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

[Simon McVittie <smcv src gnome org>]

commit 64cdc55c7ab2692368592142ff6339e6a243b846
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));