[dfsan] union extension for userdata

Hello list,

when using dfsan, i thought i could use the ‘userdata’ field in dfsan_label_info

to maintain input file offsets influencing the labeled variable.

I would label variables as tainted that get input from a file along with the

file offsets at that time (using ‘userdata’).

For dependent variables I would like to use the propagation mechanism of dfsan in

order to see the accumulated input offsets later.

So, when dfsan_union is called, I would like to have a wrapper or callback

function in effect in order to also generate the union of the input file offsets

from userdata of both input labels.

So, do you think the dfsan framework can be used to achieve this?

I am interested in a minimal invasive way to extend the dfsan_union function.

Thanks for any advice and best regards,

Heiko Eißfeldt