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Commit 5121ac67 authored by Paul Moore's avatar Paul Moore Committed by Greg Kroah-Hartman
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selinux: improve error checking in sel_write_load() 



[ Upstream commit 42c773238037c90b3302bf37a57ae3b5c3f6004a ]

Move our existing input sanity checking to the top of sel_write_load()
and add a check to ensure the buffer size is non-zero.

Move a local variable initialization from the declaration to before it
is used.

Minor style adjustments.

Reported-by: default avatarSam Sun <samsun1006219@gmail.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
[cascardo: keep fsi initialization at its declaration point as it is used earlier]
[cascardo: keep check for 64MiB size limit]
Signed-off-by: default avatarThadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 31a38a90

security/selinux/selinuxfs.c

+17 −14
Original line number Diff line number Diff line
@@ -535,6 +535,16 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
	ssize_t length;

	void *data = NULL;



	/* no partial writes */

	if (*ppos)

		return -EINVAL;

	/* no empty policies */

	if (!count)

		return -EINVAL;



	if (count > 64 * 1024 * 1024)

		return -EFBIG;



	mutex_lock(&fsi->mutex);



	length = avc_has_perm(&selinux_state,
@@ -543,23 +553,15 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
	if (length)

		goto out;



	/* No partial writes. */

	length = -EINVAL;

	if (*ppos != 0)

		goto out;



	length = -EFBIG;

	if (count > 64 * 1024 * 1024)

		goto out;



	length = -ENOMEM;

	data = vmalloc(count);

	if (!data)

	if (!data) {

		length = -ENOMEM;

		goto out;



	}

	if (copy_from_user(data, buf, count) != 0) {

		length = -EFAULT;

	if (copy_from_user(data, buf, count) != 0)

		goto out;

	}



	length = security_load_policy(fsi->state, data, count);

	if (length) {
@@ -578,6 +580,7 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf, 
		"auid=%u ses=%u lsm=selinux res=1",

		from_kuid(&init_user_ns, audit_get_loginuid(current)),

		audit_get_sessionid(current));



out:

	mutex_unlock(&fsi->mutex);

	vfree(data);