diff options
| -rw-r--r-- | sys/conf/files.i386 | 1 | ||||
| -rw-r--r-- | sys/i386/conf/files.i386 | 1 | ||||
| -rw-r--r-- | sys/kern/kern_fork.c | 7 | ||||
| -rw-r--r-- | sys/libkern/arc4random.c | 89 | ||||
| -rw-r--r-- | sys/sys/libkern.h | 1 |
5 files changed, 97 insertions, 2 deletions
diff --git a/sys/conf/files.i386 b/sys/conf/files.i386 index b0ad19ad625e..757110bd95ea 100644 --- a/sys/conf/files.i386 +++ b/sys/conf/files.i386 @@ -373,6 +373,7 @@ isa/sio.c optional sio isa/syscons_isa.c optional sc isa/vga_isa.c optional vga kern/subr_diskmbr.c standard +libkern/arc4random.c standard libkern/bcd.c standard libkern/divdi3.c standard libkern/index.c standard diff --git a/sys/i386/conf/files.i386 b/sys/i386/conf/files.i386 index b0ad19ad625e..757110bd95ea 100644 --- a/sys/i386/conf/files.i386 +++ b/sys/i386/conf/files.i386 @@ -373,6 +373,7 @@ isa/sio.c optional sio isa/syscons_isa.c optional sc isa/vga_isa.c optional vga kern/subr_diskmbr.c standard +libkern/arc4random.c standard libkern/bcd.c standard libkern/divdi3.c standard libkern/index.c standard diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index c12c965f7b69..9f3feb29f4bb 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -142,6 +142,9 @@ rfork(p, uap) int nprocs = 1; /* process 0 */ static int nextpid = 0; +static int randompid = 0; +SYSCTL_INT(_kern, OID_AUTO, randompid, CTLFLAG_RW, &randompid, 0, ""); + int fork1(p1, flags, procp) struct proc *p1; @@ -262,8 +265,8 @@ retry: * restart somewhat above 0, as the low-numbered procs * tend to include daemons that don't exit. */ - if (nextpid >= PID_MAX) { - nextpid = 100; + if (nextpid >= PID_MAX || randompid) { + nextpid = (randompid) ? arc4random() % PID_MAX : 100; pidchecked = 0; } if (nextpid >= pidchecked) { diff --git a/sys/libkern/arc4random.c b/sys/libkern/arc4random.c new file mode 100644 index 000000000000..3c4c06b1c342 --- /dev/null +++ b/sys/libkern/arc4random.c @@ -0,0 +1,89 @@ +/*- + * THE BEER-WARE LICENSE + * + * <dan@FreeBSD.ORG> wrote this file. As long as you retain this notice you + * can do whatever you want with this stuff. If we meet some day, and you + * think this stuff is worth it, you can buy me a beer in return. + * + * Dan Moschuk + * + * $FreeBSD$ + */ + +#include <sys/libkern.h> +#include <sys/time.h> + +static u_int8_t arc4_i, arc4_j; +static int arc4_initialized = 0; +static u_int8_t arc4_sbox[256]; + +static __inline void +arc4_swap(u_int8_t *a, u_int8_t *b) +{ + u_int8_t c; + + c = *a; + *a = *b; + *b = c; +} + +/* + * Initialize our S-box to its beginning defaults. + */ +static void +arc4_init(void) +{ + struct timespec ts; + u_int8_t key[256]; + int n; + + for (n = 0; n < 256; n++) + arc4_sbox[n] = (u_int8_t) n; + + nanotime(&ts); + srandom(ts.tv_sec ^ ts.tv_nsec); + for (n = 0; n < 256; n++) + key[n] = random() % 256; + + arc4_i = arc4_j = 0; + for (n = 0; n < 256; n++) + { + arc4_j = arc4_j + arc4_sbox[n] + key[n]; + arc4_swap(&arc4_sbox[n], &arc4_sbox[arc4_j]); + } + arc4_initialized = 1; +} + +/* + * Generate a random byte. + */ +static u_int8_t +arc4_randbyte(void) +{ + u_int8_t arc4_t; + + arc4_i = (arc4_i + 1) % 256; + arc4_j = (arc4_j + arc4_sbox[arc4_i]) % 256; + + arc4_swap(&arc4_sbox[arc4_i], &arc4_sbox[arc4_j]); + + arc4_t = (arc4_sbox[arc4_i] + arc4_sbox[arc4_j]) % 256; + return arc4_sbox[arc4_t]; +} + +u_int32_t +arc4random(void) +{ + u_int32_t ret; + + /* Initialize array if needed. */ + if (!arc4_initialized) + arc4_init(); + + ret = arc4_randbyte(); + ret |= arc4_randbyte() << 8; + ret |= arc4_randbyte() << 16; + ret |= arc4_randbyte() << 24; + + return ret; +} diff --git a/sys/sys/libkern.h b/sys/sys/libkern.h index 08deb16f170e..71947a0c5b90 100644 --- a/sys/sys/libkern.h +++ b/sys/sys/libkern.h @@ -61,6 +61,7 @@ static __inline u_long ulmax(u_long a, u_long b) { return (a > b ? a : b); } static __inline u_long ulmin(u_long a, u_long b) { return (a < b ? a : b); } /* Prototypes for non-quad routines. */ +u_int32_t arc4random __P((void)); int bcmp __P((const void *, const void *, size_t)); #ifndef HAVE_INLINE_FFS int ffs __P((int)); |