kern/161481: mount fails with ENAMETOOLONG with path shorter than
255 // 1023 characters
Garrett Cooper
yanegomi at gmail.com
Tue Oct 11 07:40:02 UTC 2011
>Number: 161481
>Category: kern
>Synopsis: mount fails with ENAMETOOLONG with path shorter than 255 // 1023 characters
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Oct 11 07:40:01 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Garrett Cooper
>Release: 10-CURRENT
>Organization:
n/a
>Environment:
FreeBSD fallout.local 10.0-CURRENT FreeBSD 10.0-CURRENT #2 r226242M: Mon Oct 10 20:50:51 PDT 2011 gcooper at fallout.local:/usr/obj/usr/src/sys/FALLOUT amd64
>Description:
mount(2) claims that it should fail with ENAMETOOLONG if the path is <= 255 or 1023 characters:
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
the entire length of a path name exceeded 1023 charac-
ters.
In practice, that isn't true:
# mount -t nullfs -o noatime /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/ports/distfiles /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/_.w/usr/ports/distfiles
mount_nullfs: File name too long
# echo mount -t nullfs -o noatime /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/ports/distfiles/ /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/_.w/usr/ports/distfiles | awk '{ print length($(NF - 1)), length($NF) }'
83 90
#
It's failing a bounds check in nmount and its callees. I've seen this issue with both nullfs and UFS, so it's most likely a problem in vfs_mount.c, etc.
I've seen this issue on 8.2-RELEASE (FreeNAS), as well as 9-CURRENT and 10-CURRENT.
>How-To-Repeat:
#!/bin/sh
set -e
mkdir -p /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/_.w/usr/ports/distfiles/
md=$(mdconfig -a -t swap -s 512m)
newfs /dev/$md
mount /dev/$md /nfs/scratch/freenas-2/freenas/projects/freenas8-plugins/obj.amd64/_.w/usr/ports/distfiles/
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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