[PATCH v4 06/15] crypto/hash-afalg: Implement new hash API

[Alejandro Zeise]

Updates the afalg hash driver to support the new accumulative
hashing changes as part of the patch series.

Implements opening/closing of contexts, updating hash data
and finalizing the hash digest.

In order to support the update function, a flag needs to be passed
to the kernel via the socket send call (MSG_MORE) to notify it that more
data is to be expected to calculate the hash correctly.
As a result, a new function was added to the iov helper utils to allow
passing a flag to the socket send call.

Signed-off-by: Alejandro Zeise <alejandro.zeise@seagate.com>
---
 crypto/hash-afalg.c | 126 ++++++++++++++++++++++++++++++++++++++++++++
 include/qemu/iov.h  |  26 +++++++++
 util/iov.c          |  22 +++++---
 3 files changed, 167 insertions(+), 7 deletions(-)

diff --git a/crypto/hash-afalg.c b/crypto/hash-afalg.c
index 3ebea39292..9548c04933 100644
--- a/crypto/hash-afalg.c
+++ b/crypto/hash-afalg.c
@@ -1,6 +1,7 @@
 /*
  * QEMU Crypto af_alg-backend hash/hmac support
  *
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
  * Copyright (c) 2017 HUAWEI TECHNOLOGIES CO., LTD.
  *
  * Authors:
@@ -113,6 +114,127 @@ qcrypto_afalg_hmac_ctx_new(QCryptoHashAlgorithm alg,
     return qcrypto_afalg_hash_hmac_ctx_new(alg, key, nkey, true, errp);
 }
 
+static
+QCryptoHash *qcrypto_afalg_hash_new(QCryptoHashAlgorithm alg, Error **errp)
+{
+    /* Check if hash algorithm is supported */
+    char *alg_name = qcrypto_afalg_hash_format_name(alg, false, NULL);
+    QCryptoHash *hash = NULL;
+
+    if (alg_name == NULL) {
+        error_setg(errp,
+                   "Unknown hash algorithm %d",
+                   alg);
+    } else {
+        hash = g_new(QCryptoHash, 1);
+        hash->alg = alg;
+        hash->opaque = qcrypto_afalg_hash_ctx_new(alg, errp);
+    }
+
+    return hash;
+}
+
+static
+void qcrypto_afalg_hash_free(QCryptoHash *hash)
+{
+    QCryptoAFAlg *ctx = hash->opaque;
+
+    if (ctx) {
+        qcrypto_afalg_comm_free(ctx);
+    }
+
+    g_free(hash);
+}
+
+/**
+ * Send data to the kernel's crypto core.
+ *
+ * The more_data parameter is used to notify the crypto engine
+ * that this is an "update" operation, and that more data will
+ * be provided to calculate the final hash.
+ */
+static
+int qcrypto_afalg_send_to_kernel(QCryptoAFAlg *afalg,
+                                 const struct iovec *iov,
+                                 size_t niov,
+                                 bool more_data,
+                                 Error **errp)
+{
+    int ret = 0;
+    int flags = (more_data ? MSG_MORE : 0);
+
+    /* send data to kernel's crypto core */
+    ret = iov_send_recv_with_flags(afalg->opfd, flags, iov, niov,
+                                   0, iov_size(iov, niov), true);
+    if (ret < 0) {
+        error_setg_errno(errp, errno, "Send data to afalg-core failed");
+        ret = -1;
+    } else {
+        /* No error, so return 0 */
+        ret = 0;
+    }
+
+    return ret;
+}
+
+static
+int qcrypto_afalg_recv_from_kernel(QCryptoAFAlg *afalg,
+                                   QCryptoHashAlgorithm alg,
+                                   uint8_t **result,
+                                   size_t *result_len,
+                                   Error **errp)
+{
+    struct iovec outv;
+    int ret = 0;
+    const int expected_len = qcrypto_hash_digest_len(alg);
+
+    if (*result_len == 0) {
+        *result_len = expected_len;
+        *result = g_new0(uint8_t, *result_len);
+    } else if (*result_len != expected_len) {
+        error_setg(errp,
+                   "Result buffer size %zu is not match hash %d",
+                   *result_len, expected_len);
+        ret = -1;
+    }
+
+    if (ret == 0) {
+        /* hash && get result */
+        outv.iov_base = *result;
+        outv.iov_len = *result_len;
+        ret = iov_send_recv(afalg->opfd, &outv, 1,
+                            0, iov_size(&outv, 1), false);
+        if (ret < 0) {
+            error_setg_errno(errp, errno, "Recv result from afalg-core 
failed");
+            ret = -1;
+        } else {
+            ret = 0;
+        }
+    }
+
+    return ret;
+}
+
+static
+int qcrypto_afalg_hash_update(QCryptoHash *hash,
+                              const struct iovec *iov,
+                              size_t niov,
+                              Error **errp)
+{
+    return qcrypto_afalg_send_to_kernel((QCryptoAFAlg *) hash->opaque,
+                                        iov, niov, true, errp);
+}
+
+static
+int qcrypto_afalg_hash_finalize(QCryptoHash *hash,
+                                 uint8_t **result,
+                                 size_t *result_len,
+                                 Error **errp)
+{
+    return qcrypto_afalg_recv_from_kernel((QCryptoAFAlg *) hash->opaque,
+                                          hash->alg, result, result_len, errp);
+}
+
 static int
 qcrypto_afalg_hash_hmac_bytesv(QCryptoAFAlg *hmac,
                                QCryptoHashAlgorithm alg,
@@ -205,6 +327,10 @@ static void qcrypto_afalg_hmac_ctx_free(QCryptoHmac *hmac)
 
 QCryptoHashDriver qcrypto_hash_afalg_driver = {
     .hash_bytesv = qcrypto_afalg_hash_bytesv,
+    .hash_new      = qcrypto_afalg_hash_new,
+    .hash_free     = qcrypto_afalg_hash_free,
+    .hash_update   = qcrypto_afalg_hash_update,
+    .hash_finalize = qcrypto_afalg_hash_finalize
 };
 
 QCryptoHmacDriver qcrypto_hmac_afalg_driver = {
diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index 63a1c01965..43884cdd64 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -1,6 +1,7 @@
 /*
  * Helpers for using (partial) iovecs.
  *
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
  * Copyright (C) 2010 Red Hat, Inc.
  *
  * Author(s):
@@ -75,6 +76,31 @@ iov_to_buf(const struct iovec *iov, const unsigned int 
iov_cnt,
 size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
                   size_t offset, int fillc, size_t bytes);
 
+/*
+ * Send/recv data from/to iovec buffers directly, with the provided
+ * socket flags.
+ *
+ * `offset' bytes in the beginning of iovec buffer are skipped and
+ * next `bytes' bytes are used, which must be within data of iovec.
+ *
+ *   r = iov_send_recv_with_flags(sockfd, sockflags, iov, iovcnt, offset, 
bytes, true);
+ *
+ * is logically equivalent to
+ *
+ *   char *buf = malloc(bytes);
+ *   iov_to_buf(iov, iovcnt, offset, buf, bytes);
+ *   r = send(sockfd, buf, bytes, sockflags);
+ *   free(buf);
+ *
+ * For iov_send_recv_with_flags() _whole_ area being sent or received
+ * should be within the iovec, not only beginning of it.
+ */
+ssize_t iov_send_recv_with_flags(int sockfd, int sockflags,
+                                 const struct iovec *iov,
+                                 unsigned iov_cnt, size_t offset,
+                                 size_t bytes,
+                                 bool do_send);
+
 /*
  * Send/recv data from/to iovec buffers directly
  *
diff --git a/util/iov.c b/util/iov.c
index 7e73948f5e..5644e0b73c 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -3,6 +3,7 @@
  *
  * Copyright IBM, Corp. 2007, 2008
  * Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
  *
  * Author(s):
  *  Anthony Liguori <aliguori@us.ibm.com>
@@ -92,7 +93,7 @@ size_t iov_size(const struct iovec *iov, const unsigned int 
iov_cnt)
 
 /* helper function for iov_send_recv() */
 static ssize_t
-do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
+do_send_recv(int sockfd, int flags, struct iovec *iov, unsigned iov_cnt, bool 
do_send)
 {
 #ifdef CONFIG_POSIX
     ssize_t ret;
@@ -102,8 +103,8 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned 
iov_cnt, bool do_send)
     msg.msg_iovlen = iov_cnt;
     do {
         ret = do_send
-            ? sendmsg(sockfd, &msg, 0)
-            : recvmsg(sockfd, &msg, 0);
+            ? sendmsg(sockfd, &msg, flags)
+            : recvmsg(sockfd, &msg, flags);
     } while (ret < 0 && errno == EINTR);
     return ret;
 #else
@@ -114,8 +115,8 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned 
iov_cnt, bool do_send)
     ssize_t off = 0;
     while (i < iov_cnt) {
         ssize_t r = do_send
-            ? send(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0)
-            : recv(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0);
+            ? send(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, flags)
+            : recv(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, flags);
         if (r > 0) {
             ret += r;
             off += r;
@@ -144,6 +145,13 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned 
iov_cnt, bool do_send)
 ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
                       size_t offset, size_t bytes,
                       bool do_send)
+{
+    return iov_send_recv_with_flags(sockfd, 0, _iov, iov_cnt, offset, bytes, 
do_send);
+}
+
+ssize_t iov_send_recv_with_flags(int sockfd, int sockflags, const struct iovec 
*_iov,
+                                 unsigned iov_cnt, size_t offset, size_t bytes,
+                                 bool do_send)
 {
     ssize_t total = 0;
     ssize_t ret;
@@ -192,11 +200,11 @@ ssize_t iov_send_recv(int sockfd, const struct iovec 
*_iov, unsigned iov_cnt,
             assert(iov[niov].iov_len > tail);
             orig_len = iov[niov].iov_len;
             iov[niov++].iov_len = tail;
-            ret = do_send_recv(sockfd, iov, niov, do_send);
+            ret = do_send_recv(sockfd, sockflags, iov, niov, do_send);
             /* Undo the changes above before checking for errors */
             iov[niov-1].iov_len = orig_len;
         } else {
-            ret = do_send_recv(sockfd, iov, niov, do_send);
+            ret = do_send_recv(sockfd, sockflags, iov, niov, do_send);
         }
         if (offset) {
             iov[0].iov_base -= offset;
-- 
2.34.1