From bfc5f09979d49867b373b9433edf37adce8c66dd Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Fri, 13 Sep 2019 18:24:15 -0400 Subject: 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 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'src/lib/confmgt') diff --git a/src/lib/confmgt/type_defs.c b/src/lib/confmgt/type_defs.c index 137af4ed9e..6b0eac7823 100644 --- a/src/lib/confmgt/type_defs.c +++ b/src/lib/confmgt/type_defs.c @@ -37,6 +37,7 @@ #include #include +#include ////// // 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 * -- cgit v1.2.3-54-g00ecf