On Wed, 11 Oct 2023 at 19:35, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > On Wed, 2023-10-11 at 16:55 +0300, Jarkko Sakkinen wrote: > > On Wed, 2023-10-11 at 19:12 +0530, Sumit Garg wrote: > > > On Wed, 11 Oct 2023 at 18:36, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > > > > > > > On Wed, 2023-10-11 at 18:25 +0530, Sumit Garg wrote: > > > > > On Wed, 11 Oct 2023 at 18:07, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > > > > > > > > > > > On Wed, 2023-10-11 at 17:47 +0530, Sumit Garg wrote: > > > > > > > On Wed, 11 Oct 2023 at 16:04, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > On Wed, 2023-10-11 at 13:12 +0300, Jarkko Sakkinen wrote: > > > > > > > > > On Wed, 2023-10-11 at 11:27 +0530, Sumit Garg wrote: > > > > > > > > > > On Wed, 11 Oct 2023 at 04:46, Jarkko Sakkinen <jarkko@xxxxxxxxxx> wrote: > > > > > > > > > > > > > > > > > > > > > > Do bind neither static calls nor trusted_key_exit() before a successful > > > > > > > > > > > init, in order to maintain a consistent state. In addition, depart the > > > > > > > > > > > init_trusted() in the case of a real error (i.e. getting back something > > > > > > > > > > > else than -ENODEV). > > > > > > > > > > > > > > > > > > > > > > Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > > > > > > > > > > > Closes: https://lore.kernel.org/linux-integrity/CAHk-=whOPoLaWM8S8GgoOPT7a2+nMH5h3TLKtn=R_3w4R1_Uvg@xxxxxxxxxxxxxx/ > > > > > > > > > > > Cc: stable@xxxxxxxxxxxxxxx # v5.13+ > > > > > > > > > > > Fixes: 5d0682be3189 ("KEYS: trusted: Add generic trusted keys framework") > > > > > > > > > > > Signed-off-by: Jarkko Sakkinen <jarkko@xxxxxxxxxx> > > > > > > > > > > > --- > > > > > > > > > > > security/keys/trusted-keys/trusted_core.c | 20 ++++++++++---------- > > > > > > > > > > > 1 file changed, 10 insertions(+), 10 deletions(-) > > > > > > > > > > > > > > > > > > > > > > diff --git a/security/keys/trusted-keys/trusted_core.c b/security/keys/trusted-keys/trusted_core.c > > > > > > > > > > > index 85fb5c22529a..fee1ab2c734d 100644 > > > > > > > > > > > --- a/security/keys/trusted-keys/trusted_core.c > > > > > > > > > > > +++ b/security/keys/trusted-keys/trusted_core.c > > > > > > > > > > > @@ -358,17 +358,17 @@ static int __init init_trusted(void) > > > > > > > > > > > if (!get_random) > > > > > > > > > > > get_random = kernel_get_random; > > > > > > > > > > > > > > > > > > > > > > - static_call_update(trusted_key_seal, > > > > > > > > > > > - trusted_key_sources[i].ops->seal); > > > > > > > > > > > - static_call_update(trusted_key_unseal, > > > > > > > > > > > - trusted_key_sources[i].ops->unseal); > > > > > > > > > > > - static_call_update(trusted_key_get_random, > > > > > > > > > > > - get_random); > > > > > > > > > > > - trusted_key_exit = trusted_key_sources[i].ops->exit; > > > > > > > > > > > - migratable = trusted_key_sources[i].ops->migratable; > > > > > > > > > > > - > > > > > > > > > > > ret = trusted_key_sources[i].ops->init(); > > > > > > > > > > > - if (!ret) > > > > > > > > > > > + if (!ret) { > > > > > > > > > > > + static_call_update(trusted_key_seal, trusted_key_sources[i].ops->seal); > > > > > > > > > > > + static_call_update(trusted_key_unseal, trusted_key_sources[i].ops->unseal); > > > > > > > > > > > + static_call_update(trusted_key_get_random, get_random); > > > > > > > > > > > + > > > > > > > > > > > + trusted_key_exit = trusted_key_sources[i].ops->exit; > > > > > > > > > > > + migratable = trusted_key_sources[i].ops->migratable; > > > > > > > > > > > + } > > > > > > > > > > > + > > > > > > > > > > > + if (!ret || ret != -ENODEV) > > > > > > > > > > > > > > > > > > > > As mentioned in the other thread, we should allow other trust sources > > > > > > > > > > to be initialized if the primary one fails. > > > > > > > > > > > > > > > > > > I sent the patch before I received that response but here's what you > > > > > > > > > wrote: > > > > > > > > > > > > > > > > > > "We should give other trust sources a chance to register for trusted > > > > > > > > > keys if the primary one fails." > > > > > > > > > > > > > > > > > > 1. This condition is lacking an inline comment. > > > > > > > > > 2. Neither this response or the one that you pointed out has any > > > > > > > > > explanation why for any system failure the process should > > > > > > > > > continue. > > > > > > > > > > > > > > > > > > You should really know the situations (e.g. list of posix error > > > > > > > > > code) when the process can continue and "allow list" those. This > > > > > > > > > way way too abstract. It cannot be let all possible system failures > > > > > > > > > pass. > > > > > > > > > > > > > > > > And it would nice if it printed out something for legit cases. Like > > > > > > > > "no device found" etc. And for rest it must really withdraw the whole > > > > > > > > process. > > > > > > > > > > > > > > IMO, it would be quite tricky to come up with an allow list. Can we > > > > > > > keep "EACCES", "EPERM", "ENOTSUPP" etc in that allow list? I think > > > > > > > these are all debatable. > > > > > > > > > > > > Yes, that does sounds reasonable. > > > > > > > > > > > > About the debate. Well, it is better eagerly block and tree falls down > > > > > > somewhere we can consider extending the list through a fix. > > > > > > > > > > > > This all wide open is worse than a few glitches somewhere, which are > > > > > > trivial to fix. > > > > > > > > > > > > > > > > Fair enough, I would suggest we document it appropriately such that it > > > > > is clear to the users or somebody looking at the code. > > > > > > > > I went throught the backends on how they implement init: > > > > > > > > 1. Returns -ENODEV when it does not exist. > > > > 2. Calls driver_register(). Something is wrong enough if that > > > > fails to rollback the whole procedure. > > > > 3. TPM: -ENODEV > > > > > > > > Therefore, I would keep in the existing patch since there is no weird > > > > uapi visible legacy behavior to support in the first place. And for > > > > that reason there is no good reason to have all those four POSIX rc's > > > > in the list. > > > > > > Okay I can live with this patch as long as it doesn't break the > > > intended use-case. > > > > Well this sort of policy has been already existing for some time: > > > > /* > > * encrypted_keys.ko depends on successful load of this module even if > > * trusted key implementation is not found. > > */ > > if (ret == -ENODEV) > > return 0; > > > > If we would need a list of error codes, then this is also incorrect > > implementation because the error codes that you listed should be > > also success cases. > As I mentioned before we can go ahead with this policy for trust sources and see how it pans out. > The dead obvious constraint here is that whatever error codes are > processed they need to be exact same anyway right? > > If things fall apart you should really not continue. This is IMHO > categorizes as a critical bug, Here we are discussing trust sources as multiple independent devices. If a particular device probe/init fails then it shouldn't be a blocker to probe/init another device. > not just debatable aspect on how > subsystems are engineered. I.e.I do not consider this as any sort > of API discussion per se. Agree, I see it as a policy decision for the trusted keys subsystem. -Sumit > > BR, Jarkko
