lib/display_options: avoid illegal memory access
display_options_get_banner_priv() overwrites bytes before the start of the
buffer if the buffer size is less then 3. This case occurs in the Sandbox
when executing the `ut_print` command.
Correctly handle small buffer sizes. Adjust the print unit test to catch
when bytes before the buffer are overwritten.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/display_options.c b/lib/display_options.c
index af1802e..cff20f3 100644
--- a/lib/display_options.c
+++ b/lib/display_options.c
@@ -23,7 +23,9 @@
build_tag);
if (len > size - 3)
len = size - 3;
- strcpy(buf + len, "\n\n");
+ if (len < 0)
+ len = 0;
+ snprintf(buf + len, size - len, "\n\n");
return buf;
}