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361 lines
8.0 KiB
361 lines
8.0 KiB
// 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 ceph_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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