Re: [PATCH v2 18/25] security: Introduce inode_post_set_acl hook
From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2023-08-31 22:36:25
Also in:
keyrings, linux-fsdevel, linux-integrity, linux-nfs, lkml, selinux
On 8/31/2023 3:41 AM, Roberto Sassu wrote:
From: Roberto Sassu <roberto.sassu@huawei.com> In preparation for moving IMA and EVM to the LSM infrastructure, introduce the inode_post_set_acl hook.
Repeat of new LSM hook general comment: Would you please include some explanation of how an LSM would use this hook? You might start with a description of how it is used in IMA/EVM, and why that could be generally useful.
quoted hunk ↗ jump to hunk
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Reviewed-by: Stefan Berger <stefanb@linux.ibm.com> --- fs/posix_acl.c | 1 + include/linux/lsm_hook_defs.h | 2 ++ include/linux/security.h | 7 +++++++ security/security.c | 17 +++++++++++++++++ 4 files changed, 27 insertions(+)diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 7fa1b738bbab..3b7dbea5c3ff 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c@@ -1137,6 +1137,7 @@ int vfs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, error = -EIO; if (!error) { fsnotify_xattr(dentry); + security_inode_post_set_acl(dentry, acl_name, kacl); evm_inode_post_set_acl(dentry, acl_name, kacl); }diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index 9ae573b83737..bba1fbd97207 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h@@ -157,6 +157,8 @@ LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry, const char *name) LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl) +LSM_HOOK(void, LSM_RET_VOID, inode_post_set_acl, struct dentry *dentry, + const char *acl_name, struct posix_acl *kacl) LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name) LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,diff --git a/include/linux/security.h b/include/linux/security.h index 5f296761883f..556d019ebe5c 100644 --- a/include/linux/security.h +++ b/include/linux/security.h@@ -367,6 +367,8 @@ int security_inode_setxattr(struct mnt_idmap *idmap, int security_inode_set_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl); +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, + struct posix_acl *kacl); int security_inode_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name); int security_inode_remove_acl(struct mnt_idmap *idmap,@@ -894,6 +896,11 @@ static inline int security_inode_set_acl(struct mnt_idmap *idmap, return 0; } +static inline void security_inode_post_set_acl(struct dentry *dentry, + const char *acl_name, + struct posix_acl *kacl) +{ } + static inline int security_inode_get_acl(struct mnt_idmap *idmap, struct dentry *dentry, const char *acl_name)diff --git a/security/security.c b/security/security.c index e5acb11f6ebd..4392fd878d58 100644 --- a/security/security.c +++ b/security/security.c@@ -2260,6 +2260,23 @@ int security_inode_set_acl(struct mnt_idmap *idmap, return evm_inode_set_acl(idmap, dentry, acl_name, kacl); } +/** + * security_inode_post_set_acl() - Update inode security after set_acl() + * @dentry: file + * @acl_name: acl name + * @kacl: acl struct + * + * Update inode security field after successful set_acl operation on @dentry. + * The posix acls in @kacl are identified by @acl_name. + */ +void security_inode_post_set_acl(struct dentry *dentry, const char *acl_name, + struct posix_acl *kacl) +{ + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) + return; + call_void_hook(inode_post_set_acl, dentry, acl_name, kacl); +} + /** * security_inode_get_acl() - Check if reading posix acls is allowed * @idmap: idmap of the mount