diff options
| -rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/getdents.go | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/getdents.go b/pkg/sentry/syscalls/linux/vfs2/getdents.go index a61cc5059..62e98817d 100644 --- a/pkg/sentry/syscalls/linux/vfs2/getdents.go +++ b/pkg/sentry/syscalls/linux/vfs2/getdents.go @@ -97,6 +97,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { // char d_name[]; /* Filename (null-terminated) */ // }; size := 8 + 8 + 2 + 1 + 1 + len(dirent.Name) + size = (size + 7) &^ 7 // round up to multiple of 8 if size > cb.remaining { return syserror.EINVAL } @@ -106,7 +107,12 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { usermem.ByteOrder.PutUint16(buf[16:18], uint16(size)) buf[18] = dirent.Type copy(buf[19:], dirent.Name) - buf[size-1] = 0 // NUL terminator + // Zero out all remaining bytes in buf, including the NUL terminator + // after dirent.Name. + bufTail := buf[19+len(dirent.Name):] + for i := range bufTail { + bufTail[i] = 0 + } } else { // struct linux_dirent { // unsigned long d_ino; /* Inode number */ @@ -125,6 +131,7 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { panic(fmt.Sprintf("unsupported sizeof(unsigned long): %d", cb.t.Arch().Width())) } size := 8 + 8 + 2 + 1 + 1 + 1 + len(dirent.Name) + size = (size + 7) &^ 7 // round up to multiple of sizeof(long) if size > cb.remaining { return syserror.EINVAL } @@ -133,9 +140,14 @@ func (cb *getdentsCallback) Handle(dirent vfs.Dirent) error { usermem.ByteOrder.PutUint64(buf[8:16], uint64(dirent.NextOff)) usermem.ByteOrder.PutUint16(buf[16:18], uint16(size)) copy(buf[18:], dirent.Name) - buf[size-3] = 0 // NUL terminator - buf[size-2] = 0 // zero padding byte - buf[size-1] = dirent.Type + // Zero out all remaining bytes in buf, including the NUL terminator + // after dirent.Name and the zero padding byte between the name and + // dirent type. + bufTail := buf[18+len(dirent.Name):] + for i := range bufTail { + bufTail[i] = 0 + } + bufTail[2] = dirent.Type } n, err := cb.t.CopyOutBytes(cb.addr, buf) if err != nil { |