unsigned int movelen;
dprintk("RPC: %s\n", __func__);
if (kctx->gk5e->decrypt_v2 == NULL)
return GSS_S_FAILURE;
ptr = buf->head[0].iov_base + offset;
if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
return GSS_S_DEFECTIVE_TOKEN;
flags = ptr[2];
if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
(kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
return GSS_S_BAD_SIG;
if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
dprintk("%s: token missing expected sealed flag\n", __func__);
return GSS_S_DEFECTIVE_TOKEN;
}
if (ptr[3] != 0xff)
return GSS_S_DEFECTIVE_TOKEN;
ec = be16_to_cpup((__be16 *)(ptr + 4));
rrc = be16_to_cpup((__be16 *)(ptr + 6));
seqnum = be64_to_cpup((__be64 *)(ptr + 8));
if (rrc != 0) {
err = rotate_left(kctx, offset, buf, rrc);
if (err)
return GSS_S_FAILURE;
}
err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
&headskip, &tailskip);
if (err)
return GSS_S_FAILURE;
/*
* Retrieve the decrypted gss token header and verify
* it against the original
*/
err = read_bytes_from_xdr_buf(buf,
buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
if (err) {
dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
return GSS_S_FAILURE;
}
if (memcmp(ptr, decrypted_hdr, 6)
|| memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
return GSS_S_FAILURE;
}
/* do sequencing checks */
/* it got through unscathed. Make sure the context is unexpired */
now = get_seconds();
if (now > kctx->endtime)
return GSS_S_CONTEXT_EXPIRED;
/*
* Move the head data back to the right position in xdr_buf.
* We ignore any "ec" data since it might be in the head or
* the tail, and we really don't need to deal with it.
* Note that buf->head[0].iov_len may indicate the available
* head buffer space rather than that actually occupied.
*/
movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
buf->head[0].iov_len);
memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
return GSS_S_COMPLETE;
}
u32
gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
struct xdr_buf *buf, struct page **pages)
@@ -352,6 +520,9 @@ gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
case ENCTYPE_DES_CBC_RAW:
case ENCTYPE_DES3_CBC_RAW:
return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
}
}
@@ -366,6 +537,9 @@ gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
case ENCTYPE_DES_CBC_RAW:
case ENCTYPE_DES3_CBC_RAW:
return gss_unwrap_kerberos_v1(kctx, offset, buf);
case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
return gss_unwrap_kerberos_v2(kctx, offset, buf);
}
}