[PATCH] erofs-utils: tests: add test for malformed PAX mtime parsing

This is a regression test for "erofs-utils: lib: tar: fix
fractional PAX mtime parsing".

Signed-off-by: Vansh Choudhary <[email protected]>
---
 tests/Makefile.am   |  3 +++
 tests/erofs/031     | 60 +++++++++++++++++++++++++++++++++++++++++++++
 tests/erofs/031.out |  2 ++
 3 files changed, 65 insertions(+)
 create mode 100755 tests/erofs/031
 create mode 100644 tests/erofs/031.out

diff --git a/tests/Makefile.am b/tests/Makefile.am
index cd1971a..36fbe92 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -129,6 +129,9 @@ TESTS += erofs/029
 # 030 - regression test for NULL dentry on hardlink-to-root tar entry
 TESTS += erofs/030
 
+# 031 - regression test for malformed PAX mtime acceptance
+TESTS += erofs/031
+
 # NEW TEST CASE HERE
 # TESTS += erofs/999
 
diff --git a/tests/erofs/031 b/tests/erofs/031
new file mode 100755
index 0000000..8644291
--- /dev/null
+++ b/tests/erofs/031
@@ -0,0 +1,60 @@
+#!/bin/sh
+# SPDX-License-Identifier: MIT
+#
+# Regression test for malformed PAX mtime acceptance in mkfs.erofs --tar
+#
+seq=`basename $0`
+seqres=$RESULT_DIR/$(echo $0 | awk '{print $((NF-1))"/"$NF}' FS="/")
+
+# get standard environment, filters and checks
+. "${srcdir}/common/rc"
+
+cleanup()
+{
+	cd /
+	rm -rf $tmp.*
+}
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+# real QA test starts here
+echo "QA output created by $seq"
+
+if [ -z $SCRATCH_DEV ]; then
+	SCRATCH_DEV=$tmp/erofs_$seq.img
+	rm -f $SCRATCH_DEV
+fi
+
+localdir="$tmp/$seq"
+rm -rf $localdir
+mkdir -p $localdir
+
+footar="$localdir/foo.tar"
+
+# build a PAX archive whose extended header carries a single record:
+# "22 mtime=10.123456789\n" at payload offset 512.
+: > $localdir/a
+(cd $localdir && tar --format=pax \
+	--pax-option='delete=atime,delete=ctime,mtime:=10.123456789' \
+	-cf $footar a) || _fail "failed to build input tar"
+
+# verify the PAX payload before patching, so the test fails clearly if
+# tar's output ever diverges from the expected layout.
+hdr=`dd if=$footar bs=1 skip=512 count=22 2>/dev/null`
+[ "$hdr" = "22 mtime=10.123456789" ] || \
+	_fail "unexpected PAX payload: $hdr"
+
+# overwrite the trailing '9' (offset 532) with 'x' so the record reads
+# "22 mtime=10.12345678x". sscanf("%d") would silently accept 12345678
+# and ignore the trailing 'x'; the fixed parser rejects it as -EIO.
+printf 'x' | dd of=$footar bs=1 seek=532 count=1 conv=notrunc 2>/dev/null
+
+$MKFS_EROFS_PROG --tar $SCRATCH_DEV $footar >> $seqres.full 2>&1
+rc=$?
+[ $rc -ge 128 ] && _fail "mkfs.erofs crashed on malformed PAX mtime (rc=$rc)"
+[ $rc -eq 0 ] && _fail "mkfs.erofs unexpectedly accepted malformed PAX mtime"
+
+echo Silence is golden
+status=0
+exit 0
diff --git a/tests/erofs/031.out b/tests/erofs/031.out
new file mode 100644
index 0000000..b3d0bb0
--- /dev/null
+++ b/tests/erofs/031.out
@@ -0,0 +1,2 @@
+QA output created by 031
+Silence is golden
-- 
2.43.0