From: Jeff Mahoney Subject: [PATCH] mISDN: Add support for group membership check References: bnc#564423 Patch-mainline: Unsubmitted, needs upstream consensus 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 Acked-by: Jeff Mahoney --- drivers/isdn/mISDN/core.c | 3 +++ drivers/isdn/mISDN/core.h | 1 + drivers/isdn/mISDN/socket.c | 8 ++++++++ 3 files changed, 12 insertions(+) --- a/drivers/isdn/mISDN/core.c +++ b/drivers/isdn/mISDN/core.c @@ -21,10 +21,13 @@ #include "core.h" static u_int debug; +u_int misdn_permitted_gid; MODULE_AUTHOR("Karsten Keil"); MODULE_LICENSE("GPL"); module_param(debug, uint, S_IRUGO | S_IWUSR); +module_param_named(gid, misdn_permitted_gid, uint, 0); +MODULE_PARM_DESC(gid, "Unix group for accessing misdn socket (default 0)"); static u64 device_ids; #define MAX_DEVICE_ID 63 --- 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 u_int misdn_permitted_gid; /* stack status flag */ #define mISDN_STACK_ACTION_MASK 0x0000ffff --- a/drivers/isdn/mISDN/socket.c +++ b/drivers/isdn/mISDN/socket.c @@ -608,6 +608,10 @@ data_sock_create(struct net *net, struct { struct sock *sk; + if(!capable(CAP_SYS_ADMIN) && (misdn_permitted_gid != current_gid()) + && (!in_group_p(misdn_permitted_gid))) + return -EPERM; + if (sock->type != SOCK_DGRAM) return -ESOCKTNOSUPPORT; @@ -690,6 +694,10 @@ base_sock_ioctl(struct socket *sock, uns case IMSETDEVNAME: { struct mISDN_devrename dn; + if(!capable(CAP_SYS_ADMIN) + && (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;