Detect overflow or underflow on double config values.

Any floating point value too positive or negative to distinguish
from +/-Inf, or too small to distinguish from +/-0, is an
over/underflow.
This commit is contained in:
Nick Mathewson 2019-09-13 18:24:15 -04:00
parent 9d60495903
commit bfc5f09979
2 changed files with 23 additions and 2 deletions

View File

@ -37,6 +37,7 @@
#include <stddef.h>
#include <string.h>
#include <errno.h>
//////
// CONFIG_TYPE_STRING
@ -284,15 +285,23 @@ double_parse(void *target, const char *value, char **errmsg,
(void)errmsg;
double *v = (double*)target;
char *endptr=NULL;
errno = 0;
*v = strtod(value, &endptr);
if (endptr == value || *endptr != '\0') {
// Either there are no converted characters, or there were some characters
// that didn't get converted.
tor_asprintf(errmsg, "Could not convert %s to a number.", escaped(value));
return -1;
} else {
return 0;
}
if (errno == ERANGE) {
// strtod will set errno to ERANGE on underflow or overflow.
bool underflow = -.00001 < *v && *v < .00001;
tor_asprintf(errmsg,
"%s is too %s to express as a floating-point number.",
escaped(value), underflow ? "small" : "large");
return -1;
}
return 0;
}
static char *

View File

@ -490,6 +490,14 @@ static const badval_test_t bv_negint = { "pos -10\n", "out of bounds" };
static const badval_test_t bv_badu64 = { "u64 u64\n", "malformed" };
static const badval_test_t bv_dbl1 = { "dbl xxx\n", "Could not convert" };
static const badval_test_t bv_dbl2 = { "dbl 1.0 xx\n", "Could not convert" };
static const badval_test_t bv_dbl3 = {
"dbl 1e-10000\n", "too small to express" };
static const badval_test_t bv_dbl4 = {
"dbl 1e1000\n", "too large to express" };
static const badval_test_t bv_dbl5 = {
"dbl -1e-10000\n", "too small to express" };
static const badval_test_t bv_dbl6 = {
"dbl -1e1000\n", "too large to express" };
static const badval_test_t bv_badcsvi1 =
{ "csv_interval 10 wl\n", "malformed" };
static const badval_test_t bv_badcsvi2 =
@ -1049,6 +1057,10 @@ struct testcase_t confparse_tests[] = {
BADVAL_TEST(badu64),
BADVAL_TEST(dbl1),
BADVAL_TEST(dbl2),
BADVAL_TEST(dbl3),
BADVAL_TEST(dbl4),
BADVAL_TEST(dbl5),
BADVAL_TEST(dbl6),
BADVAL_TEST(badcsvi1),
BADVAL_TEST(badcsvi2),
BADVAL_TEST(nonoption),