From f99e7b1aed7ea65ca0dbe5b182f2b9cbfdfe54db Mon Sep 17 00:00:00 2001 From: Vladimir Kondratyev Date: Sun, 24 Feb 2019 18:47:04 +0000 Subject: evdev: export event device properties through sysctl interface A big security advantage of Wayland is not allowing applications to read input devices all the time. Having /dev/input/* accessible to the user account subverts this advantage. libudev-devd was opening the evdev devices to detect their types (mouse, keyboard, touchpad, etc). This don't work if /dev/input/* is inaccessible. With the kernel exposing this information as sysctls (kern.evdev.input.*), we can work w/o /dev/input/* access, preserving the Wayland security model. Submitted by: Greg V Reviewed by: wulf, imp MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D18694 --- sys/dev/evdev/evdev.c | 91 +++++++++++++++++++++++++++++++++++++++++++ sys/dev/evdev/evdev_private.h | 4 ++ 2 files changed, 95 insertions(+) (limited to 'sys') diff --git a/sys/dev/evdev/evdev.c b/sys/dev/evdev/evdev.c index 2f5eb11b96b2..ee473ea2fbd0 100644 --- a/sys/dev/evdev/evdev.c +++ b/sys/dev/evdev/evdev.c @@ -76,6 +76,8 @@ SYSCTL_INT(_kern_evdev, OID_AUTO, rcpt_mask, CTLFLAG_RW, &evdev_rcpt_mask, 0, "bit2 - mouse hardware, bit3 - keyboard hardware"); SYSCTL_INT(_kern_evdev, OID_AUTO, sysmouse_t_axis, CTLFLAG_RW, &evdev_sysmouse_t_axis, 0, "Extract T-axis from 0-none, 1-ums, 2-psm"); +SYSCTL_NODE(_kern_evdev, OID_AUTO, input, CTLFLAG_RD, 0, + "Evdev input devices"); #endif static void evdev_start_repeat(struct evdev_dev *, uint16_t); @@ -196,6 +198,87 @@ evdev_estimate_report_size(struct evdev_dev *evdev) return (size); } +static void +evdev_sysctl_create(struct evdev_dev *evdev) +{ + struct sysctl_oid *ev_sysctl_tree; + char ev_unit_str[8]; + + snprintf(ev_unit_str, sizeof(ev_unit_str), "%d", evdev->ev_unit); + sysctl_ctx_init(&evdev->ev_sysctl_ctx); + + ev_sysctl_tree = SYSCTL_ADD_NODE_WITH_LABEL(&evdev->ev_sysctl_ctx, + SYSCTL_STATIC_CHILDREN(_kern_evdev_input), OID_AUTO, + ev_unit_str, CTLFLAG_RD, NULL, "", "device index"); + + SYSCTL_ADD_STRING(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "name", CTLFLAG_RD, + evdev->ev_name, 0, + "Input device name"); + + SYSCTL_ADD_STRUCT(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "id", CTLFLAG_RD, + &evdev->ev_id, input_id, + "Input device identification"); + + /* ioctl returns ENOENT if phys is not set. sysctl returns "" here */ + SYSCTL_ADD_STRING(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "phys", CTLFLAG_RD, + evdev->ev_shortname, 0, + "Input device short name"); + + /* ioctl returns ENOENT if uniq is not set. sysctl returns "" here */ + SYSCTL_ADD_STRING(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "uniq", CTLFLAG_RD, + evdev->ev_serial, 0, + "Input device unique number"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "props", CTLFLAG_RD, + evdev->ev_prop_flags, sizeof(evdev->ev_prop_flags), "", + "Input device properties"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "type_bits", CTLFLAG_RD, + evdev->ev_type_flags, sizeof(evdev->ev_type_flags), "", + "Input device supported events types"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "key_bits", CTLFLAG_RD, + evdev->ev_key_flags, sizeof(evdev->ev_key_flags), + "", "Input device supported keys"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "rel_bits", CTLFLAG_RD, + evdev->ev_rel_flags, sizeof(evdev->ev_rel_flags), "", + "Input device supported relative events"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "abs_bits", CTLFLAG_RD, + evdev->ev_abs_flags, sizeof(evdev->ev_abs_flags), "", + "Input device supported absolute events"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "msc_bits", CTLFLAG_RD, + evdev->ev_msc_flags, sizeof(evdev->ev_msc_flags), "", + "Input device supported miscellaneous events"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "led_bits", CTLFLAG_RD, + evdev->ev_led_flags, sizeof(evdev->ev_led_flags), "", + "Input device supported LED events"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "snd_bits", CTLFLAG_RD, + evdev->ev_snd_flags, sizeof(evdev->ev_snd_flags), "", + "Input device supported sound events"); + + SYSCTL_ADD_OPAQUE(&evdev->ev_sysctl_ctx, + SYSCTL_CHILDREN(ev_sysctl_tree), OID_AUTO, "sw_bits", CTLFLAG_RD, + evdev->ev_sw_flags, sizeof(evdev->ev_sw_flags), "", + "Input device supported switch events"); +} + static int evdev_register_common(struct evdev_dev *evdev) { @@ -235,6 +318,12 @@ evdev_register_common(struct evdev_dev *evdev) /* Create char device node */ ret = evdev_cdev_create(evdev); + if (ret != 0) + goto bail_out; + + /* Create sysctls (for device enumeration without /dev/input access rights) */ + evdev_sysctl_create(evdev); + bail_out: return (ret); } @@ -272,6 +361,8 @@ evdev_unregister(struct evdev_dev *evdev) debugf(evdev, "%s: unregistered evdev provider: %s\n", evdev->ev_shortname, evdev->ev_name); + sysctl_ctx_free(&evdev->ev_sysctl_ctx); + EVDEV_LOCK(evdev); evdev->ev_cdev->si_drv1 = NULL; /* Wake up sleepers */ diff --git a/sys/dev/evdev/evdev_private.h b/sys/dev/evdev/evdev_private.h index 71bdecaa57be..7e74bb35fe0a 100644 --- a/sys/dev/evdev/evdev_private.h +++ b/sys/dev/evdev/evdev_private.h @@ -35,6 +35,7 @@ #include #include #include +#include #include #include @@ -132,6 +133,9 @@ struct evdev_dev const struct evdev_methods * ev_methods; void * ev_softc; + /* Sysctl: */ + struct sysctl_ctx_list ev_sysctl_ctx; + LIST_ENTRY(evdev_dev) ev_link; LIST_HEAD(, evdev_client) ev_clients; }; -- cgit v1.3