On 25/09/17 18:29, Paul Eggert wrote:
> * lib/parse-datetime.y (parse_datetime2):
> * lib/posixtm.c (posixtime):
> Do not access uninitialized storage, even though the resulting
> value is never used.
> ---
> ChangeLog | 8 ++++++++
> lib/parse-datetime.y | 16 ++++++++++++++--
> lib/posixtm.c | 7 ++++++-
> 3 files changed, 28 insertions(+), 3 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index 386986ee7..9c6d73f72 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,11 @@
> +2017-09-25 Paul Eggert <[email protected]>
> +
> + parse-datetime, posixtm: avoid uninit access
> + * lib/parse-datetime.y (parse_datetime2):
> + * lib/posixtm.c (posixtime):
> + Do not access uninitialized storage, even though the resulting
> + value is never used.
> +
> 2017-09-25 Bruno Haible <[email protected]>
>
> vma-iter: Improvements for BSD platforms.
> diff --git a/lib/parse-datetime.y b/lib/parse-datetime.y
> index 9eff2dc3b..f8da02d3f 100644
> --- a/lib/parse-datetime.y
> +++ b/lib/parse-datetime.y
> @@ -2034,7 +2034,13 @@ parse_datetime2 (struct timespec *result, char const
> *p,
> if (pc.local_zones_seen)
> tm.tm_isdst = pc.local_isdst;
>
> - tm0 = tm;
> + tm0.tm_sec = tm.tm_sec;
> + tm0.tm_min = tm.tm_min;
> + tm0.tm_hour = tm.tm_hour;
> + tm0.tm_mday = tm.tm_mday;
> + tm0.tm_mon = tm.tm_mon;
> + tm0.tm_year = tm.tm_year;
> + tm0.tm_isdst = tm.tm_isdst;
>
> Start = mktime_z (tz, &tm);
>
> @@ -2064,7 +2070,13 @@ parse_datetime2 (struct timespec *result, char const
> *p,
> dbg_printf (_("error: tzalloc (\"%s\") failed\n"),
> tz2buf);
> goto fail;
> }
> - tm = tm0;
> + tm.tm_sec = tm0.tm_sec;
> + tm.tm_min = tm0.tm_min;
> + tm.tm_hour = tm0.tm_hour;
> + tm.tm_mday = tm0.tm_mday;
> + tm.tm_mon = tm0.tm_mon;
> + tm.tm_year = tm0.tm_year;
> + tm.tm_isdst = tm0.tm_isdst;
> Start = mktime_z (tz2, &tm);
> repaired = mktime_ok (tz2, &tm0, &tm, Start);
> tzfree (tz2);
> diff --git a/lib/posixtm.c b/lib/posixtm.c
> index 26a35dd3f..030f704f0 100644
> --- a/lib/posixtm.c
> +++ b/lib/posixtm.c
> @@ -182,7 +182,12 @@ posixtime (time_t *p, const char *s, unsigned int
> syntax_bits)
> if (! posix_time_parse (&tm0, s, syntax_bits))
> return false;
>
> - tm1 = tm0;
> + tm1.tm_sec = tm0.tm_sec;
> + tm1.tm_min = tm0.tm_min;
> + tm1.tm_hour = tm0.tm_hour;
> + tm1.tm_mday = tm0.tm_mday;
> + tm1.tm_mon = tm0.tm_mon;
> + tm1.tm_year = tm0.tm_year;
> tm1.tm_isdst = -1;
> t = mktime (&tm1);
>
>
This triggers the following warning with gcc-6.3
lib/posixtm.c:214:20: error: '*((void *)&tm0+20)' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
if ((tm0.tm_year ^ tm->tm_year)
~~~~~~~~~~~~~^~~~~~~~~~~~~~
It's not introducing any new issue I think, but
seems to be triggering the compiler warning due
to tm_year being explicitly set?
How about the attached to ensure tm_year is set?
cheers,
Pádraig
>From d1917dcdf83e4e754f2c5606a729faa6566e9939 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]>
Date: Thu, 23 Nov 2017 17:01:04 -0800
Subject: [PATCH] posixtm: avoid maybe-uninitialized warnings
* lib/posixtm.c (year): Ensure that tm_year is initialized.
Since commit 619700e1, gcc-6.3 at least fails to compile with:
lib/posixtm.c: In function 'posixtime':
lib/posixtm.c:214:20: error: '*((void *)&tm0+20)' may be used
uninitialized in this function [-Werror=maybe-uninitialized]
if ((tm0.tm_year ^ tm->tm_year)
~~~~~~~~~~~~~^~~~~~~~~~~~~~
---
ChangeLog | 11 +++++++++++
lib/posixtm.c | 7 ++++++-
2 files changed, 17 insertions(+), 1 deletion(-)
diff --git a/ChangeLog b/ChangeLog
index 700ee09..a24d7c2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2017-11-23 Pádraig Brady <[email protected]>
+
+ posixtm: avoid maybe-uninitialized warnings
+ * lib/posixtm.c (year): Ensure that tm_year is initialized.
+ Since commit 619700e1, gcc-6.3 at least fails to compile with:
+ lib/posixtm.c: In function 'posixtime':
+ lib/posixtm.c:214:20: error: '*((void *)&tm0+20)' may be used
+ uninitialized in this function [-Werror=maybe-uninitialized]
+ if ((tm0.tm_year ^ tm->tm_year)
+ ~~~~~~~~~~~~~^~~~~~~~~~~~~~
+
2017-11-23 Paul Eggert <[email protected]>
stat: work around Solaris bug with tv_nsec < 0
diff --git a/lib/posixtm.c b/lib/posixtm.c
index 030f704..bc75487 100644
--- a/lib/posixtm.c
+++ b/lib/posixtm.c
@@ -22,6 +22,7 @@
#include "posixtm.h"
+#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
@@ -96,7 +97,7 @@ year (struct tm *tm, const int *digit_pair, size_t n, unsigned int syntax_bits)
break;
default:
- abort ();
+ assert (!"invalid year length");
}
return true;
@@ -110,6 +111,10 @@ posix_time_parse (struct tm *tm, const char *s, unsigned int syntax_bits)
int *p;
size_t i;
+ /* Ensure tm_year initialized */
+ tm->tm_year = 0; /* Avoid uninitialized warnings */
+ assert (syntax_bits & PDS_LEADING_YEAR || syntax_bits & PDS_TRAILING_YEAR);
+
size_t s_len = strlen (s);
size_t len = s_len;
--
2.9.3
