Fix a memory leak in the mem bio

If you use a BIO and set up your own buffer that is not freed, the
memory bio will leak the BIO_BUF_MEM object it allocates.

The trouble is that the BIO_BUF_MEM is allocated and kept around,
but it is not freed if BIO_NOCLOSE is set.

The freeing of BIO_BUF_MEM was fairly confusing, simplify things
so mem_buf_free only frees the memory buffer and free the BIO_BUF_MEM
in mem_free(), where it should be done.

Alse add a test for a leak in the memory bio
Setting a memory buffer caused a leak.

Signed-off-by: Corey Minyard <minyard@acm.org>

Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8051)

1 files changed, 54 insertions, 0 deletions

diff --git a/test/bio_memleak_test.c b/test/bio_memleak_test.c
new file mode 100644
index 0000000000..36680e30a8
--- /dev/null
+++ b/test/bio_memleak_test.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright 2018 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the OpenSSL license (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 <stdio.h>
+#include <string.h>
+#include <openssl/buffer.h>
+#include <openssl/bio.h>
+
+#include "testutil.h"
+
+static int test_bio_memleak(void)
+{
+    int ok = 0;
+    BIO *bio;
+    BUF_MEM bufmem;
+    const char *str = "BIO test\n";
+    char buf[100];
+
+    bio = BIO_new(BIO_s_mem());
+    if (bio == NULL)
+        goto finish;
+    bufmem.length = strlen(str) + 1;
+    bufmem.data = (char *) str;
+    bufmem.max = bufmem.length;
+    BIO_set_mem_buf(bio, &bufmem, BIO_NOCLOSE);
+    BIO_set_flags(bio, BIO_FLAGS_MEM_RDONLY);
+
+    if (BIO_read(bio, buf, sizeof(buf)) <= 0)
+	goto finish;
+
+    ok = strcmp(buf, str) == 0;
+
+finish:
+    BIO_free(bio);
+    return ok;
+}
+
+int global_init(void)
+{
+    CRYPTO_set_mem_debug(1);
+    CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON);
+    return 1;
+}
+
+int setup_tests(void)
+{
+    ADD_TEST(test_bio_memleak);
+    return 1;
+}