Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/jiffies.h>

#include <linux/sunrpc/gss_krb5.h>

#include <linux/random.h>

#include <linux/pagemap.h>

#include <linux/crypto.h>

#ifdef RPC_DEBUG

# define RPCDBG_FACILITY        RPCDBG_AUTH

#endif

static inline int

gss_krb5_padding(int blocksize, int length)

{

        /* Most of the code is block-size independent but currently we

         * use only 8: */

        BUG_ON(blocksize != 8);

        return 8 - (length & 7);

}

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_CACHE_SHIFT;

                unsigned int offset = (buf->page_base + len - 1)

                                        & (PAGE_CACHE_SIZE - 1);

                ptr = kmap_atomic(buf->pages[last], KM_USER0);

                pad = *(ptr + offset);

                kunmap_atomic(ptr, KM_USER0);

                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;

}

static inline void

make_confounder(char *p, int blocksize)

{

        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. */

        BUG_ON(blocksize != 8);

        *q = i++;

}

/* 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. */

u32

gss_wrap_kerberos(struct gss_ctx *ctx, int offset,

                struct xdr_buf *buf, struct page **pages)

{

        struct krb5_ctx         *kctx = ctx->internal_ctx_id;

        char                    cksumdata[16];

        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};

        int                     blocksize = 0, plainlen;

        unsigned char           *ptr, *krb5_hdr, *msg_start;

        s32                     now;

        int                     headlen;

        struct page             **tmp_pages;

        u32                     seq_send;

        dprintk("RPC:       gss_wrap_kerberos\n");

        now = get_seconds();

        blocksize = crypto_blkcipher_blocksize(kctx->enc);

        gss_krb5_add_padding(buf, offset, blocksize);

        BUG_ON((buf->len - offset) % blocksize);

        plainlen = blocksize + buf->len - offset;

        headlen = g_token_size(&kctx->mech_used, 22 + plainlen) -

                                                (buf->len - offset);

        ptr = buf->head[0].iov_base + offset;

        /* shift data to make room for header. */

        /* XXX Would be cleverer to encrypt while copying. */

        /* XXX bounds checking, slack, etc. */

        memmove(ptr + headlen, ptr, buf->head[0].iov_len - offset);

        buf->head[0].iov_len += headlen;

        buf->len += headlen;

        BUG_ON((buf->len - offset - headlen) % blocksize);

        g_make_token_header(&kctx->mech_used, 22 + plainlen, &ptr);

        *ptr++ = (unsigned char) ((KG_TOK_WRAP_MSG>>8)&0xff);

        *ptr++ = (unsigned char) (KG_TOK_WRAP_MSG&0xff);

        /* ptr now at byte 2 of header described in rfc 1964, section 1.2.1: */

        krb5_hdr = ptr - 2;

        msg_start = krb5_hdr + 24;

        *(__be16 *)(krb5_hdr + 2) = htons(SGN_ALG_DES_MAC_MD5);

        memset(krb5_hdr + 4, 0xff, 4);

        *(__be16 *)(krb5_hdr + 4) = htons(SEAL_ALG_DES);

        make_confounder(msg_start, blocksize);

        /* XXXJBF: UGH!: */

        tmp_pages = buf->pages;

        buf->pages = pages;

        if (make_checksum("md5", krb5_hdr, 8, buf,

                                offset + headlen - blocksize, &md5cksum))

                return GSS_S_FAILURE;

        buf->pages = tmp_pages;

        if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,

                          md5cksum.data, md5cksum.len))

                return GSS_S_FAILURE;

        memcpy(krb5_hdr + 16,

               md5cksum.data + md5cksum.len - KRB5_CKSUM_LENGTH,

               KRB5_CKSUM_LENGTH);

        spin_lock(&krb5_seq_lock);

        seq_send = kctx->seq_send++;

        spin_unlock(&krb5_seq_lock);

        /* XXX would probably be more efficient to compute checksum

         * and encrypt at the same time: */

        if ((krb5_make_seq_num(kctx->seq, kctx->initiate ? 0 : 0xff,

                               seq_send, krb5_hdr + 16, krb5_hdr + 8)))

                return GSS_S_FAILURE;

        if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,

                                                                        pages))

                return GSS_S_FAILURE;

        return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;

}

u32

gss_unwrap_kerberos(struct gss_ctx *ctx, int offset, struct xdr_buf *buf)

{

        struct krb5_ctx         *kctx = ctx->internal_ctx_id;

        int                     signalg;

        int                     sealalg;

        char                    cksumdata[16];

        struct xdr_netobj       md5cksum = {.len = 0, .data = cksumdata};

        s32                     now;

        int                     direction;

        s32                     seqnum;

        unsigned char           *ptr;

        int                     bodysize;

        void                    *data_start, *orig_start;

        int                     data_len;

        int                     blocksize;

        dprintk("RPC:       gss_unwrap_kerberos\n");

        ptr = (u8 *)buf->head[0].iov_base + offset;

        if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,

                                        buf->len - offset))

                return GSS_S_DEFECTIVE_TOKEN;

        if ((*ptr++ != ((KG_TOK_WRAP_MSG>>8)&0xff)) ||

            (*ptr++ !=  (KG_TOK_WRAP_MSG    &0xff))   )

                return GSS_S_DEFECTIVE_TOKEN;

        /* XXX sanity-check bodysize?? */

        /* get the sign and seal algorithms */

        signalg = ptr[0] + (ptr[1] << 8);

        if (signalg != SGN_ALG_DES_MAC_MD5)

                return GSS_S_DEFECTIVE_TOKEN;

        sealalg = ptr[2] + (ptr[3] << 8);

        if (sealalg != SEAL_ALG_DES)

                return GSS_S_DEFECTIVE_TOKEN;

        if ((ptr[4] != 0xff) || (ptr[5] != 0xff))

                return GSS_S_DEFECTIVE_TOKEN;

        if (gss_decrypt_xdr_buf(kctx->enc, buf,

                        ptr + 22 - (unsigned char *)buf->head[0].iov_base))

                return GSS_S_DEFECTIVE_TOKEN;

        if (make_checksum("md5", ptr - 2, 8, buf,

                 ptr + 22 - (unsigned char *)buf->head[0].iov_base, &md5cksum))

                return GSS_S_FAILURE;

        if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,

                           md5cksum.data, md5cksum.len))

                return GSS_S_FAILURE;

        if (memcmp(md5cksum.data + 8, ptr + 14, 8))

                return GSS_S_BAD_SIG;

        /* it got through unscathed.  Make sure the context is unexpired */

        now = get_seconds();

        if (now > kctx->endtime)

                return GSS_S_CONTEXT_EXPIRED;

        /* do sequencing checks */

        if (krb5_get_seq_num(kctx->seq, ptr + 14, ptr + 6, &direction,

                                    &seqnum))

                return GSS_S_BAD_SIG;

        if ((kctx->initiate && direction != 0xff) ||

            (!kctx->initiate && direction != 0))

                return GSS_S_BAD_SIG;

        /* Copy the data back to the right position.  XXX: Would probably be

         * better to copy and encrypt at the same time. */

        blocksize = crypto_blkcipher_blocksize(kctx->enc);

        data_start = ptr + 22 + blocksize;

        orig_start = buf->head[0].iov_base + offset;

        data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;

        memmove(orig_start, data_start, data_len);

        buf->head[0].iov_len -= (data_start - orig_start);

        buf->len -= (data_start - orig_start);

        if (gss_krb5_remove_padding(buf, blocksize))

                return GSS_S_DEFECTIVE_TOKEN;

        return GSS_S_COMPLETE;

}