On Fri, 2020-02-07 at 10:49 -0700, Eric Snowberg wrote: > > > On Feb 7, 2020, at 10:40 AM, Mimi Zohar <zohar@xxxxxxxxxxxxx> wrote: > > > >> $ insmod ./foo.ko > >> insmod: ERROR: could not insert module ./foo.ko: Permission denied > >> > >> last entry from audit log: > >> type=INTEGRITY_DATA msg=audit(1581089373.076:83): pid=2874 uid=0 > >> auid=0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0- > >> s0:c0.c1023 op=appraise_data cause=invalid-signature comm="insmod" > >> name="/root/keys/modules/foo.ko" dev="dm-0" ino=10918365 > >> res=0^]UID="root" AUID=“root" > >> > >> This is because modsig_verify() will be called from within > >> ima_appraise_measurement(), > >> since try_modsig is true. Then modsig_verify() will return > >> INTEGRITY_FAIL. > > > > Why is it an "invalid signature"? For that you need to look at the > > kernel messages. Most likely it can't find the public key on the .ima > > keyring to verify the signature. > > It is invalid because the module has not been ima signed. With the IMA policy rule "appraise func=MODULE_CHECK appraise_type=imasig|modsig", IMA first tries to verify the IMA signature stored as an xattr and on failure then attempts to verify the appended signatures. The audit message above indicates that there was a signature, but the signature validation failed. Mimi
