On 1/15/24 13:17, 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_create_tmpfile hook.
As temp files can be made persistent, treat new temp files like other new files, so that the file hash is calculated and stored in the security xattr.
LSMs could also take some action after temp files have been created.
The new hook cannot return an error and cannot cause the operation to be canceled.
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com Acked-by: Casey Schaufler casey@schaufler-ca.com Reviewed-by: Mimi Zohar zohar@linux.ibm.com
Reviewed-by: Stefan Berger stefanb@linux.ibm.com
fs/namei.c | 1 + include/linux/lsm_hook_defs.h | 2 ++ include/linux/security.h | 6 ++++++ security/security.c | 15 +++++++++++++++ 4 files changed, 24 insertions(+)
diff --git a/fs/namei.c b/fs/namei.c index b7f433720b1e..adb3ab27951a 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3686,6 +3686,7 @@ static int vfs_tmpfile(struct mnt_idmap *idmap, inode->i_state |= I_LINKABLE; spin_unlock(&inode->i_lock); }
- security_inode_post_create_tmpfile(idmap, inode); ima_post_create_tmpfile(idmap, inode); return 0; }
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h index e08b9091350d..5f90914d23e0 100644 --- a/include/linux/lsm_hook_defs.h +++ b/include/linux/lsm_hook_defs.h @@ -121,6 +121,8 @@ LSM_HOOK(int, 0, inode_init_security_anon, struct inode *inode, const struct qstr *name, const struct inode *context_inode) LSM_HOOK(int, 0, inode_create, struct inode *dir, struct dentry *dentry, umode_t mode) +LSM_HOOK(void, LSM_RET_VOID, inode_post_create_tmpfile, struct mnt_idmap *idmap,
struct inode *inode)diff --git a/include/linux/security.h b/include/linux/security.h index 977dd9f7f51a..1cb604282617 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -344,6 +344,8 @@ int security_inode_init_security_anon(struct inode *inode, const struct qstr *name, const struct inode *context_inode); int security_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode); +void security_inode_post_create_tmpfile(struct mnt_idmap *idmap,
struct inode *inode);@@ -811,6 +813,10 @@ static inline int security_inode_create(struct inode *dir, return 0; } +static inline void +security_inode_post_create_tmpfile(struct mnt_idmap *idmap, struct inode *inode) +{ }
- static inline int security_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry)
diff --git a/security/security.c b/security/security.c index 750bfe2768d5..5bc7edc22923 100644 --- a/security/security.c +++ b/security/security.c @@ -2013,6 +2013,21 @@ int security_inode_create(struct inode *dir, struct dentry *dentry, } EXPORT_SYMBOL_GPL(security_inode_create); +/**
- security_inode_post_create_tmpfile() - Update inode security of new tmpfile
- @idmap: idmap of the mount
- @inode: inode of the new tmpfile
- Update inode security data after a tmpfile has been created.
- */
+void security_inode_post_create_tmpfile(struct mnt_idmap *idmap,
struct inode *inode)+{
- if (unlikely(IS_PRIVATE(inode)))
return;- call_void_hook(inode_post_create_tmpfile, idmap, inode);
+}
- /**
- security_inode_link() - Check if creating a hard link is allowed
- @old_dentry: existing file