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Diffstat (limited to 'archive/2021-12-14-log-operators-bcp-dns')
| -rw-r--r-- | archive/2021-12-14-log-operators-bcp-dns | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/archive/2021-12-14-log-operators-bcp-dns b/archive/2021-12-14-log-operators-bcp-dns new file mode 100644 index 0000000..2239c47 --- /dev/null +++ b/archive/2021-12-14-log-operators-bcp-dns @@ -0,0 +1,22 @@ +# Log operators BCP +## Outgoing DNS queries +Note that a log will be making an outgoing DNS query for a TXT record for each +call to add-leaf. The name that is being looked up is chosen by the client. The +implementation in sigsum-log-go currently uses the system resolver (it is easy +to add other options). + +Operators with a strict policy for what goes out of their systems will have to +allow arbitrary TXT records. + +This should not be a problem wrt DoS since it's not a venue for amplification +attacks (the add-leaf request is quite large compared with the DNS request +generated) and generation of excess amounts of outgoing traffic is mitigated by +DNS resolvers performing caching. + +Question: would there be any value in adding some restriction for what the name +must be? E.g., what if the left-most part had to be "sigsum"? + * Example: dig -t txt sigsum.rgdd.se + * This would allow stricter filtering than "all TXT records for all names" + which might be useful, but I'm not sure yet. If we did this, I think we + should use a label prefixed by an underscore, f.ex. "_sigsum" to avoid + collisions with natural names. |