Chuck Ebbert wrote:
On 01/11/2008 04:35 PM, Jeff Garzik wrote:
Chuck Ebbert wrote:
commit 607126c2a21cd6e9bb807fdd415c1a992f7b9009 changed command
validation
to allow short commands in 16-byte CDBs, but it also made checking more
strict. Before the change, a 10-byte SG_IO command could have its
length set
to 9 and still work. Now it fails. Not sure if this is a bug, but it has
caused at least one application to fail that used to work (qpxtool.)
[https://bugzilla.redhat.com/show_bug.cgi?id=428281]
Can you get us an example CDB? Its unclear if the hexdump in the bug
report is a returned mode page or the CDB or what...?
Not easily, but the maintainer of that program forced the length of
the MODE_SENSE(10) command to 10 and that command started working.
By looking at the source I could tell that it was setting the command
length to (1 + the index of the last byte written to the CDB) and
only wrote up to offset 8 when building the command, so it must have
been sending the command with a length of 9. (It zeroed the whole CDB
first and only wrote what it needed to.)
(And it used the C++ operator [] to build the command, that was fun
to trace...)
Even if allocation length is present in the CDB, the CDB may be missing
important information that is required to process the command. So it
may have caught a bug in the program... depending on the CDB.
Jeff
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