fix segfault when displaying empty blobs

When size is zero, subtracting one from it turns it into
ULONG_MAX which causes an out-of-bounds access on buf.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/ui-tree.c b/ui-tree.c
index c6159ec..553dbaa 100644
--- a/ui-tree.c
+++ b/ui-tree.c
@@ -25,12 +25,15 @@ static void print_text_buffer(char *buf, unsigned long size)
         html("<tr><td class='linenumbers'><pre>");
         idx = 0;
         lineno = 0;
+
+        if (size) {
         htmlf(numberfmt, ++lineno);
         while(idx < size - 1) { // skip absolute last newline
                 if (buf[idx] == '\n')
                         htmlf(numberfmt, ++lineno);
                 idx++;
         }
+        }
         html("</pre></td>\n");
         html("<td class='lines'><pre><code>");
         html_txt(buf);