[PATCH v8 2/2] e2fsck: Correct ext4 dates generated by old kernels

[David Turner <novalis@novalis.org>]

against e2fsprogs/next
--
Older kernels on 64-bit machines would incorrectly encode pre-1970
ext4 dates as post-2311 dates.  Detect and correct this (assuming the
current date is before 2242).

Includes tests for this, as well as changes to debugfs to correctly
set crtimes.

Signed-off-by: David Turner <novalis@novalis.org>
---
 debugfs/set_fields.c                  |  2 +-
 e2fsck/pass1.c                        | 43 ++++++++++++++++
 e2fsck/problem.c                      |  4 ++
 e2fsck/problem.h                      |  4 ++
 lib/extra_epoch.h                     |  2 +
 tests/f_pre_1970_date_encoding/expect | 45 ++++++++++++++++
 tests/f_pre_1970_date_encoding/name   |  1 +
 tests/f_pre_1970_date_encoding/script | 96
+++++++++++++++++++++++++++++++++++
 8 files changed, 196 insertions(+), 1 deletion(-)
 create mode 100644 lib/extra_epoch.h
 create mode 100644 tests/f_pre_1970_date_encoding/expect
 create mode 100644 tests/f_pre_1970_date_encoding/name
 create mode 100644 tests/f_pre_1970_date_encoding/script

diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c
index aad1cd8..f7c55a7 100644
--- a/debugfs/set_fields.c
+++ b/debugfs/set_fields.c
@@ -200,7 +200,7 @@ static struct field_set_info inode_fields[] = {
 		4, parse_uint },
 	{ "atime_extra", &set_inode.i_atime_extra, NULL,
 		4, parse_uint },
-	{ "crtime", &set_inode.i_crtime, NULL, 4, parse_uint },
+	{ "crtime", &set_inode.i_crtime, NULL, 4, parse_time },
 	{ "crtime_extra", &set_inode.i_crtime_extra, NULL,
 		4, parse_uint },
 	{ "bmap", NULL, NULL, 4, parse_bmap, FLAG_ARRAY },
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index ab23e42..ecbd79e 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -50,6 +50,8 @@
 
 #include "problem.h"
 
+#include "extra_epoch.h"
+
 #ifdef NO_INLINE_FUNCS
 #define _INLINE_
 #else
@@ -348,6 +350,21 @@ fix:
 				EXT2_INODE_SIZE(sb), "pass1");
 }
 
+static int check_inode_extra_negative_epoch(__u32 xtime, __u32 extra) {
+	return (xtime & (1 << 31)) != 0 &&
+		(extra & EXT4_EPOCH_MASK) == EXT4_EPOCH_MASK;
+}
+
+#define CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, xtime) \
+	check_inode_extra_negative_epoch(inode->i_##xtime, \
+					 inode->i_##xtime##_extra)
+
+/* When today's date is earlier than 2242, we assume that atimes,
+ * ctimes, crtimes, and mtimes with years in the range 2310..2378 are
+ * actually pre-1970 dates mis-encoded.
+ */
+#define EXT4_EXTRA_NEGATIVE_DATE_CUTOFF 2 * (1LL << 32)
+
 static void check_inode_extra_space(e2fsck_t ctx, struct
problem_context *pctx)
 {
 	struct ext2_super_block *sb = ctx->fs->super;
@@ -388,6 +405,32 @@ static void check_inode_extra_space(e2fsck_t ctx,
struct problem_context *pctx)
 		/* it seems inode has an extended attribute(s) in body */
 		check_ea_in_inode(ctx, pctx);
 	}
+
+	/*
+	 * If the inode's extended atime (ctime, crtime, mtime) is stored in
+	 * the old, invalid format, repair it.
+	 */
+	if (sizeof(time_t) > 4 && ctx->now < EXT4_EXTRA_NEGATIVE_DATE_CUTOFF
&&
+	    (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, atime) ||
+	     CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, ctime) ||
+	     CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, crtime) ||
+	     CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, mtime))) {
+
+		if (!fix_problem(ctx, PR_1_EA_TIME_OUT_OF_RANGE, pctx))
+			return;
+
+		if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, atime))
+			inode->i_atime_extra &= ~EXT4_EPOCH_MASK;
+		if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, ctime))
+			inode->i_ctime_extra &= ~EXT4_EPOCH_MASK;
+		if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, crtime))
+			inode->i_crtime_extra &= ~EXT4_EPOCH_MASK;
+		if (CHECK_INODE_EXTRA_NEGATIVE_EPOCH(inode, mtime))
+			inode->i_mtime_extra &= ~EXT4_EPOCH_MASK;
+		e2fsck_write_inode_full(ctx, pctx->ino, pctx->inode,
+					EXT2_INODE_SIZE(sb), "pass1");
+	}
+
 }
 
 /*
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index 897693a..b212d00 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1018,6 +1018,10 @@ static struct e2fsck_problem problem_table[] = {
 	  N_("@i %i, end of extent exceeds allowed value\n\t(logical @b %c,
physical @b %b, len %N)\n"),
 	  PROMPT_CLEAR, 0 },
 
+  /* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970 dates.
*/
+	{ PR_1_EA_TIME_OUT_OF_RANGE,
+		N_("Timestamp(s) on @i %i beyond 2310-04-04 are likely pre-1970
dates.\n"),
+		PROMPT_FIX | PR_PREEN_OK | PR_NO_OK, 0 },
 
 	/* Pass 1b errors */
 
diff --git a/e2fsck/problem.h b/e2fsck/problem.h
index ae1ed26..3710638 100644
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -593,6 +593,10 @@ struct problem_context {
 #define PR_1_EXTENT_INDEX_START_INVALID	0x01006D
 
 #define PR_1_EXTENT_END_OUT_OF_BOUNDS	0x01006E
+
+/* Timestamp(s) on inode beyond 2310-04-04 are likely pre-1970 dates.
*/
+#define PR_1_EA_TIME_OUT_OF_RANGE	0x01006F
+
 /*
  * Pass 1b errors
  */
diff --git a/lib/extra_epoch.h b/lib/extra_epoch.h
new file mode 100644
index 0000000..465c43f
--- /dev/null
+++ b/lib/extra_epoch.h
@@ -0,0 +1,2 @@
+#define EXT4_EPOCH_BITS 2
+#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
diff --git a/tests/f_pre_1970_date_encoding/expect
b/tests/f_pre_1970_date_encoding/expect
new file mode 100644
index 0000000..1a71571
--- /dev/null
+++ b/tests/f_pre_1970_date_encoding/expect
@@ -0,0 +1,45 @@
+times for year-1909 =
+ ctime: 0x8e475440:00000003
+ atime: 0x8e475440:00000003
+ mtime: 0x8e475440:00000003
+crtime: 0x8e475440:00000003
+times for year-1979 =
+ ctime: 0x11db6940:00000000
+ atime: 0x11db6940:00000000
+ mtime: 0x11db6940:00000000
+crtime: 0x11db6940:00000000
+times for year-2039 =
+ ctime: 0x82a37b40:00000001
+ atime: 0x82a37b40:00000001
+ mtime: 0x82a37b40:00000001
+crtime: 0x82a37b40:00000001
+times for year-2139 =
+ ctime: 0x3e9b9940:00000001
+ atime: 0x3e9b9940:00000001
+ mtime: 0x3e9b9940:00000001
+crtime: 0x3e9b9940:00000001
+times for year-1909 =
+ ctime: 0x8e475440:00000000
+ atime: 0x8e475440:00000000
+ mtime: 0x8e475440:00000000
+crtime: 0x8e475440:00000000
+times for year-1979 =
+ ctime: 0x11db6940:00000000
+ atime: 0x11db6940:00000000
+ mtime: 0x11db6940:00000000
+crtime: 0x11db6940:00000000
+times for year-2039 =
+ ctime: 0x82a37b40:00000001
+ atime: 0x82a37b40:00000001
+ mtime: 0x82a37b40:00000001
+crtime: 0x82a37b40:00000001
+times for year-2139 =
+ ctime: 0x3e9b9940:00000001
+ atime: 0x3e9b9940:00000001
+ mtime: 0x3e9b9940:00000001
+crtime: 0x3e9b9940:00000001
+times for year-1909 =
+ ctime: 0x8e475440:00000003
+ atime: 0x8e475440:00000003
+ mtime: 0x8e475440:00000003
+crtime: 0x8e475440:00000003
diff --git a/tests/f_pre_1970_date_encoding/name
b/tests/f_pre_1970_date_encoding/name
new file mode 100644
index 0000000..9805324
--- /dev/null
+++ b/tests/f_pre_1970_date_encoding/name
@@ -0,0 +1 @@
+correct mis-encoded pre-1970 dates
diff --git a/tests/f_pre_1970_date_encoding/script
b/tests/f_pre_1970_date_encoding/script
new file mode 100644
index 0000000..c3e12f5
--- /dev/null
+++ b/tests/f_pre_1970_date_encoding/script
@@ -0,0 +1,96 @@
+if test -x $DEBUGFS_EXE; then
+
+OUT=$test_name.log
+TIMESTAMPS=$test_name.timestamps.log
+EXP=$test_dir/expect
+FSCK_OPT=-yf
+
+create_file_with_xtime_and_extra() {
+    name=$1
+    time=$2
+    extra=$3
+    $DEBUGFS -w -R "write /dev/null $name" $TMPFILE > $OUT 2>&1
+    for xtime in atime ctime mtime crtime
+    do
+        $DEBUGFS -w -R "set_inode_field $name $xtime @$time" $TMPFILE >
$OUT 2>&1
+
+        $DEBUGFS -w -R "set_inode_field $name ${xtime}_extra $extra"
$TMPFILE > $OUT 2>&1
+    done
+}
+
+get_file_xtime_and_extra() {
+    name=$1
+    echo "times for $name =" >> $TIMESTAMPS
+    $DEBUGFS -R "stat $name" $TMPFILE 2>&1 | egrep '^( a| c| m|cr)time:
' |sed 's/ --.*//' >> $TIMESTAMPS
+}
+
+rm -f $OUT
+rm -f $TIMESTAMPS
+
+#create an empty ext4 filesystem with 256-byte inodes for testing
+dd status=none if=/dev/zero of=$TMPFILE bs=1024 count=5000
+echo  mkfs.ext4 -q -I 256 $TMPFILE >> $OUT
+yes | mkfs.ext4 -q -I 256 $TMPFILE >> $OUT 2>&1
+
+# this is a pre-1970 file encoded with the old encoding.
+# fsck should repair this
+create_file_with_xtime_and_extra year-1909 -1907928000 3
+
+# these are all already encoded correctly
+create_file_with_xtime_and_extra year-1979   299592000 0
+create_file_with_xtime_and_extra year-2039  2191752000 1
+create_file_with_xtime_and_extra year-2139  5345352000 1
+
+# confirm that the xtime is wrong on the pre-1970 file
+get_file_xtime_and_extra year-1909
+
+# and confirm that it is right on the remaining files
+get_file_xtime_and_extra year-1979
+get_file_xtime_and_extra year-2039
+get_file_xtime_and_extra year-2139
+
+# before we repair the filesystem, save off a copy so that
+# we can use it later
+
+cp $TMPFILE $TMPFILE.backup
+
+# repair the filesystem
+E2FSCK_TIME=1386393539 $FSCK $FSCK_OPT $TMPFILE >> $OUT 2>&1
+
+# check that the dates and xtime_extra on the file is now correct
+get_file_xtime_and_extra year-1909
+
+# check that the remaining dates have not been altered
+get_file_xtime_and_extra year-1979
+get_file_xtime_and_extra year-2039
+get_file_xtime_and_extra year-2139
+
+# now we need to check that after the year 2242, e2fsck does not
+# modify dates with extra_xtime=3
+
+# restore the unrepaired filesystem
+mv $TMPFILE.backup $TMPFILE
+
+#retry the repair
+E2FSCK_TIME=9270393539 $FSCK $FSCK_OPT $TMPFILE >> $OUT 2>&1
+
+# check that the 1909 file is unaltered (i.e. it has a post-2378 date)
+get_file_xtime_and_extra year-1909
+
+cmp -s $TIMESTAMPS $EXP
+status=$?
+
+if [ "$status" = 0 ] ; then
+	echo "$test_name: $test_description: ok"
+	touch $test_name.ok
+else
+	echo "$test_name: $test_description: failed"
+	diff $DIFF_OPTS $EXP $TIMESTAMPS > $test_name.failed
+fi
+
+unset OUT TIMESTAMPS EXP FSCK_OPT
+
+else #if test -x $DEBUGFS_EXE; then
+	echo "$test_name: $test_description: skipped"
+fi
+
-- 
1.8.1.2