| Message ID | 20220325223824.310119-6-zohar@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ima: support fs-verity digests and signatures | expand |
On Fri, Mar 25, 2022 at 06:38:24PM -0400, Mimi Zohar wrote: > Update the fsverity documentation related to IMA signature support. > > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> > --- > Documentation/filesystems/fsverity.rst | 20 ++++++++++++-------- > 1 file changed, 12 insertions(+), 8 deletions(-) > > diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst > index 1d831e3cbcb3..c1d355f17a54 100644 > --- a/Documentation/filesystems/fsverity.rst > +++ b/Documentation/filesystems/fsverity.rst > @@ -74,8 +74,12 @@ authenticating the files is up to userspace. However, to meet some > users' needs, fs-verity optionally supports a simple signature > verification mechanism where users can configure the kernel to require > that all fs-verity files be signed by a key loaded into a keyring; see > -`Built-in signature verification`_. Support for fs-verity file hashes > -in IMA (Integrity Measurement Architecture) policies is also planned. > +`Built-in signature verification`_. > + > +The Integrity Measurement Architecture (IMA) supports including > +fs-verity file digests and signatures in the IMA measurement list > +and verifying fs-verity based file signatures stored as security.ima > +xattrs, based on policy. This looks okay, but this would be easier to understand as a list of alternative ways to do signature verification with fs-verity: * Userspace-only * Built-in signature verification + userspace policy * IMA - Eric
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 1d831e3cbcb3..c1d355f17a54 100644 --- a/Documentation/filesystems/fsverity.rst +++ b/Documentation/filesystems/fsverity.rst @@ -74,8 +74,12 @@ authenticating the files is up to userspace. However, to meet some users' needs, fs-verity optionally supports a simple signature verification mechanism where users can configure the kernel to require that all fs-verity files be signed by a key loaded into a keyring; see -`Built-in signature verification`_. Support for fs-verity file hashes -in IMA (Integrity Measurement Architecture) policies is also planned. +`Built-in signature verification`_. + +The Integrity Measurement Architecture (IMA) supports including +fs-verity file digests and signatures in the IMA measurement list +and verifying fs-verity based file signatures stored as security.ima +xattrs, based on policy. User API ======== @@ -653,12 +657,12 @@ weren't already directly answered in other parts of this document. hashed and what to do with those hashes, such as log them, authenticate them, or add them to a measurement list. - IMA is planned to support the fs-verity hashing mechanism as an - alternative to doing full file hashes, for people who want the - performance and security benefits of the Merkle tree based hash. - But it doesn't make sense to force all uses of fs-verity to be - through IMA. As a standalone filesystem feature, fs-verity - already meets many users' needs, and it's testable like other + IMA supports the fs-verity hashing mechanism as an alternative + to full file hashes, for those who want the performance and + security benefits of the Merkle tree based hash. However, it + doesn't make sense to force all uses of fs-verity to be through + IMA. fs-verity already meets many users' needs even as a + standalone filesystem feature, and it's testable like other filesystem features e.g. with xfstests. :Q: Isn't fs-verity useless because the attacker can just modify the
Update the fsverity documentation related to IMA signature support. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> --- Documentation/filesystems/fsverity.rst | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-)