From 43b62503c286eb7b919df3c14cd1a40c1ed61028 Mon Sep 17 00:00:00 2001 From: Jeff Mahoney Date: Wed, 19 Jun 2013 10:05:36 +1000 Subject: [PATCH] mISDN: add support for group membership check 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. Signed-off-by: Jiri Slaby Acked-by: Jeff Mahoney Cc: Patrick Koppen Cc: Karsten Keil Cc: "David S. Miller" Cc: Sergei Shtylyov Signed-off-by: Andrew Morton --- 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 da30c5cb9609..174aa3f17afb 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 52695bb81ee7..5f509bf93c00 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 e47dcb9d1e91..8dcef368e9da 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; -- 2.39.5