Patch "smack: Retrieve transmuting information in smack_inode_getsecurity()" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    smack: Retrieve transmuting information in smack_inode_getsecurity()

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     smack-retrieve-transmuting-information-in-smack_inod.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 765b103c8d2a7fc0e0188826d760f2436563dff2
Author: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Date:   Thu Sep 28 18:51:37 2023 -0700

    smack: Retrieve transmuting information in smack_inode_getsecurity()
    
    commit 3a3d8fce31a49363cc31880dce5e3b0617c9c38b upstream.
    
    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@xxxxxxxxxx>
    Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
    [4.19: adjusted for the lack of helper functions]
    Fixes: d6d80cb57be4 ("Smack: Base support for overlayfs")
    Signed-off-by: Munehisa Kamata <kamatam@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index a09a9c6bbdf63..db729834d8ba9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1490,10 +1490,19 @@ static int smack_inode_getsecurity(struct inode *inode,
 	struct super_block *sbp;
 	struct inode *ip = (struct inode *)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 = inode->i_security;
+		if (ispp->smk_flags & SMK_INODE_TRANSMUTE)
+			label = TRANS_TRUE;
+		else
+			label = "";
+	} else {
 		/*
 		 * The rest of the Smack xattrs are only on sockets.
 		 */
@@ -1515,13 +1524,18 @@ static int smack_inode_getsecurity(struct inode *inode,
 			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;
 }