[systemd-devel] [PATCH] udev: Add hidraw_id and a rule file to invoke it
Andy Lutomirski
luto at amacapital.net
Wed Oct 29 14:18:56 PDT 2014
On Tue, Oct 28, 2014 at 3:46 PM, Andy Lutomirski <luto at amacapital.net> wrote:
> So far, hidraw_id detects U2F tokens and sets:
> ID_U2F_TOKEN=1
> ID_SECURITY_TOKEN=1
>
> This causes the uaccess rules to apply to U2F devices.
This works for the Plug-up security key, too.
--Andy
> ---
>
> I've never written any udev code before. Feedback welcome.
>
> If you think this doesn't belong in udev, I can try to find it another home.
>
> .gitignore | 1 +
> Makefile.am | 11 ++++
> rules/60-hidraw.rules | 7 ++
> src/udev/hidraw_id/Makefile | 1 +
> src/udev/hidraw_id/hidraw_id.c | 144 +++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 164 insertions(+)
> create mode 100644 rules/60-hidraw.rules
> create mode 120000 src/udev/hidraw_id/Makefile
> create mode 100644 src/udev/hidraw_id/hidraw_id.c
>
> diff --git a/.gitignore b/.gitignore
> index f119b574c777..4bd3cdf08f0d 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -34,6 +34,7 @@
> /exported
> /exported-*
> /gtk-doc.make
> +/hidraw_id
> /hostnamectl
> /install-tree
> /journalctl
> diff --git a/Makefile.am b/Makefile.am
> index fae946a388af..9f64687d32b1 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -3542,6 +3542,17 @@ udevlibexec_PROGRAMS += \
> ata_id
>
> # ------------------------------------------------------------------------------
> +hidraw_id_SOURCES = \
> + src/udev/hidraw_id/hidraw_id.c
> +
> +hidraw_id_LDADD = \
> + libudev-internal.la \
> + libsystemd-shared.la
> +
> +udevlibexec_PROGRAMS += \
> + hidraw_id
> +
> +# ------------------------------------------------------------------------------
> cdrom_id_SOURCES = \
> src/udev/cdrom_id/cdrom_id.c
>
> diff --git a/rules/60-hidraw.rules b/rules/60-hidraw.rules
> new file mode 100644
> index 000000000000..1ee9c812f711
> --- /dev/null
> +++ b/rules/60-hidraw.rules
> @@ -0,0 +1,7 @@
> +# do not edit this file, it will be overwritten on update
> +
> +ACTION=="remove", GOTO="hidraw_end"
> +
> +SUBSYSTEM=="hidraw", IMPORT{program}="hidraw_id --udev"
> +
> +LABEL="keyboard_end"
> diff --git a/src/udev/hidraw_id/Makefile b/src/udev/hidraw_id/Makefile
> new file mode 120000
> index 000000000000..d0b0e8e0086f
> --- /dev/null
> +++ b/src/udev/hidraw_id/Makefile
> @@ -0,0 +1 @@
> +../Makefile
> \ No newline at end of file
> diff --git a/src/udev/hidraw_id/hidraw_id.c b/src/udev/hidraw_id/hidraw_id.c
> new file mode 100644
> index 000000000000..e32f222f22f9
> --- /dev/null
> +++ b/src/udev/hidraw_id/hidraw_id.c
> @@ -0,0 +1,144 @@
> +/*
> + * Copyright (c) Andrew Lutomirski, 2014
> + *
> + * This program is free software: you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation, either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program. If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <stdio.h>
> +#include <string.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <unistd.h>
> +
> +#include "libudev.h"
> +#include "libudev-private.h"
> +
> +_printf_(6,0)
> +static void log_fn(struct udev *udev, int priority,
> + const char *file, int line, const char *fn,
> + const char *format, va_list args)
> +{
> + log_metav(priority, file, line, fn, format, args);
> +}
> +
> +int main(int argc, char **argv)
> +{
> + struct udev *udev;
> + struct udev_device *dev, *hiddev;
> + char path[4096];
> + unsigned char desc[4096];
> + int desclen;
> + int fd = -1;
> + int i;
> + int ret = 1;
> + unsigned int usage_page = 0;
> + int is_u2f_token = 0;
> +
> + if (argc != 2) {
> + fprintf(stderr, "Usage: hidraw_id SYSFS_PATH|--udev\n");
> + return 1;
> + }
> +
> + log_parse_environment();
> + log_open();
> +
> + udev = udev_new();
> +
> + udev_set_log_fn(udev, log_fn);
> +
> + if (!strcmp(argv[1], "--udev"))
> + dev = udev_device_new_from_environment(udev);
> + else
> + dev = udev_device_new_from_syspath(udev, argv[1]);
> +
> + if (!dev)
> + goto out;
> +
> + hiddev = udev_device_get_parent(dev);
> + if (!hiddev)
> + goto out;
> +
> + if (snprintf(path, sizeof(path), "%s/report_descriptor",
> + udev_device_get_syspath(hiddev)) > (int)sizeof(path))
> + return 1;
> +
> + fd = open(path, O_RDONLY | O_NOFOLLOW);
> + if (fd == -1)
> + goto out;
> +
> + desclen = read(fd, desc, sizeof(desc));
> + if (desclen <= 0)
> + goto out;
> +
> + /* Parse the report descriptor. */
> + for (i = 0; i < desclen; ) {
> + unsigned char tag = desc[i] >> 4;
> + unsigned char type = (desc[i] >> 2) & 0x3;
> + unsigned char sizecode = desc[i] & 0x3;
> + int size, j;
> + unsigned int value = 0;
> +
> + if (desc[i] == 0xfe) {
> + /* Long item; skip it. */
> + if (i + 1 >= desclen) {
> + log_error("bad report_descriptor");
> + goto out;
> + }
> + i += (desc[i+1] + 3); /* Can't overflow. */
> + continue;
> + }
> +
> + size = (sizecode < 3 ? sizecode : 4);
> + if (i + 1 + size > desclen) {
> + log_error("bad report_descriptor");
> + goto out;
> + }
> +
> + for (j = 0; j < size; j++)
> + value |= (desc[i + 1 + j] << 8*j);
> +
> + if (type == 1 && tag == 0)
> + usage_page = value;
> +
> + /*
> + * Detect U2F tokens. See:
> + * https://fidoalliance.org/specs/fido-u2f-HID-protocol-v1.0-rd-20141008.pdf
> + * http://www.usb.org/developers/hidpage/HUTRR48.pdf
> + */
> +
> + if (type == 2 && tag == 0) {
> + if (usage_page == 0xf1d0 && value == 0x1)
> + is_u2f_token = 1;
> + }
> +
> + i += 1 + size;
> + }
> +
> + if (is_u2f_token)
> + printf("ID_U2F_TOKEN=1\nID_SECURITY_TOKEN=1\n");
> +
> + ret = 0;
> +
> +out:
> + if (fd != -1)
> + close(fd);
> + if (dev)
> + udev_device_unref(dev);
> + udev_unref(udev);
> +
> + log_close();
> +
> + return ret;
> +}
> --
> 1.9.3
>
--
Andy Lutomirski
AMA Capital Management, LLC
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