Conversation
Jarkko Sakkinen
jarkko
IMHO the thing in Rust and drivers is not memory safe per se or like "overflow check type of stuff".
It's the structural integrity check that levels up over C really. E.g. in C world I check that a TPM command holding buffer is not too large.
In Rust world I'll check in byte granularity that the data coming from user space and the chip is correct.
It's the structural integrity check that levels up over C really. E.g. in C world I check that a TPM command holding buffer is not too large.
In Rust world I'll check in byte granularity that the data coming from user space and the chip is correct.
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It's a lot to say but I rarely cause over or underflows C. Cannot even remember when was the last time. But this structural integrity area is where I get more precision when using Rust.
I.e. I can almost formally do a yes/no check whether some sequence on-wire (given Box<dyn TpmCommand> capability) of data is command or response or something that differs only per byte of the set of legit commands or responses. That nails the key difference.
I.e. I can almost formally do a yes/no check whether some sequence on-wire (given Box<dyn TpmCommand> capability) of data is command or response or something that differs only per byte of the set of legit commands or responses. That nails the key difference.
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A spec update for a single new commands takes about 15 minutes to implement. I just di d that for ZGen2Phase:
tpm_struct! {
#[derive(Debug, PartialEq, Eq, Clone)]
TpmZGen2PhaseCommand,
TpmCc::ZGen2Phase,
false,
true,
1,
{
pub in_qsb: Tpm2bEccPoint,
pub in_qeb: Tpm2bEccPoint,
pub in_scheme: TpmiEccKeyExchange,
pub counter: u16,
}
}
tpm_response! {
#[derive(Debug, PartialEq, Eq, Clone)]
TpmZGen2PhaseResponse,
TpmCc::ZGen2Phase,
false,
true,
{
pub out_z1: Tpm2bEccPoint,
pub out_z2: Tpm2bEccPoint,
}
}
In addition a single line is required to ordered by cc dispatch list (there is compilation check for order):
(TpmZGen2PhaseCommand, TpmZGen2PhaseResponse, ZGen2Phase),
tpm_struct! {
#[derive(Debug, PartialEq, Eq, Clone)]
TpmZGen2PhaseCommand,
TpmCc::ZGen2Phase,
false,
true,
1,
{
pub in_qsb: Tpm2bEccPoint,
pub in_qeb: Tpm2bEccPoint,
pub in_scheme: TpmiEccKeyExchange,
pub counter: u16,
}
}
tpm_response! {
#[derive(Debug, PartialEq, Eq, Clone)]
TpmZGen2PhaseResponse,
TpmCc::ZGen2Phase,
false,
true,
{
pub out_z1: Tpm2bEccPoint,
pub out_z2: Tpm2bEccPoint,
}
}
In addition a single line is required to ordered by cc dispatch list (there is compilation check for order):
(TpmZGen2PhaseCommand, TpmZGen2PhaseResponse, ZGen2Phase),
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