1 files changed, 361 insertions, 0 deletions
diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c
new file mode 100644
index 000000000..051d22c0e
--- /dev/null
+++ b/net/ceph/crypto.c
@@ -0,0 +1,361 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/err.h>
+#include <linux/scatterlist.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <crypto/aes.h>
+#include <crypto/skcipher.h>
+#include <linux/key-type.h>
+#include <linux/sched/mm.h>
+
+#include <keys/ceph-type.h>
+#include <keys/user-type.h>
+#include <linux/ceph/decode.h>
+#include "crypto.h"
+
+/*
+ * Set ->key and ->tfm.  The rest of the key should be filled in before
+ * this function is called.
+ */
+static int set_secret(struct ceph_crypto_key *key, void *buf)
+{
+	unsigned int noio_flag;
+	int ret;
+
+	key->key = NULL;
+	key->tfm = NULL;
+
+	switch (key->type) {
+	case CEPH_CRYPTO_NONE:
+		return 0; /* nothing to do */
+	case CEPH_CRYPTO_AES:
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	if (!key->len)
+		return -EINVAL;
+
+	key->key = kmemdup(buf, key->len, GFP_NOIO);
+	if (!key->key) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* crypto_alloc_sync_skcipher() allocates with GFP_KERNEL */
+	noio_flag = memalloc_noio_save();
+	key->tfm = crypto_alloc_sync_skcipher("cbc(aes)", 0, 0);
+	memalloc_noio_restore(noio_flag);
+	if (IS_ERR(key->tfm)) {
+		ret = PTR_ERR(key->tfm);
+		key->tfm = NULL;
+		goto fail;
+	}
+
+	ret = crypto_sync_skcipher_setkey(key->tfm, key->key, key->len);
+	if (ret)
+		goto fail;
+
+	return 0;
+
+fail:
+	ceph_crypto_key_destroy(key);
+	return ret;
+}
+
+int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
+			  const struct ceph_crypto_key *src)
+{
+	memcpy(dst, src, sizeof(struct ceph_crypto_key));
+	return set_secret(dst, src->key);
+}
+
+int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end)
+{
+	if (*p + sizeof(u16) + sizeof(key->created) +
+	    sizeof(u16) + key->len > end)
+		return -ERANGE;
+	ceph_encode_16(p, key->type);
+	ceph_encode_copy(p, &key->created, sizeof(key->created));
+	ceph_encode_16(p, key->len);
+	ceph_encode_copy(p, key->key, key->len);
+	return 0;
+}
+
+int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
+{
+	int ret;
+
+	ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad);
+	key->type = ceph_decode_16(p);
+	ceph_decode_copy(p, &key->created, sizeof(key->created));
+	key->len = ceph_decode_16(p);
+	ceph_decode_need(p, end, key->len, bad);
+	ret = set_secret(key, *p);
+	memzero_explicit(*p, key->len);
+	*p += key->len;
+	return ret;
+
+bad:
+	dout("failed to decode crypto key\n");
+	return -EINVAL;
+}
+
+int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
+{
+	int inlen = strlen(inkey);
+	int blen = inlen * 3 / 4;
+	void *buf, *p;
+	int ret;
+
+	dout("crypto_key_unarmor %s\n", inkey);
+	buf = kmalloc(blen, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+	blen = ceph_unarmor(buf, inkey, inkey+inlen);
+	if (blen < 0) {
+		kfree(buf);
+		return blen;
+	}
+
+	p = buf;
+	ret = ceph_crypto_key_decode(key, &p, p + blen);
+	kfree(buf);
+	if (ret)
+		return ret;
+	dout("crypto_key_unarmor key %p type %d len %d\n", key,
+	     key->type, key->len);
+	return 0;
+}
+
+void ceph_crypto_key_destroy(struct ceph_crypto_key *key)
+{
+	if (key) {
+		kfree_sensitive(key->key);
+		key->key = NULL;
+		if (key->tfm) {
+			crypto_free_sync_skcipher(key->tfm);
+			key->tfm = NULL;
+		}
+	}
+}
+
+static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
+
+/*
+ * Should be used for buffers allocated with kvmalloc().
+ * Currently these are encrypt out-buffer (ceph_buffer) and decrypt
+ * in-buffer (msg front).
+ *
+ * Dispose of @sgt with teardown_sgtable().
+ *
+ * @prealloc_sg is to avoid memory allocation inside sg_alloc_table()
+ * in cases where a single sg is sufficient.  No attempt to reduce the
+ * number of sgs by squeezing physically contiguous pages together is
+ * made though, for simplicity.
+ */
+static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
+			 const void *buf, unsigned int buf_len)
+{
+	struct scatterlist *sg;
+	const bool is_vmalloc = is_vmalloc_addr(buf);
+	unsigned int off = offset_in_page(buf);
+	unsigned int chunk_cnt = 1;
+	unsigned int chunk_len = PAGE_ALIGN(off + buf_len);
+	int i;
+	int ret;
+
+	if (buf_len == 0) {
+		memset(sgt, 0, sizeof(*sgt));
+		return -EINVAL;
+	}
+
+	if (is_vmalloc) {
+		chunk_cnt = chunk_len >> PAGE_SHIFT;
+		chunk_len = PAGE_SIZE;
+	}
+
+	if (chunk_cnt > 1) {
+		ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS);
+		if (ret)
+			return ret;
+	} else {
+		WARN_ON(chunk_cnt != 1);
+		sg_init_table(prealloc_sg, 1);
+		sgt->sgl = prealloc_sg;
+		sgt->nents = sgt->orig_nents = 1;
+	}
+
+	for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
+		struct page *page;
+		unsigned int len = min(chunk_len - off, buf_len);
+
+		if (is_vmalloc)
+			page = vmalloc_to_page(buf);
+		else
+			page = virt_to_page(buf);
+
+		sg_set_page(sg, page, len, off);
+
+		off = 0;
+		buf += len;
+		buf_len -= len;
+	}
+	WARN_ON(buf_len != 0);
+
+	return 0;
+}
+
+static void teardown_sgtable(struct sg_table *sgt)
+{
+	if (sgt->orig_nents > 1)
+		sg_free_table(sgt);
+}
+
+static int ceph_aes_crypt(const struct ceph_crypto_key *key, bool encrypt,
+			  void *buf, int buf_len, int in_len, int *pout_len)
+{
+	SYNC_SKCIPHER_REQUEST_ON_STACK(req, key->tfm);
+	struct sg_table sgt;
+	struct scatterlist prealloc_sg;
+	char iv[AES_BLOCK_SIZE] __aligned(8);
+	int pad_byte = AES_BLOCK_SIZE - (in_len & (AES_BLOCK_SIZE - 1));
+	int crypt_len = encrypt ? in_len + pad_byte : in_len;
+	int ret;
+
+	WARN_ON(crypt_len > buf_len);
+	if (encrypt)
+		memset(buf + in_len, pad_byte, pad_byte);
+	ret = setup_sgtable(&sgt, &prealloc_sg, buf, crypt_len);
+	if (ret)
+		return ret;
+
+	memcpy(iv, aes_iv, AES_BLOCK_SIZE);
+	skcipher_request_set_sync_tfm(req, key->tfm);
+	skcipher_request_set_callback(req, 0, NULL, NULL);
+	skcipher_request_set_crypt(req, sgt.sgl, sgt.sgl, crypt_len, iv);
+
+	/*
+	print_hex_dump(KERN_ERR, "key: ", DUMP_PREFIX_NONE, 16, 1,
+		       key->key, key->len, 1);
+	print_hex_dump(KERN_ERR, " in: ", DUMP_PREFIX_NONE, 16, 1,
+		       buf, crypt_len, 1);
+	*/
+	if (encrypt)
+		ret = crypto_skcipher_encrypt(req);
+	else
+		ret = crypto_skcipher_decrypt(req);
+	skcipher_request_zero(req);
+	if (ret) {
+		pr_err("%s %scrypt failed: %d\n", __func__,
+		       encrypt ? "en" : "de", ret);
+		goto out_sgt;
+	}
+	/*
+	print_hex_dump(KERN_ERR, "out: ", DUMP_PREFIX_NONE, 16, 1,
+		       buf, crypt_len, 1);
+	*/
+
+	if (encrypt) {
+		*pout_len = crypt_len;
+	} else {
+		pad_byte = *(char *)(buf + in_len - 1);
+		if (pad_byte > 0 && pad_byte <= AES_BLOCK_SIZE &&
+		    in_len >= pad_byte) {
+			*pout_len = in_len - pad_byte;
+		} else {
+			pr_err("%s got bad padding %d on in_len %d\n",
+			       __func__, pad_byte, in_len);
+			ret = -EPERM;
+			goto out_sgt;
+		}
+	}
+
+out_sgt:
+	teardown_sgtable(&sgt);
+	return ret;
+}
+
+int ceph_crypt(const struct ceph_crypto_key *key, bool encrypt,
+	       void *buf, int buf_len, int in_len, int *pout_len)
+{
+	switch (key->type) {
+	case CEPH_CRYPTO_NONE:
+		*pout_len = in_len;
+		return 0;
+	case CEPH_CRYPTO_AES:
+		return ceph_aes_crypt(key, encrypt, buf, buf_len, in_len,
+				      pout_len);
+	default:
+		return -ENOTSUPP;
+	}
+}
+
+static int ceph_key_preparse(struct key_preparsed_payload *prep)
+{
+	struct ceph_crypto_key *ckey;
+	size_t datalen = prep->datalen;
+	int ret;
+	void *p;
+
+	ret = -EINVAL;
+	if (datalen <= 0 || datalen > 32767 || !prep->data)
+		goto err;
+
+	ret = -ENOMEM;
+	ckey = kmalloc(sizeof(*ckey), GFP_KERNEL);
+	if (!ckey)
+		goto err;
+
+	/* TODO ceph_crypto_key_decode should really take const input */
+	p = (void *)prep->data;
+	ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen);
+	if (ret < 0)
+		goto err_ckey;
+
+	prep->payload.data[0] = ckey;
+	prep->quotalen = datalen;
+	return 0;
+
+err_ckey:
+	kfree(ckey);
+err:
+	return ret;
+}
+
+static void ceph_key_free_preparse(struct key_preparsed_payload *prep)
+{
+	struct ceph_crypto_key *ckey = prep->payload.data[0];
+	ceph_crypto_key_destroy(ckey);
+	kfree(ckey);
+}
+
+static void ceph_key_destroy(struct key *key)
+{
+	struct ceph_crypto_key *ckey = key->payload.data[0];
+
+	ceph_crypto_key_destroy(ckey);
+	kfree(ckey);
+}
+
+struct key_type key_type_ceph = {
+	.name		= "ceph",
+	.preparse	= ceph_key_preparse,
+	.free_preparse	= ceph_key_free_preparse,
+	.instantiate	= generic_key_instantiate,
+	.destroy	= ceph_key_destroy,
+};
+
+int __init ceph_crypto_init(void)
+{
+	return register_key_type(&key_type_ceph);
+}
+
+void ceph_crypto_shutdown(void)
+{
+	unregister_key_type(&key_type_ceph);
+}