Merge tag 'lsm-pr-20240715' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:
 "Two LSM patches focused on cleaning up the inode xattr capability
  handling"

* tag 'lsm-pr-20240715' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  selinux,smack: remove the capability checks in the removexattr hooks
  lsm: fixup the inode xattr capability handling

1 files changed, 30 insertions, 4 deletions

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index f5cbec1e6a92..c1fe422cfbe1 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1283,6 +1283,33 @@ static int smack_inode_getattr(const struct path *path)
 }
 
 /**
+ * smack_inode_xattr_skipcap - Skip the xattr capability checks?
+ * @name: name of the xattr
+ *
+ * Returns 1 to indicate that Smack "owns" the access control rights to xattrs
+ * named @name; the LSM layer should avoid enforcing any traditional
+ * capability based access controls on this xattr.  Returns 0 to indicate that
+ * Smack does not "own" the access control rights to xattrs named @name and is
+ * deferring to the LSM layer for further access controls, including capability
+ * based controls.
+ */
+static int smack_inode_xattr_skipcap(const char *name)
+{
+	if (strncmp(name, XATTR_SMACK_SUFFIX, strlen(XATTR_SMACK_SUFFIX)))
+		return 0;
+
+	if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
+	    strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
+	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
+	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
+	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0 ||
+	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
+		return 1;
+
+	return 0;
+}
+
+/**
  * smack_inode_setxattr - Smack check for setting xattrs
  * @idmap: idmap of the mount
  * @dentry: the object
@@ -1325,8 +1352,7 @@ static int smack_inode_setxattr(struct mnt_idmap *idmap,
 		    size != TRANS_TRUE_SIZE ||
 		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
 			rc = -EINVAL;
-	} else
-		rc = cap_inode_setxattr(dentry, name, value, size, flags);
+	}
 
 	if (check_priv && !smack_privileged(CAP_MAC_ADMIN))
 		rc = -EPERM;
@@ -1435,8 +1461,7 @@ static int smack_inode_removexattr(struct mnt_idmap *idmap,
 	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
 		if (!smack_privileged(CAP_MAC_ADMIN))
 			rc = -EPERM;
-	} else
-		rc = cap_inode_removexattr(idmap, dentry, name);
+	}
 
 	if (rc != 0)
 		return rc;
@@ -5053,6 +5078,7 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
 	LSM_HOOK_INIT(inode_permission, smack_inode_permission),
 	LSM_HOOK_INIT(inode_setattr, smack_inode_setattr),
 	LSM_HOOK_INIT(inode_getattr, smack_inode_getattr),
+	LSM_HOOK_INIT(inode_xattr_skipcap, smack_inode_xattr_skipcap),
 	LSM_HOOK_INIT(inode_setxattr, smack_inode_setxattr),
 	LSM_HOOK_INIT(inode_post_setxattr, smack_inode_post_setxattr),
 	LSM_HOOK_INIT(inode_getxattr, smack_inode_getxattr),