For BSD/APPLE platform use native random calls
Solution not involving file descriptors, seeded upon fork and on
a regular basis.
MODIFY
afl-fuzz.c
afl-fuzz.c
#if defined(__APPLE__) || defined(__FreeBSD__) || defined (__OpenBSD__)
# include <sys/sysctl.h>
+# define HAVE_ARC4RANDOM 1
#endif /* __APPLE__ || __FreeBSD__ || __OpenBSD__ */
/* For systems that have sched_setaffinity; right now just Linux, but one
@@ -219,7 +220,9 @@ EXP_ST u8 skip_deterministic, /* Skip deterministic stages? */
fast_cal; /* Try to calibrate faster? */
static s32 out_fd, /* Persistent fd for out_file */
+#ifndef HAVE_ARC4RANDOM
dev_urandom_fd = -1, /* Persistent fd for /dev/urandom */
+#endif
dev_null_fd = -1, /* Persistent fd for /dev/null */
fsrv_ctl_fd, /* Fork server control pipe (write) */
fsrv_st_fd; /* Fork server status pipe (read) */
@@ -297,7 +300,9 @@ static u8 stage_val_type; /* Value type (STAGE_VAL_*) */
static u64 stage_finds[32], /* Patterns found per fuzz stage */
stage_cycles[32]; /* Execs per fuzz stage */
+#ifndef HAVE_ARC4RANDOM
static u32 rand_cnt; /* Random number counter */
+#endif
static u64 total_cal_us, /* Total calibration time (us) */
total_cal_cycles; /* Total calibration cycles */
@@ -641,14 +646,8 @@ static void trim_py(char** ret, size_t* retlen) {
int select_algorithm(void) {
int i_puppet, j_puppet;
- u32 seed[2];
-
- if (!fixed_seed) {
- ck_read(dev_urandom_fd, &seed, sizeof(seed), "/dev/urandom");
- srandom(seed[0]);
- }
- double sele = ((double)(random()%10000)*0.0001);
+ double sele = ((double)(UR(10000))*0.0001);
j_puppet = 0;
for (i_puppet = 0; i_puppet < operator_num; i_puppet++) {
if (unlikely(i_puppet == 0)) {
@@ -699,7 +698,15 @@ static u64 get_cur_time_us(void) {
have slight bias. */
static inline u32 UR(u32 limit) {
+#ifdef HAVE_ARC4RANDOM
+ if (fixed_seed) {
+ return random() % limit;
+ }
+ /* The boundary not being necessarily a power of 2,
+ we need to ensure the result uniformity. */
+ return arc4random_uniform(limit);
+#else
if (!fixed_seed && unlikely(!rand_cnt--)) {
u32 seed[2];
@@ -709,6 +716,7 @@ static inline u32 UR(u32 limit) {
}
return random() % limit;
+#endif
}
@@ -2407,7 +2415,9 @@ EXP_ST void init_forkserver(char** argv) {
close(out_dir_fd);
close(dev_null_fd);
+#ifndef HAVE_ARC4RANDOM
close(dev_urandom_fd);
+#endif
close(fileno(plot_file));
/* This should improve performance a bit, since it stops the linker from
@@ -2681,7 +2691,9 @@ static u8 run_target(char** argv, u32 timeout) {
close(dev_null_fd);
close(out_dir_fd);
+#ifndef HAVE_ARC4RANDOM
close(dev_urandom_fd);
+#endif
close(fileno(plot_file));
/* Set sane defaults for ASAN if nothing else specified. */
@@ -11466,8 +11478,10 @@ EXP_ST void setup_dirs_fds(void) {
dev_null_fd = open("/dev/null", O_RDWR);
if (dev_null_fd < 0) PFATAL("Unable to open /dev/null");
+#ifndef HAVE_ARC4RANDOM
dev_urandom_fd = open("/dev/urandom", O_RDONLY);
if (dev_urandom_fd < 0) PFATAL("Unable to open /dev/urandom");
+#endif
/* Gnuplot output file. */

For BSD/APPLE platform use native random calls

Solution not involving file descriptors, seeded upon fork and on
a regular basis.

Signed-off-by: Tobias Kortkamp <t@tobik.me>