From f09068b5a114ed28d2df2e82a7d30dde0145dc69 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:31:01 +0100 Subject: security: Introduce file_release hook In preparation for moving IMA and EVM to the LSM infrastructure, introduce the file_release hook. IMA calculates at file close the new digest of the file content and writes it to security.ima, so that appraisal at next file access succeeds. The new hook cannot return an error and cannot cause the operation to be reverted. Signed-off-by: Roberto Sassu Acked-by: Christian Brauner Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/file_table.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/file_table.c') diff --git a/fs/file_table.c b/fs/file_table.c index b991f90571b4..725407f374fa 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -367,6 +367,7 @@ static void __fput(struct file *file) eventpoll_release(file); locks_remove_file(file); + security_file_release(file); ima_file_free(file); if (unlikely(file->f_flags & FASYNC)) { if (file->f_op->fasync) -- cgit v1.2.3 From cd3cec0a02c7338ce2901c574f3935b8f6984aab Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Feb 2024 11:31:08 +0100 Subject: ima: Move to LSM infrastructure Move hardcoded IMA function calls (not appraisal-specific functions) from various places in the kernel to the LSM infrastructure, by introducing a new LSM named 'ima' (at the end of the LSM list and always enabled like 'integrity'). Having IMA before EVM in the Makefile is sufficient to preserve the relative order of the new 'ima' LSM in respect to the upcoming 'evm' LSM, and thus the order of IMA and EVM function calls as when they were hardcoded. Make moved functions as static (except ima_post_key_create_or_update(), which is not in ima_main.c), and register them as implementation of the respective hooks in the new function init_ima_lsm(). Select CONFIG_SECURITY_PATH, to ensure that the path-based LSM hook path_post_mknod is always available and ima_post_path_mknod() is always executed to mark files as new, as before the move. A slight difference is that IMA and EVM functions registered for the inode_post_setattr, inode_post_removexattr, path_post_mknod, inode_post_create_tmpfile, inode_post_set_acl and inode_post_remove_acl won't be executed for private inodes. Since those inodes are supposed to be fs-internal, they should not be of interest to IMA or EVM. The S_PRIVATE flag is used for anonymous inodes, hugetlbfs, reiserfs xattrs, XFS scrub and kernel-internal tmpfs files. Conditionally register ima_post_key_create_or_update() if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. Also, conditionally register ima_kernel_module_request() if CONFIG_INTEGRITY_ASYMMETRIC_KEYS is enabled. Finally, add the LSM_ID_IMA case in lsm_list_modules_test.c. Signed-off-by: Roberto Sassu Acked-by: Chuck Lever Acked-by: Casey Schaufler Acked-by: Christian Brauner Reviewed-by: Stefan Berger Reviewed-by: Mimi Zohar Acked-by: Mimi Zohar Signed-off-by: Paul Moore --- fs/file_table.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'fs/file_table.c') diff --git a/fs/file_table.c b/fs/file_table.c index 725407f374fa..1a0962981b48 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -26,7 +26,6 @@ #include #include #include -#include #include #include @@ -368,7 +367,6 @@ static void __fput(struct file *file) locks_remove_file(file); security_file_release(file); - ima_file_free(file); if (unlikely(file->f_flags & FASYNC)) { if (file->f_op->fasync) file->f_op->fasync(-1, file, 0); -- cgit v1.2.3