bytearray: Handle realloc() failure in byte_array_grow()

byte_array_grow() assigned the result of realloc() directly to
ba->data and increased the capacity even if realloc() failed, so the
following memcpy() in byte_array_append() wrote to NULL + len.

On failure, free the old buffer and leave the byte array in a failed
state (data == NULL), which byte_array_append() already ignores. The
callers check for that state:

- the writers (bin, xml, json, openstep and the text output formats)
  return PLIST_ERR_NO_MEM instead of handing out a NULL/truncated buffer
- node_to_xml() base64-encodes <data> directly into the grown buffer,
  so it must bail out there (only guarded by assert() before)
- the OpenStep parser returns PLIST_ERR_NO_MEM for <hex data> instead of
  silently returning truncated data

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/jplist.c b/src/jplist.c
index c29f760..d065f4d 100644
--- a/src/jplist.c
+++ b/src/jplist.c
@@ -480,6 +480,13 @@ plist_err_t plist_to_json_with_options(plist_t plist, char **plist_json, uint32_
 
     str_buf_append(outbuf, "\0", 1);
 
+    if (!outbuf->data) {
+        str_buf_free(outbuf);
+        *plist_json = NULL;
+        *length = 0;
+        return PLIST_ERR_NO_MEM;
+    }
+
     *plist_json = (char*)outbuf->data;
     *length = outbuf->len - 1;