From d639c3d61bfdbd42eb809c21a15275cc75524b7e Mon Sep 17 00:00:00 2001 From: Michael Pratt Date: Mon, 17 Sep 2018 12:15:35 -0700 Subject: Allow NULL data in mount(2) PiperOrigin-RevId: 213315267 Change-Id: I7562bcd81fb22e90aa9c7dd9eeb94803fcb8c5af --- pkg/sentry/syscalls/linux/sys_mount.go | 17 ++++++++++------- 1 file changed, 10 insertions(+), 7 deletions(-) (limited to 'pkg/sentry') diff --git a/pkg/sentry/syscalls/linux/sys_mount.go b/pkg/sentry/syscalls/linux/sys_mount.go index d70b79e4f..57cedccc1 100644 --- a/pkg/sentry/syscalls/linux/sys_mount.go +++ b/pkg/sentry/syscalls/linux/sys_mount.go @@ -46,13 +46,16 @@ func Mount(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall return 0, nil, err } - // In Linux, a full page is always copied in regardless of null - // character placement, and the address is passed to each file system. - // Most file systems always treat this data as a string, though, and so - // do all of the ones we implement. - data, err := t.CopyInString(dataAddr, usermem.PageSize) - if err != nil { - return 0, nil, err + data := "" + if dataAddr != 0 { + // In Linux, a full page is always copied in regardless of null + // character placement, and the address is passed to each file system. + // Most file systems always treat this data as a string, though, and so + // do all of the ones we implement. + data, err = t.CopyInString(dataAddr, usermem.PageSize) + if err != nil { + return 0, nil, err + } } // Ignore magic value that was required before Linux 2.4. -- cgit v1.2.3