Adding audit support to dpkg
Hi!
We got a request to add audit support to dpkg [R], and as initially mentioned on the bug report it seems the AUDIT_SOFTWARE_UPDATE format does not appear to be documented, so while looking into all this, got several questions.
[R] <https://bugs.debian.org/931748>
Quoted 1 line
From the rpm implementation and
auparse/normalize.cI gather that it
would contain the following fields, applied to dpkg:
* primary field would be "sw" which would contain something like «"nginx_1.18.0-5_amd64"», I assume that the format differing from the one in rpm is fine as that would be keyed on the next field?
* secondary field would be "sw_type" which would be «dpkg».
* field "op", which would contain entries different to rpm, such as «unpack», «configure», «install», «remove», «purge», not sure if that might be a problem?
* field "key_enforce", I take to denote whether a cryptographic verification has been performed on the .deb archive? With values «0» or «1». (This would depend on whether debsig-verify(1) has been configured to be executed or not.)
* field "gpg_res", to denote whether the aforementioned verification succeeded or not? With values «0» or «1». And while dpkg can indeed use GnuPG to verify signatures from archives, the name feels too implementation specific, perhaps it could be renamed so that it would not be very confusing, in case someone implements a check based on say x509 certificates?
* field "root_dir", to denote the installation root directory, which would map to dpkg --instdir value, with a value such as «"/"».
Anything else I might have missed or might be worth taking into account while adding the support?
Thanks,
Guillem
--
Linux-audit mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-audit
Quoted 32 lines · Guillem Jover
Hi!
We got a request to add audit support to dpkg [R], and as initially mentioned on the bug report it seems the
AUDIT_SOFTWARE_UPDATEformat does not appear to be documented, so while looking into all this, got several questions.[R] <https://bugs.debian.org/931748>
Quoted 1 line
From the rpm implementation and
auparse/normalize.cI gather that itwould contain the following fields, applied to dpkg:
* primary field would be "sw" which would contain something like «"nginx_1.18.0-5_amd64"», I assume that the format differing from the one in rpm is fine as that would be keyed on the next field?
* secondary field would be "sw_type" which would be «dpkg».
* field "op", which would contain entries different to rpm, such as «unpack», «configure», «install», «remove», «purge», not sure if that might be a problem?
* field "key_enforce", I take to denote whether a cryptographic verification has been performed on the .deb archive? With values «0» or «1». (This would depend on whether debsig-verify(1) has been configured to be executed or not.)
* field "gpg_res", to denote whether the aforementioned verification succeeded or not? With values «0» or «1». And while dpkg can indeed use GnuPG to verify signatures from archives, the name feels too implementation specific, perhaps it could be renamed so that it would not be very confusing, in case someone implements a check based on say x509 certificates?
* field "root_dir", to denote the installation root directory, which would map to dpkg --instdir value, with a value such as «"/"».
Quoted 2 lines
Anything else I might have missed or might be worth taking into account while adding the support?
I don't see any glaring issues with what you propose. In particular, the op field seems fine, sticking to single words with no spaces.
You might review these two documents to check for details:
https://github.com/linux-audit/audit-documentation/wiki/SPEC-Writing-Good-Events
And check here to see if there are already fields that are set aside for these uses and make sure there isn't a conflict of type or meaning for an existing one:
https://github.com/linux-audit/audit-documentation/blob/master/specs/fields/field-dictionary.csv
Other documents in this set might be helpful:
https://github.com/linux-audit/audit-documentation/wiki
Quoted 1 line
Guillem
- RGB
--
Richard Guy Briggs <[email protected]>
Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
--
Linux-audit mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-audit
Hello,
Quoted 5 lines · EDT Guillem Jover
We got a request to add audit support to dpkg [R], and as initially mentioned on the bug report it seems the
AUDIT_SOFTWARE_UPDATEformat does not appear to be documented, so while looking into all this, got several questions.
Quoted 8 lines
[R] <https://bugs.debian.org/931748>
Quoted 1 line
From the rpm implementation and
auparse/normalize.cI gather that itwould contain the following fields, applied to dpkg:
* primary field would be "sw" which would contain something like «"nginx_1.18.0-5_amd64"», I assume that the format differing from the one in rpm is fine as that would be keyed on the next field?
sure
Quoted 1 line
* secondary field would be "
sw_type" which would be «dpkg».
yes
Quoted 5 lines
* field "op", which would contain entries different to rpm, such as «unpack», «configure», «install», «remove», «purge», not sure if that might be a problem?
From compliance perspective, only install, update, and remove are relevant.
You want to know when something gets added or removed because they could add setuid programs or daemons that autostart. Secondly, you may be tracking current versions to resolve CVE's. So, for that purpose, you also want to know when something gets updated. Nothing else matters.
How does unpack differ from install? How does purge differ from remove? There is another event type, AUDIT_USYS_CONFIG, that tracks user space configuration changes. However, this is rarely used. Instead, what is done is watches are placed on important configuration files to see if anything opens the file for modiciation. So, would there be any need to have a configuration option for SOFTWARE_UPDATE?
Quoted 4 lines
* field "
key_enforce", I take to denote whether a cryptographic verification has been performed on the .deb archive? With values «0» or «1». (This would depend on whether debsig-verify(1) has been configured to be executed or not.)
This denotes whether signature checks is being enforced. This is independent from whether or not the signature is valid. IOW, if a signature (next field) is invalid, will the package be allowed in anyway?
Quoted 6 lines
* field "
gpg_res", to denote whether the aforementioned verification succeeded or not? With values «0» or «1». And while dpkg can indeed use GnuPG to verify signatures from archives, the name feels too implementation specific, perhaps it could be renamed so that it would not be very confusing, in case someone implements a check based on say x509 certificates?
This field is whether or not the package passes its verification with a hash, gpg signature, x509 certificate, or any other integrity scheme.
Quoted 2 lines
* field "
root_dir", to denote the installation root directory, which would map to dpkg --instdir value, with a value such as «"/"».
Yes. Rpms can be relocatable to anywhere. So, this is to document what part of the system the package will affect.
Quoted 2 lines
Anything else I might have missed or might be worth taking into account while adding the support?
I think that's pretty much it. If you wanted to see an example of the code, it is here:
https://github.com/rpm-software-management/rpm/blob/master/plugins/
audit.c#L80
-Steve
--
Linux-audit mailing list
[email protected]
https://www.redhat.com/mailman/listinfo/linux-audit