On Sun Oct 31 10, Ulrich Spoerlein wrote: > Author: uqs > Date: Sun Oct 31 09:21:27 2010 > New Revision: 214596 > URL: http://svn.freebsd.org/changeset/base/214596 > > Log: > Elaborate some more on the non-security implications of using -P
thanks a lot. i think there are a few typos though (see attached patch). cheers. alex > > Submitted by: delphij > Discussion at: svn-src-all > > Modified: > head/bin/rm/rm.1 > > Modified: head/bin/rm/rm.1 > ============================================================================== > --- head/bin/rm/rm.1 Sun Oct 31 09:05:04 2010 (r214595) > +++ head/bin/rm/rm.1 Sun Oct 31 09:21:27 2010 (r214596) > @@ -32,7 +32,7 @@ > .\" @(#)rm.1 8.5 (Berkeley) 12/5/94 > .\" $FreeBSD$ > .\" > -.Dd October 8, 2010 > +.Dd October 31, 2010 > .Dt RM 1 > .Os > .Sh NAME > @@ -100,6 +100,11 @@ Specifying this flag for a read only fil > .Nm > to generate an error message and exit. > The file will not be removed or overwritten. > +.Pp > +N.B.: The > +.Fl P > +flag is not considered a security feature > +.Pq see Sx BUGS . > .It Fl R > Attempt to remove the file hierarchy rooted in each > .Ar file > @@ -229,8 +234,12 @@ command appeared in > .Sh BUGS > The > .Fl P > -option assumes that the underlying file system updates existing blocks > -in-place and does not store new data in a new location. > -This is true for UFS, but not for ZFS or other file systems which use > -copy-on-write semantics. > -In addition, only regular files are overwritten. > +option assumes that the underlying storage overwrites file block > +when data is written to an existing offset. > +Several factors including the file system and its backing store could defeat > +this assumption. > +This includes, but is not limited to file systems that use a > +Copy-On-Write strategy (e.g. ZFS or UFS when snapshots are being used), Flash > +media that is using a wear leveling algorithm, or when the backing datastore > +does journaling, etc. > +In addition, only regular files are overwritten, other types of files are > not. -- a13x
diff --git a/bin/rm/rm.1 b/bin/rm/rm.1 index 4e4f240..ad81066 100644 --- a/bin/rm/rm.1 +++ b/bin/rm/rm.1 @@ -234,12 +234,12 @@ command appeared in .Sh BUGS The .Fl P -option assumes that the underlying storage overwrites file block +option assumes that the underlying storage overwrites file blocks when data is written to an existing offset. Several factors including the file system and its backing store could defeat this assumption. This includes, but is not limited to file systems that use a Copy-On-Write strategy (e.g. ZFS or UFS when snapshots are being used), Flash -media that is using a wear leveling algorithm, or when the backing datastore +media that are using a wear leveling algorithm, or when the backing datastore does journaling, etc. In addition, only regular files are overwritten, other types of files are not.
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