A time_t very far in the future (and past) is not representable by
struct tm and localtime(3) returns NULL, leading to a segfault

Core was generated by `pax'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  _fmt (format=0x88eb4dfbd4a "b %e  %Y", t=0x0, pt=0x761f8811dd40 "\001",
    ptlim=0x761f8811dd80 "drwxr-xr-x ", warnp=0x761f8811dd04)
    at /usr/src/lib/libc/time/strftime.c:159
159                                     pt = _add((t->tm_mon < 0 ||
(gdb) bt
#0  _fmt (format=0x88eb4dfbd4a "b %e  %Y", t=0x0, pt=0x761f8811dd40 "\001",
    ptlim=0x761f8811dd80 "drwxr-xr-x ", warnp=0x761f8811dd04)
    at /usr/src/lib/libc/time/strftime.c:159
#1  0x0000089112ad9f2a in _libc_strftime (s=0x761f8811dd40 "\001", maxsize=64,
    format=<optimized out>, t=0x0) at /usr/src/lib/libc/time/strftime.c:118
#2  0x0000088eb4e11c6f in ls_list (arcn=0x761f8811ddf0, now=1714210446,
    fp=0x89112b7cdc8 <__sF+152>) at /usr/src/bin/pax/gen_subs.c:106
#3  0x0000088eb4e04010 in list () at /usr/src/bin/pax/ar_subs.c:127
#4  0x0000088eb4e1cb18 in main (argc=3, argv=0x761f8811f7c8)
    at /usr/src/bin/pax/pax.c:326
(gdb) frame 2                                                 13:09:54 [117/446]
#2  0x0000088eb4e11c6f in ls_list (arcn=0x761f8811ddf0, now=1714210446,
    fp=0x89112b7cdc8 <__sF+152>) at /usr/src/bin/pax/gen_subs.c:106
106             if (strftime(f_date, sizeof(f_date), TIMEFMT(sbp->st_mtime, now)
,
(gdb) p sbp->st_mtime
value has been optimized out
(gdb) p arcn->sb
$2 = {st_mode = 16877, st_dev = 0, st_ino = 0, st_nlink = 2, st_uid = 1000,
  st_gid = 1000, st_rdev = 0, st_atim = {tv_sec = 1714200723,
    tv_nsec = 879795667}, st_mtim = {tv_sec = 1714200723888079566,
    tv_nsec = 0}, st_ctim = {tv_sec = 1714200723, tv_nsec = 880795660},
  st_size = 0, st_blocks = 0, st_blksize = 0, st_flags = 0, st_gen = 0,
  __st_birthtim = {tv_sec = 0, tv_nsec = 0}}

I found this with afl using the gnu tar test suite as input, I'll attach
a broken test file that triggers the segfault with "pax -vf pax_broken"

OK?

diff --git gen_subs.c gen_subs.c
index 42c70804fb7..f3a8cb775a1 100644
--- gen_subs.c
+++ gen_subs.c
@@ -75,6 +75,7 @@ void
 ls_list(ARCHD *arcn, time_t now, FILE *fp)
 {
 	struct stat *sbp;
+	struct tm * tm;
 	char f_mode[MODELEN];
 	char f_date[DATELEN];
 	int term;
@@ -103,8 +104,10 @@ ls_list(ARCHD *arcn, time_t now, FILE *fp)
 	/*
 	 * print file mode, link count, uid, gid and time
 	 */
-	if (strftime(f_date, sizeof(f_date), TIMEFMT(sbp->st_mtime, now),
-	    localtime(&(sbp->st_mtime))) == 0)
+	if ((tm = localtime(&(sbp->st_mtime))) == NULL)
+		f_date[0] = '\0';
+	else if (strftime(f_date, sizeof(f_date), TIMEFMT(sbp->st_mtime, now),
+	    tm) == 0)
 		f_date[0] = '\0';
 	(void)fprintf(fp, "%s%2u %-*.*s %-*.*s ", f_mode, sbp->st_nlink,
 		NAME_WIDTH, UT_NAMESIZE, user_from_uid(sbp->st_uid, 0),
@@ -146,6 +149,7 @@ ls_list(ARCHD *arcn, time_t now, FILE *fp)
 void
 ls_tty(ARCHD *arcn)
 {
+	struct tm * tm;
 	char f_date[DATELEN];
 	char f_mode[MODELEN];
 	time_t now = time(NULL);
@@ -153,8 +157,10 @@ ls_tty(ARCHD *arcn)
 	/*
 	 * convert time to string, and print
 	 */
-	if (strftime(f_date, DATELEN, TIMEFMT(arcn->sb.st_mtime, now),
-	    localtime(&(arcn->sb.st_mtime))) == 0)
+	if ((tm = localtime(&(arcn->sb.st_mtime))) == NULL)
+		f_date[0] = '\0';
+	else if (strftime(f_date, DATELEN, TIMEFMT(arcn->sb.st_mtime, now),
+	    tm) == 0)
 		f_date[0] = '\0';
 	strmode(arcn->sb.st_mode, f_mode);
 	tty_prnt("%s%s %s\n", f_mode, f_date, arcn->name);


-- 
In my defence, I have been left unsupervised.

• pax_broken (10K)