Subject: [PATCH AUTOSEL 5.1 211/219] Bluetooth: hidp: NUL terminate a string in the compat ioctl

From: Sasha Levin <[email-masked]>
Date: Mon, 15 Jul 2019 10:03:32 -0400

From: Dan Carpenter <[email-masked]>

[ Upstream commit dcae9052ebb0c5b2614de620323d615fcbfda7f8 ]

This change is similar to commit a1616a5ac99e ("Bluetooth: hidp: fix
buffer overflow") but for the compat ioctl.  We take a string from the
user and forgot to ensure that it's NUL terminated.

I have also changed the strncpy() in to strscpy() in hidp_setup_hid().
The difference is the strncpy() doesn't necessarily NUL terminate the
destination string.  Either change would fix the problem but it's nice
to take a belt and suspenders approach and do both.

Signed-off-by: Dan Carpenter <[email-masked]>
Signed-off-by: Marcel Holtmann <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 net/bluetooth/hidp/core.c | 2 +-
 net/bluetooth/hidp/sock.c | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
index a442e21f3894..5abd423b55fa 100644
--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -775,7 +775,7 @@ static int hidp_setup_hid(struct hidp_session *session,
 	hid->version = req->version;
 	hid->country = req->country;
 
-	strncpy(hid->name, req->name, sizeof(hid->name));
+	strscpy(hid->name, req->name, sizeof(hid->name));
 
 	snprintf(hid->phys, sizeof(hid->phys), "%pMR",
 		 &l2cap_pi(session->ctrl_sock->sk)->chan->src);
diff --git a/net/bluetooth/hidp/sock.c b/net/bluetooth/hidp/sock.c
index 2151913892ce..03be6a4baef3 100644
--- a/net/bluetooth/hidp/sock.c
+++ b/net/bluetooth/hidp/sock.c
@@ -192,6 +192,7 @@ static int hidp_sock_compat_ioctl(struct socket *sock, unsigned int cmd, unsigne
 		ca.version = ca32.version;
 		ca.flags = ca32.flags;
 		ca.idle_to = ca32.idle_to;
+		ca32.name[sizeof(ca32.name) - 1] = '\0';
 		memcpy(ca.name, ca32.name, 128);
 
 		csock = sockfd_lookup(ca.ctrl_sock, &err);
-- 
2.20.1