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-rw-r--r--changes/bug131044
-rw-r--r--src/common/util.c31
-rw-r--r--src/or/routerlist.c5
-rw-r--r--src/test/test_dir.c27
-rw-r--r--src/test/test_util.c211
5 files changed, 256 insertions, 22 deletions
diff --git a/changes/bug13104 b/changes/bug13104
new file mode 100644
index 0000000000..331db64ccc
--- /dev/null
+++ b/changes/bug13104
@@ -0,0 +1,4 @@
+ o Minor bugfixes:
+ - Fix several instances of possible integer overflow/underflow/NaN.
+ Fixes bug 13104; bugfix on 0.2.3.1-alpha and later. Patches from
+ "teor".
diff --git a/src/common/util.c b/src/common/util.c
index 97cedd519d..f4d293c838 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -2837,10 +2837,14 @@ scan_unsigned(const char **bufp, unsigned long *out, int width, int base)
while (**bufp && (hex?TOR_ISXDIGIT(**bufp):TOR_ISDIGIT(**bufp))
&& scanned_so_far < width) {
int digit = hex?hex_decode_digit(*(*bufp)++):digit_to_num(*(*bufp)++);
- unsigned long new_result = result * base + digit;
- if (new_result < result)
- return -1; /* over/underflow. */
- result = new_result;
+ // Check for overflow beforehand, without actually causing any overflow
+ // This preserves functionality on compilers that don't wrap overflow
+ // (i.e. that trap or optimise away overflow)
+ // result * base + digit > ULONG_MAX
+ // result * base > ULONG_MAX - digit
+ if (result > (ULONG_MAX - digit)/base)
+ return -1; /* Processing this digit would overflow */
+ result = result * base + digit;
++scanned_so_far;
}
@@ -2875,10 +2879,17 @@ scan_signed(const char **bufp, long *out, int width)
if (scan_unsigned(bufp, &result, width, 10) < 0)
return -1;
- if (neg) {
+ if (neg && result > 0) {
if (result > ((unsigned long)LONG_MAX) + 1)
return -1; /* Underflow */
- *out = -(long)result;
+ // Avoid overflow on the cast to signed long when result is LONG_MIN
+ // by subtracting 1 from the unsigned long positive value,
+ // then, after it has been cast to signed and negated,
+ // subtracting the original 1 (the double-subtraction is intentional).
+ // Otherwise, the cast to signed could cause a temporary long
+ // to equal LONG_MAX + 1, which is undefined.
+ // We avoid underflow on the subtraction by treating -0 as positive.
+ *out = (-(long)(result - 1)) - 1;
} else {
if (result > LONG_MAX)
return -1; /* Overflow */
@@ -3577,7 +3588,13 @@ format_helper_exit_status(unsigned char child_state, int saved_errno,
/* Convert errno to be unsigned for hex conversion */
if (saved_errno < 0) {
- unsigned_errno = (unsigned int) -saved_errno;
+ // Avoid overflow on the cast to unsigned int when result is INT_MIN
+ // by adding 1 to the signed int negative value,
+ // then, after it has been negated and cast to unsigned,
+ // adding the original 1 back (the double-addition is intentional).
+ // Otherwise, the cast to signed could cause a temporary int
+ // to equal INT_MAX + 1, which is undefined.
+ unsigned_errno = ((unsigned int) -(saved_errno + 1)) + 1;
} else {
unsigned_errno = (unsigned int) saved_errno;
}
diff --git a/src/or/routerlist.c b/src/or/routerlist.c
index a018181026..1faa05f06f 100644
--- a/src/or/routerlist.c
+++ b/src/or/routerlist.c
@@ -1804,7 +1804,7 @@ scale_array_elements_to_u64(u64_dbl_t *entries, int n_entries,
uint64_t *total_out)
{
double total = 0.0;
- double scale_factor;
+ double scale_factor = 0.0;
int i;
/* big, but far away from overflowing an int64_t */
#define SCALE_TO_U64_MAX ((int64_t) (INT64_MAX / 4))
@@ -1812,7 +1812,8 @@ scale_array_elements_to_u64(u64_dbl_t *entries, int n_entries,
for (i = 0; i < n_entries; ++i)
total += entries[i].dbl;
- scale_factor = SCALE_TO_U64_MAX / total;
+ if (total > 0.0)
+ scale_factor = SCALE_TO_U64_MAX / total;
for (i = 0; i < n_entries; ++i)
entries[i].u64 = tor_llround(entries[i].dbl * scale_factor);
diff --git a/src/test/test_dir.c b/src/test/test_dir.c
index c5eee46979..d66a3f8162 100644
--- a/src/test/test_dir.c
+++ b/src/test/test_dir.c
@@ -1733,10 +1733,37 @@ test_dir_scale_bw(void *testdata)
tt_assert(total <= (U64_LITERAL(1)<<62));
for (i=0; i<8; ++i) {
+ /* vals[2].u64 is the scaled value of 1.0 */
double ratio = ((double)vals[i].u64) / vals[2].u64;
tt_double_op(fabs(ratio - v[i]), <, .00001);
}
+ /* test handling of no entries */
+ total = 1;
+ scale_array_elements_to_u64(vals, 0, &total);
+ tt_assert(total == 0);
+
+ /* make sure we don't read the array when we have no entries
+ * may require compiler flags to catch NULL dereferences */
+ total = 1;
+ scale_array_elements_to_u64(NULL, 0, &total);
+ tt_assert(total == 0);
+
+ scale_array_elements_to_u64(NULL, 0, NULL);
+
+ /* test handling of zero totals */
+ total = 1;
+ vals[0].dbl = 0.0;
+ scale_array_elements_to_u64(vals, 1, &total);
+ tt_assert(total == 0);
+ tt_assert(vals[0].u64 == 0);
+
+ vals[0].dbl = 0.0;
+ vals[1].dbl = 0.0;
+ scale_array_elements_to_u64(vals, 2, NULL);
+ tt_assert(vals[0].u64 == 0);
+ tt_assert(vals[1].u64 == 0);
+
done:
;
}
diff --git a/src/test/test_util.c b/src/test/test_util.c
index 1b7c936fd7..1e61bb9452 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -1688,6 +1688,7 @@ static void
test_util_sscanf(void)
{
unsigned u1, u2, u3;
+ unsigned long ulng;
char s1[20], s2[10], s3[10], ch;
int r;
long lng1,lng2;
@@ -1729,11 +1730,6 @@ test_util_sscanf(void)
test_eq(0, tor_sscanf("", "%u", &u1)); /* absent number */
test_eq(0, tor_sscanf("A", "%u", &u1)); /* bogus number */
test_eq(0, tor_sscanf("-1", "%u", &u1)); /* negative number */
- test_eq(1, tor_sscanf("4294967295", "%u", &u1)); /* UINT32_MAX should work */
- test_eq(4294967295u, u1);
- test_eq(0, tor_sscanf("4294967296", "%u", &u1)); /* But not at 32 bits */
- test_eq(1, tor_sscanf("4294967296", "%9u", &u1)); /* but parsing only 9... */
- test_eq(429496729u, u1);
/* Numbers with size (eg. %2u) */
test_eq(0, tor_sscanf("-1", "%2u", &u1));
@@ -1828,46 +1824,191 @@ test_util_sscanf(void)
test_eq(int2, -1);
#if SIZEOF_INT == 4
+ /* %u */
+ /* UINT32_MAX should work */
+ test_eq(1, tor_sscanf("4294967295", "%u", &u1));
+ test_eq(4294967295U, u1);
+
+ /* But UINT32_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("4294967296", "%u", &u1));
+ /* but parsing only 9... */
+ test_eq(1, tor_sscanf("4294967296", "%9u", &u1));
+ test_eq(429496729U, u1);
+
+ /* %x */
+ /* UINT32_MAX should work */
+ test_eq(1, tor_sscanf("FFFFFFFF", "%x", &u1));
+ test_eq(0xFFFFFFFF, u1);
+
+ /* But UINT32_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("100000000", "%x", &u1));
+
+ /* %d */
+ /* INT32_MIN and INT32_MAX should work */
r = tor_sscanf("-2147483648. 2147483647.", "%d. %d.", &int1, &int2);
test_eq(r,2);
- test_eq(int1, -2147483647-1);
+ test_eq(int1, -2147483647 - 1);
test_eq(int2, 2147483647);
- r = tor_sscanf("-2147483679.", "%d.", &int1);
+ /* But INT32_MIN - 1 and INT32_MAX + 1 shouldn't work */
+ r = tor_sscanf("-2147483649.", "%d.", &int1);
test_eq(r,0);
- r = tor_sscanf("2147483678.", "%d.", &int1);
+ r = tor_sscanf("2147483648.", "%d.", &int1);
+ test_eq(r,0);
+
+ /* and the first failure stops further processing */
+ r = tor_sscanf("-2147483648. 2147483648.",
+ "%d. %d.", &int1, &int2);
+ test_eq(r,1);
+
+ r = tor_sscanf("-2147483649. 2147483647.",
+ "%d. %d.", &int1, &int2);
+ test_eq(r,0);
+
+ r = tor_sscanf("2147483648. -2147483649.",
+ "%d. %d.", &int1, &int2);
test_eq(r,0);
#elif SIZEOF_INT == 8
+ /* %u */
+ /* UINT64_MAX should work */
+ test_eq(1, tor_sscanf("18446744073709551615", "%u", &u1));
+ test_eq(18446744073709551615U, u1);
+
+ /* But UINT64_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("18446744073709551616", "%u", &u1));
+ /* but parsing only 19... */
+ test_eq(1, tor_sscanf("18446744073709551616", "%19u", &u1));
+ test_eq(1844674407370955161U, u1);
+
+ /* %x */
+ /* UINT64_MAX should work */
+ test_eq(1, tor_sscanf("FFFFFFFFFFFFFFFF", "%x", &u1));
+ test_eq(0xFFFFFFFFFFFFFFFF, u1);
+
+ /* But UINT64_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("10000000000000000", "%x", &u1));
+
+ /* %d */
+ /* INT64_MIN and INT64_MAX should work */
r = tor_sscanf("-9223372036854775808. 9223372036854775807.",
"%d. %d.", &int1, &int2);
test_eq(r,2);
- test_eq(int1, -9223372036854775807-1);
+ test_eq(int1, -9223372036854775807 - 1);
test_eq(int2, 9223372036854775807);
+ /* But INT64_MIN - 1 and INT64_MAX + 1 shouldn't work */
r = tor_sscanf("-9223372036854775809.", "%d.", &int1);
test_eq(r,0);
r = tor_sscanf("9223372036854775808.", "%d.", &int1);
test_eq(r,0);
+
+ /* and the first failure stops further processing */
+ r = tor_sscanf("-9223372036854775808. 9223372036854775808.",
+ "%d. %d.", &int1, &int2);
+ test_eq(r,1);
+
+ r = tor_sscanf("-9223372036854775809. 9223372036854775807.",
+ "%d. %d.", &int1, &int2);
+ test_eq(r,0);
+
+ r = tor_sscanf("9223372036854775808. -9223372036854775809.",
+ "%d. %d.", &int1, &int2);
+ test_eq(r,0);
#endif
#if SIZEOF_LONG == 4
+ /* %lu */
+ /* UINT32_MAX should work */
+ test_eq(1, tor_sscanf("4294967295", "%lu", &ulng));
+ test_eq(4294967295UL, ulng);
+
+ /* But UINT32_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("4294967296", "%lu", &ulng));
+ /* but parsing only 9... */
+ test_eq(1, tor_sscanf("4294967296", "%9lu", &ulng));
+ test_eq(429496729UL, ulng);
+
+ /* %lx */
+ /* UINT32_MAX should work */
+ test_eq(1, tor_sscanf("FFFFFFFF", "%lx", &ulng));
+ test_eq(0xFFFFFFFFUL, ulng);
+
+ /* But UINT32_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("100000000", "%lx", &ulng));
+
+ /* %ld */
+ /* INT32_MIN and INT32_MAX should work */
r = tor_sscanf("-2147483648. 2147483647.", "%ld. %ld.", &lng1, &lng2);
test_eq(r,2);
- test_eq(lng1, -2147483647 - 1);
- test_eq(lng2, 2147483647);
+ test_eq(lng1, -2147483647L - 1L);
+ test_eq(lng2, 2147483647L);
+
+ /* But INT32_MIN - 1 and INT32_MAX + 1 shouldn't work */
+ r = tor_sscanf("-2147483649.", "%ld.", &lng1);
+ test_eq(r,0);
+
+ r = tor_sscanf("2147483648.", "%ld.", &lng1);
+ test_eq(r,0);
+
+ /* and the first failure stops further processing */
+ r = tor_sscanf("-2147483648. 2147483648.",
+ "%ld. %ld.", &lng1, &lng2);
+ test_eq(r,1);
+
+ r = tor_sscanf("-2147483649. 2147483647.",
+ "%ld. %ld.", &lng1, &lng2);
+ test_eq(r,0);
+
+ r = tor_sscanf("2147483648. -2147483649.",
+ "%ld. %ld.", &lng1, &lng2);
+ test_eq(r,0);
#elif SIZEOF_LONG == 8
+ /* %lu */
+ /* UINT64_MAX should work */
+ test_eq(1, tor_sscanf("18446744073709551615", "%lu", &ulng));
+ test_eq(18446744073709551615UL, ulng);
+
+ /* But UINT64_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("18446744073709551616", "%lu", &ulng));
+ /* but parsing only 19... */
+ test_eq(1, tor_sscanf("18446744073709551616", "%19lu", &ulng));
+ test_eq(1844674407370955161UL, ulng);
+
+ /* %lx */
+ /* UINT64_MAX should work */
+ test_eq(1, tor_sscanf("FFFFFFFFFFFFFFFF", "%lx", &ulng));
+ test_eq(0xFFFFFFFFFFFFFFFFUL, ulng);
+
+ /* But UINT64_MAX + 1 shouldn't work */
+ test_eq(0, tor_sscanf("10000000000000000", "%lx", &ulng));
+
+ /* %ld */
+ /* INT64_MIN and INT64_MAX should work */
r = tor_sscanf("-9223372036854775808. 9223372036854775807.",
"%ld. %ld.", &lng1, &lng2);
test_eq(r,2);
- test_eq(lng1, -9223372036854775807L - 1);
+ test_eq(lng1, -9223372036854775807L - 1L);
test_eq(lng2, 9223372036854775807L);
+ /* But INT64_MIN - 1 and INT64_MAX + 1 shouldn't work */
+ r = tor_sscanf("-9223372036854775809.", "%ld.", &lng1);
+ test_eq(r,0);
+
+ r = tor_sscanf("9223372036854775808.", "%ld.", &lng1);
+ test_eq(r,0);
+
+ /* and the first failure stops further processing */
r = tor_sscanf("-9223372036854775808. 9223372036854775808.",
"%ld. %ld.", &lng1, &lng2);
test_eq(r,1);
- r = tor_sscanf("-9223372036854775809. 9223372036854775808.",
+
+ r = tor_sscanf("-9223372036854775809. 9223372036854775807.",
+ "%ld. %ld.", &lng1, &lng2);
+ test_eq(r,0);
+
+ r = tor_sscanf("9223372036854775808. -9223372036854775809.",
"%ld. %ld.", &lng1, &lng2);
test_eq(r,0);
#endif
@@ -2484,12 +2625,17 @@ test_util_exit_status(void *ptr)
int n;
(void)ptr;
+
+ clear_hex_errno(hex_errno);
+ test_streq("", hex_errno);
clear_hex_errno(hex_errno);
n = format_helper_exit_status(0, 0, hex_errno);
test_streq("0/0\n", hex_errno);
test_eq(n, strlen(hex_errno));
+#if SIZEOF_INT == 4
+
clear_hex_errno(hex_errno);
n = format_helper_exit_status(0, 0x7FFFFFFF, hex_errno);
test_streq("0/7FFFFFFF\n", hex_errno);
@@ -2500,6 +2646,21 @@ test_util_exit_status(void *ptr)
test_streq("FF/-80000000\n", hex_errno);
test_eq(n, strlen(hex_errno));
test_eq(n, HEX_ERRNO_SIZE);
+
+#elif SIZEOF_INT == 8
+
+ clear_hex_errno(hex_errno);
+ n = format_helper_exit_status(0, 0x7FFFFFFFFFFFFFFF, hex_errno);
+ test_streq("0/7FFFFFFFFFFFFFFF\n", hex_errno);
+ test_eq(n, strlen(hex_errno));
+
+ clear_hex_errno(hex_errno);
+ n = format_helper_exit_status(0xFF, -0x8000000000000000, hex_errno);
+ test_streq("FF/-8000000000000000\n", hex_errno);
+ test_eq(n, strlen(hex_errno));
+ test_eq(n, HEX_ERRNO_SIZE);
+
+#endif
clear_hex_errno(hex_errno);
n = format_helper_exit_status(0x7F, 0, hex_errno);
@@ -2510,6 +2671,9 @@ test_util_exit_status(void *ptr)
n = format_helper_exit_status(0x08, -0x242, hex_errno);
test_streq("8/-242\n", hex_errno);
test_eq(n, strlen(hex_errno));
+
+ clear_hex_errno(hex_errno);
+ test_streq("", hex_errno);
done:
;
@@ -3195,6 +3359,27 @@ test_util_di_ops(void)
test_eq(neq1, !eq1);
}
+ /* exhaustively white-box test tor_memeq
+ * against each possible (single-byte) bit difference
+ * some arithmetic bugs only appear with certain bit patterns */
+ {
+ const uint8_t z = 0;
+ uint8_t ii = 0;
+ for (i = 0; i < 256; i++) {
+ ii = (uint8_t)i;
+ test_eq(tor_memeq(&z, &ii, 1), z == ii);
+ }
+
+ /* exhaustively white-box test tor_memcmp
+ * against each possible single-byte numeric difference
+ * some arithmetic bugs only appear with certain bit patterns */
+ for (i = 0; i < 256; i++) {
+ ii = (uint8_t)i;
+ test_eq(tor_memcmp(&z, &ii, 1) > 0 ? GT : EQ, z > ii ? GT : EQ);
+ test_eq(tor_memcmp(&ii, &z, 1) < 0 ? LT : EQ, ii < z ? LT : EQ);
+ }
+ }
+
tt_int_op(1, ==, safe_mem_is_zero("", 0));
tt_int_op(1, ==, safe_mem_is_zero("", 1));
tt_int_op(0, ==, safe_mem_is_zero("a", 1));
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