Re: Row data is reflected in DETAIL message when constraints fail on insert/update

On Thu, Jun 20, 2019 at 05:22:20PM +0200, Shay Rojansky wrote:

> It seems generally agreed that all data from the database should be
> considered potentially sensitive and should therefore not be leaked in log
> messages - unless an explicit, informed opt-in is done. It is extremely
> easy to imagine a (poorly-written) UI or web application which simply
> surfaces database exceptions, allowing attackers to potentially extract
> data from the database. In the worst case, passwords and other auth
> information may get exposed in this way, but even any sort of personal
> information is a big problem.
>
> It seems worth at least having a conversation about it...

Sure, but we are currently exploring whether the database
reflects any values that it had not been given by the same
user beforehand.

There might be another scenario:

user enters value for column 1

app adds in secret-to-the-user value for column 2

UPDATE fails

error message reflects val 1 and secret val 2

app displays both values

user knows secret value 2

but I don't see how PostgreSQL can do anything *reasonable*
about that short of sitting tight-and-mum and not reflect
much of *anything* beyond "error". And even that can be a
side channel.

Karsten
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