commit bfc5f09979d49867b373b9433edf37adce8c66dd Author: Nick Mathewson nickm@torproject.org Date: Fri Sep 13 18:24:15 2019 -0400
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. --- src/lib/confmgt/type_defs.c | 13 +++++++++++-- src/test/test_confparse.c | 12 ++++++++++++ 2 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/src/lib/confmgt/type_defs.c b/src/lib/confmgt/type_defs.c index 137af4ed9..6b0eac782 100644 --- a/src/lib/confmgt/type_defs.c +++ b/src/lib/confmgt/type_defs.c @@ -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 * diff --git a/src/test/test_confparse.c b/src/test/test_confparse.c index a4da6c7c9..f04853af7 100644 --- a/src/test/test_confparse.c +++ b/src/test/test_confparse.c @@ -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),