@@ -343,16 +343,33 @@ convert_to_one_line(struct buffer *buf)

     }

 }

-/* NOTE: requires that string be null terminated */

-void

-buf_write_string_file(const struct buffer *buf, const char *filename, int fd)

+bool

+buffer_write_file(const char *filename, const struct buffer *buf)

 {

-    const int len = strlen((char *) BPTR(buf));

-    const int size = write(fd, BPTR(buf), len);

-    if (size != len)

+    bool ret = false;

+    int fd = platform_open(filename, O_CREAT | O_TRUNC | O_WRONLY,

+                           S_IRUSR | S_IWUSR);

+    if (fd == -1)

+    {

+        msg(M_ERRNO, "Cannot open file '%s' for write", filename);

+        return false;

+    }

+

+    const int size = write(fd, BPTR(buf), BLEN(buf));

+    if (size != BLEN(buf))

     {

-        msg(M_ERR, "Write error on file '%s'", filename);

+        msg(M_ERRNO, "Write error on file '%s'", filename);

+        goto cleanup;

+    }

+

+    ret = true;

+cleanup:

+    if (close(fd) < 0)

+    {

+        msg(M_ERRNO, "Close error on file %s", filename);

+        ret = false;

     }

+    return ret;

 }

 /*

@@ -469,11 +469,15 @@ const char *skip_leading_whitespace(const char *str);

 void string_null_terminate(char *str, int len, int capacity);

-/*

- * Write string in buf to file descriptor fd.

- * NOTE: requires that string be null terminated.

+/**

+ * Write buffer contents to file.

+ *

+ * @param filename  The filename to write the buffer to.

+ * @param buf       The buffer to write to the file.

+ *

+ * @return true on success, false otherwise.

  */

-void buf_write_string_file(const struct buffer *buf, const char *filename, int fd);

+bool buffer_write_file(const char *filename, const struct buffer *buf);

 /*

  * write a string to the end of a buffer that was

@@ -1418,36 +1418,24 @@ read_key_file(struct key2 *key2, const char *file, const unsigned int flags)

     gc_free(&gc);

 }

-/*

- * Write key to file, return number of random bits

- * written.

- */

 int

 write_key_file(const int nkeys, const char *filename)

 {

     struct gc_arena gc = gc_new();

-    int fd, i;

-    int nbits = 0;

+    int nbits = nkeys * sizeof(struct key) * 8;

     /* must be large enough to hold full key file */

     struct buffer out = alloc_buf_gc(2048, &gc);

-    struct buffer nbits_head_text = alloc_buf_gc(128, &gc);

     /* how to format the ascii file representation of key */

     const int bytes_per_line = 16;

-    /* open key file */

-    fd = platform_open(filename, O_CREAT | O_TRUNC | O_WRONLY, S_IRUSR | S_IWUSR);

-

-    if (fd == -1)

-    {

-        msg(M_ERR, "Cannot open shared secret file '%s' for write", filename);

-    }

-

+    /* write header */

+    buf_printf(&out, "#\n# %d bit OpenVPN static key\n#\n", nbits);

     buf_printf(&out, "%s\n", static_key_head);

-    for (i = 0; i < nkeys; ++i)

+    for (int i = 0; i < nkeys; ++i)

     {

         struct key key;

         char *fmt;

@@ -1463,9 +1451,6 @@ write_key_file(const int nkeys, const char *filename)

                             "\n",

                             &gc);

-        /* increment random bits counter */

-        nbits += sizeof(key) * 8;

-

         /* write to holding buffer */

         buf_printf(&out, "%s\n", fmt);

@@ -1476,16 +1461,10 @@ write_key_file(const int nkeys, const char *filename)

     buf_printf(&out, "%s\n", static_key_foot);

-    /* write number of bits */

-    buf_printf(&nbits_head_text, "#\n# %d bit OpenVPN static key\n#\n", nbits);

-    buf_write_string_file(&nbits_head_text, filename, fd);

-

     /* write key file, now formatted in out, to file */

-    buf_write_string_file(&out, filename, fd);

-

-    if (close(fd))

+    if(!buffer_write_file(filename, &out))

     {

-        msg(M_ERR, "Close error on shared secret file %s", filename);

+        nbits = -1;

     }

     /* zero memory which held file content (memory will be freed by GC) */

@@ -271,6 +271,11 @@ struct crypto_options

 #define RKF_INLINE       (1<<1)

 void read_key_file(struct key2 *key2, const char *file, const unsigned int flags);

+/**

+ * Write nkeys 1024-bits keys to file.

+ *

+ * @returns number of random bits written, or -1 on failure.

+ */

 int write_key_file(const int nkeys, const char *filename);

 int read_passphrase_hash(const char *passphrase_file,

@@ -1041,6 +1041,10 @@ do_genkey(const struct options *options)

         }

         nbits_written = write_key_file(2, options->shared_secret_file);

+        if (nbits_written < 0)

+        {

+            msg(M_FATAL, "Failed to write key file");

+        }

         msg(D_GENKEY | M_NOPREFIX,

             "Randomly generated %d bit key written to %s", nbits_written,