| Message ID | 20211202215507.298415-6-zohar@linux.ibm.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ima: support fs-verity signatures stored as | expand |
On Thu, Dec 02, 2021 at 04:55:07PM -0500, 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 | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst > index 1d831e3cbcb3..c71f6e365df5 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`_. > + > +IMA (Integrity Measurement Architecture) supports fs-verity file > +digests based signatures stored as security.ima xattrs, which are > +identified by the signature type IMA_VERITY_DIGSIG. > + > > User API > ======== > @@ -653,13 +657,13 @@ 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 > - filesystem features e.g. with xfstests. > + IMA supports 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 filesystem > + features e.g. with xfstests. > Isn't there IMA documentation that can be linked to? - Eric
diff --git a/Documentation/filesystems/fsverity.rst b/Documentation/filesystems/fsverity.rst index 1d831e3cbcb3..c71f6e365df5 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`_. + +IMA (Integrity Measurement Architecture) supports fs-verity file +digests based signatures stored as security.ima xattrs, which are +identified by the signature type IMA_VERITY_DIGSIG. + User API ======== @@ -653,13 +657,13 @@ 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 - filesystem features e.g. with xfstests. + IMA supports 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 filesystem + features e.g. with xfstests. :Q: Isn't fs-verity useless because the attacker can just modify the hashes in the Merkle tree, which is stored on-disk?
Update the fsverity documentation related to IMA signature support. Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> --- Documentation/filesystems/fsverity.rst | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)