diff options
Diffstat (limited to 'sys/libkern')
| -rw-r--r-- | sys/libkern/arc4random.c | 43 |
1 files changed, 26 insertions, 17 deletions
diff --git a/sys/libkern/arc4random.c b/sys/libkern/arc4random.c index 909d750..3a3227c 100644 --- a/sys/libkern/arc4random.c +++ b/sys/libkern/arc4random.c @@ -12,8 +12,12 @@ __FBSDID("$FreeBSD$"); #include <sys/types.h> +#include <sys/param.h> +#include <sys/kernel.h> #include <sys/random.h> #include <sys/libkern.h> +#include <sys/lock.h> +#include <sys/mutex.h> #include <sys/time.h> #define ARC4_RESEED_BYTES 65536 @@ -21,10 +25,10 @@ __FBSDID("$FreeBSD$"); #define ARC4_KEYBYTES (256 / 8) static u_int8_t arc4_i, arc4_j; -static int arc4_initialized = 0; static int arc4_numruns = 0; static u_int8_t arc4_sbox[256]; static time_t arc4_t_reseed; +static struct mtx arc4_mtx; static u_int8_t arc4_randbyte(void); @@ -53,6 +57,8 @@ arc4_randomstir (void) * device is not loaded -- MarkM. */ r = read_random(key, ARC4_KEYBYTES); + getmicrouptime(&tv_now); + mtx_lock(&arc4_mtx); /* If r == 0 || -1, just use what was on the stack. */ if (r > 0) { for (n = r; n < sizeof(key); n++) @@ -65,9 +71,17 @@ arc4_randomstir (void) } /* Reset for next reseed cycle. */ - getmicrouptime(&tv_now); arc4_t_reseed = tv_now.tv_sec + ARC4_RESEED_SECONDS; arc4_numruns = 0; + + /* + * Throw away the first N words of output, as suggested in the + * paper "Weaknesses in the Key Scheduling Algorithm of RC4" + * by Fluher, Mantin, and Shamir. (N = 256 in our case.) + */ + for (n = 0; n < 256*4; n++) + arc4_randbyte(); + mtx_unlock(&arc4_mtx); } /* @@ -78,22 +92,16 @@ arc4_init(void) { int n; + mtx_init(&arc4_mtx, "arc4_mtx", NULL, MTX_DEF); arc4_i = arc4_j = 0; for (n = 0; n < 256; n++) arc4_sbox[n] = (u_int8_t) n; - arc4_randomstir(); - arc4_initialized = 1; - - /* - * Throw away the first N words of output, as suggested in the - * paper "Weaknesses in the Key Scheduling Algorithm of RC4" - * by Fluher, Mantin, and Shamir. (N = 256 in our case.) - */ - for (n = 0; n < 256*4; n++) - arc4_randbyte(); + arc4_t_reseed = 0; } +SYSINIT(arc4_init, SI_SUB_LOCK, SI_ORDER_ANY, arc4_init, NULL); + /* * Generate a random byte. */ @@ -111,26 +119,27 @@ arc4_randbyte(void) return arc4_sbox[arc4_t]; } +/* + * MPSAFE + */ void arc4rand(void *ptr, u_int len, int reseed) { u_char *p; struct timeval tv; - /* Initialize array if needed. */ - if (!arc4_initialized) - arc4_init(); - getmicrouptime(&tv); - arc4_numruns += len; if (reseed || (arc4_numruns > ARC4_RESEED_BYTES) || (tv.tv_sec > arc4_t_reseed)) arc4_randomstir(); + mtx_lock(&arc4_mtx); + arc4_numruns += len; p = ptr; while (len--) *p++ = arc4_randbyte(); + mtx_unlock(&arc4_mtx); } uint32_t |
