Date: Wed, 11 Sep 2002 10:31:09 +0200 (CEST) From: Thomas Seck <tmseck@netcologne.de> To: FreeBSD-gnats-submit@FreeBSD.org Subject: docs/42651: [PATCH] mount([28]) do not document vfs.usermount Message-ID: <20020911083109.820DC285B0@mail.tmseck.homedns.org>
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>Number: 42651 >Category: docs >Synopsis: [PATCH] mount([28]) do not document vfs.usermount >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-doc >State: open >Quarter: >Keywords: >Date-Required: >Class: doc-bug >Submitter-Id: current-users >Arrival-Date: Wed Sep 11 01:40:01 PDT 2002 >Closed-Date: >Last-Modified: >Originator: Thomas Seck >Release: FreeBSD 4.6-STABLE i386 >Organization: private site >Environment: FreeBSD CVS repository as of Sept. 9, 2002. >Description: Non-root users may be privileged to issue calls to mount(2) by setting the sysctl vfs.usermount to a nonzero value. Neither this nor the implicit restrictions (user must own mount point, the nosuid and nodev option are always set) are documented in mount(2) or mount(8). >How-To-Repeat: n/a >Fix: I suggest the following patches (BTW, mount(8) nowadays uses the term "file system" while mount(2) still uses "filesystem"): Index: src/lib/libc/sys/mount.2 =================================================================== RCS file: /home/ncvs/src/lib/libc/sys/mount.2,v retrieving revision 1.28 diff -u -r1.28 mount.2 --- src/lib/libc/sys/mount.2 1 Oct 2001 16:09:02 -0000 1.28 +++ src/lib/libc/sys/mount.2 11 Sep 2002 07:48:02 -0000 @@ -74,6 +74,12 @@ of a successful mount are swept under the carpet so to speak, and are unavailable until the filesystem is unmounted. .Pp +By default only the super-user may call the +.Fn mount +function. This restriction can be removed by setting the sysctl +.Em vfs.usermount +to a non-zero value. +.Pp The following .Ar flags may be specified to @@ -87,11 +93,13 @@ .It Dv MNT_NOEXEC Do not allow files to be executed from the filesystem. .It Dv MNT_NOSUID -Do not honor setuid or setgid bits on files when executing them. +Do not honor setuid or setgid bits on files when executing them. This flag is +automatically set when the caller is not the super-user. .It Dv MNT_NOATIME Disable update of file access times. .It Dv MNT_NODEV -Do not interpret special files on the filesystem. +Do not interpret special files on the filesystem. This flag is automatically +set when the caller is not the super-user. .It Dv MNT_SUIDDIR Directories with the SUID bit set chown new files to their own owner. .It Dv MNT_SYNCHRONOUS @@ -176,7 +184,8 @@ function will fail when one of the following occurs: .Bl -tag -width Er .It Bq Er EPERM -The caller is not the super-user. +The caller is not the super-user and not the owner of +.Ar dir . .It Bq Er ENAMETOOLONG A component of a pathname exceeded 255 characters, or the entire length of a path name exceeded 1023 characters. @@ -253,7 +262,9 @@ function may fail with one of the following errors: .Bl -tag -width Er .It Bq Er EPERM -The caller is not the super-user. +The caller is not the super-user and not the user that issued the corresponding +.Xr mount 2 +call. .It Bq Er ENOTDIR A component of the path is not a directory. .It Bq Er ENAMETOOLONG @@ -280,6 +291,7 @@ .Sh SEE ALSO .Xr lsvfs 1 , .Xr mount 8 , +.Xr sysctl 8 , .Xr umount 8 .Sh BUGS Some of the error codes need translation to more obvious messages. Index: src/sbin/mount/mount.8 =================================================================== RCS file: /home/ncvs/src/sbin/mount/mount.8,v retrieving revision 1.52 diff -u -r1.52 mount.8 --- src/sbin/mount/mount.8 21 Aug 2002 18:10:52 -0000 1.52 +++ src/sbin/mount/mount.8 11 Sep 2002 08:00:13 -0000 @@ -158,7 +158,8 @@ .It Cm nodev Do not interpret character or block special devices on the file system. This option is useful for a server that has file systems containing -special devices for architectures other than its own. +special devices for architectures other than its own. This option is always set +when the user does not have super-user privileges. .It Cm noexec Do not allow execution of any binaries on the mounted file system. This option is useful for a server that has file systems containing @@ -168,7 +169,8 @@ Note: this option is worthless if a public available suid or sgid wrapper like .Xr suidperl 1 -is installed on your system. +is installed on your system. It is automatically set when the user does not +have super-user privileges. .It Cm nosymfollow Do not follow symlinks on the mounted file system. @@ -436,6 +438,7 @@ .Xr mount_udf 8 , .Xr mount_umapfs 8 , .Xr mount_unionfs 8 , +.Xr sysctl 8 , .Xr umount 8 .Sh BUGS It is possible for a corrupted file system to cause a crash. >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message
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