diff mbox series

[v2,19/25] security: Introduce inode_post_remove_acl hook

Message ID 20230831104136.903180-20-roberto.sassu@huaweicloud.com (mailing list archive)
State New
Headers show
Series security: Move IMA and EVM to the LSM infrastructure | expand

Commit Message

Roberto Sassu Aug. 31, 2023, 10:41 a.m. UTC 
From: Roberto Sassu <roberto.sassu@huawei.com>

In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_remove_acl hook.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 fs/posix_acl.c                |  1 +
 include/linux/lsm_hook_defs.h |  2 ++
 include/linux/security.h      |  8 ++++++++
 security/security.c           | 17 +++++++++++++++++
 4 files changed, 28 insertions(+)

Comments

Casey Schaufler Aug. 31, 2023, 10:36 p.m. UTC | #1 
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_remove_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.


>
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  fs/posix_acl.c                |  1 +
>  include/linux/lsm_hook_defs.h |  2 ++
>  include/linux/security.h      |  8 ++++++++
>  security/security.c           | 17 +++++++++++++++++
>  4 files changed, 28 insertions(+)
>
> diff --git a/fs/posix_acl.c b/fs/posix_acl.c
> index 3b7dbea5c3ff..2a2a2750b3e9 100644
> --- a/fs/posix_acl.c
> +++ b/fs/posix_acl.c
> @@ -1246,6 +1246,7 @@ int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
>  		error = -EIO;
>  	if (!error) {
>  		fsnotify_xattr(dentry);
> +		security_inode_post_remove_acl(idmap, dentry, acl_name);
>  		evm_inode_post_remove_acl(idmap, dentry, acl_name);
>  	}
>  
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index bba1fbd97207..eedc26790a07 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -163,6 +163,8 @@ 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,
>  	 struct dentry *dentry, const char *acl_name)
> +LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
> +	 struct dentry *dentry, const char *acl_name)
>  LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
>  LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
>  	 struct dentry *dentry)
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 556d019ebe5c..e543ae80309b 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -373,6 +373,9 @@ 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,
>  			      struct dentry *dentry, const char *acl_name);
> +void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +				    struct dentry *dentry,
> +				    const char *acl_name);
>  void security_inode_post_setxattr(struct dentry *dentry, const char *name,
>  				  const void *value, size_t size, int flags);
>  int security_inode_getxattr(struct dentry *dentry, const char *name);
> @@ -915,6 +918,11 @@ static inline int security_inode_remove_acl(struct mnt_idmap *idmap,
>  	return 0;
>  }
>  
> +static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +						  struct dentry *dentry,
> +						  const char *acl_name)
> +{ }
> +
>  static inline void security_inode_post_setxattr(struct dentry *dentry,
>  		const char *name, const void *value, size_t size, int flags)
>  { }
> diff --git a/security/security.c b/security/security.c
> index 4392fd878d58..32c3dc34432e 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2323,6 +2323,23 @@ int security_inode_remove_acl(struct mnt_idmap *idmap,
>  	return evm_inode_remove_acl(idmap, dentry, acl_name);
>  }
>  
> +/**
> + * security_inode_post_remove_acl() - Update inode sec after remove_acl op
> + * @idmap: idmap of the mount
> + * @dentry: file
> + * @acl_name: acl name
> + *
> + * Update inode security field after successful remove_acl operation on @dentry
> + * in @idmap. The posix acls are identified by @acl_name.
> + */
> +void security_inode_post_remove_acl(struct mnt_idmap *idmap,
> +				    struct dentry *dentry, const char *acl_name)
> +{
> +	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> +		return;
> +	call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name);
> +}
> +
>  /**
>   * security_inode_post_setxattr() - Update the inode after a setxattr operation
>   * @dentry: file
diff mbox series

Patch

diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 3b7dbea5c3ff..2a2a2750b3e9 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -1246,6 +1246,7 @@  int vfs_remove_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 		error = -EIO;
 	if (!error) {
 		fsnotify_xattr(dentry);
+		security_inode_post_remove_acl(idmap, dentry, acl_name);
 		evm_inode_post_remove_acl(idmap, dentry, acl_name);
 	}
 
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index bba1fbd97207..eedc26790a07 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -163,6 +163,8 @@  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,
 	 struct dentry *dentry, const char *acl_name)
+LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
+	 struct dentry *dentry, const char *acl_name)
 LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
 LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
 	 struct dentry *dentry)
diff --git a/include/linux/security.h b/include/linux/security.h
index 556d019ebe5c..e543ae80309b 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -373,6 +373,9 @@  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,
 			      struct dentry *dentry, const char *acl_name);
+void security_inode_post_remove_acl(struct mnt_idmap *idmap,
+				    struct dentry *dentry,
+				    const char *acl_name);
 void security_inode_post_setxattr(struct dentry *dentry, const char *name,
 				  const void *value, size_t size, int flags);
 int security_inode_getxattr(struct dentry *dentry, const char *name);
@@ -915,6 +918,11 @@  static inline int security_inode_remove_acl(struct mnt_idmap *idmap,
 	return 0;
 }
 
+static inline void security_inode_post_remove_acl(struct mnt_idmap *idmap,
+						  struct dentry *dentry,
+						  const char *acl_name)
+{ }
+
 static inline void security_inode_post_setxattr(struct dentry *dentry,
 		const char *name, const void *value, size_t size, int flags)
 { }
diff --git a/security/security.c b/security/security.c
index 4392fd878d58..32c3dc34432e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2323,6 +2323,23 @@  int security_inode_remove_acl(struct mnt_idmap *idmap,
 	return evm_inode_remove_acl(idmap, dentry, acl_name);
 }
 
+/**
+ * security_inode_post_remove_acl() - Update inode sec after remove_acl op
+ * @idmap: idmap of the mount
+ * @dentry: file
+ * @acl_name: acl name
+ *
+ * Update inode security field after successful remove_acl operation on @dentry
+ * in @idmap. The posix acls are identified by @acl_name.
+ */
+void security_inode_post_remove_acl(struct mnt_idmap *idmap,
+				    struct dentry *dentry, const char *acl_name)
+{
+	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+		return;
+	call_void_hook(inode_post_remove_acl, idmap, dentry, acl_name);
+}
+
 /**
  * security_inode_post_setxattr() - Update the inode after a setxattr operation
  * @dentry: file