From af46a3e21dd5d74710b67125a9848b5ba2e03e92 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Sun, 6 Feb 2022 12:39:32 -0800
Subject: [PATCH 3/4] Fix integer overflows in timestamp output

* src/copyin.c (long_format): Fix some unlikely integer overflow bugs.
Work even if (current_time - when) overflows, which is
possible if time_t is unsigned.
Do not assume that system integer types fit into unsigned long.
Simplify by using %ju.  No need for local tbuf array.
---
 src/copyin.c | 56 ++++++++++++++++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/src/copyin.c b/src/copyin.c
index fb30cf6..0af23a0 100644
--- a/src/copyin.c
+++ b/src/copyin.c
@@ -730,42 +730,50 @@ void
 long_format (struct cpio_file_stat *file_hdr, char const *link_name)
 {
   char mbuf[11];
-  char tbuf[40];
-  time_t when;
-
   mode_string (file_hdr->c_mode, mbuf);
   mbuf[10] = '\0';
 
-  /* Get time values ready to print.  */
-  when = file_hdr->c_mtime;
-  strcpy (tbuf, ctime (&when));
-  if (current_time - when > 6L * 30L * 24L * 60L * 60L
-      || current_time - when < 0L)
-    {
-      /* The file is older than 6 months, or in the future.
-	 Show the year instead of the time of day.  */
-      strcpy (tbuf + 11, tbuf + 19);
-    }
-  tbuf[16] = '\0';
-
-  printf ("%s %3lu ", mbuf, (unsigned long) file_hdr->c_nlink);
+  uintmax_t nlink = file_hdr->c_nlink;
+  printf ("%s %3ju ", mbuf, nlink);
 
   if (numeric_uid)
-    printf ("%-8u %-8u ", (unsigned int) file_hdr->c_uid,
-	    (unsigned int) file_hdr->c_gid);
+    {
+      uintmax_t uid = file_hdr->c_uid, gid = file_hdr->c_gid;
+      printf ("%-8ju %-8ju ", uid, gid);
+    }
   else
     printf ("%-8.8s %-8.8s ", getuser (file_hdr->c_uid),
 	    getgroup (file_hdr->c_gid));
 
   if ((file_hdr->c_mode & CP_IFMT) == CP_IFCHR
       || (file_hdr->c_mode & CP_IFMT) == CP_IFBLK)
-    printf ("%3lu, %3lu ",
-	    (unsigned long) file_hdr->c_rdev_maj,
-	    (unsigned long) file_hdr->c_rdev_min);
+    {
+      uintmax_t maj = file_hdr->c_rdev_maj, min = file_hdr->c_rdev_min;
+      printf ("%3ju, %3ju ", maj, min);
+    }
   else
-    printf ("%8"PRIuMAX" ", (uintmax_t) file_hdr->c_filesize);
+    {
+      uintmax_t filesize = file_hdr->c_filesize;
+      printf ("%8ju ", filesize);
+    }
 
-  printf ("%s ", tbuf + 4);
+  /* Get time values ready to print.  Do not worry about ctime failing,
+     or a year outside the range 1000-9999, since 0 <= WHEN < 2**33.  */
+  time_t when = file_hdr->c_mtime;
+  char *tbuf = ctime (&when);
+  int six_months = 6 * 30 * 24 * 60 * 60;
+  bool recent = ((current_time < six_months
+		  || current_time - six_months <= when)
+		 && when <= current_time);
+  if (!recent)
+    {
+      /* The file is older than 6 months, or in the future.
+	 Show the year instead of the time of day.  */
+      memcpy (tbuf + 11, tbuf + 19, sizeof " 1970" - 1);
+    }
+  tbuf[16] = ' ';
+  tbuf[17] = '\0';
+  printf ("%s", tbuf + 4);
 
   printf ("%s", quotearg (file_hdr->c_name));
   if (link_name)
@@ -773,7 +781,7 @@ long_format (struct cpio_file_stat *file_hdr, char const *link_name)
       printf (" -> ");
       printf ("%s", quotearg (link_name));
     }
-  putc ('\n', stdout);
+  putchar ('\n');
 }
 
 /* Read a pattern file (for the -E option).  Put a list of
-- 
2.32.0