From: Paul Moore <paul@paul-moore.com>
To: selinux@vger.kernel.org
Subject: [PATCH] selinux: improve error checking in sel_write_load()
Date: Mon, 4 Mar 2024 22:12:22 -0500 [thread overview]
Message-ID: <20240305031221.492421-2-paul@paul-moore.com> (raw)
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.
Signed-off-by: Paul Moore <paul@paul-moore.com>
---
security/selinux/selinuxfs.c | 30 ++++++++++++++++--------------
1 file changed, 16 insertions(+), 14 deletions(-)
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 0619a1cbbfbe..d18581d741e8 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -571,11 +571,18 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- struct selinux_fs_info *fsi = file_inode(file)->i_sb->s_fs_info;
+ struct selinux_fs_info *fsi;
struct selinux_load_state load_state;
ssize_t length;
void *data = NULL;
+ /* no partial writes */
+ if (*ppos)
+ return -EINVAL;
+ /* no empty policies */
+ if (!count)
+ return -EINVAL;
+
mutex_lock(&selinux_state.policy_mutex);
length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
@@ -583,26 +590,22 @@ 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(data, count, &load_state);
if (length) {
pr_warn_ratelimited("SELinux: failed to load policy\n");
goto out;
}
-
+ 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");
@@ -611,13 +614,12 @@ static ssize_t sel_write_load(struct file *file, const char __user *buf,
}
selinux_policy_commit(&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(&selinux_state.policy_mutex);
vfree(data);
--
2.44.0
next reply other threads:[~2024-03-05 3:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-05 3:12 Paul Moore [this message]
2024-03-08 19:52 ` [PATCH] selinux: improve error checking in sel_write_load() Paul Moore
2024-03-26 20:42 ` Paul Moore
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