Add files via upload

src/nfc_linux.c

@@ -0,0 +1,356 @@
+/*
+ * Copyright (c) 2020-2022 Yubico AB. All rights reserved.
+ * Use of this source code is governed by a BSD-style
+ * license that can be found in the LICENSE file.
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <sys/socket.h>
+
+#include <linux/nfc.h>
+
+#include <errno.h>
+#include <libudev.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "fido.h"
+#include "fido/param.h"
+#include "netlink.h"
+#include "iso7816.h"
+
+struct nfc_linux {
+	int             fd;
+	uint32_t        dev;
+	uint32_t        target;
+	sigset_t	sigmask;
+	const sigset_t *sigmaskp;
+	struct fido_nl *nl;
+};
+
+static char *
+get_parent_attr(struct udev_device *dev, const char *subsystem,
+    const char *devtype, const char *attr)
+{
+	struct udev_device *parent;
+	const char *value;
+
+	if ((parent = udev_device_get_parent_with_subsystem_devtype(dev,
+	    subsystem, devtype)) == NULL || (value =
+	    udev_device_get_sysattr_value(parent, attr)) == NULL)
+		return NULL;
+
+	return strdup(value);
+}
+
+static char *
+get_usb_attr(struct udev_device *dev, const char *attr)
+{
+	return get_parent_attr(dev, "usb", "usb_device", attr);
+}
+
+static int
+copy_info(fido_dev_info_t *di, struct udev *udev,
+    struct udev_list_entry *udev_entry)
+{
+	const char *name;
+	char *str;
+	struct udev_device *dev = NULL;
+	uint64_t id;
+	int ok = -1;
+
+	memset(di, 0, sizeof(*di));
+
+	if ((name = udev_list_entry_get_name(udev_entry)) == NULL ||
+	    (dev = udev_device_new_from_syspath(udev, name)) == NULL)
+		goto fail;
+	if (asprintf(&di->path, "%s/%s", FIDO_NFC_PREFIX, name) == -1) {
+		di->path = NULL;
+		goto fail;
+	}
+	if (nfc_is_fido(di->path) == false) {
+		fido_log_debug("%s: nfc_is_fido: %s", __func__, di->path);
+		goto fail;
+	}
+	if ((di->manufacturer = get_usb_attr(dev, "manufacturer")) == NULL)
+		di->manufacturer = strdup("");
+	if ((di->product = get_usb_attr(dev, "product")) == NULL)
+		di->product = strdup("");
+	if (di->manufacturer == NULL || di->product == NULL)
+		goto fail;
+	/* XXX assumes USB for vendor/product info */
+	if ((str = get_usb_attr(dev, "idVendor")) != NULL &&
+	    fido_to_uint64(str, 16, &id) == 0 && id <= UINT16_MAX)
+		di->vendor_id = (int16_t)id;
+	free(str);
+	if ((str = get_usb_attr(dev, "idProduct")) != NULL &&
+	    fido_to_uint64(str, 16, &id) == 0 && id <= UINT16_MAX)
+		di->product_id = (int16_t)id;
+	free(str);
+
+	ok = 0;
+fail:
+	if (dev != NULL)
+		udev_device_unref(dev);
+
+	if (ok < 0) {
+		free(di->path);
+		free(di->manufacturer);
+		free(di->product);
+		explicit_bzero(di, sizeof(*di));
+	}
+
+	return ok;
+}
+
+static int
+sysnum_from_syspath(const char *path)
+{
+	struct udev *udev = NULL;
+	struct udev_device *dev = NULL;
+	const char *str;
+	uint64_t idx64;
+	int idx = -1;
+
+	if ((udev = udev_new()) != NULL &&
+	    (dev = udev_device_new_from_syspath(udev, path)) != NULL &&
+	    (str = udev_device_get_sysnum(dev)) != NULL &&
+	    fido_to_uint64(str, 10, &idx64) == 0 && idx64 < INT_MAX)
+		idx = (int)idx64;
+
+	if (dev != NULL)
+		udev_device_unref(dev);
+	if (udev != NULL)
+		udev_unref(udev);
+
+	return idx;
+}
+
+int
+fido_nfc_manifest(fido_dev_info_t *devlist, size_t ilen, size_t *olen)
+{
+	struct udev *udev = NULL;
+	struct udev_enumerate *udev_enum = NULL;
+	struct udev_list_entry *udev_list;
+	struct udev_list_entry *udev_entry;
+	int r = FIDO_ERR_INTERNAL;
+
+	*olen = 0;
+
+	if (ilen == 0)
+		return FIDO_OK;
+
+	if (devlist == NULL)
+		return FIDO_ERR_INVALID_ARGUMENT;
+
+	if ((udev = udev_new()) == NULL ||
+	    (udev_enum = udev_enumerate_new(udev)) == NULL)
+		goto fail;
+
+	if (udev_enumerate_add_match_subsystem(udev_enum, "nfc") < 0 ||
+	    udev_enumerate_scan_devices(udev_enum) < 0)
+		goto fail;
+
+	if ((udev_list = udev_enumerate_get_list_entry(udev_enum)) == NULL) {
+		r = FIDO_OK; /* zero nfc devices */
+		goto fail;
+	}
+
+	udev_list_entry_foreach(udev_entry, udev_list) {
+		if (copy_info(&devlist[*olen], udev, udev_entry) == 0) {
+			devlist[*olen].io = (fido_dev_io_t) {
+				fido_nfc_open,
+				fido_nfc_close,
+				fido_nfc_read,
+				fido_nfc_write,
+			};
+			devlist[*olen].transport = (fido_dev_transport_t) {
+				fido_nfc_rx,
+				fido_nfc_tx,
+			};
+			if (++(*olen) == ilen)
+				break;
+		}
+	}
+
+	r = FIDO_OK;
+fail:
+	if (udev_enum != NULL)
+		udev_enumerate_unref(udev_enum);
+	if (udev != NULL)
+		udev_unref(udev);
+
+	return r;
+}
+
+static int
+nfc_target_connect(struct nfc_linux *ctx)
+{
+	struct sockaddr_nfc sa;
+
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_family = AF_NFC;
+	sa.dev_idx = ctx->dev;
+	sa.target_idx = ctx->target;
+	sa.nfc_protocol = NFC_PROTO_ISO14443;
+
+	if ((ctx->fd = socket(AF_NFC, SOCK_SEQPACKET | SOCK_CLOEXEC,
+	    NFC_SOCKPROTO_RAW)) == -1) {
+		fido_log_error(errno, "%s: socket", __func__);
+		return -1;
+	}
+	if (connect(ctx->fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
+		fido_log_error(errno, "%s: connect", __func__);
+		if (close(ctx->fd) == -1)
+			fido_log_error(errno, "%s: close", __func__);
+		ctx->fd = -1;
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+nfc_free(struct nfc_linux **ctx_p)
+{
+	struct nfc_linux *ctx;
+
+	if (ctx_p == NULL || (ctx = *ctx_p) == NULL)
+		return;
+	if (ctx->fd != -1 && close(ctx->fd) == -1)
+		fido_log_error(errno, "%s: close", __func__);
+	if (ctx->nl != NULL)
+		fido_nl_free(&ctx->nl);
+
+	free(ctx);
+	*ctx_p = NULL;
+}
+
+static struct nfc_linux *
+nfc_new(uint32_t dev)
+{
+	struct nfc_linux *ctx;
+
+	if ((ctx = calloc(1, sizeof(*ctx))) == NULL ||
+	    (ctx->nl = fido_nl_new()) == NULL) {
+		nfc_free(&ctx);
+		return NULL;
+	}
+
+	ctx->fd = -1;
+	ctx->dev = dev;
+
+	return ctx;
+}
+
+void *
+fido_nfc_open(const char *path)
+{
+	struct nfc_linux *ctx = NULL;
+	int idx;
+
+	if (strncmp(path, FIDO_NFC_PREFIX, strlen(FIDO_NFC_PREFIX)) != 0) {
+		fido_log_debug("%s: bad prefix", __func__);
+		goto fail;
+	}
+	if ((idx = sysnum_from_syspath(path + strlen(FIDO_NFC_PREFIX))) < 0 ||
+	    (ctx = nfc_new((uint32_t)idx)) == NULL) {
+		fido_log_debug("%s: nfc_new", __func__);
+		goto fail;
+	}
+	if (fido_nl_power_nfc(ctx->nl, ctx->dev) < 0 ||
+	    fido_nl_get_nfc_target(ctx->nl, ctx->dev, &ctx->target) < 0 ||
+	    nfc_target_connect(ctx) < 0) {
+		fido_log_debug("%s: netlink", __func__);
+		goto fail;
+	}
+
+	return ctx;
+fail:
+	nfc_free(&ctx);
+	return NULL;
+}
+
+void
+fido_nfc_close(void *handle)
+{
+	struct nfc_linux *ctx = handle;
+
+	nfc_free(&ctx);
+}
+
+int
+fido_nfc_set_sigmask(void *handle, const fido_sigset_t *sigmask)
+{
+	struct nfc_linux *ctx = handle;
+
+	ctx->sigmask = *sigmask;
+	ctx->sigmaskp = &ctx->sigmask;
+
+	return FIDO_OK;
+}
+
+int
+fido_nfc_read(void *handle, unsigned char *buf, size_t len, int ms)
+{
+	struct nfc_linux *ctx = handle;
+	struct iovec iov[2];
+	uint8_t preamble;
+	ssize_t	r;
+
+	memset(&iov, 0, sizeof(iov));
+	iov[0].iov_base = &preamble;
+	iov[0].iov_len = sizeof(preamble);
+	iov[1].iov_base = buf;
+	iov[1].iov_len = len;
+
+	if (fido_hid_unix_wait(ctx->fd, ms, ctx->sigmaskp) < 0) {
+		fido_log_debug("%s: fido_hid_unix_wait", __func__);
+		return -1;
+	}
+	if ((r = readv(ctx->fd, iov, nitems(iov))) == -1) {
+		fido_log_error(errno, "%s: read", __func__);
+		return -1;
+	}
+	if (r < 1) {
+		fido_log_debug("%s: %zd < 1", __func__, r);
+		return -1;
+	}
+	if (preamble != 0x00) {
+		fido_log_debug("%s: preamble", __func__);
+		return -1;
+	}
+
+	r--;
+	fido_log_xxd(buf, (size_t)r, "%s", __func__);
+
+	return (int)r;
+}
+
+int
+fido_nfc_write(void *handle, const unsigned char *buf, size_t len)
+{
+	struct nfc_linux *ctx = handle;
+	ssize_t	r;
+
+	fido_log_xxd(buf, len, "%s", __func__);
+
+	if (len > INT_MAX) {
+		fido_log_debug("%s: len", __func__);
+		return -1;
+	}
+	if ((r = write(ctx->fd, buf, len)) == -1) {
+		fido_log_error(errno, "%s: write", __func__);
+		return -1;
+	}
+	if (r < 0 || (size_t)r != len) {
+		fido_log_debug("%s: %zd != %zu", __func__, r, len);
+		return -1;
+	}
+
+	return (int)r;
+}