gss_krb5: add remaining pieces to enable AES encryption support
Add the remaining pieces to enable support for Kerberos AES encryption types. Signed-off-by: Kevin Coffman <kwc@citi.umich.edu> Signed-off-by: Steve Dickson <steved@redhat.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Kevin Coffman
committed by
Trond Myklebust
Trond Myklebust
parent
de9c17eb4a
commit
934a95aa1c
@@ -41,6 +41,7 @@
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#include <linux/crypto.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/random.h>
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#include <linux/sunrpc/gss_krb5.h>
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#include <linux/sunrpc/xdr.h>
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@@ -478,3 +479,250 @@ xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
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return 0;
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}
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static u32
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gss_krb5_cts_crypt(struct crypto_blkcipher *cipher, struct xdr_buf *buf,
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u32 offset, u8 *iv, struct page **pages, int encrypt)
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{
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u32 ret;
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struct scatterlist sg[1];
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struct blkcipher_desc desc = { .tfm = cipher, .info = iv };
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u8 data[crypto_blkcipher_blocksize(cipher) * 2];
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struct page **save_pages;
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u32 len = buf->len - offset;
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BUG_ON(len > crypto_blkcipher_blocksize(cipher) * 2);
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/*
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* For encryption, we want to read from the cleartext
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* page cache pages, and write the encrypted data to
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* the supplied xdr_buf pages.
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*/
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save_pages = buf->pages;
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if (encrypt)
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buf->pages = pages;
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ret = read_bytes_from_xdr_buf(buf, offset, data, len);
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buf->pages = save_pages;
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if (ret)
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goto out;
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sg_init_one(sg, data, len);
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if (encrypt)
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ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, len);
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else
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ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, len);
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if (ret)
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goto out;
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ret = write_bytes_to_xdr_buf(buf, offset, data, len);
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out:
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return ret;
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}
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u32
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gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
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struct xdr_buf *buf, int ec, struct page **pages)
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{
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u32 err;
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struct xdr_netobj hmac;
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u8 *cksumkey;
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u8 *ecptr;
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struct crypto_blkcipher *cipher, *aux_cipher;
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int blocksize;
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struct page **save_pages;
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int nblocks, nbytes;
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struct encryptor_desc desc;
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u32 cbcbytes;
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if (kctx->initiate) {
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cipher = kctx->initiator_enc;
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aux_cipher = kctx->initiator_enc_aux;
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cksumkey = kctx->initiator_integ;
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} else {
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cipher = kctx->acceptor_enc;
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aux_cipher = kctx->acceptor_enc_aux;
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cksumkey = kctx->acceptor_integ;
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}
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blocksize = crypto_blkcipher_blocksize(cipher);
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/* hide the gss token header and insert the confounder */
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offset += GSS_KRB5_TOK_HDR_LEN;
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if (xdr_extend_head(buf, offset, blocksize))
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return GSS_S_FAILURE;
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gss_krb5_make_confounder(buf->head[0].iov_base + offset, blocksize);
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offset -= GSS_KRB5_TOK_HDR_LEN;
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if (buf->tail[0].iov_base != NULL) {
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ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
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} else {
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buf->tail[0].iov_base = buf->head[0].iov_base
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+ buf->head[0].iov_len;
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buf->tail[0].iov_len = 0;
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ecptr = buf->tail[0].iov_base;
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}
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memset(ecptr, 'X', ec);
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buf->tail[0].iov_len += ec;
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buf->len += ec;
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/* copy plaintext gss token header after filler (if any) */
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memcpy(ecptr + ec, buf->head[0].iov_base + offset,
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GSS_KRB5_TOK_HDR_LEN);
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buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
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buf->len += GSS_KRB5_TOK_HDR_LEN;
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/* Do the HMAC */
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hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
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hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
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/*
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* When we are called, pages points to the real page cache
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* data -- which we can't go and encrypt! buf->pages points
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* to scratch pages which we are going to send off to the
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* client/server. Swap in the plaintext pages to calculate
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* the hmac.
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*/
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save_pages = buf->pages;
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buf->pages = pages;
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err = make_checksum_v2(kctx, NULL, 0, buf,
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offset + GSS_KRB5_TOK_HDR_LEN, cksumkey, &hmac);
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buf->pages = save_pages;
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if (err)
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return GSS_S_FAILURE;
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nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
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nblocks = (nbytes + blocksize - 1) / blocksize;
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cbcbytes = 0;
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if (nblocks > 2)
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cbcbytes = (nblocks - 2) * blocksize;
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memset(desc.iv, 0, sizeof(desc.iv));
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if (cbcbytes) {
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desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
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desc.fragno = 0;
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desc.fraglen = 0;
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desc.pages = pages;
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desc.outbuf = buf;
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desc.desc.info = desc.iv;
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desc.desc.flags = 0;
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desc.desc.tfm = aux_cipher;
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sg_init_table(desc.infrags, 4);
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sg_init_table(desc.outfrags, 4);
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err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
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cbcbytes, encryptor, &desc);
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if (err)
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goto out_err;
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}
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/* Make sure IV carries forward from any CBC results. */
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err = gss_krb5_cts_crypt(cipher, buf,
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offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
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desc.iv, pages, 1);
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if (err) {
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err = GSS_S_FAILURE;
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goto out_err;
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}
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/* Now update buf to account for HMAC */
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buf->tail[0].iov_len += kctx->gk5e->cksumlength;
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buf->len += kctx->gk5e->cksumlength;
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out_err:
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if (err)
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err = GSS_S_FAILURE;
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return err;
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}
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u32
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gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
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u32 *headskip, u32 *tailskip)
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{
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struct xdr_buf subbuf;
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u32 ret = 0;
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u8 *cksum_key;
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struct crypto_blkcipher *cipher, *aux_cipher;
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struct xdr_netobj our_hmac_obj;
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u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
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u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
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int nblocks, blocksize, cbcbytes;
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struct decryptor_desc desc;
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if (kctx->initiate) {
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cipher = kctx->acceptor_enc;
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aux_cipher = kctx->acceptor_enc_aux;
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cksum_key = kctx->acceptor_integ;
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} else {
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cipher = kctx->initiator_enc;
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aux_cipher = kctx->initiator_enc_aux;
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cksum_key = kctx->initiator_integ;
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}
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blocksize = crypto_blkcipher_blocksize(cipher);
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/* create a segment skipping the header and leaving out the checksum */
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xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
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(buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
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kctx->gk5e->cksumlength));
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nblocks = (subbuf.len + blocksize - 1) / blocksize;
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cbcbytes = 0;
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if (nblocks > 2)
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cbcbytes = (nblocks - 2) * blocksize;
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memset(desc.iv, 0, sizeof(desc.iv));
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if (cbcbytes) {
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desc.fragno = 0;
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desc.fraglen = 0;
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desc.desc.info = desc.iv;
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desc.desc.flags = 0;
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desc.desc.tfm = aux_cipher;
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sg_init_table(desc.frags, 4);
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ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
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if (ret)
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goto out_err;
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}
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/* Make sure IV carries forward from any CBC results. */
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ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
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if (ret)
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goto out_err;
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/* Calculate our hmac over the plaintext data */
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our_hmac_obj.len = sizeof(our_hmac);
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our_hmac_obj.data = our_hmac;
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ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
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cksum_key, &our_hmac_obj);
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if (ret)
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goto out_err;
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/* Get the packet's hmac value */
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ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
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pkt_hmac, kctx->gk5e->cksumlength);
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if (ret)
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goto out_err;
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if (memcmp(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
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ret = GSS_S_BAD_SIG;
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goto out_err;
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}
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*headskip = crypto_blkcipher_blocksize(cipher);
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*tailskip = kctx->gk5e->cksumlength;
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out_err:
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if (ret && ret != GSS_S_BAD_SIG)
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ret = GSS_S_FAILURE;
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return ret;
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}
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