diff options
| -rw-r--r-- | arch/x86/syscalls/syscall_32.tbl | 1 | ||||
| -rw-r--r-- | arch/x86/syscalls/syscall_64.tbl | 1 | ||||
| -rw-r--r-- | drivers/char/random.c | 40 | ||||
| -rw-r--r-- | include/linux/syscalls.h | 3 | ||||
| -rw-r--r-- | include/uapi/asm-generic/unistd.h | 4 | ||||
| -rw-r--r-- | include/uapi/linux/random.h | 9 |
6 files changed, 54 insertions, 4 deletions
diff --git a/arch/x86/syscalls/syscall_32.tbl b/arch/x86/syscalls/syscall_32.tbl index d6b8679..5b46a61 100644 --- a/arch/x86/syscalls/syscall_32.tbl +++ b/arch/x86/syscalls/syscall_32.tbl @@ -360,3 +360,4 @@ 351 i386 sched_setattr sys_sched_setattr 352 i386 sched_getattr sys_sched_getattr 353 i386 renameat2 sys_renameat2 +355 i386 getrandom sys_getrandom diff --git a/arch/x86/syscalls/syscall_64.tbl b/arch/x86/syscalls/syscall_64.tbl index ec255a1..0dc4bf8 100644 --- a/arch/x86/syscalls/syscall_64.tbl +++ b/arch/x86/syscalls/syscall_64.tbl @@ -323,6 +323,7 @@ 314 common sched_setattr sys_sched_setattr 315 common sched_getattr sys_sched_getattr 316 common renameat2 sys_renameat2 +318 common getrandom sys_getrandom # # x32-specific system call numbers start at 512 to avoid cache impact diff --git a/drivers/char/random.c b/drivers/char/random.c index aa22fe5..7d1682e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -258,6 +258,8 @@ #include <linux/kmemcheck.h> #include <linux/workqueue.h> #include <linux/irq.h> +#include <linux/syscalls.h> +#include <linux/completion.h> #include <asm/processor.h> #include <asm/uaccess.h> @@ -404,6 +406,7 @@ static struct poolinfo { */ static DECLARE_WAIT_QUEUE_HEAD(random_read_wait); static DECLARE_WAIT_QUEUE_HEAD(random_write_wait); +static DECLARE_WAIT_QUEUE_HEAD(urandom_init_wait); static struct fasync_struct *fasync; /********************************************************************** @@ -657,6 +660,7 @@ retry: r->entropy_total = 0; if (r == &nonblocking_pool) { prandom_reseed_late(); + wake_up_interruptible(&urandom_init_wait); pr_notice("random: %s pool is initialized\n", r->name); } } @@ -1174,13 +1178,14 @@ static ssize_t extract_entropy_user(struct entropy_store *r, void __user *buf, { ssize_t ret = 0, i; __u8 tmp[EXTRACT_SIZE]; + int large_request = (nbytes > 256); trace_extract_entropy_user(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_); xfer_secondary_pool(r, nbytes); nbytes = account(r, nbytes, 0, 0); while (nbytes) { - if (need_resched()) { + if (large_request && need_resched()) { if (signal_pending(current)) { if (ret == 0) ret = -ERESTARTSYS; @@ -1355,7 +1360,7 @@ static int arch_random_refill(void) } static ssize_t -random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +_random_read(int nonblock, char __user *buf, size_t nbytes) { ssize_t n; @@ -1379,7 +1384,7 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) if (arch_random_refill()) continue; - if (file->f_flags & O_NONBLOCK) + if (nonblock) return -EAGAIN; wait_event_interruptible(random_read_wait, @@ -1391,6 +1396,12 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) } static ssize_t +random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) +{ + return _random_read(file->f_flags & O_NONBLOCK, buf, nbytes); +} + +static ssize_t urandom_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos) { int ret; @@ -1533,6 +1544,29 @@ const struct file_operations urandom_fops = { .llseek = noop_llseek, }; +SYSCALL_DEFINE3(getrandom, char __user *, buf, size_t, count, + unsigned int, flags) +{ + if (flags & ~(GRND_NONBLOCK|GRND_RANDOM)) + return -EINVAL; + + if (count > INT_MAX) + count = INT_MAX; + + if (flags & GRND_RANDOM) + return _random_read(flags & GRND_NONBLOCK, buf, count); + + if (unlikely(nonblocking_pool.initialized == 0)) { + if (flags & GRND_NONBLOCK) + return -EAGAIN; + wait_event_interruptible(urandom_init_wait, + nonblocking_pool.initialized); + if (signal_pending(current)) + return -ERESTARTSYS; + } + return urandom_read(NULL, buf, count, NULL); +} + /*************************************************************** * Random UUID interface * diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index b0881a0..43324a8 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -866,4 +866,7 @@ asmlinkage long sys_process_vm_writev(pid_t pid, asmlinkage long sys_kcmp(pid_t pid1, pid_t pid2, int type, unsigned long idx1, unsigned long idx2); asmlinkage long sys_finit_module(int fd, const char __user *uargs, int flags); +asmlinkage long sys_getrandom(char __user *buf, size_t count, + unsigned int flags); + #endif diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 3336406..1d104a2 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -699,9 +699,11 @@ __SYSCALL(__NR_sched_setattr, sys_sched_setattr) __SYSCALL(__NR_sched_getattr, sys_sched_getattr) #define __NR_renameat2 276 __SYSCALL(__NR_renameat2, sys_renameat2) +#define __NR_getrandom 278 +__SYSCALL(__NR_getrandom, sys_getrandom) #undef __NR_syscalls -#define __NR_syscalls 277 +#define __NR_syscalls 279 /* * All syscalls below here should go away really, diff --git a/include/uapi/linux/random.h b/include/uapi/linux/random.h index fff3528..3f93d16 100644 --- a/include/uapi/linux/random.h +++ b/include/uapi/linux/random.h @@ -40,4 +40,13 @@ struct rand_pool_info { __u32 buf[0]; }; +/* + * 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 + #endif /* _UAPI_LINUX_RANDOM_H */ |
