Adding message size limit in receive function pgproto3

[Jrmy2402]

Hello,

I would like to propose the addition of a feature to limit the size of messages received by the Backend.Receive() function. Specifically, it would be useful to set a maximum message size parameter to prevent the processing of unusually large messages that might impact performance or pose security risks.

In certain situations, especially when dealing with external or untrusted data sources, there is a potential risk of receiving and processing very large messages, which could lead to performance degradation or exploitation through buffer overflow or similar attacks.

If this proposal aligns with your vision for pgx, I'd be more than willing to contribute by opening a Merge Request to implement this feature.

Thank you for considering this proposal, and for your continuous efforts in maintaining and improving pgx.

[jackc]

I'm open to the idea, but I'm not sure exactly how it would be used or what the interface would look like.

Extremely large messages are possible. PostgreSQL allows fields of up to 1 GB. So presumably a single DataRow could be at least that big.

[Jrmy2402]

I created the pull request #1839 to add the feature.
Please, tell me if it seems ok for you or not.

[jackc]

Merged

[Jrmy2402]

Hi, when do you forecast creating a new release of PGX so I can use the tag instead of the master branch?
Thanks in advance

[Jrmy2402]

Hi, I have pushed a new commit to expose MaxExpectedBodyLen and ActualBodyLen in ExceededMaxBodyLenErr struct.
#1862
Please, tell me if it seems ok for you or not.

[jackc]

Merged.