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/*
* COPYRIGHT (c) 2008
* The Regents of the University of Michigan
* ALL RIGHTS RESERVED
*
* Permission is granted to use, copy, create derivative works
* and redistribute this software and such derivative works
* for any purpose, so long as the name of The University of
* Michigan is not used in any advertising or publicity
* pertaining to the use of distribution of this software
* without specific, written prior authorization. If the
* above copyright notice or any other identification of the
* University of Michigan is included in any copy of any
* portion of this software, then the disclaimer below must
* also be included.
*
* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
* FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
* PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
* MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
* WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
* REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
* FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
* CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
* OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGES.
*/
#include <crypto/skcipher.h>
#include <linux/types.h>
#include <linux/jiffies.h>
#include <linux/sunrpc/gss_krb5.h>
#include <linux/random.h>
#include <linux/pagemap.h>
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
static inline int
gss_krb5_padding(int blocksize, int length)
{
return blocksize - (length % blocksize);
}
static inline void
gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
{
int padding = gss_krb5_padding(blocksize, buf->len - offset);
char *p;
struct kvec *iov;
if (buf->page_len || buf->tail[0].iov_len)
iov = &buf->tail[0];
else
iov = &buf->head[0];
p = iov->iov_base + iov->iov_len;
iov->iov_len += padding;
buf->len += padding;
memset(p, padding, padding);
}
static inline int
gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
{
u8 *ptr;
u8 pad;
size_t len = buf->len;
if (len <= buf->head[0].iov_len) {
pad = *(u8 *)(buf->head[0].iov_base + len - 1);
if (pad > buf->head[0].iov_len)
return -EINVAL;
buf->head[0].iov_len -= pad;
goto out;
} else
len -= buf->head[0].iov_len;
if (len <= buf->page_len) {
unsigned int last = (buf->page_base + len - 1)
>>PAGE_SHIFT;
unsigned int offset = (buf->page_base + len - 1)
& (PAGE_SIZE - 1);
ptr = kmap_atomic(buf->pages[last]);
pad = *(ptr + offset);
kunmap_atomic(ptr);
goto out;
} else
len -= buf->page_len;
BUG_ON(len > buf->tail[0].iov_len);
pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
out:
/* XXX: NOTE: we do not adjust the page lengths--they represent
* a range of data in the real filesystem page cache, and we need
* to know that range so the xdr code can properly place read data.
* However adjusting the head length, as we do above, is harmless.
* In the case of a request that fits into a single page, the server
* also uses length and head length together to determine the original
* start of the request to copy the request for deferal; so it's
* easier on the server if we adjust head and tail length in tandem.
* It's not really a problem that we don't fool with the page and
* tail lengths, though--at worst badly formed xdr might lead the
* server to attempt to parse the padding.
* XXX: Document all these weird requirements for gss mechanism
* wrap/unwrap functions. */
if (pad > blocksize)
return -EINVAL;
if (buf->len > pad)
buf->len -= pad;
else
return -EINVAL;
return 0;
}
void
gss_krb5_make_confounder(char *p, u32 conflen)
{
static u64 i = 0;
u64 *q = (u64 *)p;
/* rfc1964 claims this should be "random". But all that's really
* necessary is that it be unique. And not even that is necessary in
* our case since our "gssapi" implementation exists only to support
* rpcsec_gss, so we know that the only buffers we will ever encrypt
* already begin with a unique sequence number. Just to hedge my bets
* I'll make a half-hearted attempt at something unique, but ensuring
* uniqueness would mean worrying about atomicity and rollover, and I
* don't care enough. */
/* initialize to random value */
if (i == 0) {
i = prandom_u32();
i = (i << 32) | prandom_u32();
}
switch (conflen) {
case 16:
*q++ = i++;
/* fall through */
case 8:
*q++ = i++;
break;
default:
BUG();
}
}
/* Assumptions: the head and tail of inbuf are ours to play with.
* The pages, however, may be real pages in the page cache and we replace
* them with scratch pages from **pages before writing to them. */
/* XXX: obviously the above should be documentation of wrap interface,
* and shouldn't be in this kerberos-specific file. */
/* XXX factor out common code with seal/unseal. */
static u32
gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
struct xdr_buf *buf, struct page **pages)
{
char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
.data = cksumdata};
int blocksize = 0, plainlen;
unsigned char *ptr, *msg_start;
s32 now;
int headlen;
struct page **tmp_pages;
u32 seq_send;
u8 *cksumkey;
u32 conflen = kctx->gk5e->conflen;
dprintk("RPC: %s\n", __func__);
now = get_seconds();
blocksize = crypto_sync_skcipher_blocksize(kctx->enc);
gss_krb5_add_padding(buf, offset, blocksize);
BUG_ON((buf->len - offset) % blocksize);
plainlen = conflen + buf->len - offset;
headlen = g_token_size(&kctx->mech_used,
GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
(buf->len - offset);
ptr = buf->head[0].iov_base + offset;
/* shift data to make room for header. */
xdr_extend_head(buf, offset, headlen);
/* XXX Would be cleverer to encrypt while copying. */
BUG_ON((buf->len - offset - headlen) % blocksize);
g_make_token_header(&kctx->mech_used,
GSS_KRB5_TOK_HDR_LEN +
kctx->gk5e->cksumlength + plainlen, &ptr);
/* ptr now at header described in rfc 1964, section 1.2.1: */
ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
/*
* signalg and sealalg are stored as if they were converted from LE
* to host endian, even though they're opaque pairs of bytes according
* to the RFC.
*/
*(__le16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
*(__le16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
ptr[6] = 0xff;
ptr[7] = 0xff;
gss_krb5_make_confounder(msg_start, conflen);
if (kctx->gk5e->keyed_cksum)
|