| #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_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; |
| 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(); |
| |
| checksum_type = CKSUMTYPE_RSA_MD5; |
| 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_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; |
| /* XXXJBF: */ BUG_ON(buf->head[0].iov_base + offset + headlen != msg_start + blocksize); |
| |
| *(__be16 *)(krb5_hdr + 2) = htons(SGN_ALG_DES_MAC_MD5); |
| memset(krb5_hdr + 4, 0xff, 4); |
| *(__be16 *)(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; |
| |
| 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); |
| |
| 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_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); |
| |
| ret = GSS_S_DEFECTIVE_TOKEN; |
| if (gss_krb5_remove_padding(buf, blocksize)) |
| goto out; |
| |
| ret = GSS_S_COMPLETE; |
| out: |
| return ret; |
| } |