[gcr/wip/smcv/issue42: 3/3] gck-slot: Initialize struct tm to all-zeroes

[Niels De Graef <nielsdg src gnome org>]

commit b1c8213b64fdfcad8c4ae0ff33a31105c0a0a312
Author: Simon McVittie <smcv debian org>
Date:   Sun Mar 15 13:00:08 2020 +0000

    gck-slot: Initialize struct tm to all-zeroes
    
    If the format string for strptime() doesn't include a time zone,
    then the tm_isdst member will be left uninitialized (see NOTES in
    Linux strptime(3)). This means we will be off by an hour from the
    intended time if whatever arbitrary junk is on the stack happens to
    include a positive value for tm.tm_isdst.
    
    Resolves: https://gitlab.gnome.org/GNOME/gcr/issues/42
    Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=953981
    Signed-off-by: Simon McVittie <smcv debian org>

 gck/gck-slot.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/gck/gck-slot.c b/gck/gck-slot.c
index f3b2f97..f00857f 100644
--- a/gck/gck-slot.c
+++ b/gck/gck-slot.c
@@ -607,7 +607,9 @@ _gck_token_info_from_pkcs11 (CK_TOKEN_INFO_PTR info)
 {
        GckTokenInfo *token_info;
        gchar *string;
-       struct tm tm;
+       /* Must be zero-filled, because strptime will leave tm_isdst
+        * unchanged */
+       struct tm tm = { 0 };
 
        token_info = g_new0 (GckTokenInfo, 1);
        token_info->label = gck_string_from_chars (info->label, sizeof (info->label));