android_kernel_google_msm/include/linux/random.h

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/*
* include/linux/random.h
*
* Include file for the random number generator.
*/
#ifndef _LINUX_RANDOM_H
#define _LINUX_RANDOM_H
#include <linux/types.h>
#include <linux/ioctl.h>
#include <linux/irqnr.h>
/* ioctl()'s for the random number generator */
/* Get the entropy count. */
#define RNDGETENTCNT _IOR( 'R', 0x00, int )
/* Add to (or subtract from) the entropy count. (Superuser only.) */
#define RNDADDTOENTCNT _IOW( 'R', 0x01, int )
/* Get the contents of the entropy pool. (Superuser only.) */
#define RNDGETPOOL _IOR( 'R', 0x02, int [2] )
/*
* Write bytes into the entropy pool and add to the entropy count.
* (Superuser only.)
*/
#define RNDADDENTROPY _IOW( 'R', 0x03, int [2] )
/* Clear entropy count to 0. (Superuser only.) */
#define RNDZAPENTCNT _IO( 'R', 0x04 )
/* Clear the entropy pool and associated counters. (Superuser only.) */
#define RNDCLEARPOOL _IO( 'R', 0x06 )
struct rand_pool_info {
int entropy_count;
int buf_size;
__u32 buf[0];
};
struct rnd_state {
__u32 s1, s2, s3;
};
/* Exported functions */
BACKPORT: random: introduce getrandom(2) system call Almost clean cherry pick of c6e9d6f38894798696f23c8084ca7edbf16ee895, includes change made by merge 0891ad829d2a0501053703df66029e843e3b8365. The getrandom(2) system call was requested by the LibreSSL Portable developers. It is analoguous to the getentropy(2) system call in OpenBSD. The rationale of this system call is to provide resiliance against file descriptor exhaustion attacks, where the attacker consumes all available file descriptors, forcing the use of the fallback code where /dev/[u]random is not available. Since the fallback code is often not well-tested, it is better to eliminate this potential failure mode entirely. The other feature provided by this new system call is the ability to request randomness from the /dev/urandom entropy pool, but to block until at least 128 bits of entropy has been accumulated in the /dev/urandom entropy pool. Historically, the emphasis in the /dev/urandom development has been to ensure that urandom pool is initialized as quickly as possible after system boot, and preferably before the init scripts start execution. This is because changing /dev/urandom reads to block represents an interface change that could potentially break userspace which is not acceptable. In practice, on most x86 desktop and server systems, in general the entropy pool can be initialized before it is needed (and in modern kernels, we will printk a warning message if not). However, on an embedded system, this may not be the case. And so with this new interface, we can provide the functionality of blocking until the urandom pool has been initialized. Any userspace program which uses this new functionality must take care to assure that if it is used during the boot process, that it will not cause the init scripts or other portions of the system startup to hang indefinitely. SYNOPSIS #include <linux/random.h> int getrandom(void *buf, size_t buflen, unsigned int flags); DESCRIPTION The system call getrandom() fills the buffer pointed to by buf with up to buflen random bytes which can be used to seed user space random number generators (i.e., DRBG's) or for other cryptographic uses. It should not be used for Monte Carlo simulations or other programs/algorithms which are doing probabilistic sampling. If the GRND_RANDOM flags bit is set, then draw from the /dev/random pool instead of the /dev/urandom pool. The /dev/random pool is limited based on the entropy that can be obtained from environmental noise, so if there is insufficient entropy, the requested number of bytes may not be returned. If there is no entropy available at all, getrandom(2) will either block, or return an error with errno set to EAGAIN if the GRND_NONBLOCK bit is set in flags. If the GRND_RANDOM bit is not set, then the /dev/urandom pool will be used. Unlike using read(2) to fetch data from /dev/urandom, if the urandom pool has not been sufficiently initialized, getrandom(2) will block (or return -1 with the errno set to EAGAIN if the GRND_NONBLOCK bit is set in flags). The getentropy(2) system call in OpenBSD can be emulated using the following function: int getentropy(void *buf, size_t buflen) { int ret; if (buflen > 256) goto failure; ret = getrandom(buf, buflen, 0); if (ret < 0) return ret; if (ret == buflen) return 0; failure: errno = EIO; return -1; } RETURN VALUE On success, the number of bytes that was filled in the buf is returned. This may not be all the bytes requested by the caller via buflen if insufficient entropy was present in the /dev/random pool, or if the system call was interrupted by a signal. On error, -1 is returned, and errno is set appropriately. ERRORS EINVAL An invalid flag was passed to getrandom(2) EFAULT buf is outside the accessible address space. EAGAIN The requested entropy was not available, and getentropy(2) would have blocked if the GRND_NONBLOCK flag was not set. EINTR While blocked waiting for entropy, the call was interrupted by a signal handler; see the description of how interrupted read(2) calls on "slow" devices are handled with and without the SA_RESTART flag in the signal(7) man page. NOTES For small requests (buflen <= 256) getrandom(2) will not return EINTR when reading from the urandom pool once the entropy pool has been initialized, and it will return all of the bytes that have been requested. This is the recommended way to use getrandom(2), and is designed for compatibility with OpenBSD's getentropy() system call. However, if you are using GRND_RANDOM, then getrandom(2) may block until the entropy accounting determines that sufficient environmental noise has been gathered such that getrandom(2) will be operating as a NRBG instead of a DRBG for those people who are working in the NIST SP 800-90 regime. Since it may block for a long time, these guarantees do *not* apply. The user may want to interrupt a hanging process using a signal, so blocking until all of the requested bytes are returned would be unfriendly. For this reason, the user of getrandom(2) MUST always check the return value, in case it returns some error, or if fewer bytes than requested was returned. In the case of !GRND_RANDOM and small request, the latter should never happen, but the careful userspace code (and all crypto code should be careful) should check for this anyway! Finally, unless you are doing long-term key generation (and perhaps not even then), you probably shouldn't be using GRND_RANDOM. The cryptographic algorithms used for /dev/urandom are quite conservative, and so should be sufficient for all purposes. The disadvantage of GRND_RANDOM is that it can block, and the increased complexity required to deal with partially fulfilled getrandom(2) requests. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Zach Brown <zab@zabbo.net> Bug: http://b/29621447 Change-Id: I189ba74070dd6d918b0fdf83ff30bb74ec0f7556 (cherry picked from commit 4af712e8df998475736f3e2727701bd31e3751a9) [flex1911]: backport to 3.4
2014-07-17 08:13:05 +00:00
/*
* Flags for getrandom(2)
*
* GRND_NONBLOCK Don't block and return EAGAIN instead
* GRND_RANDOM Use the /dev/random pool instead of /dev/urandom
*/
#define GRND_NONBLOCK 0x0001
#define GRND_RANDOM 0x0002
#ifdef __KERNEL__
extern void add_device_randomness(const void *, unsigned int);
extern void add_input_randomness(unsigned int type, unsigned int code,
unsigned int value);
extern void add_interrupt_randomness(int irq, int irq_flags);
extern void get_random_bytes(void *buf, int nbytes);
random: add new get_random_bytes_arch() function commit c2557a303ab6712bb6e09447df828c557c710ac9 upstream. Create a new function, get_random_bytes_arch() which will use the architecture-specific hardware random number generator if it is present. Change get_random_bytes() to not use the HW RNG, even if it is avaiable. The reason for this is that the hw random number generator is fast (if it is present), but it requires that we trust the hardware manufacturer to have not put in a back door. (For example, an increasing counter encrypted by an AES key known to the NSA.) It's unlikely that Intel (for example) was paid off by the US Government to do this, but it's impossible for them to prove otherwise --- especially since Bull Mountain is documented to use AES as a whitener. Hence, the output of an evil, trojan-horse version of RDRAND is statistically indistinguishable from an RDRAND implemented to the specifications claimed by Intel. Short of using a tunnelling electronic microscope to reverse engineer an Ivy Bridge chip and disassembling and analyzing the CPU microcode, there's no way for us to tell for sure. Since users of get_random_bytes() in the Linux kernel need to be able to support hardware systems where the HW RNG is not present, most time-sensitive users of this interface have already created their own cryptographic RNG interface which uses get_random_bytes() as a seed. So it's much better to use the HW RNG to improve the existing random number generator, by mixing in any entropy returned by the HW RNG into /dev/random's entropy pool, but to always _use_ /dev/random's entropy pool. This way we get almost of the benefits of the HW RNG without any potential liabilities. The only benefits we forgo is the speed/performance enhancements --- and generic kernel code can't depend on depend on get_random_bytes() having the speed of a HW RNG anyway. For those places that really want access to the arch-specific HW RNG, if it is available, we provide get_random_bytes_arch(). Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Ed Tam <etam@google.com>
2012-07-05 14:35:23 +00:00
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);
#ifndef MODULE
extern const struct file_operations random_fops, urandom_fops;
#endif
unsigned int get_random_int(void);
unsigned long get_random_long(void);
unsigned long randomize_range(unsigned long start, unsigned long end, unsigned long len);
random32: rename random32 to prandom This renames all random32 functions to have 'prandom_' prefix as follows: void prandom_seed(u32 seed); /* rename from srandom32() */ u32 prandom_u32(void); /* rename from random32() */ void prandom_seed_state(struct rnd_state *state, u64 seed); /* rename from prandom32_seed() */ u32 prandom_u32_state(struct rnd_state *state); /* rename from prandom32() */ The purpose of this renaming is to prevent some kernel developers from assuming that prandom32() and random32() might imply that only prandom32() was the one using a pseudo-random number generator by prandom32's "p", and the result may be a very embarassing security exposure. This concern was expressed by Theodore Ts'o. And furthermore, I'm going to introduce new functions for getting the requested number of pseudo-random bytes. If I continue to use both prandom32 and random32 prefixes for these functions, the confusion is getting worse. As a result of this renaming, "prandom_" is the common prefix for pseudo-random number library. Currently, srandom32() and random32() are preserved because it is difficult to rename too many users at once. Change-Id: I8c4118c9356d1917048ea435f32b68e20d04b577 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Robert Love <robert.w.love@intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: David Laight <david.laight@aculab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eilon Greenstein <eilong@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 00:04:23 +00:00
u32 prandom_u32(void);
void prandom_bytes(void *buf, int nbytes);
random32: rename random32 to prandom This renames all random32 functions to have 'prandom_' prefix as follows: void prandom_seed(u32 seed); /* rename from srandom32() */ u32 prandom_u32(void); /* rename from random32() */ void prandom_seed_state(struct rnd_state *state, u64 seed); /* rename from prandom32_seed() */ u32 prandom_u32_state(struct rnd_state *state); /* rename from prandom32() */ The purpose of this renaming is to prevent some kernel developers from assuming that prandom32() and random32() might imply that only prandom32() was the one using a pseudo-random number generator by prandom32's "p", and the result may be a very embarassing security exposure. This concern was expressed by Theodore Ts'o. And furthermore, I'm going to introduce new functions for getting the requested number of pseudo-random bytes. If I continue to use both prandom32 and random32 prefixes for these functions, the confusion is getting worse. As a result of this renaming, "prandom_" is the common prefix for pseudo-random number library. Currently, srandom32() and random32() are preserved because it is difficult to rename too many users at once. Change-Id: I8c4118c9356d1917048ea435f32b68e20d04b577 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Robert Love <robert.w.love@intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: David Laight <david.laight@aculab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eilon Greenstein <eilong@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 00:04:23 +00:00
void prandom_seed(u32 seed);
void prandom_reseed_late(void);
random32: rename random32 to prandom This renames all random32 functions to have 'prandom_' prefix as follows: void prandom_seed(u32 seed); /* rename from srandom32() */ u32 prandom_u32(void); /* rename from random32() */ void prandom_seed_state(struct rnd_state *state, u64 seed); /* rename from prandom32_seed() */ u32 prandom_u32_state(struct rnd_state *state); /* rename from prandom32() */ The purpose of this renaming is to prevent some kernel developers from assuming that prandom32() and random32() might imply that only prandom32() was the one using a pseudo-random number generator by prandom32's "p", and the result may be a very embarassing security exposure. This concern was expressed by Theodore Ts'o. And furthermore, I'm going to introduce new functions for getting the requested number of pseudo-random bytes. If I continue to use both prandom32 and random32 prefixes for these functions, the confusion is getting worse. As a result of this renaming, "prandom_" is the common prefix for pseudo-random number library. Currently, srandom32() and random32() are preserved because it is difficult to rename too many users at once. Change-Id: I8c4118c9356d1917048ea435f32b68e20d04b577 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Robert Love <robert.w.love@intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: David Laight <david.laight@aculab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eilon Greenstein <eilong@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 00:04:23 +00:00
/*
* These macros are preserved for backward compatibility and should be
* removed as soon as a transition is finished.
*/
#define random32() prandom_u32()
#define srandom32(seed) prandom_seed(seed)
u32 prandom_u32_state(struct rnd_state *);
void prandom_bytes_state(struct rnd_state *state, void *buf, int nbytes);
/*
* Handle minimum values for seeds
*/
static inline u32 __seed(u32 x, u32 m)
{
return (x < m) ? x + m : x;
}
/**
random32: rename random32 to prandom This renames all random32 functions to have 'prandom_' prefix as follows: void prandom_seed(u32 seed); /* rename from srandom32() */ u32 prandom_u32(void); /* rename from random32() */ void prandom_seed_state(struct rnd_state *state, u64 seed); /* rename from prandom32_seed() */ u32 prandom_u32_state(struct rnd_state *state); /* rename from prandom32() */ The purpose of this renaming is to prevent some kernel developers from assuming that prandom32() and random32() might imply that only prandom32() was the one using a pseudo-random number generator by prandom32's "p", and the result may be a very embarassing security exposure. This concern was expressed by Theodore Ts'o. And furthermore, I'm going to introduce new functions for getting the requested number of pseudo-random bytes. If I continue to use both prandom32 and random32 prefixes for these functions, the confusion is getting worse. As a result of this renaming, "prandom_" is the common prefix for pseudo-random number library. Currently, srandom32() and random32() are preserved because it is difficult to rename too many users at once. Change-Id: I8c4118c9356d1917048ea435f32b68e20d04b577 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Robert Love <robert.w.love@intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: David Laight <david.laight@aculab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eilon Greenstein <eilong@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 00:04:23 +00:00
* prandom_seed_state - set seed for prandom_u32_state().
* @state: pointer to state structure to receive the seed.
* @seed: arbitrary 64-bit value to use as a seed.
*/
random32: rename random32 to prandom This renames all random32 functions to have 'prandom_' prefix as follows: void prandom_seed(u32 seed); /* rename from srandom32() */ u32 prandom_u32(void); /* rename from random32() */ void prandom_seed_state(struct rnd_state *state, u64 seed); /* rename from prandom32_seed() */ u32 prandom_u32_state(struct rnd_state *state); /* rename from prandom32() */ The purpose of this renaming is to prevent some kernel developers from assuming that prandom32() and random32() might imply that only prandom32() was the one using a pseudo-random number generator by prandom32's "p", and the result may be a very embarassing security exposure. This concern was expressed by Theodore Ts'o. And furthermore, I'm going to introduce new functions for getting the requested number of pseudo-random bytes. If I continue to use both prandom32 and random32 prefixes for these functions, the confusion is getting worse. As a result of this renaming, "prandom_" is the common prefix for pseudo-random number library. Currently, srandom32() and random32() are preserved because it is difficult to rename too many users at once. Change-Id: I8c4118c9356d1917048ea435f32b68e20d04b577 Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Robert Love <robert.w.love@intel.com> Cc: Michel Lespinasse <walken@google.com> Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: David Laight <david.laight@aculab.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eilon Greenstein <eilong@broadcom.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18 00:04:23 +00:00
static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
{
u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
random32: fix off-by-one in seeding requirement [ Upstream commit 51c37a70aaa3f95773af560e6db3073520513912 ] For properly initialising the Tausworthe generator [1], we have a strict seeding requirement, that is, s1 > 1, s2 > 7, s3 > 15. Commit 697f8d0348 ("random32: seeding improvement") introduced a __seed() function that imposes boundary checks proposed by the errata paper [2] to properly ensure above conditions. However, we're off by one, as the function is implemented as: "return (x < m) ? x + m : x;", and called with __seed(X, 1), __seed(X, 7), __seed(X, 15). Thus, an unwanted seed of 1, 7, 15 would be possible, whereas the lower boundary should actually be of at least 2, 8, 16, just as GSL does. Fix this, as otherwise an initialization with an unwanted seed could have the effect that Tausworthe's PRNG properties cannot not be ensured. Note that this PRNG is *not* used for cryptography in the kernel. [1] http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme.ps [2] http://www.iro.umontreal.ca/~lecuyer/myftp/papers/tausme2.ps Joint work with Hannes Frederic Sowa. Change-Id: I9c63774e7a0cd5d747469b11b8769867484f36f9 Fixes: 697f8d0348a6 ("random32: seeding improvement") Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Florian Weimer <fweimer@redhat.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-11-11 11:20:32 +00:00
state->s1 = __seed(i, 2);
state->s2 = __seed(i, 8);
state->s3 = __seed(i, 16);
}
#ifdef CONFIG_ARCH_RANDOM
# include <asm/archrandom.h>
#else
static inline int arch_get_random_long(unsigned long *v)
{
return 0;
}
static inline int arch_get_random_int(unsigned int *v)
{
return 0;
}
#endif
#endif /* __KERNEL___ */
#endif /* _LINUX_RANDOM_H */