From: Tyson Smith <[email protected]>
This will prevent open coding rand() & ff to get a random byte and the
off-by-one's that accompany it (rand() % ff or rand() & 255). Made
substitutions where possible which led to fixing existing off-by-ones.
---
fault-write.c | 2 +-
include/random.h | 1 +
interesting-numbers.c | 8 ++++----
random.c | 4 ++--
syscalls/mremap.c | 2 +-
syscalls/perf_event_open.c | 6 +++---
syscalls/setsockopt.c | 2 +-
7 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/fault-write.c b/fault-write.c
index 86a5a46..9384954 100644
--- a/fault-write.c
+++ b/fault-write.c
@@ -66,7 +66,7 @@ static void generate_random_page(char *page)
return;
case 2:
- memset(page, rand() % 0xff, page_size);
+ memset(page, RAND_BYTE(), page_size);
return;
case 3:
diff --git a/include/random.h b/include/random.h
index b8f8d2c..ce0b159 100644
--- a/include/random.h
+++ b/include/random.h
@@ -14,6 +14,7 @@
#endif
#define rand_bool() (rand() & 1)
+#define RAND_BYTE() (rand() & 0xff)
extern unsigned int seed;
unsigned int init_seed(unsigned int seed);
diff --git a/interesting-numbers.c b/interesting-numbers.c
index aeb0335..918f2a0 100644
--- a/interesting-numbers.c
+++ b/interesting-numbers.c
@@ -26,7 +26,7 @@ static unsigned char get_interesting_8bit_value(void)
case 0: return 1; // one
case 1: return 0xff; // max
case 2: return 1UL << (rand() & 7); // 2^n (1 -> 128)
- case 3: return rand() & 0xff; // 0 -> 0xff
+ case 3: return RAND_BYTE(); // 0 -> 0xff
default: return 0; // zero
}
}
@@ -36,7 +36,7 @@ static unsigned short get_interesting_16bit_value(void)
switch (rand() % 4) {
case 0: return 0x8000 >> (rand() & 7); // 2^n (0x100 -> 0x8000)
case 1: return rand() & 0xffff; // 0 -> 0xffff
- case 2: return 0xff00 | (rand() & 0xff); // 0xff00 -> 0xffff
+ case 2: return 0xff00 | RAND_BYTE(); // 0xff00 -> 0xffff
default: return 0xffff; // max
}
}
@@ -49,7 +49,7 @@ static unsigned int get_interesting_32bit_value(void)
case 2: return 0xff << (rand() % 25);
case 3: return 0xffff0000;
case 4: return 0xffffe000;
- case 5: return 0xffffff00 | (rand() & 0xff);
+ case 5: return 0xffffff00 | RAND_BYTE();
case 6: return 0xffffffff - page_size;
case 7: return page_size;
case 8: return page_size * ((rand() % (0xffffffff/page_size)) + 1);
@@ -101,7 +101,7 @@ unsigned long get_interesting_value(void)
case 1: return 0x7fffffff00000000UL | low;
case 2: return 0x8000000000000000UL | low;
case 3: return 0xffffffff00000000UL | low;
- case 4: return 0xffffffffffffff00UL | (rand() & 0xff);
+ case 4: return 0xffffffffffffff00UL | RAND_BYTE();
case 5: return 0xffffffffffffffffUL - page_size;
case 6: return PAGE_OFFSET | (low << 4);
case 7: return KERNEL_ADDR | (low & 0xffffff);
diff --git a/random.c b/random.c
index a1ff7a8..aab85b0 100644
--- a/random.c
+++ b/random.c
@@ -22,7 +22,7 @@ void generate_rand_bytes(unsigned char *ptr, unsigned int len)
switch (choice) {
case 0:
/* Complete garbage. */
- ptr[i] = rand();
+ ptr[i] = RAND_BYTE();
break;
case 1:
/* printable text strings. */
@@ -99,7 +99,7 @@ static unsigned long rept8(unsigned int num)
unsigned int i;
unsigned char c;
- c = rand() % 256;
+ c = RAND_BYTE();
for (i = rand() % (num - 1) ; i > 0; --i)
r = (r << 8) | c;
diff --git a/syscalls/mremap.c b/syscalls/mremap.c
index ae47091..ee937b2 100644
--- a/syscalls/mremap.c
+++ b/syscalls/mremap.c
@@ -35,7 +35,7 @@ static void sanitise_mremap(struct syscallrecord *rec)
unsigned long align = alignments[rand() %
ARRAY_SIZE(alignments)];
unsigned int shift = (__WORDSIZE / 2) - 1;
- newaddr = rand() % 256;
+ newaddr = RAND_BYTE();
newaddr <<= shift;
newaddr |= align;
newaddr &= ~(align - 1);
diff --git a/syscalls/perf_event_open.c b/syscalls/perf_event_open.c
index 7f68375..241ecfd 100644
--- a/syscalls/perf_event_open.c
+++ b/syscalls/perf_event_open.c
@@ -562,7 +562,7 @@ static long long random_cache_config(void)
cache_id = PERF_COUNT_HW_CACHE_NODE;
break;
case 7:
- cache_id = rand() % 256;
+ cache_id = RAND_BYTE();
break;
default:
cache_id = 0;
@@ -580,7 +580,7 @@ static long long random_cache_config(void)
hw_cache_op_id = PERF_COUNT_HW_CACHE_OP_PREFETCH;
break;
case 3:
- hw_cache_op_id = rand() % 256;
+ hw_cache_op_id = RAND_BYTE();
break;
default:
hw_cache_op_id = 0;
@@ -595,7 +595,7 @@ static long long random_cache_config(void)
hw_cache_op_result_id = PERF_COUNT_HW_CACHE_RESULT_MISS;
break;
case 2:
- hw_cache_op_result_id = rand() % 256;
+ hw_cache_op_result_id = RAND_BYTE();
break;
default:
hw_cache_op_result_id = 0;
diff --git a/syscalls/setsockopt.c b/syscalls/setsockopt.c
index dd9a239..e2480e8 100644
--- a/syscalls/setsockopt.c
+++ b/syscalls/setsockopt.c
@@ -95,7 +95,7 @@ void do_setsockopt(struct sockopt *so)
if (ONE_IN(100)) {
so->level = rand();
- so->optname = (rand() % 0x100); /* random operation. */
+ so->optname = RAND_BYTE(); /* random operation. */
} else {
ssoptrs[rand() % ARRAY_SIZE(ssoptrs)].func(so);
}
--
1.9.1
--
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