util/base64: add a note about zero length strings

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/util/base64.c b/lib/util/base64.c
index 842c22ffdb0..7acc83d0eaf 100644
--- a/lib/util/base64.c
+++ b/lib/util/base64.c
@@ -115,8 +115,16 @@ _PUBLIC_ char *base64_encode_data_blob(TALLOC_CTX *mem_ctx, DATA_BLOB data)
 	size_t out_cnt, len, output_len;
 	char *result;
 
-        if (!data.length || !data.data)
+	/*
+	 * Note: we return NULL for a zero-length blob, even though it can be
+	 * encoded as a zero length string in base64.
+	 *
+	 * FIXME, perhaps, but we need to check carefully before changing
+	 * this.
+	 */
+        if (data.length == 0 || data.data == NULL) {
 		return NULL;
+	}
 
 	out_cnt = 0;
 	len = data.length;