crypto: introduce new module for computing hash digests

Introduce a new crypto/ directory that will (eventually) contain
all the cryptographic related code. This initially defines a
wrapper for initializing gnutls and for computing hashes with
gnutls. The former ensures that gnutls is guaranteed to be
initialized exactly once in QEMU regardless of CLI args. The
block quorum code currently fails to initialize gnutls so it
only works by luck, if VNC server TLS is not requested. The
hash APIs avoids the need to litter the rest of the code with
preprocessor checks and simplifies callers by allocating the
correct amount of memory for the requested hash.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1435770638-25715-2-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 189 insertions, 0 deletions

diff --git a/include/crypto/hash.h b/include/crypto/hash.h
new file mode 100644
index 0000000000..b5acbf638c
--- /dev/null
+++ b/include/crypto/hash.h
@@ -0,0 +1,189 @@
+/*
+ * QEMU Crypto hash algorithms
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QCRYPTO_HASH_H__
+#define QCRYPTO_HASH_H__
+
+#include "qemu-common.h"
+#include "qapi/error.h"
+
+typedef enum {
+    QCRYPTO_HASH_ALG_MD5,
+    QCRYPTO_HASH_ALG_SHA1,
+    QCRYPTO_HASH_ALG_SHA256,
+
+    QCRYPTO_HASH_ALG_LAST
+} QCryptoHashAlgorithm;
+
+
+/**
+ * qcrypto_hash_supports:
+ * @alg: the hash algorithm
+ *
+ * Determine if @alg hash algorithm is supported by the
+ * current configured build.
+ *
+ * Returns: true if the algorithm is supported, false otherwise
+ */
+gboolean qcrypto_hash_supports(QCryptoHashAlgorithm alg);
+
+/**
+ * qcrypto_hash_bytesv:
+ * @alg: the hash algorithm
+ * @iov: the array of memory regions to hash
+ * @niov: the length of @iov
+ * @result: pointer to hold output hash
+ * @resultlen: pointer to hold length of @result
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory regions
+ * present in @iov. The @result pointer will be
+ * filled with raw bytes representing the computed
+ * hash, which will have length @resultlen. The
+ * memory pointer in @result must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_bytesv(QCryptoHashAlgorithm alg,
+                        const struct iovec *iov,
+                        size_t niov,
+                        uint8_t **result,
+                        size_t *resultlen,
+                        Error **errp);
+
+/**
+ * qcrypto_hash_bytes:
+ * @alg: the hash algorithm
+ * @buf: the memory region to hash
+ * @len: the length of @buf
+ * @result: pointer to hold output hash
+ * @resultlen: pointer to hold length of @result
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory region
+ * @buf of length @len. The @result pointer will be
+ * filled with raw bytes representing the computed
+ * hash, which will have length @resultlen. The
+ * memory pointer in @result must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_bytes(QCryptoHashAlgorithm alg,
+                       const char *buf,
+                       size_t len,
+                       uint8_t **result,
+                       size_t *resultlen,
+                       Error **errp);
+
+/**
+ * qcrypto_hash_digestv:
+ * @alg: the hash algorithm
+ * @iov: the array of memory regions to hash
+ * @niov: the length of @iov
+ * @digest: pointer to hold output hash
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory regions
+ * present in @iov. The @digest pointer will be
+ * filled with the printable hex digest of the computed
+ * hash, which will be terminated by '\0'. The
+ * memory pointer in @digest must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_digestv(QCryptoHashAlgorithm alg,
+                         const struct iovec *iov,
+                         size_t niov,
+                         char **digest,
+                         Error **errp);
+
+/**
+ * qcrypto_hash_digest:
+ * @alg: the hash algorithm
+ * @buf: the memory region to hash
+ * @len: the length of @buf
+ * @digest: pointer to hold output hash
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory region
+ * @buf of length @len. The @digest pointer will be
+ * filled with the printable hex digest of the computed
+ * hash, which will be terminated by '\0'. The
+ * memory pointer in @digest must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_digest(QCryptoHashAlgorithm alg,
+                        const char *buf,
+                        size_t len,
+                        char **digest,
+                        Error **errp);
+
+/**
+ * qcrypto_hash_base64v:
+ * @alg: the hash algorithm
+ * @iov: the array of memory regions to hash
+ * @niov: the length of @iov
+ * @base64: pointer to hold output hash
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory regions
+ * present in @iov. The @base64 pointer will be
+ * filled with the base64 encoding of the computed
+ * hash, which will be terminated by '\0'. The
+ * memory pointer in @base64 must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_base64v(QCryptoHashAlgorithm alg,
+                         const struct iovec *iov,
+                         size_t niov,
+                         char **base64,
+                         Error **errp);
+
+/**
+ * qcrypto_hash_base64:
+ * @alg: the hash algorithm
+ * @buf: the memory region to hash
+ * @len: the length of @buf
+ * @base64: pointer to hold output hash
+ * @errp: pointer to uninitialized error object
+ *
+ * Computes the hash across all the memory region
+ * @buf of length @len. The @base64 pointer will be
+ * filled with the base64 encoding of the computed
+ * hash, which will be terminated by '\0'. The
+ * memory pointer in @base64 must be released
+ * with a call to g_free() when no longer required.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int qcrypto_hash_base64(QCryptoHashAlgorithm alg,
+                        const char *buf,
+                        size_t len,
+                        char **base64,
+                        Error **errp);
+
+#endif /* QCRYPTO_HASH_H__ */