kernel/linux.git/security/integrity/integrity.h, branch v4.14.85

ima: re-introduce own integrity cache lock

2018-12-01T08:43:00+00:00

commit 0d73a55208e94fc9fb6deaeea61438cd3280d4c0 upstream. Before IMA appraisal was introduced, IMA was using own integrity cache lock along with i_mutex. process_measurement and ima_file_free took the iint->mutex first and then the i_mutex, while setxattr, chmod and chown took the locks in reverse order. To resolve the potential deadlock, i_mutex was moved to protect entire IMA functionality and the redundant iint->mutex was eliminated. Solution was based on the assumption that filesystem code does not take i_mutex further. But when file is opened with O_DIRECT flag, direct-io implementation takes i_mutex and produces deadlock. Furthermore, certain other filesystem operations, such as llseek, also take i_mutex. More recently some filesystems have replaced their filesystem specific lock with the global i_rwsem to read a file. As a result, when IMA attempts to calculate the file hash, reading the file attempts to take the i_rwsem again. To resolve O_DIRECT related deadlock problem, this patch re-introduces iint->mutex. But to eliminate the original chmod() related deadlock problem, this patch eliminates the requirement for chmod hooks to take the iint->mutex by introducing additional atomic iint->attr_flags to indicate calling of the hooks. The allowed locking order is to take the iint->mutex first and then the i_rwsem. Original flags were cleared in chmod(), setxattr() or removwxattr() hooks and tested when file was closed or opened again. New atomic flags are set or cleared in those hooks and tested to clear iint->flags on close or on open. Atomic flags are following: * IMA_CHANGE_ATTR - indicates that chATTR() was called (chmod, chown, chgrp) and file attributes have changed. On file open, it causes IMA to clear iint->flags to re-evaluate policy and perform IMA functions again. * IMA_CHANGE_XATTR - indicates that setxattr or removexattr was called and extended attributes have changed. On file open, it causes IMA to clear iint->flags IMA_DONE_MASK to re-appraise. * IMA_UPDATE_XATTR - indicates that security.ima needs to be updated. It is cleared if file policy changes and no update is needed. * IMA_DIGSIG - indicates that file security.ima has signature and file security.ima must not update to file has on file close. * IMA_MUST_MEASURE - indicates the file is in the measurement policy. Fixes: Commit 6552321831dc ("xfs: remove i_iolock and use i_rwsem in the VFS inode instead") Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar Cc: Aditya Kali Signed-off-by: Greg Kroah-Hartman

EVM: Add support for portable signature format

2018-12-01T08:43:00+00:00

commit 50b977481fce90aa5fbda55e330b9d722733e358 upstream. The EVM signature includes the inode number and (optionally) the filesystem UUID, making it impractical to ship EVM signatures in packages. This patch adds a new portable format intended to allow distributions to include EVM signatures. It is identical to the existing format but hardcodes the inode and generation numbers to 0 and does not include the filesystem UUID even if the kernel is configured to do so. Removing the inode means that the metadata and signature from one file could be copied to another file without invalidating it. This is avoided by ensuring that an IMA xattr is present during EVM validation. Portable signatures are intended to be immutable - ie, they will never be transformed into HMACs. Based on earlier work by Dmitry Kasatkin and Mikhail Kurinnoi. Signed-off-by: Matthew Garrett Cc: Dmitry Kasatkin Cc: Mikhail Kurinnoi Signed-off-by: Mimi Zohar Cc: Aditya Kali Signed-off-by: Greg Kroah-Hartman

integrity: Small code improvements

2017-06-21T18:37:12+00:00

These changes are too small to warrant their own patches: The keyid and sig_size members of struct signature_v2_hdr are in BE format, so use a type that makes this assumption explicit. Also, use beXX_to_cpu instead of __beXX_to_cpu to read them. Change integrity_kernel_read to take a void * buffer instead of char * buffer, so that callers don't have to use a cast if they provide a buffer that isn't a char *. Add missing #endif comment in ima.h pointing out which macro it refers to. Add missing fall through comment in ima_appraise.c. Constify mask_tokens and func_tokens arrays. Signed-off-by: Thiago Jung Bauermann Signed-off-by: Mimi Zohar

integrity: add measured_pcrs field to integrity cache

2016-06-30T05:14:19+00:00

To keep track of which measurements have been extended to which PCRs, this patch defines a new integrity_iint_cache field named measured_pcrs. This field is a bitmask of the PCRs measured. Each bit corresponds to a PCR index. For example, bit 10 corresponds to PCR 10. Signed-off-by: Eric Richter Signed-off-by: Mimi Zohar

ima: fix ima_inode_post_setattr

2016-05-01T13:23:52+00:00

Changing file metadata (eg. uid, guid) could result in having to re-appraise a file's integrity, but does not change the "new file" status nor the security.ima xattr. The IMA_PERMIT_DIRECTIO and IMA_DIGSIG_REQUIRED flags are policy rule specific. This patch only resets these flags, not the IMA_NEW_FILE or IMA_DIGSIG flags. With this patch, changing the file timestamp will not remove the file signature on new files. Reported-by: Dmitry Rozhkov Signed-off-by: Mimi Zohar Tested-by: Dmitry Rozhkov

Merge tag 'keys-next-20160303' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs into next

2016-03-04T00:39:53+00:00

X.509: Make algo identifiers text instead of enum

2016-03-03T21:49:27+00:00

Make the identifier public key and digest algorithm fields text instead of enum. Signed-off-by: David Howells Acked-by: Herbert Xu

ima: remove firmware and module specific cached status info

2016-02-21T14:06:13+00:00

Each time a file is read by the kernel, the file should be re-measured and the file signature re-appraised, based on policy. As there is no need to preserve the status information, this patch replaces the firmware and module specific cache status with a generic one named read_file. This change simplifies adding support for other files read by the kernel. Signed-off-by: Mimi Zohar Acked-by: Petko Manolov Acked-by: Dmitry Kasatkin

ima: define a new hook to measure and appraise a file already in memory

2016-02-21T03:35:08+00:00

This patch defines a new IMA hook ima_post_read_file() for measuring and appraising files read by the kernel. The caller loads the file into memory before calling this function, which calculates the hash followed by the normal IMA policy based processing. Changelog v5: - fail ima_post_read_file() if either file or buf is NULL v3: - rename ima_hash_and_process_file() to ima_post_read_file() v1: - split patch Signed-off-by: Mimi Zohar Acked-by: Dmitry Kasatkin

evm: load an x509 certificate from the kernel

2015-12-15T13:31:19+00:00

This patch defines a configuration option and the evm_load_x509() hook to load an X509 certificate onto the EVM trusted kernel keyring. Changes in v4: * Patch description updated Changes in v3: * Removed EVM_X509_PATH definition. CONFIG_EVM_X509_PATH is used directly. Changes in v2: * default key patch changed to /etc/keys Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar