git: ca89e1535509 - main - tzcode: Don't treat TZDEFAULT as tainted

The branch main has been updated by des:

URL: https://cgit.FreeBSD.org/src/commit/?id=ca89e15355097e9b57bf4e17a50506e081fe04b3

commit ca89e15355097e9b57bf4e17a50506e081fe04b3
Author:     Dag-Erling Smørgrav <des@FreeBSD.org>
AuthorDate: 2025-09-01 06:33:28 +0000
Commit:     Dag-Erling Smørgrav <des@FreeBSD.org>
CommitDate: 2025-09-01 06:33:47 +0000

    tzcode: Don't treat TZDEFAULT as tainted
    
    tzset() calls zoneinit() with the FROMENV flag set unconditionally, so
    if TZ is unset and we use TZDEFAULT instead, we were still treating it
    as if it came from the environment.  Unset the FROMENV flag if name is
    null and we switch to TZDEFAULT, or if, after skipping the optional
    leading colon, we find that name is identical to TZDEFAULT.
    
    This incorporates upstream change d0e0b00f846c ("Avoid unnecessary
    access, stat calls").
    
    Fixes:          b6ea2513f776 ("tzcode: Limit TZ for setugid programs")
    Event:          Oslo Hackathon 202508
    Reviewed by:    philip
    Differential Revision:  https://reviews.freebsd.org/D52240
---
 contrib/tzcode/localtime.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/contrib/tzcode/localtime.c b/contrib/tzcode/localtime.c
index a80d422f2955..15afeeecb6d0 100644
--- a/contrib/tzcode/localtime.c
+++ b/contrib/tzcode/localtime.c
@@ -615,6 +615,7 @@ tzloadbody(char const *name, struct state *sp, char tzloadflags,
 		name = TZDEFAULT;
 		if (! name)
 		  return EINVAL;
+		tzloadflags &= ~TZLOAD_FROMENV;
 	}
 
 	if (name[0] == ':')
@@ -670,11 +671,13 @@ tzloadbody(char const *name, struct state *sp, char tzloadflags,
 	fid = _open(name, (O_RDONLY | O_BINARY | O_CLOEXEC | O_CLOFORK
 			  | O_IGNORE_CTTY | O_NOCTTY));
 #else /* __FreeBSD__ */
+	if ((tzloadflags & TZLOAD_FROMENV) && strcmp(name, TZDEFAULT) == 0)
+          tzloadflags &= ~TZLOAD_FROMENV;
 	relname = name;
 	if (strncmp(relname, TZDIR "/", strlen(TZDIR) + 1) == 0)
 	  relname += strlen(TZDIR) + 1;
 	dd = _open(TZDIR, O_DIRECTORY | O_RDONLY);
-	if (issetugid() && (tzloadflags & TZLOAD_FROMENV)) {
+	if ((tzloadflags & TZLOAD_FROMENV) && issetugid()) {
 	  if (dd < 0)
 	    return errno;
 	  if (fstatat(dd, name, &sb, AT_RESOLVE_BENEATH) < 0) {
@@ -1624,14 +1627,13 @@ zoneinit(struct state *sp, char const *name, char tzloadflags)
 static void
 tzset_unlocked(void)
 {
+  char const *name = getenv("TZ");
 #ifdef __FreeBSD__
-  tzset_unlocked_name(getenv("TZ"));
+  tzset_unlocked_name(name);
 }
 static void
 tzset_unlocked_name(char const *name)
 {
-#else
-  char const *name = getenv("TZ");
 #endif
   struct state *sp = lclptr;
   int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;