4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Paul Moore <paul@xxxxxxxxxxxxxx>
[ 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@xxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
[cascardo: keep fsi initialization at its declaration point as it is used earlier]
[cascardo: keep check for 64MiB size limit]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
security/selinux/selinuxfs.c | 31 +++++++++++++++++--------------
1 file changed, 17 insertions(+), 14 deletions(-)
diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index 60b3f16bb5c7b..c35aab9f24471 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -536,6 +536,16 @@ 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,
@@ -544,23 +554,15 @@ 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;
-
- 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);
if (length) {
@@ -579,6 +581,7 @@ 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);
--
2.43.0
