[PATCH 39/58] LSM: Use lsm_context in inode_getsecctx hooks

[Casey Schaufler]

Convert SELinux and Smack to use the lsm_context structure
instead of a context/secid pair. There is some scaffolding involved
that will be removed when the related data is updated.

Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
---
 include/linux/lsm_hooks.h  |  7 +++----
 security/security.c        | 11 +++++++++--
 security/selinux/hooks.c   |  6 +++---
 security/smack/smack_lsm.c |  6 +++---
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index c983d573a005..20e59e0b775f 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -1394,11 +1394,10 @@
  *	@ctxlen contains the length of @ctx.
  *
  * @inode_getsecctx:
- *	On success, returns 0 and fills out @ctx and @ctxlen with the security
+ *	On success, returns 0 and fills out @cp with the security
  *	context for the given @inode.
  *	@inode we wish to get the security context of.
- *	@ctx is a pointer in which to place the allocated security context.
- *	@ctxlen points to the place to put the length of @ctx.
+ *	@cp is a pointer in which to place the allocated security context.
  *
  * Security hooks for using the eBPF maps and programs functionalities through
  * eBPF syscalls.
@@ -1671,7 +1670,7 @@ union security_list_options {
 	void (*inode_invalidate_secctx)(struct inode *inode);
 	int (*inode_notifysecctx)(struct inode *inode, void *ctx, u32 ctxlen);
 	int (*inode_setsecctx)(struct dentry *dentry, void *ctx, u32 ctxlen);
-	int (*inode_getsecctx)(struct inode *inode, void **ctx, u32 *ctxlen);
+	int (*inode_getsecctx)(struct inode *inode, struct lsm_context *cp);
 
 #ifdef CONFIG_SECURITY_NETWORK
 	int (*unix_stream_connect)(struct sock *sock, struct sock *other,
diff --git a/security/security.c b/security/security.c
index 84f27428b62d..0c23ffdd92c9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1992,7 +1992,7 @@ int security_secctx_to_secid(const char *secdata, u32 seclen,
 {
 	struct lsm_context lc;
 
-	lc.context = secdata;
+	lc.context = (char *)secdata;
 	lc.len = seclen;
 	lsm_export_init(l);
 	return call_one_int_hook(secctx_to_secid, 0, &lc, l);
@@ -2025,7 +2025,14 @@ EXPORT_SYMBOL(security_inode_setsecctx);
 
 int security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
 {
-	return call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, ctx, ctxlen);
+	struct lsm_context lc = { .context = NULL, .len = 0, };
+	int rc;
+
+	rc = call_int_hook(inode_getsecctx, -EOPNOTSUPP, inode, &lc);
+
+	*ctx = (void *)lc.context;
+	*ctxlen = lc.len;
+	return rc;
 }
 EXPORT_SYMBOL(security_inode_getsecctx);
 
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index a2257ccaee5c..e881f42d3ff8 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -6355,14 +6355,14 @@ static int selinux_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 	return __vfs_setxattr_noperm(dentry, XATTR_NAME_SELINUX, ctx, ctxlen, 0);
 }
 
-static int selinux_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static int selinux_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
 {
 	int len = 0;
 	len = selinux_inode_getsecurity(inode, XATTR_SELINUX_SUFFIX,
-						ctx, true);
+						(void **)&cp->context, true);
 	if (len < 0)
 		return len;
-	*ctxlen = len;
+	cp->len = len;
 	return 0;
 }
 #ifdef CONFIG_KEYS
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 78c01ef707eb..46eead699e1d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4484,12 +4484,12 @@ static int smack_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)
 	return __vfs_setxattr_noperm(dentry, XATTR_NAME_SMACK, ctx, ctxlen, 0);
 }
 
-static int smack_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)
+static int smack_inode_getsecctx(struct inode *inode, struct lsm_context *cp)
 {
 	struct smack_known *skp = smk_of_inode(inode);
 
-	*ctx = skp->smk_known;
-	*ctxlen = strlen(skp->smk_known);
+	cp->context = skp->smk_known;
+	cp->len = strlen(skp->smk_known);
 	return 0;
 }
 
-- 
2.19.1