From: Stephen Boyd <swboyd@chromium.org> To: "Theodore Y . Ts'o" <tytso@mit.edu>, Hsin-Yi Wang <hsinyi@chromium.org>, linux-arm-kernel@lists.infradead.org Cc: Russell King <linux@armlinux.org.uk>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, "H . Peter Anvin" <hpa@zytor.com>, "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>, Kate Stewart <kstewart@linuxfoundation.org>, "David S . Miller" <davem@davemloft.net>, Viresh Kumar <viresh.kumar@linaro.org>, Marek Szyprowski <m.szyprowski@samsung.com>, Arnd Bergmann <arnd@arndb.de>, Marc Zyngier <maz@kernel.org>, Julien Thierry <julien.thierry.kdev@gmail.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Wei Li <liwei391@huawei.com>, Anders Roxell <anders.roxell@linaro.org>, Rob Herring <robh@kernel.org>, Aaro Koskinen <aaro.koskinen@nokia.com>, Daniel Thompson <daniel.thompson@linaro.org>, Tim Chen <tim.c.chen@linux.intel.com>, Rik van Riel <riel@surriel.com>, Waiman Long <longman@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Armijn Hemel <armijn@tjaldur.nl>, Grzegorz Halat <ghalat@redhat.com>, Len Brown <len.brown@intel.com>, Shaokun Zhang <zhangshaokun@hisilicon.com>, Mike Rapoport <rppt@linux.vnet.ibm.com>, Kees Cook <keescook@chromium.org>, Guenter Roeck <groeck@chromium.org>, Andrew Morton <akpm@linux-foundation.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Alexey Dobriyan <adobriyan@gmail.com>, Yury Norov <ynorov@marvell.com>, Josh Poimboeuf <jpoimboe@redhat.com>, Jiri Kosina <jkosina@suse.cz>, Mukesh Ojha <mojha@codeaurora.org>, linux-kernel@vger.kernel.org Subject: Re: [PATCH v9 2/3] fdt: add support for rng-seed Date: Thu, 22 Aug 2019 10:39:51 -0700 [thread overview] Message-ID: <5d5ed368.1c69fb81.419fc.0803@mx.google.com> (raw) In-Reply-To: <20190822071522.143986-3-hsinyi@chromium.org> Quoting Hsin-Yi Wang (2019-08-22 00:15:22) > Introducing a chosen node, rng-seed, which is an entropy that can be > passed to kernel called very early to increase initial device > randomness. Bootloader should provide this entropy and the value is > read from /chosen/rng-seed in DT. > > Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(), > since early_init_dt_scan_chosen() would modify fdt to erase rng-seed. > > Add a new interface add_bootloader_randomness() for rng-seed use case. > Depends on whether the seed is trustworthy, rng seed would be passed to > add_hwgenerator_randomness(). Otherwise it would be passed to > add_device_randomness(). Decision is controlled by kernel config > RANDOM_TRUST_BOOTLOADER. > > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> > Reviewed-by: Stephen Boyd <swboyd@chromium.org> > Reviewed-by: Rob Herring <robh@kernel.org> > --- > Change from v8: > * Add a new interface add_bootloader_randomness > * Add a new kernel config > --- > drivers/char/Kconfig | 10 ++++++++++ > drivers/char/random.c | 15 +++++++++++++++ > drivers/of/fdt.c | 14 ++++++++++++-- > include/linux/random.h | 1 + > 4 files changed, 38 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig > index 96156c729a31..5974a5906fd0 100644 > --- a/drivers/char/Kconfig > +++ b/drivers/char/Kconfig > @@ -551,3 +551,13 @@ config RANDOM_TRUST_CPU > has not installed a hidden back door to compromise the CPU's > random number generation facilities. This can also be configured > at boot with "random.trust_cpu=on/off". > + > +config RANDOM_TRUST_BOOTLOADER > + bool "Trust the bootloader to initialize Linux's CRNG" > + default n You can drop the default. > + help > + Bootloader could provide rng-seed set in /chosen/rng-seed in DT to help > + increase initial device randomness. Assume the entropy provided is > + trustworthy, it would be regarded as true hardware RNGs and update the > + entropy estimate. Otherwise it would be regarded as device input that > + could help mix the entropy pool, but won't be added to actual entropy. Maybe reword this to something like: Some bootloaders can provide entropy to increase the kernel's initial device randomness. Say Y here to assume the entropy provided by the booloader is trustworthy so it will be added to the kernel's entropy pool. Otherwise, say N here so it will be regarded as device input that only mixes the entropy pool. > \ No newline at end of file > diff --git a/drivers/char/random.c b/drivers/char/random.c > index 5d5ea4ce1442..29d3ff3de1e1 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -2445,3 +2445,18 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, > credit_entropy_bits(poolp, entropy); > } > EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); > + > +/* Handle random seed passed by bootloader. > + * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise > + * it would be regarded as device data. > + * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER. > + */ > +void add_bootloader_randomness(const void *buf, unsigned int size) > +{ > +#ifdef CONFIG_RANDOM_TRUST_BOOTLOADER > + add_hwgenerator_randomness(buf, size, size * 8); > +#else > + add_device_randomness(buf, size); > +#endif Maybe use if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER)) add_hwgenerator_randomness(buf, size, size * 8); else add_device_randomness(buf, size); > +} > +EXPORT_SYMBOL_GPL(add_bootloader_randomness); > \ No newline at end of file
WARNING: multiple messages have this Message-ID (diff)
From: Stephen Boyd <swboyd@chromium.org> To: "Theodore Y . Ts'o" <tytso@mit.edu>, Hsin-Yi Wang <hsinyi@chromium.org>, linux-arm-kernel@lists.infradead.org Cc: Kate Stewart <kstewart@linuxfoundation.org>, Peter Zijlstra <peterz@infradead.org>, Catalin Marinas <catalin.marinas@arm.com>, Mukesh Ojha <mojha@codeaurora.org>, Grzegorz Halat <ghalat@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>, Guenter Roeck <groeck@chromium.org>, Will Deacon <will@kernel.org>, Marek Szyprowski <m.szyprowski@samsung.com>, Rob Herring <robh@kernel.org>, Daniel Thompson <daniel.thompson@linaro.org>, Anders Roxell <anders.roxell@linaro.org>, Yury Norov <ynorov@marvell.com>, Marc Zyngier <maz@kernel.org>, Russell King <linux@armlinux.org.uk>, Aaro Koskinen <aaro.koskinen@nokia.com>, Ingo Molnar <mingo@redhat.com>, Viresh Kumar <viresh.kumar@linaro.org>, Waiman Long <longman@redhat.com>, "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>, Wei Li <liwei391@huawei.com>, Alexey Dobriyan <adobriyan@gmail.com>, Julien Thierry <julien.thierry.kdev@gmail.com>, Len Brown <len.brown@intel.com>, Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>, Rik van Riel <riel@surriel.com>, Shaokun Zhang <zhangshaokun@hisilicon.com>, Mike Rapoport <rppt@linux.vnet.ibm.com>, Borislav Petkov <bp@alien8.de>, Josh Poimboeuf <jpoimboe@redhat.com>, Thomas Gleixner <tglx@linutronix.de>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Marcelo Tosatti <mtosatti@redhat.com>, linux-kernel@vger.kernel.org, Armijn Hemel <armijn@tjaldur.nl>, Jiri Kosina <jkosina@suse.cz>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Andrew Morton <akpm@linux-foundation.org>, Tim Chen <tim.c.chen@linux.intel.com>, "David S . Miller" <davem@davemloft.net> Subject: Re: [PATCH v9 2/3] fdt: add support for rng-seed Date: Thu, 22 Aug 2019 10:39:51 -0700 [thread overview] Message-ID: <5d5ed368.1c69fb81.419fc.0803@mx.google.com> (raw) In-Reply-To: <20190822071522.143986-3-hsinyi@chromium.org> Quoting Hsin-Yi Wang (2019-08-22 00:15:22) > Introducing a chosen node, rng-seed, which is an entropy that can be > passed to kernel called very early to increase initial device > randomness. Bootloader should provide this entropy and the value is > read from /chosen/rng-seed in DT. > > Obtain of_fdt_crc32 for CRC check after early_init_dt_scan_nodes(), > since early_init_dt_scan_chosen() would modify fdt to erase rng-seed. > > Add a new interface add_bootloader_randomness() for rng-seed use case. > Depends on whether the seed is trustworthy, rng seed would be passed to > add_hwgenerator_randomness(). Otherwise it would be passed to > add_device_randomness(). Decision is controlled by kernel config > RANDOM_TRUST_BOOTLOADER. > > Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> > Reviewed-by: Stephen Boyd <swboyd@chromium.org> > Reviewed-by: Rob Herring <robh@kernel.org> > --- > Change from v8: > * Add a new interface add_bootloader_randomness > * Add a new kernel config > --- > drivers/char/Kconfig | 10 ++++++++++ > drivers/char/random.c | 15 +++++++++++++++ > drivers/of/fdt.c | 14 ++++++++++++-- > include/linux/random.h | 1 + > 4 files changed, 38 insertions(+), 2 deletions(-) > > diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig > index 96156c729a31..5974a5906fd0 100644 > --- a/drivers/char/Kconfig > +++ b/drivers/char/Kconfig > @@ -551,3 +551,13 @@ config RANDOM_TRUST_CPU > has not installed a hidden back door to compromise the CPU's > random number generation facilities. This can also be configured > at boot with "random.trust_cpu=on/off". > + > +config RANDOM_TRUST_BOOTLOADER > + bool "Trust the bootloader to initialize Linux's CRNG" > + default n You can drop the default. > + help > + Bootloader could provide rng-seed set in /chosen/rng-seed in DT to help > + increase initial device randomness. Assume the entropy provided is > + trustworthy, it would be regarded as true hardware RNGs and update the > + entropy estimate. Otherwise it would be regarded as device input that > + could help mix the entropy pool, but won't be added to actual entropy. Maybe reword this to something like: Some bootloaders can provide entropy to increase the kernel's initial device randomness. Say Y here to assume the entropy provided by the booloader is trustworthy so it will be added to the kernel's entropy pool. Otherwise, say N here so it will be regarded as device input that only mixes the entropy pool. > \ No newline at end of file > diff --git a/drivers/char/random.c b/drivers/char/random.c > index 5d5ea4ce1442..29d3ff3de1e1 100644 > --- a/drivers/char/random.c > +++ b/drivers/char/random.c > @@ -2445,3 +2445,18 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, > credit_entropy_bits(poolp, entropy); > } > EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); > + > +/* Handle random seed passed by bootloader. > + * If the seed is trustworthy, it would be regarded as hardware RNGs. Otherwise > + * it would be regarded as device data. > + * The decision is controlled by CONFIG_RANDOM_TRUST_BOOTLOADER. > + */ > +void add_bootloader_randomness(const void *buf, unsigned int size) > +{ > +#ifdef CONFIG_RANDOM_TRUST_BOOTLOADER > + add_hwgenerator_randomness(buf, size, size * 8); > +#else > + add_device_randomness(buf, size); > +#endif Maybe use if (IS_ENABLED(CONFIG_RANDOM_TRUST_BOOTLOADER)) add_hwgenerator_randomness(buf, size, size * 8); else add_device_randomness(buf, size); > +} > +EXPORT_SYMBOL_GPL(add_bootloader_randomness); > \ No newline at end of file _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-08-22 17:39 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-22 7:15 [PATCH v9 0/3] add support for rng-seed Hsin-Yi Wang 2019-08-22 7:15 ` Hsin-Yi Wang 2019-08-22 7:15 ` [PATCH v9 1/3] arm64: map FDT as RW for early_init_dt_scan() Hsin-Yi Wang 2019-08-22 7:15 ` Hsin-Yi Wang 2019-08-22 7:15 ` [PATCH v9 2/3] fdt: add support for rng-seed Hsin-Yi Wang 2019-08-22 7:15 ` Hsin-Yi Wang 2019-08-22 16:03 ` Theodore Y. Ts'o 2019-08-22 16:03 ` Theodore Y. Ts'o 2019-08-22 17:39 ` Stephen Boyd [this message] 2019-08-22 17:39 ` Stephen Boyd 2019-08-24 19:04 ` Kees Cook 2019-08-24 19:04 ` Kees Cook 2019-08-29 10:03 ` Hsin-Yi Wang 2019-08-29 10:03 ` Hsin-Yi Wang 2019-08-29 15:45 ` Theodore Y. Ts'o 2019-08-29 15:45 ` Theodore Y. Ts'o 2019-08-29 16:25 ` Kees Cook 2019-08-29 16:22 ` Kees Cook 2019-08-29 16:22 ` Kees Cook 2019-08-22 7:15 ` [PATCH v9 3/3] arm64: kexec_file: add rng-seed support Hsin-Yi Wang 2019-08-22 7:15 ` Hsin-Yi Wang
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