[RFC][PATCH 2/5] smack: Handle SMACK64TRANSMUTE in smack_inode_setsecurity()

[Roberto Sassu <roberto.sassu@huaweicloud.com>]

From: Roberto Sassu <roberto.sassu@huawei.com>

If the SMACK64TRANSMUTE xattr is provided, and the inode is a directory,
update the in-memory inode flags by setting SMK_INODE_TRANSMUTE.

Cc: stable@vger.kernel.org
Fixes: 5c6d1125f8db ("Smack: Transmute labels on specified directories") # v2.6.38.x
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 security/smack/smack_lsm.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 53fc6a1034d..162ca400f07 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2802,6 +2802,15 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
 		return -EINVAL;
 
+	if (strcmp(name, XATTR_SMACK_TRANSMUTE) == 0) {
+		if (!S_ISDIR(inode->i_mode) || size != TRANS_TRUE_SIZE ||
+		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
+			return -EINVAL;
+
+		nsp->smk_flags |= SMK_INODE_TRANSMUTE;
+		return 0;
+	}
+
 	skp = smk_import_entry(value, size);
 	if (IS_ERR(skp))
 		return PTR_ERR(skp);
-- 
2.25.1