Re: [PATCH 1/2] audit: fix NUL handling in untrusted strings
Steve Grubb wrote:
On Thursday 11 September 2008 14:10:12 Miloslav Trmač wrote:
>> As a side note I'm concerned there may be places in the user audit
>> code which treat string data as null terminated (at least that is my
>> recollection).
>>
> Yes, auditd adds a NUL terminator to the audit record, and then treats
> it as a regular NUL-terminated string; if the audit record contains an
> embedded NUL byte, the rest of the record is discarded by auditd.
>
In every case where this occurs (kernel or user space), the field values are
expected to be encoded to prevent it from being discarded.
This is true. The proposed patch defeats the encoding of the entire data
block and thus fails the criteria Steve correctly states is a requirement.
The concern I have in the user level audit code is not with handling the
encoded string values which is fine, but rather with the handling the
decoded string block.
--
John Dennis <jdennis(a)redhat.com>
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