diff mbox series

[32/59] Reject invalid TZ strings in TZif files

Message ID	20250105055750.1668721-33-eggert@cs.ucla.edu (mailing list archive)
State	New
Headers	DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 8801E385840B From: Paul Eggert <eggert@cs.ucla.edu> To: libc-alpha@sourceware.org Cc: Paul Eggert <eggert@cs.ucla.edu> Subject: [PATCH 32/59] Reject invalid TZ strings in TZif files Date: Sat, 4 Jan 2025 21:57:07 -0800 Message-ID: <20250105055750.1668721-33-eggert@cs.ucla.edu> In-Reply-To: <01207110-bd60-46ae-9c08-fb39c2011067@cs.ucla.edu> References: <01207110-bd60-46ae-9c08-fb39c2011067@cs.ucla.edu> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: list Errors-To: libc-alpha-bounces~patchwork=sourceware.org@sourceware.org
Series	time: sync mktime from Gnulib \| [00/59] time: sync mktime from Gnulib [01/59] Split intprops.h into two [02/59] Support stdckdint.h internally if older GCC [03/59] Fix mishandling of default DST rule [04/59] Don't worry about !TZDEFAULT [05/59] Support static_assert in pre-C23 C [06/59] Sync mktime.c from Gnulib 2024-10-04 [07/59] Document mktime out-of-range + tm_isdst [08/59] Push tzset lock into callers of time functions [09/59] Omit parse_offset unnecessary tz == '\0' [10/59] Don’t assume TZif bloat is likely [11/59] tzset no longer calls ftello [12/59] Check TZif files more carefully [13/59] Remove alignment assumption from __tzfile_read [14/59] Treat oddball UTC offset strings as zero [15/59] Simplify __tz_compute [16/59] Improve performance in 2 BC [17/59] Don’t mishandle years < 1970 in compute_change [18/59] Match RFC 9636 names [19/59] Trivial tzset_internal speedup [20/59] Fix obscure bug when stdoffset == dstoffset [21/59] Document assumption that NO_DST == 0 [22/59] __use_tzfile is boolean [23/59] Minor tzfile.c clarity improvements [24/59] Stop using zic's -y option [25/59] Fix mishandling of default DST rule [26/59] Simplify treatment of missing and empty TZ [27/59] TZ="" always means UTC sans leap seconds [28/59] Prefer "UTC" for UTC [29/59] Simplify setting tz_rules to UTC [30/59] Update tzname etc. even if TZ is unchanged [31/59] "POSIX TZ" -> "proleptic TZ" [32/59] Reject invalid TZ strings in TZif files [33/59] Reject TZif files containing '\0' in TZ string [34/59] mktime should not consult 'daylight' [35/59] Remove __use_tzfile [36/59] Remove arbitrary limit on TZ, TZDIR lengths [37/59] Tighten setuid TZif file name check [38/59] Avoid a malloc in __tzfile_read [39/59] Free earlier in __tzfile_read [40/59] Improve __tzfile_read TZ="" comment [41/59] Refactor enum tz_rule_type [42/59] __offtime now returns struct tm [43/59] Fix overflow checking in offtime [44/59] Handle TZif time type 0 correctly [45/59] Remove invalid tzset tests from tst-bz29951.c [46/59] tzset, not localtime, now parses TZif TZ spec [47/59] Minor compute_change widening tweak [48/59] Minor SECSPERDAY widening tweak [49/59] Remove leap-second goto from __tzfile_compute [50/59] Remove use_last label from __tzfile_compute [51/59] Refactor ‘if’ in __tzfile_compute [52/59] Refactor localtime ‘if’ in __tzfile_compute [53/59] Refactor post-transition-table ‘if’ [54/59] Refactor __tzfile_compute to avoid two gotos [55/59] Refactor __tzfile_compute index local [56/59] mktime: prefer bool to int [57/59] mktime: port __mktime64 locking to Gnulib [58/59] mktime: improve tm_isdst heuristic [59/59] time: test DST adjustment for DST-less zones

Checks

Context	Check	Description
redhat-pt-bot/TryBot-apply_patch	success	Patch applied to master at the time it was sent

Commit Message

Paul Eggert Jan. 5, 2025, 5:57 a.m. UTC

  Previously, the code could have had quirky behavior if a TZif
file's TZ string was corrupted.  Now, the code reliably ignores
such a string.
* time/tzfile.c (__tzfile_compute): If the proleptic TZ string
is invalid, do not use it.
* time/tzset.c (__tzset_parse_tz): Return a success indication.
Do not try to parse DST rule if there is no DST.
---
 time/tzfile.c |  5 +++--
 time/tzset.c  | 15 ++++++---------
 time/tzset.h  |  2 +-
 3 files changed, 10 insertions(+), 12 deletions(-)

diff mbox series

Patch

diff --git a/time/tzfile.c b/time/tzfile.c
index d30faedfa2..dae6b2b613 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -620,8 +620,9 @@  __tzfile_compute (__time64_t timer, int use_localtime,
 	      goto found;
 	    }
 
-	  /* Parse the proleptic TZ string.  */
-	  __tzset_parse_tz (tzspec);
+	  /* Parse the proleptic TZ string.  If this fails do not use it.  */
+	  if (__glibc_unlikely (! __tzset_parse_tz (tzspec)))
+	    goto use_last;
 
 	  /* Convert to broken down structure.  If this fails do not
 	     use the string.  */
diff --git a/time/tzset.c b/time/tzset.c
index 7fdce9de7b..e4fbf729b8 100644
--- a/time/tzset.c
+++ b/time/tzset.c
@@ -350,7 +350,7 @@  parse_rule (const char **tzp, int whichrule)
 }
 
 /* Parse a proleptic TZ string.  */
-void
+bool
 __tzset_parse_tz (const char *tz)
 {
   /* Clear out old state and reset to UTC.  */
@@ -360,17 +360,13 @@  __tzset_parse_tz (const char *tz)
   tz_rules[0].name = tz_rules[1].name = "UTC";
 
   /* Get the standard time zone abbreviations.  */
-  if (parse_tzname (&tz, 0) && parse_offset (&tz, 0))
+  bool ok = parse_tzname (&tz, 0) && parse_offset (&tz, 0);
+  if (ok)
     {
       /* Get the DST time zone abbreviation (if any).  */
       if (*tz != '\0')
-	{
-	  if (parse_tzname (&tz, 1))
-	    parse_offset (&tz, 1);
-	  /* Figure out the standard <-> DST rules.  */
-	  if (parse_rule (&tz, 0))
-	    parse_rule (&tz, 1);
-	}
+	ok = (parse_tzname (&tz, 1) && parse_offset (&tz, 1)
+	      && parse_rule (&tz, 0) && parse_rule (&tz, 1));
       else
 	{
 	  /* There is no DST.  */
@@ -380,6 +376,7 @@  __tzset_parse_tz (const char *tz)
     }
 
   update_vars ();
+  return ok;
 }
 
 /* Interpret the TZ envariable.  */
diff --git a/time/tzset.h b/time/tzset.h
index 3687c044e3..61c85fba75 100644
--- a/time/tzset.h
+++ b/time/tzset.h
@@ -14,7 +14,7 @@  extern void __tzfile_read (const char *file) attribute_hidden;
 extern void __tzfile_compute (__time64_t timer, int use_localtime,
 			      int *leap_correct, bool *leap_hit,
 			      struct tm *tp) attribute_hidden;
-extern void __tzset_parse_tz (const char *tz) attribute_hidden;
+extern bool __tzset_parse_tz (const char *tz) attribute_hidden;
 extern void __tz_compute (__time64_t timer, struct tm *tm)
   __THROW attribute_hidden;