Create libcrypto support for BIO_new_from_core_bio()

Previously the concept of wrapping an OSSL_CORE_BIO in a real BIO was an
internal only concept for our own providers. Since this is likely to be
generally useful, we make it a part of the public API.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15072)

1 files changed, 170 insertions, 0 deletions

diff --git a/crypto/bio/bss_core.c b/crypto/bio/bss_core.c
new file mode 100644
index 0000000000..2baabe614e
--- /dev/null
+++ b/crypto/bio/bss_core.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/core_dispatch.h>
+#include "bio_local.h"
+#include "internal/cryptlib.h"
+
+typedef struct {
+    OSSL_FUNC_BIO_read_ex_fn *c_bio_read_ex;
+    OSSL_FUNC_BIO_write_ex_fn *c_bio_write_ex;
+    OSSL_FUNC_BIO_gets_fn *c_bio_gets;
+    OSSL_FUNC_BIO_puts_fn *c_bio_puts;
+    OSSL_FUNC_BIO_ctrl_fn *c_bio_ctrl;
+} BIO_CORE_GLOBALS;
+
+static void bio_core_globals_free(void *vbcg)
+{
+    OPENSSL_free(vbcg);
+}
+
+static void *bio_core_globals_new(OSSL_LIB_CTX *ctx)
+{
+    return OPENSSL_zalloc(sizeof(BIO_CORE_GLOBALS));
+}
+
+static const OSSL_LIB_CTX_METHOD bio_core_globals_method = {
+    bio_core_globals_new,
+    bio_core_globals_free,
+};
+
+static ossl_inline BIO_CORE_GLOBALS *get_globals(OSSL_LIB_CTX *libctx)
+{
+    return ossl_lib_ctx_get_data(libctx, OSSL_LIB_CTX_BIO_CORE_INDEX,
+                                 &bio_core_globals_method);
+}
+
+static int bio_core_read_ex(BIO *bio, char *data, size_t data_len,
+                            size_t *bytes_read)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(bio->libctx);
+
+    if (bcgbl->c_bio_read_ex == NULL)
+        return 0;
+    return bcgbl->c_bio_read_ex(BIO_get_data(bio), data, data_len, bytes_read);
+}
+
+static int bio_core_write_ex(BIO *bio, const char *data, size_t data_len,
+                             size_t *written)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(bio->libctx);
+
+    if (bcgbl->c_bio_write_ex == NULL)
+        return 0;
+    return bcgbl->c_bio_write_ex(BIO_get_data(bio), data, data_len, written);
+}
+
+static long bio_core_ctrl(BIO *bio, int cmd, long num, void *ptr)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(bio->libctx);
+
+    if (bcgbl->c_bio_ctrl == NULL)
+        return -1;
+    return bcgbl->c_bio_ctrl(BIO_get_data(bio), cmd, num, ptr);
+}
+
+static int bio_core_gets(BIO *bio, char *buf, int size)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(bio->libctx);
+
+    if (bcgbl->c_bio_gets == NULL)
+        return -1;
+    return bcgbl->c_bio_gets(BIO_get_data(bio), buf, size);
+}
+
+static int bio_core_puts(BIO *bio, const char *str)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(bio->libctx);
+
+    if (bcgbl->c_bio_puts == NULL)
+        return -1;
+    return bcgbl->c_bio_puts(BIO_get_data(bio), str);
+}
+
+static int bio_core_new(BIO *bio)
+{
+    BIO_set_init(bio, 1);
+
+    return 1;
+}
+
+static int bio_core_free(BIO *bio)
+{
+    BIO_set_init(bio, 0);
+
+    return 1;
+}
+
+static const BIO_METHOD corebiometh = {
+    BIO_TYPE_CORE_TO_PROV,
+    "BIO to Core filter",
+    bio_core_write_ex,
+    NULL,
+    bio_core_read_ex,
+    NULL,
+    bio_core_puts,
+    bio_core_gets,
+    bio_core_ctrl,
+    bio_core_new,
+    bio_core_free,
+    NULL,
+};
+
+const BIO_METHOD *BIO_s_core(void)
+{
+    return &corebiometh;
+}
+
+BIO *BIO_new_from_core_bio(OSSL_LIB_CTX *libctx, OSSL_CORE_BIO *corebio)
+{
+    BIO *outbio;
+    BIO_CORE_GLOBALS *bcgbl = get_globals(libctx);
+
+    /* Check the library context has been initialised with the callbacks */
+    if (bcgbl->c_bio_write_ex == NULL && bcgbl->c_bio_read_ex == NULL)
+        return NULL;
+
+    if ((outbio = BIO_new_ex(libctx, BIO_s_core())) == NULL)
+        return NULL;
+
+    BIO_set_data(outbio, corebio);
+    return outbio;
+}
+
+int ossl_bio_init_core(OSSL_LIB_CTX *libctx, const OSSL_DISPATCH *fns)
+{
+    BIO_CORE_GLOBALS *bcgbl = get_globals(libctx);
+
+    for (; fns->function_id != 0; fns++) {
+        switch (fns->function_id) {
+        case OSSL_FUNC_BIO_READ_EX:
+            if (bcgbl->c_bio_read_ex == NULL)
+                bcgbl->c_bio_read_ex = OSSL_FUNC_BIO_read_ex(fns);
+            break;
+        case OSSL_FUNC_BIO_WRITE_EX:
+            if (bcgbl->c_bio_write_ex == NULL)
+                bcgbl->c_bio_write_ex = OSSL_FUNC_BIO_write_ex(fns);
+            break;
+        case OSSL_FUNC_BIO_GETS:
+            if (bcgbl->c_bio_gets == NULL)
+                bcgbl->c_bio_gets = OSSL_FUNC_BIO_gets(fns);
+            break;
+        case OSSL_FUNC_BIO_PUTS:
+            if (bcgbl->c_bio_puts == NULL)
+                bcgbl->c_bio_puts = OSSL_FUNC_BIO_puts(fns);
+            break;
+        case OSSL_FUNC_BIO_CTRL:
+            if (bcgbl->c_bio_ctrl == NULL)
+                bcgbl->c_bio_ctrl = OSSL_FUNC_BIO_ctrl(fns);
+            break;
+        }
+    }
+
+    return 1;
+}