From: Jeff Mahoney <jeffm@suse.com>
Date: Tue, 7 May 2013 15:01:02 +0200
Subject: mISDN: Add support for group membership check
References: bnc#564423
Patch-mainline: Submitted https://lkml.org/lkml/2013/5/22/527
This patch adds a module parameter to allow a group access to the
mISDN devices. Otherwise, unpriviledged users on systems with ISDN
hardware have the ability to dial out, potentially causing expensive
bills.
Based on a different implementation by Patrick Koppen <isdn4linux@koppen.de>.
[v2]
- convert to the new UID/GID API
- fix whitespace issues (per Sergei)
Acked-by: Jeff Mahoney <jeffm@suse.com>
Cc: Patrick Koppen <isdn4linux@koppen.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Karsten Keil <isdn@linux-pingi.de>
Cc: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
---
drivers/isdn/mISDN/core.c | 6 ++++++
drivers/isdn/mISDN/core.h | 1 +
drivers/isdn/mISDN/socket.c | 9 +++++++++
3 files changed, 16 insertions(+)
diff --git a/drivers/isdn/mISDN/core.c b/drivers/isdn/mISDN/core.c
index da30c5c..174aa3f 100644
--- a/drivers/isdn/mISDN/core.c
+++ b/drivers/isdn/mISDN/core.c
@@ -21,10 +21,14 @@
#include "core.h"
static u_int debug;
+static u_int gid;
+kgid_t misdn_permitted_gid;
MODULE_AUTHOR("Karsten Keil");
MODULE_LICENSE("GPL");
module_param(debug, uint, S_IRUGO | S_IWUSR);
+module_param(gid, uint, 0);
+MODULE_PARM_DESC(gid, "Unix group for accessing misdn socket (default 0)");
static u64 device_ids;
#define MAX_DEVICE_ID 63
@@ -372,6 +376,8 @@ mISDNInit(void)
{
int err;
+ misdn_permitted_gid = make_kgid(current_user_ns(), gid);
+
printk(KERN_INFO "Modular ISDN core version %d.%d.%d\n",
MISDN_MAJOR_VERSION, MISDN_MINOR_VERSION, MISDN_RELEASE);
mISDN_init_clock(&debug);
diff --git a/drivers/isdn/mISDN/core.h b/drivers/isdn/mISDN/core.h
index 52695bb..5f509bf 100644
--- a/drivers/isdn/mISDN/core.h
+++ b/drivers/isdn/mISDN/core.h
@@ -17,6 +17,7 @@
extern struct mISDNdevice *get_mdevice(u_int);
extern int get_mdevice_count(void);
+extern kgid_t misdn_permitted_gid;
/* stack status flag */
#define mISDN_STACK_ACTION_MASK 0x0000ffff
diff --git a/drivers/isdn/mISDN/socket.c b/drivers/isdn/mISDN/socket.c
index e47dcb9..8dcef36 100644
--- a/drivers/isdn/mISDN/socket.c
+++ b/drivers/isdn/mISDN/socket.c
@@ -612,6 +612,11 @@ data_sock_create(struct net *net, struct socket *sock, int protocol)
{
struct sock *sk;
+ if (!capable(CAP_SYS_ADMIN) &&
+ !gid_eq(misdn_permitted_gid, current_gid()) &&
+ !in_group_p(misdn_permitted_gid))
+ return -EPERM;
+
if (sock->type != SOCK_DGRAM)
return -ESOCKTNOSUPPORT;
@@ -694,6 +699,10 @@ base_sock_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
case IMSETDEVNAME:
{
struct mISDN_devrename dn;
+ if (!capable(CAP_SYS_ADMIN) &&
+ !gid_eq(misdn_permitted_gid, current_gid()) &&
+ !in_group_p(misdn_permitted_gid))
+ return -EPERM;
if (copy_from_user(&dn, (void __user *)arg,
sizeof(dn))) {
err = -EFAULT;
--
1.8.2.3