/**
* smk_import - import a smack label
* @string: a text string that might be a Smack label
* @len: the maximum size, or zero if it is NULL terminated.
*
* Returns a pointer to the label in the label list that
* matches the passed string, adding it if necessary.
*/
char *smk_import(const char *string, int len)
{
struct smack_known *skp;
skp = smk_import_entry(string, len);
if (skp == NULL)
return NULL;
return skp->smk_known;
}
/**
* smk_write_cipso - write() for /smack/cipso
* @file: file pointer, not actually used
* @buf: where to get the data from
* @count: bytes sent
* @ppos: where to start
*
* Accepts only one cipso rule per write call.
* Returns number of bytes written or error code, as appropriate
*/
static ssize_t smk_write_cipso(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct smack_known *skp;
struct smack_cipso *scp = NULL;
char mapcatset[SMK_LABELLEN];
int maplevel;
int cat;
int catlen;
ssize_t rc = -EINVAL;
char *data = NULL;
char *rule;
int ret;
int i;
/*
* Must have privilege.
* No partial writes.
* Enough data must be present.
*/
if (!capable(CAP_MAC_ADMIN))
return -EPERM;
if (*ppos != 0)
return -EINVAL;
if (count < SMK_CIPSOMIN || count > SMK_CIPSOMAX)
return -EINVAL;
data = kzalloc(count + 1, GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
if (copy_from_user(data, buf, count) != 0) {
rc = -EFAULT;
goto unlockedout;
}
/* labels cannot begin with a '-' */
if (data[0] == '-') {
rc = -EINVAL;
goto unlockedout;
}
data[count] = '\0';
rule = data;
/*
* Only allow one writer at a time. Writes should be
* quite rare and small in any case.
*/
mutex_lock(&smack_cipso_lock);
skp = smk_import_entry(rule, 0);
if (skp == NULL)
goto out;
rule += SMK_LABELLEN;
ret = sscanf(rule, "%d", &maplevel);
if (ret != 1 || maplevel > SMACK_CIPSO_MAXLEVEL)
goto out;
rule += SMK_DIGITLEN;
ret = sscanf(rule, "%d", &catlen);
if (ret != 1 || catlen > SMACK_CIPSO_MAXCATNUM)
goto out;
if (count != (SMK_CIPSOMIN + catlen * SMK_DIGITLEN))
goto out;
memset(mapcatset, 0, sizeof(mapcatset));
for (i = 0; i < catlen; i++) {
rule += SMK_DIGITLEN;
ret = sscanf(rule, "%d", &cat);
if (ret != 1 || cat > SMACK_CIPSO_MAXCATVAL)
goto out;
smack_catset_bit(cat, mapcatset);
}
if (skp->smk_cipso == NULL) {
scp = kzalloc(sizeof(struct smack_cipso), GFP_KERNEL);
if (scp == NULL) {
rc = -ENOMEM;
goto out;
}
}
spin_lock_bh(&skp->smk_cipsolock);
if (scp == NULL)
scp = skp->smk_cipso;
else
skp->smk_cipso = scp;
scp->smk_level = maplevel;
memcpy(scp->smk_catset, mapcatset, sizeof(mapcatset));
spin_unlock_bh(&skp->smk_cipsolock);
rc = count;
out:
mutex_unlock(&smack_cipso_lock);
unlockedout:
kfree(data);
return rc;
}
