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author | uqs <uqs@FreeBSD.org> | 2010-10-31 09:21:27 +0000 |
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committer | uqs <uqs@FreeBSD.org> | 2010-10-31 09:21:27 +0000 |
commit | da8e054ad100a876cdf64a28404bdacf3d01531d (patch) | |
tree | feb8cd157fde70c2e1ff43ef48d97d163dcdcc73 /bin/rm/rm.1 | |
parent | 1847561168ca9b53de57ec9467d27f5ae9d8e107 (diff) | |
download | FreeBSD-src-da8e054ad100a876cdf64a28404bdacf3d01531d.zip FreeBSD-src-da8e054ad100a876cdf64a28404bdacf3d01531d.tar.gz |
Elaborate some more on the non-security implications of using -P
Submitted by: delphij
Discussion at: svn-src-all
Diffstat (limited to 'bin/rm/rm.1')
-rw-r--r-- | bin/rm/rm.1 | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/bin/rm/rm.1 b/bin/rm/rm.1 index ff573e00..4e4f240 100644 --- a/bin/rm/rm.1 +++ b/bin/rm/rm.1 @@ -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 file will cause .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. |