diff mbox series

[v4,10/19] Smack: Abstract use of file security blob

Message ID bd7c5604-ebb1-b42b-cf29-589494dbb1c5@schaufler-ca.com (mailing list archive)
State Superseded
Headers show
Series LSM: Module stacking for SARA and Landlock | expand

Commit Message

Casey Schaufler Sept. 22, 2018, 12:18 a.m. UTC 
Don't use the file->f_security pointer directly.
Provide a helper function that provides the security blob pointer.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 security/smack/smack.h     |  5 +++++
 security/smack/smack_lsm.c | 12 ++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

Comments

Kees Cook Sept. 22, 2018, 2:51 a.m. UTC | #1 
On Fri, Sep 21, 2018 at 5:18 PM, Casey Schaufler <casey@schaufler-ca.com> wrote:
> Don't use the file->f_security pointer directly.
> Provide a helper function that provides the security blob pointer.
>
> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees
diff mbox series

Patch

diff --git a/security/smack/smack.h b/security/smack/smack.h
index 01a922856eba..22ca30379209 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -361,6 +361,11 @@  static inline struct task_smack *smack_cred(const struct cred *cred)
 	return cred->security;
 }
 
+static inline struct smack_known **smack_file(const struct file *file)
+{
+	return (struct smack_known **)&file->f_security;
+}
+
 /*
  * Is the directory transmuting?
  */
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a06ea8aa89c4..9ec595f0c3f1 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1571,9 +1571,9 @@  static void smack_inode_getsecid(struct inode *inode, u32 *secid)
  */
 static int smack_file_alloc_security(struct file *file)
 {
-	struct smack_known *skp = smk_of_current();
+	struct smack_known **blob = smack_file(file);
 
-	file->f_security = skp;
+	*blob = smk_of_current();
 	return 0;
 }
 
@@ -1813,7 +1813,9 @@  static int smack_mmap_file(struct file *file,
  */
 static void smack_file_set_fowner(struct file *file)
 {
-	file->f_security = smk_of_current();
+	struct smack_known **blob = smack_file(file);
+
+	*blob = smk_of_current();
 }
 
 /**
@@ -1830,6 +1832,7 @@  static void smack_file_set_fowner(struct file *file)
 static int smack_file_send_sigiotask(struct task_struct *tsk,
 				     struct fown_struct *fown, int signum)
 {
+	struct smack_known **blob;
 	struct smack_known *skp;
 	struct smack_known *tkp = smk_of_task(smack_cred(tsk->cred));
 	struct file *file;
@@ -1842,7 +1845,8 @@  static int smack_file_send_sigiotask(struct task_struct *tsk,
 	file = container_of(fown, struct file, f_owner);
 
 	/* we don't log here as rc can be overriden */
-	skp = file->f_security;
+	blob = smack_file(file);
+	skp = *blob;
 	rc = smk_access(skp, tkp, MAY_DELIVER, NULL);
 	rc = smk_bu_note("sigiotask", skp, tkp, MAY_DELIVER, rc);
 	if (rc != 0 && has_capability(tsk, CAP_MAC_OVERRIDE))