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selinux: shrink critical section in sel_write_load()

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Currently sel_write_load() takes the policy mutex earlier than
necessary. Move the taking of the mutex later. This avoids
holding it unnecessarily across the vmalloc() and copy_from_user()
of the policy data.

Cc: stable@vger.kernel.org
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Stephen Smalley 2026-04-30 14:36:52 -04:00 committed by Paul Moore
parent a02cd68055
commit 868f31e406
1 changed files with 8 additions and 10 deletions
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18
security/selinux/selinuxfs.c
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@ -553,34 +553,31 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
if (!count)
return -EINVAL;
mutex_lock(&selinux_state.policy_mutex);
length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
SECCLASS_SECURITY, SECURITY__LOAD_POLICY, NULL);
if (length)
goto out;
return length;
data = vmalloc(count);
if (!data) {
length = -ENOMEM;
goto out;
}
if (!data)
return -ENOMEM;
if (copy_from_user(data, buf, count) != 0) {
length = -EFAULT;
goto out;
}
mutex_lock(&selinux_state.policy_mutex);
length = security_load_policy(data, count, &load_state);
if (length) {
pr_warn_ratelimited("SELinux: failed to load policy\n");
goto out;
goto out_unlock;
}
fsi = file_inode(file)->i_sb->s_fs_info;
length = sel_make_policy_nodes(fsi, load_state.policy);
if (length) {
pr_warn_ratelimited("SELinux: failed to initialize selinuxfs\n");
selinux_policy_cancel(&load_state);
goto out;
goto out_unlock;
}
selinux_policy_commit(&load_state);
@ -590,8 +587,9 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
from_kuid(&init_user_ns, audit_get_loginuid(current)),
audit_get_sessionid(current));
out:
out_unlock:
mutex_unlock(&selinux_state.policy_mutex);
out:
vfree(data);
return length;
}