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 Acked-by: Paul Moore paul@paul-moore.com Acked-by: Christian Brauner brauner@kernel.org 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 9280aa5d60a7..c7ac7fdf0f25 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3705,6 +3705,7 @@ 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 dba5d8204dc5..87f60b47dfca 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) LSM_HOOK(int, 0, inode_link, struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) LSM_HOOK(int, 0, inode_unlink, struct inode *dir, struct dentry *dentry) 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); int security_inode_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry); int security_inode_unlink(struct inode *dir, struct dentry *dentry); @@ -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 b55f9ad294cc..59d49e5c2671 100644 --- a/security/security.c +++ b/security/security.c @@ -2014,6 +2014,21 @@ 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