mirror of https://gitee.com/openkylin/linux.git
627 lines
18 KiB
C
627 lines
18 KiB
C
/*
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* COPYRIGHT (c) 2008
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* The Regents of the University of Michigan
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* ALL RIGHTS RESERVED
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*
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* Permission is granted to use, copy, create derivative works
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* and redistribute this software and such derivative works
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* for any purpose, so long as the name of The University of
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* Michigan is not used in any advertising or publicity
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* pertaining to the use of distribution of this software
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* without specific, written prior authorization. If the
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* above copyright notice or any other identification of the
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* University of Michigan is included in any copy of any
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* portion of this software, then the disclaimer below must
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* also be included.
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*
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* THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
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* FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
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* PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
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* MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
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* WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
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* REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
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* FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
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* CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
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* OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
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* IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGES.
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*/
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#include <crypto/skcipher.h>
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#include <linux/types.h>
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#include <linux/jiffies.h>
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#include <linux/sunrpc/gss_krb5.h>
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#include <linux/random.h>
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#include <linux/pagemap.h>
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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static inline int
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gss_krb5_padding(int blocksize, int length)
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{
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return blocksize - (length % blocksize);
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}
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static inline void
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gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
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{
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int padding = gss_krb5_padding(blocksize, buf->len - offset);
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char *p;
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struct kvec *iov;
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if (buf->page_len || buf->tail[0].iov_len)
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iov = &buf->tail[0];
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else
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iov = &buf->head[0];
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p = iov->iov_base + iov->iov_len;
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iov->iov_len += padding;
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buf->len += padding;
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memset(p, padding, padding);
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}
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static inline int
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gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
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{
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u8 *ptr;
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u8 pad;
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size_t len = buf->len;
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if (len <= buf->head[0].iov_len) {
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pad = *(u8 *)(buf->head[0].iov_base + len - 1);
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if (pad > buf->head[0].iov_len)
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return -EINVAL;
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buf->head[0].iov_len -= pad;
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goto out;
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} else
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len -= buf->head[0].iov_len;
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if (len <= buf->page_len) {
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unsigned int last = (buf->page_base + len - 1)
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>>PAGE_SHIFT;
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unsigned int offset = (buf->page_base + len - 1)
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& (PAGE_SIZE - 1);
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ptr = kmap_atomic(buf->pages[last]);
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pad = *(ptr + offset);
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kunmap_atomic(ptr);
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goto out;
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} else
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len -= buf->page_len;
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BUG_ON(len > buf->tail[0].iov_len);
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pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
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out:
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/* XXX: NOTE: we do not adjust the page lengths--they represent
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* a range of data in the real filesystem page cache, and we need
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* to know that range so the xdr code can properly place read data.
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* However adjusting the head length, as we do above, is harmless.
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* In the case of a request that fits into a single page, the server
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* also uses length and head length together to determine the original
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* start of the request to copy the request for deferal; so it's
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* easier on the server if we adjust head and tail length in tandem.
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* It's not really a problem that we don't fool with the page and
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* tail lengths, though--at worst badly formed xdr might lead the
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* server to attempt to parse the padding.
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* XXX: Document all these weird requirements for gss mechanism
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* wrap/unwrap functions. */
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if (pad > blocksize)
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return -EINVAL;
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if (buf->len > pad)
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buf->len -= pad;
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else
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return -EINVAL;
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return 0;
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}
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void
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gss_krb5_make_confounder(char *p, u32 conflen)
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{
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static u64 i = 0;
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u64 *q = (u64 *)p;
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/* rfc1964 claims this should be "random". But all that's really
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* necessary is that it be unique. And not even that is necessary in
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* our case since our "gssapi" implementation exists only to support
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* rpcsec_gss, so we know that the only buffers we will ever encrypt
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* already begin with a unique sequence number. Just to hedge my bets
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* I'll make a half-hearted attempt at something unique, but ensuring
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* uniqueness would mean worrying about atomicity and rollover, and I
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* don't care enough. */
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/* initialize to random value */
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if (i == 0) {
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i = prandom_u32();
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i = (i << 32) | prandom_u32();
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}
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switch (conflen) {
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case 16:
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*q++ = i++;
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/* fall through */
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case 8:
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*q++ = i++;
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break;
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default:
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BUG();
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}
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}
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/* Assumptions: the head and tail of inbuf are ours to play with.
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* The pages, however, may be real pages in the page cache and we replace
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* them with scratch pages from **pages before writing to them. */
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/* XXX: obviously the above should be documentation of wrap interface,
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* and shouldn't be in this kerberos-specific file. */
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/* XXX factor out common code with seal/unseal. */
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static u32
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gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
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struct xdr_buf *buf, struct page **pages)
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{
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char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
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.data = cksumdata};
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int blocksize = 0, plainlen;
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unsigned char *ptr, *msg_start;
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s32 now;
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int headlen;
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struct page **tmp_pages;
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u32 seq_send;
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u8 *cksumkey;
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u32 conflen = kctx->gk5e->conflen;
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dprintk("RPC: %s\n", __func__);
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now = get_seconds();
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blocksize = crypto_skcipher_blocksize(kctx->enc);
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gss_krb5_add_padding(buf, offset, blocksize);
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BUG_ON((buf->len - offset) % blocksize);
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plainlen = conflen + buf->len - offset;
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headlen = g_token_size(&kctx->mech_used,
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GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
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(buf->len - offset);
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ptr = buf->head[0].iov_base + offset;
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/* shift data to make room for header. */
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xdr_extend_head(buf, offset, headlen);
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/* XXX Would be cleverer to encrypt while copying. */
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BUG_ON((buf->len - offset - headlen) % blocksize);
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g_make_token_header(&kctx->mech_used,
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GSS_KRB5_TOK_HDR_LEN +
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kctx->gk5e->cksumlength + plainlen, &ptr);
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/* ptr now at header described in rfc 1964, section 1.2.1: */
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ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
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ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
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msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
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/*
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* signalg and sealalg are stored as if they were converted from LE
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* to host endian, even though they're opaque pairs of bytes according
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* to the RFC.
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*/
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*(__le16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
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*(__le16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
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ptr[6] = 0xff;
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ptr[7] = 0xff;
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gss_krb5_make_confounder(msg_start, conflen);
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if (kctx->gk5e->keyed_cksum)
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cksumkey = kctx->cksum;
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else
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cksumkey = NULL;
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/* XXXJBF: UGH!: */
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tmp_pages = buf->pages;
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buf->pages = pages;
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if (make_checksum(kctx, ptr, 8, buf, offset + headlen - conflen,
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cksumkey, KG_USAGE_SEAL, &md5cksum))
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return GSS_S_FAILURE;
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buf->pages = tmp_pages;
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memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
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spin_lock(&krb5_seq_lock);
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seq_send = kctx->seq_send++;
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spin_unlock(&krb5_seq_lock);
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/* XXX would probably be more efficient to compute checksum
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* and encrypt at the same time: */
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if ((krb5_make_seq_num(kctx, kctx->seq, kctx->initiate ? 0 : 0xff,
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seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
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return GSS_S_FAILURE;
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if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
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struct crypto_skcipher *cipher;
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int err;
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cipher = crypto_alloc_skcipher(kctx->gk5e->encrypt_name, 0,
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CRYPTO_ALG_ASYNC);
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if (IS_ERR(cipher))
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return GSS_S_FAILURE;
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krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
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err = gss_encrypt_xdr_buf(cipher, buf,
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offset + headlen - conflen, pages);
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crypto_free_skcipher(cipher);
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if (err)
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return GSS_S_FAILURE;
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} else {
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if (gss_encrypt_xdr_buf(kctx->enc, buf,
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offset + headlen - conflen, pages))
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return GSS_S_FAILURE;
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}
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return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
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}
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static u32
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gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
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{
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int signalg;
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int sealalg;
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char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
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struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
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.data = cksumdata};
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s32 now;
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int direction;
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s32 seqnum;
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unsigned char *ptr;
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int bodysize;
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void *data_start, *orig_start;
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int data_len;
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int blocksize;
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u32 conflen = kctx->gk5e->conflen;
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int crypt_offset;
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u8 *cksumkey;
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dprintk("RPC: gss_unwrap_kerberos\n");
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ptr = (u8 *)buf->head[0].iov_base + offset;
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if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
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buf->len - offset))
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return GSS_S_DEFECTIVE_TOKEN;
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if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
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(ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
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return GSS_S_DEFECTIVE_TOKEN;
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/* XXX sanity-check bodysize?? */
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/* get the sign and seal algorithms */
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signalg = ptr[2] + (ptr[3] << 8);
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if (signalg != kctx->gk5e->signalg)
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return GSS_S_DEFECTIVE_TOKEN;
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sealalg = ptr[4] + (ptr[5] << 8);
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if (sealalg != kctx->gk5e->sealalg)
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return GSS_S_DEFECTIVE_TOKEN;
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if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
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return GSS_S_DEFECTIVE_TOKEN;
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/*
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* Data starts after token header and checksum. ptr points
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* to the beginning of the token header
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*/
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crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
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(unsigned char *)buf->head[0].iov_base;
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/*
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* Need plaintext seqnum to derive encryption key for arcfour-hmac
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*/
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if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
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ptr + 8, &direction, &seqnum))
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return GSS_S_BAD_SIG;
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if ((kctx->initiate && direction != 0xff) ||
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(!kctx->initiate && direction != 0))
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return GSS_S_BAD_SIG;
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if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
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struct crypto_skcipher *cipher;
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int err;
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cipher = crypto_alloc_skcipher(kctx->gk5e->encrypt_name, 0,
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CRYPTO_ALG_ASYNC);
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if (IS_ERR(cipher))
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return GSS_S_FAILURE;
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krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
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err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
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crypto_free_skcipher(cipher);
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if (err)
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return GSS_S_DEFECTIVE_TOKEN;
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} else {
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if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
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return GSS_S_DEFECTIVE_TOKEN;
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}
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if (kctx->gk5e->keyed_cksum)
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cksumkey = kctx->cksum;
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else
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cksumkey = NULL;
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if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
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cksumkey, KG_USAGE_SEAL, &md5cksum))
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return GSS_S_FAILURE;
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if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
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kctx->gk5e->cksumlength))
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return GSS_S_BAD_SIG;
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/* it got through unscathed. Make sure the context is unexpired */
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now = get_seconds();
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if (now > kctx->endtime)
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return GSS_S_CONTEXT_EXPIRED;
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/* do sequencing checks */
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/* Copy the data back to the right position. XXX: Would probably be
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* better to copy and encrypt at the same time. */
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blocksize = crypto_skcipher_blocksize(kctx->enc);
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data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
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conflen;
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orig_start = buf->head[0].iov_base + offset;
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data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
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memmove(orig_start, data_start, data_len);
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buf->head[0].iov_len -= (data_start - orig_start);
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buf->len -= (data_start - orig_start);
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if (gss_krb5_remove_padding(buf, blocksize))
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return GSS_S_DEFECTIVE_TOKEN;
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return GSS_S_COMPLETE;
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}
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/*
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* We can shift data by up to LOCAL_BUF_LEN bytes in a pass. If we need
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* to do more than that, we shift repeatedly. Kevin Coffman reports
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* seeing 28 bytes as the value used by Microsoft clients and servers
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* with AES, so this constant is chosen to allow handling 28 in one pass
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* without using too much stack space.
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*
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* If that proves to a problem perhaps we could use a more clever
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* algorithm.
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*/
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#define LOCAL_BUF_LEN 32u
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static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
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{
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char head[LOCAL_BUF_LEN];
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char tmp[LOCAL_BUF_LEN];
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unsigned int this_len, i;
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BUG_ON(shift > LOCAL_BUF_LEN);
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read_bytes_from_xdr_buf(buf, 0, head, shift);
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for (i = 0; i + shift < buf->len; i += LOCAL_BUF_LEN) {
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this_len = min(LOCAL_BUF_LEN, buf->len - (i + shift));
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read_bytes_from_xdr_buf(buf, i+shift, tmp, this_len);
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write_bytes_to_xdr_buf(buf, i, tmp, this_len);
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}
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write_bytes_to_xdr_buf(buf, buf->len - shift, head, shift);
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}
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static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
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{
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int shifted = 0;
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int this_shift;
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shift %= buf->len;
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while (shifted < shift) {
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this_shift = min(shift - shifted, LOCAL_BUF_LEN);
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rotate_buf_a_little(buf, this_shift);
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shifted += this_shift;
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}
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}
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static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
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{
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struct xdr_buf subbuf;
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xdr_buf_subsegment(buf, &subbuf, base, buf->len - base);
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_rotate_left(&subbuf, shift);
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}
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static u32
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gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
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struct xdr_buf *buf, struct page **pages)
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{
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int blocksize;
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u8 *ptr, *plainhdr;
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s32 now;
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u8 flags = 0x00;
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__be16 *be16ptr;
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__be64 *be64ptr;
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u32 err;
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dprintk("RPC: %s\n", __func__);
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if (kctx->gk5e->encrypt_v2 == NULL)
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return GSS_S_FAILURE;
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/* make room for gss token header */
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if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
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return GSS_S_FAILURE;
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/* construct gss token header */
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ptr = plainhdr = buf->head[0].iov_base + offset;
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*ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
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*ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
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if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
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flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
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if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
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flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
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/* We always do confidentiality in wrap tokens */
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flags |= KG2_TOKEN_FLAG_SEALED;
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*ptr++ = flags;
|
|
*ptr++ = 0xff;
|
|
be16ptr = (__be16 *)ptr;
|
|
|
|
blocksize = crypto_skcipher_blocksize(kctx->acceptor_enc);
|
|
*be16ptr++ = 0;
|
|
/* "inner" token header always uses 0 for RRC */
|
|
*be16ptr++ = 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, 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;
|
|
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));
|
|
|
|
/*
|
|
* NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
|
|
* doesn't want it checked; see page 6 of rfc 2203.
|
|
*/
|
|
|
|
if (rrc != 0)
|
|
rotate_left(offset + 16, buf, rrc);
|
|
|
|
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;
|
|
|
|
/* Trim off the trailing "extra count" and checksum blob */
|
|
xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
|
|
return GSS_S_COMPLETE;
|
|
}
|
|
|
|
u32
|
|
gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
|
|
struct xdr_buf *buf, struct page **pages)
|
|
{
|
|
struct krb5_ctx *kctx = gctx->internal_ctx_id;
|
|
|
|
switch (kctx->enctype) {
|
|
default:
|
|
BUG();
|
|
case ENCTYPE_DES_CBC_RAW:
|
|
case ENCTYPE_DES3_CBC_RAW:
|
|
case ENCTYPE_ARCFOUR_HMAC:
|
|
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);
|
|
}
|
|
}
|
|
|
|
u32
|
|
gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
|
|
{
|
|
struct krb5_ctx *kctx = gctx->internal_ctx_id;
|
|
|
|
switch (kctx->enctype) {
|
|
default:
|
|
BUG();
|
|
case ENCTYPE_DES_CBC_RAW:
|
|
case ENCTYPE_DES3_CBC_RAW:
|
|
case ENCTYPE_ARCFOUR_HMAC:
|
|
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);
|
|
}
|
|
}
|
|
|