[PATCH 4/5] smack: always "instantiate" inode in smack_inode_init_security()

[Konstantin Andreev]

If memory allocation for the SMACK64TRANSMUTE
xattr value fails in smack_inode_init_security(),
the SMK_INODE_INSTANT flag is not set in
(struct inode_smack *issp)->smk_flags,
leaving the inode as not "instantiated".

It does not matter if fs frees the inode
after failed smack_inode_init_security() call,
but there is no guarantee for this.

To be safe, mark the inode as "instantiated",
even if allocation of xattr values fails.

Signed-off-by: Konstantin Andreev <andreev at swemel.ru>
---

I have found one execution path
that does not explicitly free inode after
failed security_inode_init_security() call:

    fs/f2fs/recovery.c`recover_data()
    `fs/f2fs/recovery.c`recover_dentry(entry->inode,)
     `...
      `security_inode_init_security(,,,f2fs_initxattrs,)

and some pathes with unclear decision.
May they be affected or not, it is safer
to always "instantiate" inode.

 security/smack/smack_lsm.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 2b46a2867226..fb23254c8a54 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1016,6 +1016,8 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
 	struct task_smack *tsp = smack_cred(current_cred());
 	struct inode_smack * const issp = smack_inode(inode);
 	struct smack_known *dsp = smk_of_inode(dir);
+	int rc = 0;
+	int transflag = 0;
 	bool trans_cred;
 	bool trans_rule;
 
@@ -1044,18 +1046,20 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
 			issp->smk_inode = dsp;
 
 		if (S_ISDIR(inode->i_mode)) {
-			issp->smk_flags |= SMK_INODE_TRANSMUTE;
+			transflag = SMK_INODE_TRANSMUTE;
 
 			if (xattr_dupval(xattrs, xattr_count,
 				XATTR_SMACK_TRANSMUTE,
 				TRANS_TRUE,
 				TRANS_TRUE_SIZE
 			))
-				return -ENOMEM;
+				rc = -ENOMEM;
 		}
 	}
 
-	issp->smk_flags |= SMK_INODE_INSTANT;
+	issp->smk_flags |= (SMK_INODE_INSTANT | transflag);
+	if (rc)
+		return rc;
 
 	return xattr_dupval(xattrs, xattr_count,
 			    XATTR_SMACK_SUFFIX,
-- 
2.43.0