[Feature] add GA346 baseline version
Change-Id: Ic62933698569507dcf98240cdf5d9931ae34348f
diff --git a/src/kernel/linux/v4.19/fs/verity/hash_algs.c b/src/kernel/linux/v4.19/fs/verity/hash_algs.c
new file mode 100644
index 0000000..31e6d7d
--- /dev/null
+++ b/src/kernel/linux/v4.19/fs/verity/hash_algs.c
@@ -0,0 +1,280 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * fs/verity/hash_algs.c: fs-verity hash algorithms
+ *
+ * Copyright 2019 Google LLC
+ */
+
+#include "fsverity_private.h"
+
+#include <crypto/hash.h>
+#include <linux/scatterlist.h>
+
+/* The hash algorithms supported by fs-verity */
+struct fsverity_hash_alg fsverity_hash_algs[] = {
+ [FS_VERITY_HASH_ALG_SHA256] = {
+ .name = "sha256",
+ .digest_size = SHA256_DIGEST_SIZE,
+ .block_size = SHA256_BLOCK_SIZE,
+ },
+ [FS_VERITY_HASH_ALG_SHA512] = {
+ .name = "sha512",
+ .digest_size = SHA512_DIGEST_SIZE,
+ .block_size = SHA512_BLOCK_SIZE,
+ },
+};
+
+/**
+ * fsverity_get_hash_alg() - validate and prepare a hash algorithm
+ * @inode: optional inode for logging purposes
+ * @num: the hash algorithm number
+ *
+ * Get the struct fsverity_hash_alg for the given hash algorithm number, and
+ * ensure it has a hash transform ready to go. The hash transforms are
+ * allocated on-demand so that we don't waste resources unnecessarily, and
+ * because the crypto modules may be initialized later than fs/verity/.
+ *
+ * Return: pointer to the hash alg on success, else an ERR_PTR()
+ */
+const struct fsverity_hash_alg *fsverity_get_hash_alg(const struct inode *inode,
+ unsigned int num)
+{
+ struct fsverity_hash_alg *alg;
+ struct crypto_ahash *tfm;
+ int err;
+
+ if (num >= ARRAY_SIZE(fsverity_hash_algs) ||
+ !fsverity_hash_algs[num].name) {
+ fsverity_warn(inode, "Unknown hash algorithm number: %u", num);
+ return ERR_PTR(-EINVAL);
+ }
+ alg = &fsverity_hash_algs[num];
+
+ /* pairs with cmpxchg() below */
+ tfm = READ_ONCE(alg->tfm);
+ if (likely(tfm != NULL))
+ return alg;
+ /*
+ * Using the shash API would make things a bit simpler, but the ahash
+ * API is preferable as it allows the use of crypto accelerators.
+ */
+ tfm = crypto_alloc_ahash(alg->name, 0, 0);
+ if (IS_ERR(tfm)) {
+ if (PTR_ERR(tfm) == -ENOENT) {
+ fsverity_warn(inode,
+ "Missing crypto API support for hash algorithm \"%s\"",
+ alg->name);
+ return ERR_PTR(-ENOPKG);
+ }
+ fsverity_err(inode,
+ "Error allocating hash algorithm \"%s\": %ld",
+ alg->name, PTR_ERR(tfm));
+ return ERR_CAST(tfm);
+ }
+
+ err = -EINVAL;
+ if (WARN_ON(alg->digest_size != crypto_ahash_digestsize(tfm)))
+ goto err_free_tfm;
+ if (WARN_ON(alg->block_size != crypto_ahash_blocksize(tfm)))
+ goto err_free_tfm;
+
+ pr_info("%s using implementation \"%s\"\n",
+ alg->name, crypto_ahash_driver_name(tfm));
+
+ /* pairs with READ_ONCE() above */
+ if (cmpxchg(&alg->tfm, NULL, tfm) != NULL)
+ crypto_free_ahash(tfm);
+
+ return alg;
+
+err_free_tfm:
+ crypto_free_ahash(tfm);
+ return ERR_PTR(err);
+}
+
+/**
+ * fsverity_prepare_hash_state() - precompute the initial hash state
+ * @alg: hash algorithm
+ * @salt: a salt which is to be prepended to all data to be hashed
+ * @salt_size: salt size in bytes, possibly 0
+ *
+ * Return: NULL if the salt is empty, otherwise the kmalloc()'ed precomputed
+ * initial hash state on success or an ERR_PTR() on failure.
+ */
+const u8 *fsverity_prepare_hash_state(const struct fsverity_hash_alg *alg,
+ const u8 *salt, size_t salt_size)
+{
+ u8 *hashstate = NULL;
+ struct ahash_request *req = NULL;
+ u8 *padded_salt = NULL;
+ size_t padded_salt_size;
+ struct scatterlist sg;
+ DECLARE_CRYPTO_WAIT(wait);
+ int err;
+
+ if (salt_size == 0)
+ return NULL;
+
+ hashstate = kmalloc(crypto_ahash_statesize(alg->tfm), GFP_KERNEL);
+ if (!hashstate)
+ return ERR_PTR(-ENOMEM);
+
+ req = ahash_request_alloc(alg->tfm, GFP_KERNEL);
+ if (!req) {
+ err = -ENOMEM;
+ goto err_free;
+ }
+
+ /*
+ * Zero-pad the salt to the next multiple of the input size of the hash
+ * algorithm's compression function, e.g. 64 bytes for SHA-256 or 128
+ * bytes for SHA-512. This ensures that the hash algorithm won't have
+ * any bytes buffered internally after processing the salt, thus making
+ * salted hashing just as fast as unsalted hashing.
+ */
+ padded_salt_size = round_up(salt_size, alg->block_size);
+ padded_salt = kzalloc(padded_salt_size, GFP_KERNEL);
+ if (!padded_salt) {
+ err = -ENOMEM;
+ goto err_free;
+ }
+ memcpy(padded_salt, salt, salt_size);
+
+ sg_init_one(&sg, padded_salt, padded_salt_size);
+ ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
+ CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &wait);
+ ahash_request_set_crypt(req, &sg, NULL, padded_salt_size);
+
+ err = crypto_wait_req(crypto_ahash_init(req), &wait);
+ if (err)
+ goto err_free;
+
+ err = crypto_wait_req(crypto_ahash_update(req), &wait);
+ if (err)
+ goto err_free;
+
+ err = crypto_ahash_export(req, hashstate);
+ if (err)
+ goto err_free;
+out:
+ ahash_request_free(req);
+ kfree(padded_salt);
+ return hashstate;
+
+err_free:
+ kfree(hashstate);
+ hashstate = ERR_PTR(err);
+ goto out;
+}
+
+/**
+ * fsverity_hash_page() - hash a single data or hash page
+ * @params: the Merkle tree's parameters
+ * @inode: inode for which the hashing is being done
+ * @req: preallocated hash request
+ * @page: the page to hash
+ * @out: output digest, size 'params->digest_size' bytes
+ *
+ * Hash a single data or hash block, assuming block_size == PAGE_SIZE.
+ * The hash is salted if a salt is specified in the Merkle tree parameters.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fsverity_hash_page(const struct merkle_tree_params *params,
+ const struct inode *inode,
+ struct ahash_request *req, struct page *page, u8 *out)
+{
+ struct scatterlist sg;
+ DECLARE_CRYPTO_WAIT(wait);
+ int err;
+
+ if (WARN_ON(params->block_size != PAGE_SIZE))
+ return -EINVAL;
+
+ sg_init_table(&sg, 1);
+ sg_set_page(&sg, page, PAGE_SIZE, 0);
+ ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
+ CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &wait);
+ ahash_request_set_crypt(req, &sg, out, PAGE_SIZE);
+
+ if (params->hashstate) {
+ err = crypto_ahash_import(req, params->hashstate);
+ if (err) {
+ fsverity_err(inode,
+ "Error %d importing hash state", err);
+ return err;
+ }
+ err = crypto_ahash_finup(req);
+ } else {
+ err = crypto_ahash_digest(req);
+ }
+
+ err = crypto_wait_req(err, &wait);
+ if (err)
+ fsverity_err(inode, "Error %d computing page hash", err);
+ return err;
+}
+
+/**
+ * fsverity_hash_buffer() - hash some data
+ * @alg: the hash algorithm to use
+ * @data: the data to hash
+ * @size: size of data to hash, in bytes
+ * @out: output digest, size 'alg->digest_size' bytes
+ *
+ * Hash some data which is located in physically contiguous memory (i.e. memory
+ * allocated by kmalloc(), not by vmalloc()). No salt is used.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int fsverity_hash_buffer(const struct fsverity_hash_alg *alg,
+ const void *data, size_t size, u8 *out)
+{
+ struct ahash_request *req;
+ struct scatterlist sg;
+ DECLARE_CRYPTO_WAIT(wait);
+ int err;
+
+ req = ahash_request_alloc(alg->tfm, GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ sg_init_one(&sg, data, size);
+ ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
+ CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &wait);
+ ahash_request_set_crypt(req, &sg, out, size);
+
+ err = crypto_wait_req(crypto_ahash_digest(req), &wait);
+
+ ahash_request_free(req);
+ return err;
+}
+
+void __init fsverity_check_hash_algs(void)
+{
+ size_t i;
+
+ /*
+ * Sanity check the hash algorithms (could be a build-time check, but
+ * they're in an array)
+ */
+ for (i = 0; i < ARRAY_SIZE(fsverity_hash_algs); i++) {
+ const struct fsverity_hash_alg *alg = &fsverity_hash_algs[i];
+
+ if (!alg->name)
+ continue;
+
+ BUG_ON(alg->digest_size > FS_VERITY_MAX_DIGEST_SIZE);
+
+ /*
+ * For efficiency, the implementation currently assumes the
+ * digest and block sizes are powers of 2. This limitation can
+ * be lifted if the code is updated to handle other values.
+ */
+ BUG_ON(!is_power_of_2(alg->digest_size));
+ BUG_ON(!is_power_of_2(alg->block_size));
+ }
+}