You can easily use the unix split command and cat to scan files of any size. Or
use perl to break stream file segments to the stream. The first file in a split
or segment contains the file time and will need to be concatenated to the
beginning of each split or segment so clamav knows what it is. It doesn't matter
if the file makes no sense just so long as no malware is found. You will need
two split sizes in order to ensure a signature doesn't span splits which means
at least two runs of each large file, but that is trivial when scripted. SSD
drives would be useful.
dp
On 1/25/19 10:12 AM, Paul Kosinski wrote:
I understand that it's impractical for ClamAV to scan exceedingly large
files, as it could fill up RAM and/or page forever. But the current 4GB
hard limit is overly restrictive, especially since 32-bit addresses and
numbers are ancient history in current OSes.
In particular, scanning big archives immediately after downloading is
desirable, since there can be malware that attacks the de-compressing or
de-archiving mechanism itself. Thus simply scanning the individual
contained files isn't completely adequate.
Is there any plan to allow scanning bigger files? There still are,
after all, size limits specifiable in the config file(s), and warnings
about the consequences of setting limits too big can be documented.
On Fri, 25 Jan 2019 14:32:55 +0000
"Micah Snyder (micasnyd)" <micas...@cisco.com> wrote:
Re garding specific limits, I'm sorry to say that ClamAV is presently
limited to max file size of 4GB on most systems (and, I think
unintentionally, 2GB on some systems).
-Micah
On Jan 24, 2019, at 4:23 PM, J.R.
<themadbea...@gmail.com<mailto:themadbea...@gmail.com>> wrote:
I think I framed my problem statement differently.
So, our requirement is similar the one asked by John in the
below link. I do not know if the solution proposed is a correct one..
Also, how do you propose I should scan an archive of 100GB ( let's
say) size. Does clamav have any limitations on scanning a single file
of such huge size ??
Without knowing more about this "archive" it's hard to say if ClamAV
will even pick up anything, due to the reason Micah gave in his reply.
But another issue is if this is just one humongous file you are trying
to shove through and say it *does* trigger some virus... How are you
going to know what / where the virus is? All you know is its somewhere
in your massive archive file...
You would be much better off scanning the individual files as you
assemble said archive, and obviously only need to scan files where an
infection would make sense (i.e. a text file isn't going to contain a
virus)...
There are stream settings in the clamd.conf, but I don't know what the
hard upper-limits are.
In cases like this, it's probably best to assemble you own sample
archives, one clean & one infected, and run through your proposed
process. If it works as intended, then create a few more samples and
re-test... If it doesn't work as intended then you'll need to re-think
your process...
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