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Message-id: <1342021770-23684-1-git-send-email-r.krypa@samsung.com>
Date: Wed, 11 Jul 2012 17:49:30 +0200
From: Rafal Krypa <r.krypa@...sung.com>
To: Casey Schaufler <casey@...aufler-ca.com>
Cc: linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
Rafal Krypa <r.krypa@...sung.com>
Subject: [PATCH] Smack: implement revoking all rules for a subject label
Add /smack/revoke-subject special file. Writing a SMACK label to this file will
set the access to '-' for all access rules with that subject label.
Targeted for git://git.gitorious.org/smack-next/kernel.git
Signed-off-by: Rafal Krypa <r.krypa@...sung.com>
---
Documentation/security/Smack.txt | 3 ++
security/smack/smackfs.c | 75 ++++++++++++++++++++++++++++++++++++++
2 files changed, 78 insertions(+)
diff --git a/Documentation/security/Smack.txt b/Documentation/security/Smack.txt
index a416479..e68536d 100644
--- a/Documentation/security/Smack.txt
+++ b/Documentation/security/Smack.txt
@@ -194,6 +194,9 @@ onlycap
these capabilities are effective at for processes with any
label. The value is set by writing the desired label to the
file or cleared by writing "-" to the file.
+revoke-subject
+ Writing a Smack label here sets the access to '-' for all access
+ rules with that subject label.
You can add access rules in /etc/smack/accesses. They take the form:
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index d31e6d9..c434441 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -49,6 +49,7 @@ enum smk_inos {
SMK_LOAD_SELF2 = 15, /* load task specific rules with long labels */
SMK_ACCESS2 = 16, /* make an access check with long labels */
SMK_CIPSO2 = 17, /* load long label -> CIPSO mapping */
+ SMK_REVOKE_SUBJ = 18, /* set rules with subject label to '-' */
};
/*
@@ -1992,6 +1993,77 @@ static const struct file_operations smk_access2_ops = {
};
/**
+ * smk_write_revoke_subj - write() for /smack/revoke-subject
+ * @file: file pointer
+ * @buf: data from user space
+ * @count: bytes sent
+ * @ppos: where to start - must be 0
+ */
+static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ char *data = NULL;
+ const char *cp = NULL;
+ struct smack_known *skp;
+ struct smack_rule *sp;
+ struct list_head *rule_list;
+ struct mutex *rule_lock;
+ int rc = count;
+
+ if (*ppos != 0)
+ return -EINVAL;
+
+ if (!smack_privileged(CAP_MAC_ADMIN))
+ return -EPERM;
+
+ if (count == 0 || count > SMK_LONGLABEL)
+ return -EINVAL;
+
+ data = kzalloc(count, GFP_KERNEL);
+ if (data == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(data, buf, count) != 0) {
+ rc = -EFAULT;
+ goto free_out;
+ }
+
+ cp = smk_parse_smack(data, count);
+ if (cp == NULL) {
+ rc = -EINVAL;
+ goto free_out;
+ }
+
+ skp = smk_find_entry(cp);
+ if (skp == NULL) {
+ rc = -EINVAL;
+ goto free_out;
+ }
+
+ rule_list = &skp->smk_rules;
+ rule_lock = &skp->smk_rules_lock;
+
+ mutex_lock(rule_lock);
+
+ list_for_each_entry_rcu(sp, rule_list, list)
+ sp->smk_access = 0;
+
+ mutex_unlock(rule_lock);
+
+free_out:
+ kfree(data);
+ kfree(cp);
+ return rc;
+}
+
+static const struct file_operations smk_revoke_subj_ops = {
+ .write = smk_write_revoke_subj,
+ .read = simple_transaction_read,
+ .release = simple_transaction_release,
+ .llseek = generic_file_llseek,
+};
+
+/**
* smk_fill_super - fill the /smackfs superblock
* @sb: the empty superblock
* @data: unused
@@ -2037,6 +2109,9 @@ static int smk_fill_super(struct super_block *sb, void *data, int silent)
"access2", &smk_access2_ops, S_IRUGO|S_IWUGO},
[SMK_CIPSO2] = {
"cipso2", &smk_cipso2_ops, S_IRUGO|S_IWUSR},
+ [SMK_REVOKE_SUBJ] = {
+ "revoke-subject", &smk_revoke_subj_ops,
+ S_IRUGO|S_IWUSR},
/* last one */
{""}
};
--
1.7.10.4
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