On Thu, 28 May 2020 19:36:55 +0200, Roberto Sassu wrote: > > > From: linux-integrity-owner@xxxxxxxxxxxxxxx [mailto:linux-integrity- > > owner@xxxxxxxxxxxxxxx] On Behalf Of Takashi Iwai > > On Thu, 28 May 2020 17:35:16 +0200, > > Takashi Iwai wrote: > > > > > > Hi Roberto, > > > > > > it seems that the recent changes in IMA in linux-next caused a > > > regression: namely it triggers an Oops when booting with the options > > > ima_policy=tcb ima_template_fmt='d-ng|n-ng|d|ng' > > > > And further experiment revealed that passing only ima_template_fmt=d > > is enough for triggering the bug. Other formats don't matter. > > > > (snip) > > > It's a KVM instance without any TPM stuff, just passed the options > > > above. I could trigger the same bug on a bare metal, too. > > > > > > Then I performed bisection and it spotted the commit: > > > 6f1a1d103b48b1533a9c804e7a069e2c8e937ce7 > > > ima: Switch to ima_hash_algo for boot aggregate > > > > > > Actually reverting this commit fixed the Oops again. > > > > So, looking at the fact above (triggered by "d") and this bisection > > result, it seems that the issue is specific to ima_eventdigest_init(). > > The difference from others is that this has a check by > > ima_template_hash_algo_allowed(), and currently the check allows only > > SHA1 and MD5, while now SHA256 is assigned as default. So I tested > > adding SHA256 there like below, and it seems working. > > > > Hopefully I'm heading to a right direction... > > Hi Takashi > > boot_aggregate is the only entry for which there is no file descriptor. > The file descriptor is used to recalculate the digest if it is not SHA1 > or MD5. For boot_aggregate, we should use instead > ima_calc_boot_aggregate(). I will provide a patch. > > I see that the .file member of event_data in > ima_add_boot_aggregate() is not initialized. Can you please try > to set .file to NULL? Tested and it didn't help. The field was already zero-initialized via C99-style initialization, I believe. thanks, Takashi > > Thanks > > Roberto > > HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 > Managing Director: Li Peng, Li Jian, Shi Yanli > > > thanks, > > > > Takashi > > > > --- a/security/integrity/ima/ima_template_lib.c > > +++ b/security/integrity/ima/ima_template_lib.c > > @@ -13,7 +13,8 @@ > > > > static bool ima_template_hash_algo_allowed(u8 algo) > > { > > - if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_MD5) > > + if (algo == HASH_ALGO_SHA1 || algo == HASH_ALGO_SHA256 || > > + algo == HASH_ALGO_MD5) > > return true; > > > > return false; >
