ABI: evm: place a second what at the next line

Originally, get_abi.pl was using spaces to separate What: parameters,
but there are several references that declare things like:

/sys/class/powercap/

ABI: evm: place a second what at the next line

Originally, get_abi.pl was using spaces to separate What: parameters,
but there are several references that declare things like:

/sys/class/powercap/.../<power zone>/enabled

So, the logic was changes in order to properly address it.
That broke the second What added by
Changeset 18e49b304633 ("ABI: security: fix location for evm and ima_policy").

As the only file that defines multiple What: at the same line is
this file, let's move the second What: to a separate line.

Fixes: 18e49b304633 ("ABI: security: fix location for evm and ima_policy")
Fixes: ab9c14805b37 ("scripts: get_abi.pl: Better handle multiple What parameters")
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Link: https://lore.kernel.org/r/1f1e29ccdc0dd0ec089a67b8a4e9650517c6137a.1632823172.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

ABI: security: fix location for evm and ima_policy

The What: definitions there are wrong, pointing to different
locations than what's expected.

Reviewed-by: Mimi Zohar <[email protected]>
Signed-

ABI: security: fix location for evm and ima_policy

The What: definitions there are wrong, pointing to different
locations than what's expected.

Reviewed-by: Mimi Zohar <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Link: https://lore.kernel.org/r/b2563ac34c2e234cdd728f0c701b57ac9023c45a.1631782432.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

evm: Deprecate EVM_ALLOW_METADATA_WRITES

This patch deprecates the usage of EVM_ALLOW_METADATA_WRITES, as it is no
longer necessary. All the issues that prevent the usage of EVM portable
signatures

evm: Deprecate EVM_ALLOW_METADATA_WRITES

This patch deprecates the usage of EVM_ALLOW_METADATA_WRITES, as it is no
longer necessary. All the issues that prevent the usage of EVM portable
signatures just with a public key loaded have been solved.

This flag will remain available for a short time to ensure that users are
able to use EVM without it.

Signed-off-by: Roberto Sassu <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>

show more ...

evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded

EVM_ALLOW_METADATA_WRITES is an EVM initialization flag that can be set to
temporarily disable metadata verification until all xat

evm: Refuse EVM_ALLOW_METADATA_WRITES only if an HMAC key is loaded

EVM_ALLOW_METADATA_WRITES is an EVM initialization flag that can be set to
temporarily disable metadata verification until all xattrs/attrs necessary
to verify an EVM portable signature are copied to the file. This flag is
cleared when EVM is initialized with an HMAC key, to avoid that the HMAC is
calculated on unverified xattrs/attrs.

Currently EVM unnecessarily denies setting this flag if EVM is initialized
with a public key, which is not a concern as it cannot be used to trust
xattrs/attrs updates. This patch removes this limitation.

Fixes: ae1ba1676b88e ("EVM: Allow userland to permit modification of EVM-protected metadata")
Signed-off-by: Roberto Sassu <[email protected]>
Cc: [email protected] # 4.16.x
Signed-off-by: Mimi Zohar <[email protected]>

show more ...

docs: ABI: testing: make the files compatible with ReST output

Some files over there won't parse well by Sphinx.

Fix them.

Acked-by: Jonathan Cameron <[email protected]> # for IIO
Acked-

docs: ABI: testing: make the files compatible with ReST output

Some files over there won't parse well by Sphinx.

Fix them.

Acked-by: Jonathan Cameron <[email protected]> # for IIO
Acked-by: Fabrice Gasnier <[email protected]>
Acked-by: Jonathan Corbet <[email protected]>
Signed-off-by: Mauro Carvalho Chehab <[email protected]>
Link: https://lore.kernel.org/r/58cf3c2d611e0197fb215652719ebd82ca2658db.1604042072.git.mchehab+huawei@kernel.org
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

EVM: Allow runtime modification of the set of verified xattrs

Sites may wish to provide additional metadata alongside files in order
to make more fine-grained security decisions[1]. The security of

EVM: Allow runtime modification of the set of verified xattrs

Sites may wish to provide additional metadata alongside files in order
to make more fine-grained security decisions[1]. The security of this is
enhanced if this metadata is protected, something that EVM makes
possible. However, the kernel cannot know about the set of extended
attributes that local admins may wish to protect, and hardcoding this
policy in the kernel makes it difficult to change over time and less
convenient for distributions to enable.

This patch adds a new /sys/kernel/security/integrity/evm/evm_xattrs node,
which can be read to obtain the current set of EVM-protected extended
attributes or written to in order to add new entries. Extending this list
will not change the validity of any existing signatures provided that the
file in question does not have any of the additional extended attributes -
missing xattrs are skipped when calculating the EVM hash.

[1] For instance, a package manager could install information about the
package uploader in an additional extended attribute. Local LSM policy
could then be associated with that extended attribute in order to
restrict the privileges available to packages from less trusted
uploaders.

Signed-off-by: Matthew Garrett <[email protected]>
Reviewed-by: James Morris <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>

show more ...

EVM: Allow userland to permit modification of EVM-protected metadata

When EVM is enabled it forbids modification of metadata protected by
EVM unless there is already a valid EVM signature. If any mo

EVM: Allow userland to permit modification of EVM-protected metadata

When EVM is enabled it forbids modification of metadata protected by
EVM unless there is already a valid EVM signature. If any modification
is made, the kernel will then generate a new EVM HMAC. However, this
does not map well on use cases which use only asymmetric EVM signatures,
as in this scenario the kernel is unable to generate new signatures.

This patch extends the /sys/kernel/security/evm interface to allow
userland to request that modification of these xattrs be permitted. This
is only permitted if no keys have already been loaded. In this
configuration, modifying the metadata will invalidate the EVM appraisal
on the file in question. This allows packaging systems to write out new
files, set the relevant extended attributes and then move them into
place.

There's also some refactoring of the use of evm_initialized in order to
avoid heading down codepaths that assume there's a key available.

Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>

show more ...

EVM: Allow userspace to signal an RSA key has been loaded

EVM will only perform validation once a key has been loaded. This key
may either be a symmetric trusted key (for HMAC validation and creatio

EVM: Allow userspace to signal an RSA key has been loaded

EVM will only perform validation once a key has been loaded. This key
may either be a symmetric trusted key (for HMAC validation and creation)
or the public half of an asymmetric key (for digital signature
validation). The /sys/kernel/security/evm interface allows userland to
signal that a symmetric key has been loaded, but does not allow userland
to signal that an asymmetric public key has been loaded.

This patch extends the interface to permit userspace to pass a bitmask
of loaded key types. It also allows userspace to block loading of a
symmetric key in order to avoid a compromised system from being able to
load an additional key type later.

Signed-off-by: Matthew Garrett <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>

show more ...

Documentation: fix security related doc refs

Make security document refs valid.

Signed-off-by: Tom Saeger <[email protected]>
Signed-off-by: Jonathan Corbet <[email protected]>

evm: re-release

EVM protects a file's security extended attributes(xattrs) against integrity
attacks. This patchset provides the framework and an initial method. The
initial method maintains an HM

evm: re-release

EVM protects a file's security extended attributes(xattrs) against integrity
attacks. This patchset provides the framework and an initial method. The
initial method maintains an HMAC-sha1 value across the security extended
attributes, storing the HMAC value as the extended attribute 'security.evm'.
Other methods of validating the integrity of a file's metadata will be posted
separately (eg. EVM-digital-signatures).

While this patchset does authenticate the security xattrs, and
cryptographically binds them to the inode, coming extensions will bind other
directory and inode metadata for more complete protection. To help simplify
the review and upstreaming process, each extension will be posted separately
(eg. IMA-appraisal, IMA-appraisal-directory). For a general overview of the
proposed Linux integrity subsystem, refer to Dave Safford's whitepaper:
http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf.

EVM depends on the Kernel Key Retention System to provide it with a
trusted/encrypted key for the HMAC-sha1 operation. The key is loaded onto the
root's keyring using keyctl. Until EVM receives notification that the key has
been successfully loaded onto the keyring (echo 1 > <securityfs>/evm), EVM can
not create or validate the 'security.evm' xattr, but returns INTEGRITY_UNKNOWN.
Loading the key and signaling EVM should be done as early as possible. Normally
this is done in the initramfs, which has already been measured as part of the
trusted boot. For more information on creating and loading existing
trusted/encrypted keys, refer to Documentation/keys-trusted-encrypted.txt. A
sample dracut patch, which loads the trusted/encrypted key and enables EVM, is
available from http://linux-ima.sourceforge.net/#EVM.

Based on the LSMs enabled, the set of EVM protected security xattrs is defined
at compile. EVM adds the following three calls to the existing security hooks:
evm_inode_setxattr(), evm_inode_post_setxattr(), and evm_inode_removexattr. To
initialize and update the 'security.evm' extended attribute, EVM defines three
calls: evm_inode_post_init(), evm_inode_post_setattr() and
evm_inode_post_removexattr() hooks. To verify the integrity of a security
xattr, EVM exports evm_verifyxattr().

Changelog v7:
- Fixed URL in EVM ABI documentation

Changelog v6: (based on Serge Hallyn's review)
- fix URL in patch description
- remove evm_hmac_size definition
- use SHA1_DIGEST_SIZE (removed both MAX_DIGEST_SIZE and evm_hmac_size)
- moved linux include before other includes
- test for crypto_hash_setkey failure
- fail earlier for invalid key
- clear entire encrypted key, even on failure
- check xattr name length before comparing xattr names

Changelog:
- locking based on i_mutex, remove evm_mutex
- using trusted/encrypted keys for storing the EVM key used in the HMAC-sha1
operation.
- replaced crypto hash with shash (Dmitry Kasatkin)
- support for additional methods of verifying the security xattrs
(Dmitry Kasatkin)
- iint not allocated for all regular files, but only for those appraised
- Use cap_sys_admin in lieu of cap_mac_admin
- Use __vfs_setxattr_noperm(), without permission checks, from EVM

Signed-off-by: Mimi Zohar <[email protected]>
Acked-by: Serge Hallyn <[email protected]>

show more ...