362 lines
8.0 KiB
C
362 lines
8.0 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/ceph/ceph_debug.h>
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#include <linux/err.h>
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#include <linux/scatterlist.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <crypto/aes.h>
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#include <crypto/skcipher.h>
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#include <linux/key-type.h>
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#include <linux/sched/mm.h>
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#include <keys/ceph-type.h>
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#include <keys/user-type.h>
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#include <linux/ceph/decode.h>
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#include "crypto.h"
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/*
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* Set ->key and ->tfm. The rest of the key should be filled in before
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* this function is called.
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*/
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static int set_secret(struct ceph_crypto_key *key, void *buf)
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{
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unsigned int noio_flag;
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int ret;
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key->key = NULL;
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key->tfm = NULL;
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switch (key->type) {
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case CEPH_CRYPTO_NONE:
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return 0; /* nothing to do */
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case CEPH_CRYPTO_AES:
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break;
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default:
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return -ENOTSUPP;
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}
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if (!key->len)
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return -EINVAL;
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key->key = kmemdup(buf, key->len, GFP_NOIO);
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if (!key->key) {
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ret = -ENOMEM;
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goto fail;
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}
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/* crypto_alloc_sync_skcipher() allocates with GFP_KERNEL */
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noio_flag = memalloc_noio_save();
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key->tfm = crypto_alloc_sync_skcipher("cbc(aes)", 0, 0);
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memalloc_noio_restore(noio_flag);
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if (IS_ERR(key->tfm)) {
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ret = PTR_ERR(key->tfm);
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key->tfm = NULL;
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goto fail;
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}
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ret = crypto_sync_skcipher_setkey(key->tfm, key->key, key->len);
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if (ret)
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goto fail;
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return 0;
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fail:
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ceph_crypto_key_destroy(key);
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return ret;
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}
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int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
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const struct ceph_crypto_key *src)
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{
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memcpy(dst, src, sizeof(struct ceph_crypto_key));
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return set_secret(dst, src->key);
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}
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int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end)
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{
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if (*p + sizeof(u16) + sizeof(key->created) +
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sizeof(u16) + key->len > end)
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return -ERANGE;
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ceph_encode_16(p, key->type);
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ceph_encode_copy(p, &key->created, sizeof(key->created));
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ceph_encode_16(p, key->len);
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ceph_encode_copy(p, key->key, key->len);
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return 0;
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}
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int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
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{
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int ret;
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ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad);
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key->type = ceph_decode_16(p);
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ceph_decode_copy(p, &key->created, sizeof(key->created));
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key->len = ceph_decode_16(p);
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ceph_decode_need(p, end, key->len, bad);
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ret = set_secret(key, *p);
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memzero_explicit(*p, key->len);
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*p += key->len;
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return ret;
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bad:
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dout("failed to decode crypto key\n");
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return -EINVAL;
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}
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int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
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{
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int inlen = strlen(inkey);
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int blen = inlen * 3 / 4;
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void *buf, *p;
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int ret;
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dout("crypto_key_unarmor %s\n", inkey);
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buf = kmalloc(blen, GFP_NOFS);
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if (!buf)
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return -ENOMEM;
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blen = ceph_unarmor(buf, inkey, inkey+inlen);
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if (blen < 0) {
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kfree(buf);
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return blen;
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}
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p = buf;
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ret = ceph_crypto_key_decode(key, &p, p + blen);
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kfree(buf);
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if (ret)
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return ret;
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dout("crypto_key_unarmor key %p type %d len %d\n", key,
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key->type, key->len);
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return 0;
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}
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void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
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{
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if (key) {
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kfree_sensitive(key->key);
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key->key = NULL;
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if (key->tfm) {
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crypto_free_sync_skcipher(key->tfm);
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key->tfm = NULL;
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}
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}
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}
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static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
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/*
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* Should be used for buffers allocated with kvmalloc().
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* Currently these are encrypt out-buffer (ceph_buffer) and decrypt
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* in-buffer (msg front).
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*
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* Dispose of @sgt with teardown_sgtable().
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*
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* @prealloc_sg is to avoid memory allocation inside sg_alloc_table()
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* in cases where a single sg is sufficient. No attempt to reduce the
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* number of sgs by squeezing physically contiguous pages together is
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* made though, for simplicity.
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*/
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static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
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const void *buf, unsigned int buf_len)
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{
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struct scatterlist *sg;
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const bool is_vmalloc = is_vmalloc_addr(buf);
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unsigned int off = offset_in_page(buf);
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unsigned int chunk_cnt = 1;
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unsigned int chunk_len = PAGE_ALIGN(off + buf_len);
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int i;
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int ret;
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if (buf_len == 0) {
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memset(sgt, 0, sizeof(*sgt));
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return -EINVAL;
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}
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if (is_vmalloc) {
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chunk_cnt = chunk_len >> PAGE_SHIFT;
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chunk_len = PAGE_SIZE;
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}
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if (chunk_cnt > 1) {
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ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS);
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if (ret)
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return ret;
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} else {
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WARN_ON(chunk_cnt != 1);
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sg_init_table(prealloc_sg, 1);
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sgt->sgl = prealloc_sg;
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sgt->nents = sgt->orig_nents = 1;
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}
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for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
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struct page *page;
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unsigned int len = min(chunk_len - off, buf_len);
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if (is_vmalloc)
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page = vmalloc_to_page(buf);
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else
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page = virt_to_page(buf);
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sg_set_page(sg, page, len, off);
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off = 0;
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buf += len;
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buf_len -= len;
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}
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WARN_ON(buf_len != 0);
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return 0;
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}
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static void teardown_sgtable(struct sg_table *sgt)
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{
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if (sgt->orig_nents > 1)
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sg_free_table(sgt);
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}
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static int ceph_aes_crypt(const struct ceph_crypto_key *key, bool encrypt,
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void *buf, int buf_len, int in_len, int *pout_len)
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{
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SYNC_SKCIPHER_REQUEST_ON_STACK(req, key->tfm);
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struct sg_table sgt;
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struct scatterlist prealloc_sg;
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char iv[AES_BLOCK_SIZE] __aligned(8);
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int pad_byte = AES_BLOCK_SIZE - (in_len & (AES_BLOCK_SIZE - 1));
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int crypt_len = encrypt ? in_len + pad_byte : in_len;
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int ret;
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WARN_ON(crypt_len > buf_len);
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if (encrypt)
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memset(buf + in_len, pad_byte, pad_byte);
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ret = setup_sgtable(&sgt, &prealloc_sg, buf, crypt_len);
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if (ret)
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return ret;
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memcpy(iv, aes_iv, AES_BLOCK_SIZE);
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skcipher_request_set_sync_tfm(req, key->tfm);
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skcipher_request_set_callback(req, 0, NULL, NULL);
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skcipher_request_set_crypt(req, sgt.sgl, sgt.sgl, crypt_len, iv);
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/*
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print_hex_dump(KERN_ERR, "key: ", DUMP_PREFIX_NONE, 16, 1,
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key->key, key->len, 1);
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print_hex_dump(KERN_ERR, " in: ", DUMP_PREFIX_NONE, 16, 1,
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buf, crypt_len, 1);
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*/
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if (encrypt)
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ret = crypto_skcipher_encrypt(req);
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else
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ret = crypto_skcipher_decrypt(req);
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skcipher_request_zero(req);
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if (ret) {
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pr_err("%s %scrypt failed: %d\n", __func__,
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encrypt ? "en" : "de", ret);
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goto out_sgt;
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}
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/*
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print_hex_dump(KERN_ERR, "out: ", DUMP_PREFIX_NONE, 16, 1,
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buf, crypt_len, 1);
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*/
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if (encrypt) {
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*pout_len = crypt_len;
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} else {
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pad_byte = *(char *)(buf + in_len - 1);
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if (pad_byte > 0 && pad_byte <= AES_BLOCK_SIZE &&
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in_len >= pad_byte) {
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*pout_len = in_len - pad_byte;
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} else {
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pr_err("%s got bad padding %d on in_len %d\n",
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__func__, pad_byte, in_len);
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ret = -EPERM;
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goto out_sgt;
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}
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}
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out_sgt:
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teardown_sgtable(&sgt);
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return ret;
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}
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int ceph_crypt(const struct ceph_crypto_key *key, bool encrypt,
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void *buf, int buf_len, int in_len, int *pout_len)
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{
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switch (key->type) {
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case CEPH_CRYPTO_NONE:
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*pout_len = in_len;
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return 0;
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case CEPH_CRYPTO_AES:
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return ceph_aes_crypt(key, encrypt, buf, buf_len, in_len,
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pout_len);
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default:
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return -ENOTSUPP;
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}
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}
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static int ceph_key_preparse(struct key_preparsed_payload *prep)
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{
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struct ceph_crypto_key *ckey;
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size_t datalen = prep->datalen;
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int ret;
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void *p;
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ret = -EINVAL;
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if (datalen <= 0 || datalen > 32767 || !prep->data)
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goto err;
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ret = -ENOMEM;
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ckey = kmalloc(sizeof(*ckey), GFP_KERNEL);
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if (!ckey)
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goto err;
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/* TODO ceph_crypto_key_decode should really take const input */
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p = (void *)prep->data;
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ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen);
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if (ret < 0)
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goto err_ckey;
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prep->payload.data[0] = ckey;
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prep->quotalen = datalen;
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return 0;
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err_ckey:
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kfree(ckey);
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err:
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return ret;
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}
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static void ceph_key_free_preparse(struct key_preparsed_payload *prep)
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{
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struct ceph_crypto_key *ckey = prep->payload.data[0];
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ceph_crypto_key_destroy(ckey);
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kfree(ckey);
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}
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static void ceph_key_destroy(struct key *key)
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{
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struct ceph_crypto_key *ckey = key->payload.data[0];
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ceph_crypto_key_destroy(ckey);
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kfree(ckey);
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}
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struct key_type key_type_ceph = {
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.name = "ceph",
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.preparse = ceph_key_preparse,
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.free_preparse = ceph_key_free_preparse,
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.instantiate = generic_key_instantiate,
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.destroy = ceph_key_destroy,
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};
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int __init ceph_crypto_init(void)
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{
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return register_key_type(&key_type_ceph);
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}
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void ceph_crypto_shutdown(void)
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{
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unregister_key_type(&key_type_ceph);
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}
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