smack: Retrieve transmuting information in smack_inode_getsecurity()

Enhance smack_inode_getsecurity() to retrieve the value for
SMACK64TRANSMUTE from the inode security blob, similarly to SMACK64.

This helps to display accurate values in the situation where the security
labels come from mount options and not from xattrs.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 7a3e9ab137d85bcf4b0fa11604cb2e095b59dfe3..c7e37ed2799a4455cbbb688658505f169ebf9b30 100644 (file)
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1463,10 +1463,19 @@ static int smack_inode_getsecurity(struct mnt_idmap *idmap,
        struct super_block *sbp;
        struct inode *ip = inode;
        struct smack_known *isp;
+       struct inode_smack *ispp;
+       size_t label_len;
+       char *label = NULL;
 
-       if (strcmp(name, XATTR_SMACK_SUFFIX) == 0)
+       if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
                isp = smk_of_inode(inode);
-       else {
+       } else if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
+               ispp = smack_inode(inode);
+               if (ispp->smk_flags & SMK_INODE_TRANSMUTE)
+                       label = TRANS_TRUE;
+               else
+                       label = "";
+       } else {
                /*
                 * The rest of the Smack xattrs are only on sockets.
                 */
@@ -1488,13 +1497,18 @@ static int smack_inode_getsecurity(struct mnt_idmap *idmap,
                        return -EOPNOTSUPP;
        }
 
+       if (!label)
+               label = isp->smk_known;
+
+       label_len = strlen(label);
+
        if (alloc) {
-               *buffer = kstrdup(isp->smk_known, GFP_KERNEL);
+               *buffer = kstrdup(label, GFP_KERNEL);
                if (*buffer == NULL)
                        return -ENOMEM;
        }
 
-       return strlen(isp->smk_known);
+       return label_len;
 }