isofs: fix Y2038 and Y2156 issues in Rock Ridge TF entry

This change implements the Rock Ridge TF entry LONG_FORM bit, which uses
the ISO 9660 17-byte date format (up to year 9999, with 10ms precision)
instead of the 7-byte date format (up to year 2155, with 1s precision).

Previously the LONG_FORM bit was ignored; and isofs would entirely
misinterpret the date as the wrong format, resulting in garbage
timestamps on the filesystem.

The Y2038 issue in iso_date() is fixed by returning a struct timespec64
instead of an int.

parse_rock_ridge_inode_internal() is fixed so it does proper bounds
checks of the TF entry timestamps.

Signed-off-by: Jonas 'Sortie' Termansen <[e-mail]>
Signed-off-by: Jan Kara <[e-mail]>
Link: https://patch.msgid.link/[e-mail]

fs/isofs/inode.c

···
 	unsigned long offset;
 	struct iso_inode_info *ei = ISOFS_I(inode);
 	int ret = -EIO;
+	struct timespec64 ts;
 
 	block = ei->i_iget5_block;
 	bh = sb_bread(inode->i_sb, block);
···
 			inode->i_ino, de->flags[-high_sierra]);
 	}
 #endif
-	inode_set_mtime_to_ts(inode,
-			      inode_set_atime_to_ts(inode, inode_set_ctime(inode, iso_date(de->date, high_sierra), 0)));
+	ts = iso_date(de->date, high_sierra ? ISO_DATE_HIGH_SIERRA : 0);
+	inode_set_ctime_to_ts(inode, ts);
+	inode_set_atime_to_ts(inode, ts);
+	inode_set_mtime_to_ts(inode, ts);
 
 	ei->i_first_extent = (isonum_733(de->extent) +
 			isonum_711(de->ext_attr_length));

fs/isofs/isofs.h

···
 	/* Ignore bigendian datum due to broken mastering programs */
 	return get_unaligned_le32(p);
 }
-extern int iso_date(u8 *, int);
+#define ISO_DATE_HIGH_SIERRA (1 << 0)
+#define ISO_DATE_LONG_FORM (1 << 1)
+struct timespec64 iso_date(u8 *p, int flags);
 
 struct inode;		/* To make gcc happy */
 

fs/isofs/rock.c

···
 				}
 			}
 			break;
-		case SIG('T', 'F'):
+		case SIG('T', 'F'): {
+			int flags, size, slen;
+
+			flags = rr->u.TF.flags & TF_LONG_FORM ? ISO_DATE_LONG_FORM : 0;
+			size = rr->u.TF.flags & TF_LONG_FORM ? 17 : 7;
+			slen = rr->len - 5;
 			/*
 			 * Some RRIP writers incorrectly place ctime in the
 			 * TF_CREATE field. Try to handle this correctly for
···
 			 */
 			/* Rock ridge never appears on a High Sierra disk */
 			cnt = 0;
-			if (rr->u.TF.flags & TF_CREATE) {
-				inode_set_ctime(inode,
-						iso_date(rr->u.TF.times[cnt++].time, 0),
-						0);
+			if ((rr->u.TF.flags & TF_CREATE) && size <= slen) {
+				inode_set_ctime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
 			}
-			if (rr->u.TF.flags & TF_MODIFY) {
-				inode_set_mtime(inode,
-						iso_date(rr->u.TF.times[cnt++].time, 0),
-						0);
+			if ((rr->u.TF.flags & TF_MODIFY) && size <= slen) {
+				inode_set_mtime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
 			}
-			if (rr->u.TF.flags & TF_ACCESS) {
-				inode_set_atime(inode,
-						iso_date(rr->u.TF.times[cnt++].time, 0),
-						0);
+			if ((rr->u.TF.flags & TF_ACCESS) && size <= slen) {
+				inode_set_atime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
 			}
-			if (rr->u.TF.flags & TF_ATTRIBUTES) {
-				inode_set_ctime(inode,
-						iso_date(rr->u.TF.times[cnt++].time, 0),
-						0);
+			if ((rr->u.TF.flags & TF_ATTRIBUTES) && size <= slen) {
+				inode_set_ctime_to_ts(inode,
+						iso_date(rr->u.TF.data + size * cnt++, flags));
+				slen -= size;
 			}
 			break;
+		}
 		case SIG('S', 'L'):
 			{
 				int slen;

fs/isofs/rock.h

···
 	__u8 location[8];
 };
 
-struct stamp {
-	__u8 time[7];		/* actually 6 unsigned, 1 signed */
-} __attribute__ ((packed));
-
 struct RR_TF_s {
 	__u8 flags;
-	struct stamp times[];	/* Variable number of these beasts */
+	__u8 data[];
 } __attribute__ ((packed));
 
 /* Linux-specific extension for transparent decompression */

fs/isofs/util.c

···
  * to GMT.  Thus  we should always be correct.
  */
 
-int iso_date(u8 *p, int flag)
+struct timespec64 iso_date(u8 *p, int flags)
 {
 	int year, month, day, hour, minute, second, tz;
-	int crtime;
+	struct timespec64 ts;
 
-	year = p[0];
-	month = p[1];
-	day = p[2];
-	hour = p[3];
-	minute = p[4];
-	second = p[5];
-	if (flag == 0) tz = p[6]; /* High sierra has no time zone */
-	else tz = 0;
-	
-	if (year < 0) {
-		crtime = 0;
+	if (flags & ISO_DATE_LONG_FORM) {
+		year = (p[0] - '0') * 1000 +
+		       (p[1] - '0') * 100 +
+		       (p[2] - '0') * 10 +
+		       (p[3] - '0') - 1900;
+		month = ((p[4] - '0') * 10 + (p[5] - '0'));
+		day = ((p[6] - '0') * 10 + (p[7] - '0'));
+		hour = ((p[8] - '0') * 10 + (p[9] - '0'));
+		minute = ((p[10] - '0') * 10 + (p[11] - '0'));
+		second = ((p[12] - '0') * 10 + (p[13] - '0'));
+		ts.tv_nsec = ((p[14] - '0') * 10 + (p[15] - '0')) * 10000000;
+		tz = p[16];
 	} else {
-		crtime = mktime64(year+1900, month, day, hour, minute, second);
+		year = p[0];
+		month = p[1];
+		day = p[2];
+		hour = p[3];
+		minute = p[4];
+		second = p[5];
+		ts.tv_nsec = 0;
+		/* High sierra has no time zone */
+		tz = flags & ISO_DATE_HIGH_SIERRA ? 0 : p[6];
+	}
+
+	if (year < 0) {
+		ts.tv_sec = 0;
+	} else {
+		ts.tv_sec = mktime64(year+1900, month, day, hour, minute, second);
 
 		/* sign extend */
 		if (tz & 0x80)
 			tz |= (-1 << 8);
-		
+
 		/* 
 		 * The timezone offset is unreliable on some disks,
 		 * so we make a sanity check.  In no case is it ever
···
 		 * for pointing out the sign error.
 		 */
 		if (-52 <= tz && tz <= 52)
-			crtime -= tz * 15 * 60;
+			ts.tv_sec -= tz * 15 * 60;
 	}
-	return crtime;
-}		
+	return ts;
+}