Quoting Thiago Jung Bauermann (bauerman@xxxxxxxxxxxxxxxxxx):
>
> Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> writes:
> > On Wed, 2018-03-14 at 21:03 -0300, Thiago Jung Bauermann wrote:
> >> Hello Serge,
> >>
> >> Thanks for quickly reviewing these patches!
> >>
> >> Serge E. Hallyn <serge@xxxxxxxxxx> writes:
> >>
> >> > Quoting Thiago Jung Bauermann (bauerman@xxxxxxxxxxxxxxxxxx):
> >> >> From: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
> >> >> @@ -241,16 +241,20 @@ int ima_appraise_measurement(enum ima_hooks func,
> >> >> }
> >> >>
> >> >> status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
> >> >> - if ((status != INTEGRITY_PASS) &&
> >> >> - (status != INTEGRITY_PASS_IMMUTABLE) &&
> >> >> - (status != INTEGRITY_UNKNOWN)) {
> >> >> - if ((status == INTEGRITY_NOLABEL)
> >> >> - || (status == INTEGRITY_NOXATTRS))
> >> >> - cause = "missing-HMAC";
> >> >> - else if (status == INTEGRITY_FAIL)
> >> >> - cause = "invalid-HMAC";
> >> >> + switch (status) {
> >> >> + case INTEGRITY_PASS:
> >> >> + case INTEGRITY_PASS_IMMUTABLE:
> >> >> + case INTEGRITY_UNKNOWN:
> >> >
> >> > Wouldn't it be more future-proof to replace this with a 'default', or
> >> > to at least add a "default: BUG()" to catch new status values?
> >>
> >> I agree. I like the "default: BUG()" option.
> >
> > Agreed. I would put it at the end after INTEGRITY_FAIL.
>
> Ok, what about the version below?
Since the status is returned by evm, it seems like an actual BUG() is
appropriate, but ok.
Acked-by: Serge Hallyn <serge@xxxxxxxxxx>
>
> >>
> >> >> + break;
> >> >> + case INTEGRITY_NOXATTRS: /* No EVM protected xattrs. */
> >> >> + case INTEGRITY_NOLABEL: /* No security.evm xattr. */
> >> >> + cause = "missing-HMAC";
> >> >> + goto out;
> >> >> + case INTEGRITY_FAIL: /* Invalid HMAC/signature. */
> >> >> + cause = "invalid-HMAC";
> >> >> goto out;
> >> >> }
> >> >> +
> >> >> switch (xattr_value->type) {
> >> >> case IMA_XATTR_DIGEST_NG:
> >> >> /* first byte contains algorithm id */
> >> >> @@ -316,17 +320,20 @@ int ima_appraise_measurement(enum ima_hooks func,
> >> >> integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
> >> >> op, cause, rc, 0);
> >> >> } else if (status != INTEGRITY_PASS) {
> >> >> + /* Fix mode, but don't replace file signatures. */
> >> >> if ((ima_appraise & IMA_APPRAISE_FIX) &&
> >> >> (!xattr_value ||
> >> >> xattr_value->type != EVM_IMA_XATTR_DIGSIG)) {
> >> >> if (!ima_fix_xattr(dentry, iint))
> >> >> status = INTEGRITY_PASS;
> >> >> - } else if ((inode->i_size == 0) &&
> >> >> - (iint->flags & IMA_NEW_FILE) &&
> >> >> - (xattr_value &&
> >> >> - xattr_value->type == EVM_IMA_XATTR_DIGSIG)) {
> >> >> + }
> >> >> +
> >> >> + /* Permit new files with file signatures, but without data. */
> >> >> + if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE &&
> >> >
> >> > This may be correct, but it's not identical to what you're replacing.
> >> > Since in either case you're setting status to INTEGRITY_PASS the final
> >> > result is the same, but with a few extra possible steps. Not sure
> >> > whether that matters.
> >>
> >> Good point. I'll have to defer this one to Mimi though.
> >
> > The end result is the same, but add some needed comments.
Yes, the same, but with a few extra possible steps, impacting performance,
so I just wanted to call that out.
-serge
