From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephan Mueller Subject: [PATCH v7 1/5] random: Blocking API for accessing nonblocking_pool Date: Wed, 20 May 2015 19:44:39 +0200 Message-ID: <143216583.t5fUODkLsI@tachyon.chronox.de> References: <1693038.ndeE0L22jl@tachyon.chronox.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: pebolle@tiscali.nl, andreas.steffen@strongswan.org, tytso@mit.edu, sandyinchina@gmail.com, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org To: herbert@gondor.apana.org.au Return-path: In-Reply-To: <1693038.ndeE0L22jl@tachyon.chronox.de> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org The added API calls provide a synchronous function call get_blocking_random_bytes where the caller is blocked until the nonblocking_pool is initialized. CC: Andreas Steffen CC: Theodore Ts'o CC: Sandy Harris Signed-off-by: Stephan Mueller --- drivers/char/random.c | 18 ++++++++++++++++++ include/linux/random.h | 1 + 2 files changed, 19 insertions(+) diff --git a/drivers/char/random.c b/drivers/char/random.c index 9cd6968..3d1c027 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1245,6 +1245,24 @@ void get_random_bytes(void *buf, int nbytes) EXPORT_SYMBOL(get_random_bytes); /* + * Equivalent function to get_random_bytes with the difference that this + * function blocks the request until the nonblocking_pool is initialized. + */ +void get_blocking_random_bytes(void *buf, int nbytes) +{ + int rc; + + if (unlikely(nonblocking_pool.initialized == 0)) { + do { + rc = wait_event_interruptible(urandom_init_wait, + nonblocking_pool.initialized); + } while (rc == -ERESTARTSYS); + } + extract_entropy(&nonblocking_pool, buf, nbytes, 0, 0); +} +EXPORT_SYMBOL(get_blocking_random_bytes); + +/* * This function will use the architecture-specific hardware random * number generator if it is available. The arch-specific hw RNG will * almost certainly be faster than what we can do in software, but it diff --git a/include/linux/random.h b/include/linux/random.h index b05856e..796267d 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -14,6 +14,7 @@ extern void add_input_randomness(unsigned int type, unsigned int code, extern void add_interrupt_randomness(int irq, int irq_flags); extern void get_random_bytes(void *buf, int nbytes); +extern void get_blocking_random_bytes(void *buf, int nbytes); extern void get_random_bytes_arch(void *buf, int nbytes); void generate_random_uuid(unsigned char uuid_out[16]); extern int random_int_secret_init(void); -- 2.1.0