[comp.sys.amiga] Bug in FFS overwrites files with the w protection bit off

jms@tardis.Tymnet.COM (Joe Smith) (01/16/90)

After seeing some bug reports listed in the docs for SKSH, I tried some
of experiments of my own.

HARDCOPY v1.0 recorded on 15-Jan-90 23:12:01 to file "ffs.bug"
To end the HARDCOPY session and close the file, type HARDCOPY END

1.FFS1:Misc> echo >test test
1.FFS1:Misc> type test
test
1.FFS1:Misc> protect test sub w	;Turn off the writeable bit
1.FFS1:Misc> list test
test                           5 ----r-ed Today     23:12:34
1.FFS1:Misc> echo >>test next	;This should fail - cannot append
1.FFS1:Misc> type test		;It does
test
1.FFS1:Misc> echo >test foo	;This should fail
1.FFS1:Misc> type test		;What happened??
1.FFS1:Misc> list test		;It got wiped out!!
test                       empty ----r-ed Today     23:13:19
1.FFS1:Misc> echo >foo foo
1.FFS1:Misc> copy foo test	;This should fail
Error while Writing
Destination file "test" removed
1.FFS1:Misc> list test		;"Removed"?  That should not happen!
Can't examine "test": object not found
1.FFS1:Misc> list foo
foo                            4 ----rwed Today     23:13:50
1.FFS1:Misc> type foo
foo
1.FFS1:Misc> copy foo *
foo
1.FFS1:Misc> protect foo sub r	;Turn off the readable bit
1.FFS1:Misc> type foo		;Why is there no error message here?
1.FFS1:Misc> copy foo *		;This does report an error
Error while Reading
1.FFS1:Misc> echo >test test
1.FFS1:Misc> protect test re	;Turn off both the w and deleteable bits
1.FFS1:Misc> list test
test                           5 ----r-e- Today     23:15:03
1.FFS1:Misc> echo >>test 2nd	;This fails, but no error message
1.FFS1:Misc> type test
test
1.FFS1:Misc> echo >test foo	;This fails, with correct error message
SHELL error: Unable to open redirection file
1.FFS1:Misc> list test
test                           5 ----r-e- Today     23:15:03
1.FFS1:Misc> copy foo test	;This fails, with correct error message
Can't open test - file is protected from deletion
1.FFS1:Misc> hardcopy end

Summary: If the W bit is off but the D bit is on, AmigaDos and/or c:copy
can still destroy your file.  These tests were performed on a hard disk
using C:copy and L:FastFileSystem from the WB 1.3.2 disk.
-- 
Joe Smith (408)922-6220 | SMTP: JMS@F74.TYMNET.COM or jms@gemini.tymnet.com
BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms
PO Box 49019, MS-D21    | PDP-10 support: My car's license plate is "POPJ P,"
San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga speaks for me."

stefanb@cip-s02.informatik.rwth-aachen.de (Becker) (01/17/90)

This happens with DME too. If the w-bit is off an the d-bit is on, your
file will be empty, but DME says 'OK'. Does this bug occur under the old
file system?

	Stefan