diff options
Diffstat (limited to 'drivers/char')
-rw-r--r-- | drivers/char/mem.c | 2 | ||||
-rw-r--r-- | drivers/char/random.c | 72 |
2 files changed, 18 insertions, 56 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index cc296f0823bd..9f586025dbe6 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -707,7 +707,7 @@ static const struct memdev { [5] = { "zero", 0666, &zero_fops, FMODE_NOWAIT }, [7] = { "full", 0666, &full_fops, 0 }, [8] = { "random", 0666, &random_fops, 0 }, - [9] = { "urandom", 0666, &urandom_fops, 0 }, + [9] = { "urandom", 0666, &random_fops, 0 }, #ifdef CONFIG_PRINTK [11] = { "kmsg", 0644, &kmsg_fops, 0 }, #endif diff --git a/drivers/char/random.c b/drivers/char/random.c index 8171c3bbf460..9831797e0699 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -89,17 +89,14 @@ static LIST_HEAD(random_ready_list); /* Control how we warn userspace. */ static struct ratelimit_state unseeded_warning = RATELIMIT_STATE_INIT("warn_unseeded_randomness", HZ, 3); -static struct ratelimit_state urandom_warning = - RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3); static int ratelimit_disable __read_mostly; module_param_named(ratelimit_disable, ratelimit_disable, int, 0644); MODULE_PARM_DESC(ratelimit_disable, "Disable random ratelimit suppression"); /* * Returns whether or not the input pool has been seeded and thus guaranteed - * to supply cryptographically secure random numbers. This applies to: the - * /dev/urandom device, the get_random_bytes function, and the get_random_{u32, - * ,u64,int,long} family of functions. + * to supply cryptographically secure random numbers. This applies to + * get_random_bytes() and get_random_{u32,u64,int,long}(). * * Returns: true if the input pool has been seeded. * false if the input pool has not been seeded. @@ -115,10 +112,10 @@ static void try_to_generate_entropy(void); /* * Wait for the input pool to be seeded and thus guaranteed to supply - * cryptographically secure random numbers. This applies to: the /dev/urandom - * device, the get_random_bytes function, and the get_random_{u32,u64,int,long} - * family of functions. Using any of these functions without first calling - * this function forfeits the guarantee of security. + * cryptographically secure random numbers. This applies to + * get_random_bytes() and get_random_{u32,u64,int,long}(). Using any + * of these functions without first calling this function means that + * the returned numbers might not be cryptographically secure. * * Returns: 0 if the input pool has been seeded. * -ERESTARTSYS if the function was interrupted by a signal. @@ -256,10 +253,10 @@ static void _warn_unseeded_randomness(const char *func_name, void *caller, void * unsigned long get_random_long() * * These interfaces will return the requested number of random bytes - * into the given buffer or as a return value. This is equivalent to - * a read from /dev/urandom. The integer family of functions may be - * higher performance for one-off random integers, because they do a - * bit of buffering. + * into the given buffer or as a return value. The returned numbers are + * the same as those of getrandom(0). The integer family of functions may + * be higher performance for one-off random integers, because they do a + * bit of buffering and do not invoke reseeding. * *********************************************************************/ @@ -336,11 +333,6 @@ static void crng_reseed(void) unseeded_warning.missed); unseeded_warning.missed = 0; } - if (urandom_warning.missed) { - pr_notice("%d urandom warning(s) missed due to ratelimiting\n", - urandom_warning.missed); - urandom_warning.missed = 0; - } } } @@ -993,10 +985,8 @@ int __init rand_initialize(void) pr_notice("crng init done (trusting CPU's manufacturer)\n"); } - if (ratelimit_disable) { - urandom_warning.interval = 0; + if (ratelimit_disable) unseeded_warning.interval = 0; - } return 0; } @@ -1386,20 +1376,16 @@ static void try_to_generate_entropy(void) * getrandom(2) is the primary modern interface into the RNG and should * be used in preference to anything else. * - * Reading from /dev/random has the same functionality as calling - * getrandom(2) with flags=0. In earlier versions, however, it had - * vastly different semantics and should therefore be avoided, to - * prevent backwards compatibility issues. - * - * Reading from /dev/urandom has the same functionality as calling - * getrandom(2) with flags=GRND_INSECURE. Because it does not block - * waiting for the RNG to be ready, it should not be used. + * Reading from /dev/random and /dev/urandom both have the same effect + * as calling getrandom(2) with flags=0. (In earlier versions, however, + * they each had different semantics.) * * Writing to either /dev/random or /dev/urandom adds entropy to * the input pool but does not credit it. * - * Polling on /dev/random indicates when the RNG is initialized, on - * the read side, and when it wants new entropy, on the write side. + * Polling on /dev/random or /dev/urandom indicates when the RNG + * is initialized, on the read side, and when it wants new entropy, + * on the write side. * * Both /dev/random and /dev/urandom have the same set of ioctls for * adding entropy, getting the entropy count, zeroing the count, and @@ -1484,21 +1470,6 @@ static ssize_t random_write(struct file *file, const char __user *buffer, return (ssize_t)count; } -static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes, - loff_t *ppos) -{ - static int maxwarn = 10; - - if (!crng_ready() && maxwarn > 0) { - maxwarn--; - if (__ratelimit(&urandom_warning)) - pr_notice("%s: uninitialized urandom read (%zd bytes read)\n", - current->comm, nbytes); - } - - return get_random_bytes_user(buf, nbytes); -} - static ssize_t random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { @@ -1585,15 +1556,6 @@ const struct file_operations random_fops = { .llseek = noop_llseek, }; -const struct file_operations urandom_fops = { - .read = urandom_read, - .write = random_write, - .unlocked_ioctl = random_ioctl, - .compat_ioctl = compat_ptr_ioctl, - .fasync = random_fasync, - .llseek = noop_llseek, -}; - /******************************************************************** * |