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Hallyn" , linux-usb@vger.kernel.org, Greg Kroah-Hartman Subject: [PATCH 03/11] Creation of "usb_device_auth" LSM hook Date: Mon, 12 Jun 2017 18:56:52 +0200 Message-Id: <1497286620-15027-4-git-send-email-s.mesoraca16@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1497286620-15027-1-git-send-email-s.mesoraca16@gmail.com> References: <1497286620-15027-1-git-send-email-s.mesoraca16@gmail.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Creation of a new LSM hook that can be used to authorize or deauthorize new USB devices via the usb authorization interface. The same hook can also prevent the authorization of a USB device via "/sys/bus/usb/devices/DEVICE/authorized". Using this hook an LSM could provide an higher level of granularity than the current authorization interface. Signed-off-by: Salvatore Mesoraca Cc: linux-usb@vger.kernel.org Cc: Greg Kroah-Hartman --- drivers/usb/core/hub.c | 4 ++++ drivers/usb/core/sysfs.c | 6 +++++- include/linux/lsm_hooks.h | 6 ++++++ include/linux/security.h | 7 +++++++ security/security.c | 5 +++++ 5 files changed, 27 insertions(+), 1 deletion(-) diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index b8bb20d..58be4f0 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include @@ -4831,6 +4832,9 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus, if (udev->quirks & USB_QUIRK_DELAY_INIT) msleep(1000); + if (security_usb_device_auth(udev)) + usb_deauthorize_device(udev); + /* consecutive bus-powered hubs aren't reliable; they can * violate the voltage drop budget. if the new child has * a "powered" LED, users should notice we didn't enable it diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index dfc68ed..fce9d39 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -17,6 +17,7 @@ #include #include #include +#include #include "usb.h" /* Active configuration fields */ @@ -742,8 +743,11 @@ static ssize_t authorized_store(struct device *dev, result = -EINVAL; else if (val == 0) result = usb_deauthorize_device(usb_dev); - else + else { + if (security_usb_device_auth(usb_dev)) + return -EPERM; result = usb_authorize_device(usb_dev); + } return result < 0 ? result : size; } static DEVICE_ATTR_IGNORE_LOCKDEP(authorized, S_IRUGO | S_IWUSR, diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index bd274db..cc0937e 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1189,6 +1189,10 @@ * to the @parent process for tracing. * @parent contains the task_struct structure for debugger process. * Return 0 if permission is granted. + * @usb_device_auth: + * Check if @udev device should be authorized or not. + * @udev contains the usb_device structure for the USB device. + * Return 0 if the device is allowed. * @capget: * Get the @effective, @inheritable, and @permitted capability sets for * the @target process. The hook may also perform permission checking to @@ -1352,6 +1356,7 @@ int (*ptrace_access_check)(struct task_struct *child, unsigned int mode); int (*ptrace_traceme)(struct task_struct *parent); + int (*usb_device_auth)(const struct usb_device *udev); int (*capget)(struct task_struct *target, kernel_cap_t *effective, kernel_cap_t *inheritable, kernel_cap_t *permitted); int (*capset)(struct cred *new, const struct cred *old, @@ -1670,6 +1675,7 @@ struct security_hook_heads { struct list_head binder_transfer_file; struct list_head ptrace_access_check; struct list_head ptrace_traceme; + struct list_head usb_device_auth; struct list_head capget; struct list_head capset; struct list_head capable; diff --git a/include/linux/security.h b/include/linux/security.h index af675b5..19bc364 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -30,6 +30,7 @@ #include #include #include +#include struct linux_binprm; struct cred; @@ -196,6 +197,7 @@ int security_binder_transfer_file(struct task_struct *from, struct task_struct *to, struct file *file); int security_ptrace_access_check(struct task_struct *child, unsigned int mode); int security_ptrace_traceme(struct task_struct *parent); +int security_usb_device_auth(const struct usb_device *udev); int security_capget(struct task_struct *target, kernel_cap_t *effective, kernel_cap_t *inheritable, @@ -434,6 +436,11 @@ static inline int security_ptrace_traceme(struct task_struct *parent) return cap_ptrace_traceme(parent); } +static inline int security_usb_device_auth(const struct usb_device *udev) +{ + return 0; +} + static inline int security_capget(struct task_struct *target, kernel_cap_t *effective, kernel_cap_t *inheritable, diff --git a/security/security.c b/security/security.c index 42c8028..e390f99 100644 --- a/security/security.c +++ b/security/security.c @@ -214,6 +214,11 @@ int security_ptrace_traceme(struct task_struct *parent) return call_int_hook(ptrace_traceme, 0, parent); } +int security_usb_device_auth(const struct usb_device *udev) +{ + return call_int_hook(usb_device_auth, 0, udev); +} + int security_capget(struct task_struct *target, kernel_cap_t *effective, kernel_cap_t *inheritable,