linux-kernel - [PATCH v2 13/25] security: Introduce inode_post

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230831104136.903180-14-roberto.sassu@huaweicloud.com>
Date:   Thu, 31 Aug 2023 12:41:24 +0200
From:   Roberto Sassu <roberto.sassu@...weicloud.com>
To:     viro@...iv.linux.org.uk, brauner@...nel.org,
        chuck.lever@...cle.com, jlayton@...nel.org, neilb@...e.de,
        kolga@...app.com, Dai.Ngo@...cle.com, tom@...pey.com,
        zohar@...ux.ibm.com, dmitry.kasatkin@...il.com,
        paul@...l-moore.com, jmorris@...ei.org, serge@...lyn.com,
        dhowells@...hat.com, jarkko@...nel.org,
        stephen.smalley.work@...il.com, eparis@...isplace.org,
        casey@...aufler-ca.com
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-nfs@...r.kernel.org, linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        selinux@...r.kernel.org, Roberto Sassu <roberto.sassu@...wei.com>,
        Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH v2 13/25] security: Introduce inode_post_removexattr hook

From: Roberto Sassu <roberto.sassu@...wei.com>

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

Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>
Reviewed-by: Stefan Berger <stefanb@...ux.ibm.com>
---
 fs/xattr.c                    |  9 +++++----
 include/linux/lsm_hook_defs.h |  2 ++
 include/linux/security.h      |  5 +++++
 security/security.c           | 14 ++++++++++++++
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index e7bbb7f57557..4a0280295686 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -552,11 +552,12 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
 		goto out;
 
 	error = __vfs_removexattr(idmap, dentry, name);
+	if (error)
+		goto out;
 
-	if (!error) {
-		fsnotify_xattr(dentry);
-		evm_inode_post_removexattr(dentry, name);
-	}
+	fsnotify_xattr(dentry);
+	security_inode_post_removexattr(dentry, name);
+	evm_inode_post_removexattr(dentry, name);
 
 out:
 	return error;
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 995d30336cfa..1153e7163b8b 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -148,6 +148,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
 LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
 LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *name)
+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(int, 0, inode_get_acl, struct mnt_idmap *idmap,
diff --git a/include/linux/security.h b/include/linux/security.h
index 820899db5276..665bba3e0081 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -374,6 +374,7 @@ int security_inode_getxattr(struct dentry *dentry, const char *name);
 int security_inode_listxattr(struct dentry *dentry);
 int security_inode_removexattr(struct mnt_idmap *idmap,
 			       struct dentry *dentry, const char *name);
+void security_inode_post_removexattr(struct dentry *dentry, const char *name);
 int security_inode_need_killpriv(struct dentry *dentry);
 int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
 int security_inode_getsecurity(struct mnt_idmap *idmap,
@@ -919,6 +920,10 @@ static inline int security_inode_removexattr(struct mnt_idmap *idmap,
 	return cap_inode_removexattr(idmap, dentry, name);
 }
 
+static inline void security_inode_post_removexattr(struct dentry *dentry,
+						   const char *name)
+{ }
+
 static inline int security_inode_need_killpriv(struct dentry *dentry)
 {
 	return cap_inode_need_killpriv(dentry);
diff --git a/security/security.c b/security/security.c
index 764a6f28b3b9..3947159ba5e9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2354,6 +2354,20 @@ int security_inode_removexattr(struct mnt_idmap *idmap,
 	return evm_inode_removexattr(idmap, dentry, name);
 }
 
+/**
+ * security_inode_post_removexattr() - Update the inode after a removexattr op
+ * @dentry: file
+ * @name: xattr name
+ *
+ * Update the inode after a successful removexattr operation.
+ */
+void security_inode_post_removexattr(struct dentry *dentry, const char *name)
+{
+	if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+		return;
+	call_void_hook(inode_post_removexattr, dentry, name);
+}
+
 /**
  * security_inode_need_killpriv() - Check if security_inode_killpriv() required
  * @dentry: associated dentry
-- 
2.34.1