linux/security
Roberto Sassu 75a323e604 evm: Make it independent from 'integrity' LSM
Define a new structure for EVM-specific metadata, called evm_iint_cache,
and embed it in the inode security blob. Introduce evm_iint_inode() to
retrieve metadata, and register evm_inode_alloc_security() for the
inode_alloc_security LSM hook, to initialize the structure (before
splitting metadata, this task was done by iint_init_always()).

Keep the non-NULL checks after calling evm_iint_inode() except in
evm_inode_alloc_security(), to take into account inodes for which
security_inode_alloc() was not called. When using shared metadata,
obtaining a NULL pointer from integrity_iint_find() meant that the file
wasn't in the IMA policy. Now, because IMA and EVM use disjoint metadata,
the EVM status has to be stored for every inode regardless of the IMA
policy.

Given that from now on EVM relies on its own metadata, remove the iint
parameter from evm_verifyxattr(). Also, directly retrieve the iint in
evm_verify_hmac(), called by both evm_verifyxattr() and
evm_verify_current_integrity(), since now there is no performance penalty
in retrieving EVM metadata (constant time).

Replicate the management of the IMA_NEW_FILE flag, by introducing
evm_post_path_mknod() and evm_file_release() to respectively set and clear
the newly introduced flag EVM_NEW_FILE, at the same time IMA does. Like for
IMA, select CONFIG_SECURITY_PATH when EVM is enabled, to ensure that files
are marked as new.

Unlike ima_post_path_mknod(), evm_post_path_mknod() cannot check if a file
must be appraised. Thus, it marks all affected files. Also, it does not
clear EVM_NEW_FILE depending on i_version, but that is not a problem
because IMA_NEW_FILE is always cleared when set in ima_check_last_writer().

Move the EVM-specific flag EVM_IMMUTABLE_DIGSIG to
security/integrity/evm/evm.h, since that definition is now unnecessary in
the common integrity layer.

Finally, switch to the LSM reservation mechanism for the EVM xattr, and
consequently decrement by one the number of xattrs to allocate in
security_inode_init_security().

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2024-02-15 23:43:47 -05:00
..
apparmor exec: Check __FMODE_EXEC instead of in_execve for LSMs 2024-01-24 11:38:58 -08:00
bpf lsm: mark the lsm_id variables are marked as static 2023-11-12 22:54:42 -05:00
integrity evm: Make it independent from 'integrity' LSM 2024-02-15 23:43:47 -05:00
keys ima: Move to LSM infrastructure 2024-02-15 23:43:46 -05:00
landlock Landlock updates for v6.8-rc1 2024-01-09 13:22:15 -08:00
loadpin lsm: mark the lsm_id variables are marked as static 2023-11-12 22:54:42 -05:00
lockdown LSM: Identify modules by more than name 2023-11-12 22:54:42 -05:00
safesetid lsm: mark the lsm_id variables are marked as static 2023-11-12 22:54:42 -05:00
selinux security: Align inode_setattr hook definition with EVM 2024-02-15 23:43:41 -05:00
smack security: Align inode_setattr hook definition with EVM 2024-02-15 23:43:41 -05:00
tomoyo exec: Check __FMODE_EXEC instead of in_execve for LSMs 2024-01-24 11:38:58 -08:00
yama lsm: mark the lsm_id variables are marked as static 2023-11-12 22:54:42 -05:00
commoncap.c lsm: mark the lsm_id variables are marked as static 2023-11-12 22:54:42 -05:00
device_cgroup.c device_cgroup: Fix kernel-doc warnings in device_cgroup 2023-06-21 09:30:49 -04:00
inode.c security: convert to new timestamp accessors 2023-10-18 14:08:31 +02:00
Kconfig mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATOR 2023-05-24 15:38:17 +02:00
Kconfig.hardening hardening: Move BUG_ON_DATA_CORRUPTION to hardening options 2023-08-15 14:57:25 -07:00
lsm_audit.c lsm: fix a number of misspellings 2023-05-25 17:52:15 -04:00
lsm_syscalls.c LSM: Helpers for attribute names and filling lsm_ctx 2023-11-12 22:54:42 -05:00
Makefile LSM: syscalls for current process attributes 2023-11-12 22:54:42 -05:00
min_addr.c sysctl: pass kernel pointers to ->proc_handler 2020-04-27 02:07:40 -04:00
security.c evm: Make it independent from 'integrity' LSM 2024-02-15 23:43:47 -05:00