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: Sam Sun <samsun1006219@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
[cascardo: keep fsi initialization at its declaration point as it is used earlier]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Paul Moore 2024-10-25 11:20:46 -03:00 committed by Greg Kroah-Hartman
parent 5660bcc4dd
commit 8251093971

View File

@ -621,6 +621,13 @@ 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;
mutex_lock(&fsi->state->policy_mutex);
length = avc_has_perm(&selinux_state,
@ -629,26 +636,21 @@ 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 = -ENOMEM;
data = vmalloc(count);
if (!data)
if (!data) {
length = -ENOMEM;
goto out;
length = -EFAULT;
if (copy_from_user(data, buf, count) != 0)
}
if (copy_from_user(data, buf, count) != 0) {
length = -EFAULT;
goto out;
}
length = security_load_policy(fsi->state, data, count, &load_state);
if (length) {
pr_warn_ratelimited("SELinux: failed to load policy\n");
goto out;
}
length = sel_make_policy_nodes(fsi, load_state.policy);
if (length) {
pr_warn_ratelimited("SELinux: failed to initialize selinuxfs\n");
@ -657,13 +659,12 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
}
selinux_policy_commit(fsi->state, &load_state);
length = count;
audit_log(audit_context(), GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
"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->state->policy_mutex);
vfree(data);