Linux as well as other operating systems can provide /dev/random and
/dev/urandom device to service userspace need for randomness.
Add a driver to use /dev/random for blocking and /dev/urandom for
non-blocking barebox random numbers.
Signed-off-by: Ahmad Fatoum <ahmad@xxxxxx>
---
arch/sandbox/board/Makefile | 1 +
arch/sandbox/board/board.c | 7 +++
arch/sandbox/board/dev-random.c | 24 +++++++
.../sandbox/mach-sandbox/include/mach/linux.h | 7 +++
drivers/hw_random/Kconfig | 8 +++
drivers/hw_random/Makefile | 1 +
drivers/hw_random/dev-random.c | 63 +++++++++++++++++++
7 files changed, 111 insertions(+)
create mode 100644 arch/sandbox/board/dev-random.c
create mode 100644 drivers/hw_random/dev-random.c
diff --git a/arch/sandbox/board/Makefile b/arch/sandbox/board/Makefile
index b6c271c858c6..26f6cb192269 100644
--- a/arch/sandbox/board/Makefile
+++ b/arch/sandbox/board/Makefile
@@ -5,5 +5,6 @@ obj-y += console.o
obj-y += devices.o
obj-y += dtb.o
obj-y += poweroff.o
+obj-y += dev-random.o
extra-y += barebox.lds
diff --git a/arch/sandbox/board/board.c b/arch/sandbox/board/board.c
index 1f6392d15ed3..ad2bc910c342 100644
--- a/arch/sandbox/board/board.c
+++ b/arch/sandbox/board/board.c
@@ -42,6 +42,11 @@ static struct device_d sdl_device = {
.platform_data = &mode,
};
+static struct device_d devrandom_device = {
+ .id = DEVICE_ID_DYNAMIC,
+ .name = "devrandom",
+};
+
static int devices_init(void)
{
platform_device_register(&tap_device);
@@ -54,6 +59,8 @@ static int devices_init(void)
platform_device_register(&sdl_device);
+ platform_device_register(&devrandom_device);
+
return 0;
}
diff --git a/arch/sandbox/board/dev-random.c b/arch/sandbox/board/dev-random.c
new file mode 100644
index 000000000000..f65e5ef6e5ed
--- /dev/null
+++ b/arch/sandbox/board/dev-random.c
@@ -0,0 +1,24 @@
+#include <common.h>
+#include <mach/linux.h>
+
+devrandom_t *devrandom_init(void) {
+ devrandom_t *fds = xzalloc(sizeof(*fds));
+
+ fds->randomfd = linux_open("/dev/random", false);
+ if (fds->randomfd < 0)
+ return ERR_PTR(-EPERM);
+
+ fds->urandomfd = linux_open("/dev/urandom", false);
+ if (fds->urandomfd < 0)
+ return ERR_PTR(-EPERM);
+
+ return fds;
+}
+
+int devrandom_read(devrandom_t *devrandom, void *buf, size_t len, int wait)
+{
+ if (wait)
+ return linux_read(devrandom->randomfd, buf, len);
+
+ return linux_read(devrandom->urandomfd, buf, len);
+}
diff --git a/arch/sandbox/mach-sandbox/include/mach/linux.h b/arch/sandbox/mach-sandbox/include/mach/linux.h
index c344285473e6..1e64d41c6a5e 100644
--- a/arch/sandbox/mach-sandbox/include/mach/linux.h
+++ b/arch/sandbox/mach-sandbox/include/mach/linux.h
@@ -51,4 +51,11 @@ void barebox_libftdi1_gpio_set_value(struct ft2232_bitbang *ftbb,
int barebox_libftdi1_update(struct ft2232_bitbang *ftbb);
void barebox_libftdi1_close(void);
+typedef struct {
+ int randomfd;
+ int urandomfd;
+} devrandom_t;
+devrandom_t *devrandom_init(void);
+int devrandom_read(devrandom_t *devrandom, void *buf, size_t len, int wait);
+
#endif /* __ASM_ARCH_LINUX_H */
diff --git a/drivers/hw_random/Kconfig b/drivers/hw_random/Kconfig
index d1297a48d0bb..c57928204d30 100644
--- a/drivers/hw_random/Kconfig
+++ b/drivers/hw_random/Kconfig
@@ -14,4 +14,12 @@ config HWRNG_MXC_RNGC
This driver provides kernel-side support for the Random Number
Generator hardware found on some Freescale i.MX processors.
+config HWRNG_DEV_RANDOM
+ tristate "Linux /dev/random and /dev/urandom RNG"
+ depends on SANDBOX
+ default y
+ help
+ This driver allows use of the host provided /dev/random
+ and /dev/urandom as barebox HWRNGs.
+
endif
diff --git a/drivers/hw_random/Makefile b/drivers/hw_random/Makefile
index 79c238c48d60..8be62f38b740 100644
--- a/drivers/hw_random/Makefile
+++ b/drivers/hw_random/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_HWRNG) += core.o
obj-$(CONFIG_HWRNG_MXC_RNGC) += mxc-rngc.o
+obj-$(CONFIG_HWRNG_DEV_RANDOM) += dev-random.o
diff --git a/drivers/hw_random/dev-random.c b/drivers/hw_random/dev-random.c
new file mode 100644
index 000000000000..2170db7437ce
--- /dev/null
+++ b/drivers/hw_random/dev-random.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Ahmad Fatoum, Pengutronix
+ */
+
+#include <common.h>
+#include <init.h>
+#include <linux/hw_random.h>
+#include <mach/linux.h>
+
+struct devrandom_rnd {
+ struct hwrng hwrng;
+ devrandom_t *priv;
+};
+
+static inline struct devrandom_rnd *to_rnd(struct hwrng *hwrng)
+{
+ return container_of(hwrng, struct devrandom_rnd, hwrng);
+}
+
+static int devrandom_rnd_read(struct hwrng *hwrng, void *buf, size_t max, bool wait)
+{
+ return devrandom_read(to_rnd(hwrng)->priv, buf, max, wait);
+}
+
+static int devrandom_rnd_init(struct hwrng *hwrng)
+{
+ devrandom_t *devrandom = devrandom_init();
+ if (IS_ERR(devrandom))
+ return PTR_ERR(devrandom);
+
+ to_rnd(hwrng)->priv = devrandom;
+ return 0;
+}
+
+static int devrandom_rnd_probe(struct device_d *dev)
+{
+ struct devrandom_rnd *rnd;
+ int ret;
+
+ rnd = xzalloc(sizeof(*rnd));
+
+ rnd->hwrng.name = dev->name;
+ rnd->hwrng.read = devrandom_rnd_read;
+ rnd->hwrng.init = devrandom_rnd_init;
+
+ ret = hwrng_register(dev, &rnd->hwrng);
+ if (ret) {
+ dev_err(dev, "failed to register: %s\n", strerror(-ret));
+
+ return ret;
+ }
+
+ dev_info(dev, "Registered.\n");
+
+ return 0;
+}
+
+static struct driver_d devrandom_rnd_driver = {
+ .name = "devrandom",
+ .probe = devrandom_rnd_probe,
+};
+device_platform_driver(devrandom_rnd_driver);
--
2.20.1
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