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From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Matthew Garrett <mjg59@google.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>,
	"linux-integrity@vger.kernel.org"
	<linux-integrity@vger.kernel.org>,
	Mikhail Kurinnoi <viewizard@viewizard.com>
Subject: Re: [RFC] EVM: Add support for portable signature format
Date: Mon, 30 Oct 2017 11:31:44 -0400	[thread overview]
Message-ID: <1509377504.3583.97.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <CACdnJuvTEAs8tg2LoktmMRUzAMrfY5qTOeawTWCkvqit4A4huw@mail.gmail.com>

On Mon, 2017-10-30 at 13:17 +0000, Matthew Garrett wrote:
> On Mon, Oct 30, 2017 at 12:38 PM, Mimi Zohar <zohar@linux.vnet.ibm.com> wrote:
> > On Fri, 2017-10-27 at 10:41 +0000, Dmitry Kasatkin wrote:
> >
> >> > @@ -345,7 +350,8 @@ int evm_inode_setxattr(struct dentry *dentry, const
> >> > char *xattr_name,
> >> >     if (strcmp(xattr_name, XATTR_NAME_EVM) == 0) {
> >> >             if (!xattr_value_len)
> >> >                     return -EINVAL;
> >> > -           if (xattr_data->type != EVM_IMA_XATTR_DIGSIG)
> >> > +           if (xattr_data->type != EVM_IMA_XATTR_DIGSIG &&
> >> > +               xattr_data->type != EVM_XATTR_PORTABLE_DIGSIG)
> >> >                     return -EPERM;
> >> >     }
> >>
> >> Also I have an impression that evm_protect_xattr will allow to set
> >> security.ima for example,
> >> And it will cause to try to re-calculate hmac over immutable
> >> signature...
> >
> > Right, it will allow evm_inode_post_setxattr() to replace the new file
> > signature with an HMAC.
> 
> evm_inode_setxattr() will call evm_protect_xattr(), which will call
> evm_verify_xattr(). This will return INTEGRITY_PASS_IMMUTABLE, which
> will result in evm_protect_xattr() returning -EPERM, so we never get
> to inode_post_setxattr().

Oh, I missed that.

  reply	other threads:[~2017-10-30 15:31 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-26  8:31 [RFC] EVM: Add support for portable signature format Matthew Garrett
2017-10-26  9:03 ` Mikhail Kurinnoi
2017-10-26  9:08   ` Matthew Garrett
2017-10-26  9:46     ` Mikhail Kurinnoi
2017-10-26 19:22       ` Mimi Zohar
2017-10-30 10:53         ` Matthew Garrett
2017-10-30 11:36           ` Mimi Zohar
2017-10-30 11:51             ` Matthew Garrett
2017-10-30 12:14               ` Mimi Zohar
2017-10-27 10:27 ` Dmitry Kasatkin
2017-10-30 12:30   ` Mimi Zohar
2017-10-30 13:21     ` Matthew Garrett
2017-10-30 13:58       ` Mimi Zohar
2017-10-30 14:04         ` Matthew Garrett
2017-10-27 10:41 ` Dmitry Kasatkin
2017-10-30 12:38   ` Mimi Zohar
2017-10-30 13:17     ` Matthew Garrett
2017-10-30 15:31       ` Mimi Zohar [this message]
2017-10-30 15:36         ` Matthew Garrett
2017-11-01 17:54           ` Matthew Garrett
2017-11-01 18:25             ` Mimi Zohar

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