[PATCH 3/7] LSM: Two hooks for manipulating struct lsm_prop

[Casey Schaufler <casey@schaufler-ca.com>]

security_update_lsmprop() updates the property of the
specified LSM in the @dest structure with that in the @src.

security_secctx_to_lsmprop() sets the @prop field associated
with the LSM specified to the value of the passed security
context.

LSM specific implementations of these hooks to follow.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/lsm_hook_defs.h |  4 ++++
 include/linux/security.h      | 16 ++++++++++++++++
 security/security.c           | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 65c9609ec207..679c40a8e127 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -305,7 +305,11 @@ LSM_HOOK(int, 0, ismaclabel, const char *name)
 LSM_HOOK(int, -EOPNOTSUPP, secid_to_secctx, u32 secid, struct lsm_context *cp)
 LSM_HOOK(int, -EOPNOTSUPP, lsmprop_to_secctx, struct lsm_prop *prop,
 	 struct lsm_context *cp)
+LSM_HOOK(void, LSM_RET_VOID, update_lsmprop, struct lsm_prop *dest,
+	 struct lsm_prop *src, int lsmid)
 LSM_HOOK(int, 0, secctx_to_secid, const char *secdata, u32 seclen, u32 *secid)
+LSM_HOOK(int, -EINVAL, secctx_to_lsmprop, const char *secdata, u32 seclen,
+	 struct lsm_prop *prop)
 LSM_HOOK(void, LSM_RET_VOID, release_secctx, struct lsm_context *cp)
 LSM_HOOK(void, LSM_RET_VOID, inode_invalidate_secctx, struct inode *inode)
 LSM_HOOK(int, 0, inode_notifysecctx, struct inode *inode, void *ctx, u32 ctxlen)
diff --git a/include/linux/security.h b/include/linux/security.h
index 153e9043058f..19adc19eb9af 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -576,6 +576,11 @@ int security_secid_to_secctx(u32 secid, struct lsm_context *cp);
 int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp,
 			       int lsmid);
 int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid);
+int security_secctx_to_lsmprop(const char *secdata, u32 seclen,
+			       struct lsm_prop *prop, int lsmid);
+
+void security_update_lsmprop(struct lsm_prop *dest, struct lsm_prop *src,
+			     int lsmid);
 void security_release_secctx(struct lsm_context *cp);
 void security_inode_invalidate_secctx(struct inode *inode);
 int security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen);
@@ -1581,6 +1586,11 @@ static inline int security_lsmprop_to_secctx(struct lsm_prop *prop,
 	return -EOPNOTSUPP;
 }
 
+static inline void security_update_lsmprop(struct lsm_prop *dest,
+					   struct lsm_prop *src, int lsmid)
+{
+}
+
 static inline int security_secctx_to_secid(const char *secdata,
 					   u32 seclen,
 					   u32 *secid)
@@ -1588,6 +1598,12 @@ static inline int security_secctx_to_secid(const char *secdata,
 	return -EOPNOTSUPP;
 }
 
+static inline int security_secctx_to_lsmprop(const char *secdata, u32 seclen,
+					     struct lsm_prop *prop, int lsmid)
+{
+	return -EOPNOTSUPP;
+}
+
 static inline void security_release_secctx(struct lsm_context *cp)
 {
 }
diff --git a/security/security.c b/security/security.c
index 71aea8fdf014..1dec0037370b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -3965,6 +3965,13 @@ int security_lsmprop_to_secctx(struct lsm_prop *prop, struct lsm_context *cp,
 }
 EXPORT_SYMBOL(security_lsmprop_to_secctx);
 
+void security_update_lsmprop(struct lsm_prop *dest, struct lsm_prop *src,
+			     int lsmid)
+{
+	call_void_hook(update_lsmprop, dest, src, lsmid);
+}
+EXPORT_SYMBOL(security_update_lsmprop);
+
 /**
  * security_secctx_to_secid() - Convert a secctx to a secid
  * @secdata: secctx
@@ -3982,6 +3989,31 @@ int security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)
 }
 EXPORT_SYMBOL(security_secctx_to_secid);
 
+/**
+ * security_secctx_to_lsmprop() - Convert a secctx to a lsmprop
+ * @secdata: secctx
+ * @seclen: length of secctx
+ * @prop: prop
+ * @lsmid: which LSM the context is appropriate to.
+ *
+ * Convert security context to an lsmprop.
+ *
+ * Return: Returns 0 on success, error on failure.
+ */
+int security_secctx_to_lsmprop(const char *secdata, u32 seclen,
+			       struct lsm_prop *prop, int lsmid)
+{
+	struct lsm_static_call *scall;
+
+	lsm_for_each_hook(scall, secctx_to_lsmprop) {
+		if (lsmid != LSM_ID_UNDEF && lsmid != scall->hl->lsmid->id)
+			continue;
+		return scall->hl->hook.secctx_to_lsmprop(secdata, seclen, prop);
+	}
+	return LSM_RET_DEFAULT(secctx_to_lsmprop);
+}
+EXPORT_SYMBOL(security_secctx_to_lsmprop);
+
 /**
  * security_release_secctx() - Free a secctx buffer
  * @cp: the security context
-- 
2.54.0