--- /dev/null
+#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 <asm/scatterlist.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;
+ int 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) {
+ int last = (buf->page_base + len - 1)
+ >>PAGE_CACHE_SHIFT;
+ int offset = (buf->page_base + len - 1)
+ & (PAGE_CACHE_SIZE - 1);
+ ptr = kmap_atomic(buf->pages[last], KM_SKB_SUNRPC_DATA);
+ pad = *(ptr + offset);
+ kunmap_atomic(ptr, KM_SKB_SUNRPC_DATA);
+ 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;
+ s32 checksum_type;
+ 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();
+
+ switch (kctx->signalg) {
+ case SGN_ALG_DES_MAC_MD5:
+ checksum_type = CKSUMTYPE_RSA_MD5;
+ break;
+ default:
+ dprintk("RPC: gss_krb5_seal: kctx->signalg %d not"
+ " supported\n", kctx->signalg);
+ goto out_err;
+ }
+ if (kctx->sealalg != SEAL_ALG_NONE && kctx->sealalg != SEAL_ALG_DES) {
+ dprintk("RPC: gss_krb5_seal: kctx->sealalg %d not supported\n",
+ kctx->sealalg);
+ goto out_err;
+ }
+
+ blocksize = crypto_tfm_alg_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;
+ /* XXXJBF: */ BUG_ON(buf->head[0].iov_base + offset + headlen != msg_start + blocksize);
+
+ *(u16 *)(krb5_hdr + 2) = htons(kctx->signalg);
+ memset(krb5_hdr + 4, 0xff, 4);
+ *(u16 *)(krb5_hdr + 4) = htons(kctx->sealalg);
+
+ make_confounder(msg_start, blocksize);
+
+ /* XXXJBF: UGH!: */
+ tmp_pages = buf->pages;
+ buf->pages = pages;
+ if (make_checksum(checksum_type, krb5_hdr, 8, buf,
+ offset + headlen - blocksize, &md5cksum))
+ goto out_err;
+ buf->pages = tmp_pages;
+
+ switch (kctx->signalg) {
+ case SGN_ALG_DES_MAC_MD5:
+ if (krb5_encrypt(kctx->seq, NULL, md5cksum.data,
+ md5cksum.data, md5cksum.len))
+ goto out_err;
+ memcpy(krb5_hdr + 16,
+ md5cksum.data + md5cksum.len - KRB5_CKSUM_LENGTH,
+ KRB5_CKSUM_LENGTH);
+
+ dprintk("RPC: make_seal_token: cksum data: \n");
+ print_hexl((u32 *) (krb5_hdr + 16), KRB5_CKSUM_LENGTH, 0);
+ break;
+ default:
+ BUG();
+ }
+
+ 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)))
+ goto out_err;
+
+ if (gss_encrypt_xdr_buf(kctx->enc, buf, offset + headlen - blocksize,
+ pages))
+ goto out_err;
+
+ return ((kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE);
+out_err:
+ return GSS_S_FAILURE;
+}
+
+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;
+ s32 checksum_type;
+ char cksumdata[16];
+ struct xdr_netobj md5cksum = {.len = 0, .data = cksumdata};
+ s32 now;
+ int direction;
+ s32 seqnum;
+ unsigned char *ptr;
+ int bodysize;
+ u32 ret = GSS_S_DEFECTIVE_TOKEN;
+ 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))
+ goto out;
+
+ if ((*ptr++ != ((KG_TOK_WRAP_MSG>>8)&0xff)) ||
+ (*ptr++ != (KG_TOK_WRAP_MSG &0xff)) )
+ goto out;
+
+ /* XXX sanity-check bodysize?? */
+
+ /* get the sign and seal algorithms */
+
+ signalg = ptr[0] + (ptr[1] << 8);
+ sealalg = ptr[2] + (ptr[3] << 8);
+
+ /* Sanity checks */
+
+ if ((ptr[4] != 0xff) || (ptr[5] != 0xff))
+ goto out;
+
+ if (sealalg == 0xffff)
+ goto out;
+
+ /* in the current spec, there is only one valid seal algorithm per
+ key type, so a simple comparison is ok */
+
+ if (sealalg != kctx->sealalg)
+ goto out;
+
+ /* there are several mappings of seal algorithms to sign algorithms,
+ but few enough that we can try them all. */
+
+ if ((kctx->sealalg == SEAL_ALG_NONE && signalg > 1) ||
+ (kctx->sealalg == SEAL_ALG_1 && signalg != SGN_ALG_3) ||
+ (kctx->sealalg == SEAL_ALG_DES3KD &&
+ signalg != SGN_ALG_HMAC_SHA1_DES3_KD))
+ goto out;
+
+ if (gss_decrypt_xdr_buf(kctx->enc, buf,
+ ptr + 22 - (unsigned char *)buf->head[0].iov_base))
+ goto out;
+
+ /* compute the checksum of the message */
+
+ /* initialize the the cksum */
+ switch (signalg) {
+ case SGN_ALG_DES_MAC_MD5:
+ checksum_type = CKSUMTYPE_RSA_MD5;
+ break;
+ default:
+ ret = GSS_S_DEFECTIVE_TOKEN;
+ goto out;
+ }
+
+ switch (signalg) {
+ case SGN_ALG_DES_MAC_MD5:
+ ret = make_checksum(checksum_type, ptr - 2, 8, buf,
+ ptr + 22 - (unsigned char *)buf->head[0].iov_base, &md5cksum);
+ if (ret)
+ goto out;
+
+ ret = krb5_encrypt(kctx->seq, NULL, md5cksum.data,
+ md5cksum.data, md5cksum.len);
+ if (ret)
+ goto out;
+
+ if (memcmp(md5cksum.data + 8, ptr + 14, 8)) {
+ ret = GSS_S_BAD_SIG;
+ goto out;
+ }
+ break;
+ default:
+ ret = GSS_S_DEFECTIVE_TOKEN;
+ goto out;
+ }
+
+ /* it got through unscathed. Make sure the context is unexpired */
+
+ now = get_seconds();
+
+ ret = GSS_S_CONTEXT_EXPIRED;
+ if (now > kctx->endtime)
+ goto out;
+
+ /* do sequencing checks */
+
+ ret = GSS_S_BAD_SIG;
+ if ((ret = krb5_get_seq_num(kctx->seq, ptr + 14, ptr + 6, &direction,
+ &seqnum)))
+ goto out;
+
+ if ((kctx->initiate && direction != 0xff) ||
+ (!kctx->initiate && direction != 0))
+ goto out;
+
+ /* Copy the data back to the right position. XXX: Would probably be
+ * better to copy and encrypt at the same time. */
+
+ blocksize = crypto_tfm_alg_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);
+
+ ret = GSS_S_DEFECTIVE_TOKEN;
+ if (gss_krb5_remove_padding(buf, blocksize))
+ goto out;
+
+ ret = GSS_S_COMPLETE;
+out:
+ return ret;
+}
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