/* * Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * Licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. * A copy of the License is located at * * http://aws.amazon.com/apache2.0 * * or in the "license" file accompanying this file. This file is distributed * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either * express or implied. See the License for the specific language governing * permissions and limitations under the License. */ #include "utils/s2n_asn1_time.h" #include "s2n_safety.h" #include #include typedef enum parser_state { ON_YEAR_DIGIT_1 = 0, ON_YEAR_DIGIT_2, ON_YEAR_DIGIT_3, ON_YEAR_DIGIT_4, ON_MONTH_DIGIT_1, ON_MONTH_DIGIT_2, ON_DAY_DIGIT_1, ON_DAY_DIGIT_2, ON_HOUR_DIGIT_1, ON_HOUR_DIGIT_2, ON_MINUTE_DIGIT_1, ON_MINUTE_DIGIT_2, ON_SECOND_DIGIT_1, ON_SECOND_DIGIT_2, ON_SUBSECOND, ON_TIMEZONE, ON_OFFSET_HOURS_DIGIT_1, ON_OFFSET_HOURS_DIGIT_2, ON_OFFSET_MINUTES_DIGIT_1, ON_OFFSET_MINUTES_DIGIT_2, FINISHED, PARSE_ERROR } parser_state; static inline long get_gmt_offset(struct tm *t) { #if defined(__FreeBSD__) || defined(__NetBSD__) || defined(__ANDROID__) || defined(ANDROID) || defined(__APPLE__) && defined(__MACH__) return t->tm_gmtoff; #else return t->__tm_gmtoff; #endif } static inline void get_current_timesettings(long *gmt_offset, int *is_dst) { struct tm time_ptr = {0}; time_t raw_time; time(&raw_time); localtime_r(&raw_time, &time_ptr); *gmt_offset = get_gmt_offset(&time_ptr); *is_dst = time_ptr.tm_isdst; } /* this is just a standard state machine for ASN1 date format... nothing special. * just do a character at a time and change the state per character encountered. * when finished the above time structure should be filled in along with some * crazy timezone info we'll need shortly afterwards.*/ static parser_state process_state(parser_state state, char current_char, struct parser_args *args) { switch (state) { case ON_YEAR_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_year = args->current_digit; return ON_YEAR_DIGIT_2; case ON_YEAR_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_year = args->time.tm_year * 10 + args->current_digit; return ON_YEAR_DIGIT_3; case ON_YEAR_DIGIT_3: char_to_digit(current_char, args->current_digit); args->time.tm_year = args->time.tm_year * 10 + args->current_digit; return ON_YEAR_DIGIT_4; case ON_YEAR_DIGIT_4: char_to_digit(current_char, args->current_digit); args->time.tm_year = args->time.tm_year * 10 + args->current_digit; args->time.tm_year -= 1900; if (args->time.tm_year < 0) { return PARSE_ERROR; } return ON_MONTH_DIGIT_1; case ON_MONTH_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_mon = args->current_digit; return ON_MONTH_DIGIT_2; case ON_MONTH_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_mon = args->time.tm_mon * 10 + args->current_digit; args->time.tm_mon -= 1; if (args->time.tm_mon < 0 || args->time.tm_mon > 11) { return PARSE_ERROR; } return ON_DAY_DIGIT_1; case ON_DAY_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_mday = args->current_digit; return ON_DAY_DIGIT_2; case ON_DAY_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_mday = args->time.tm_mday * 10 + args->current_digit; if (args->time.tm_mday < 0 || args->time.tm_mday > 31) { return PARSE_ERROR; } return ON_HOUR_DIGIT_1; case ON_HOUR_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_hour = args->current_digit; return ON_HOUR_DIGIT_2; case ON_HOUR_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_hour = args->time.tm_hour * 10 + args->current_digit; if (args->time.tm_hour < 0 || args->time.tm_hour > 23) { return PARSE_ERROR; } return ON_MINUTE_DIGIT_1; case ON_MINUTE_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_min = args->current_digit; return ON_MINUTE_DIGIT_2; case ON_MINUTE_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_min = args->time.tm_min * 10 + args->current_digit; if (args->time.tm_min < 0 || args->time.tm_min > 59) { return PARSE_ERROR; } return ON_SECOND_DIGIT_1; case ON_SECOND_DIGIT_1: char_to_digit(current_char, args->current_digit); args->time.tm_sec = args->current_digit; return ON_SECOND_DIGIT_2; case ON_SECOND_DIGIT_2: char_to_digit(current_char, args->current_digit); args->time.tm_sec = args->time.tm_sec * 10 + args->current_digit; if (args->time.tm_sec < 0 || args->time.tm_sec > 59) { return PARSE_ERROR; } return ON_SUBSECOND; case ON_SUBSECOND: if (current_char == '.' || isdigit(current_char)) { return ON_SUBSECOND; } /* fall through */ case ON_TIMEZONE: if (current_char == 'Z' || current_char == 'z') { args->local_time_assumed = 0; return FINISHED; } else if (current_char == '-') { args->local_time_assumed = 0; args->offset_negative = 1; return ON_OFFSET_HOURS_DIGIT_1; } else if (current_char == '+') { args->local_time_assumed = 0; args->offset_negative = 0; return ON_OFFSET_HOURS_DIGIT_1; } return PARSE_ERROR; case ON_OFFSET_HOURS_DIGIT_1: char_to_digit(current_char, args->current_digit); args->offset_hours = args->current_digit; return ON_OFFSET_HOURS_DIGIT_2; case ON_OFFSET_HOURS_DIGIT_2: char_to_digit(current_char, args->current_digit); args->offset_hours = args->offset_hours * 10 + args->current_digit; if (args->offset_hours < 0 || args->offset_hours > 23) { return PARSE_ERROR; } return ON_OFFSET_MINUTES_DIGIT_1; case ON_OFFSET_MINUTES_DIGIT_1: char_to_digit(current_char, args->current_digit); args->offset_minutes = args->current_digit; return ON_OFFSET_MINUTES_DIGIT_2; case ON_OFFSET_MINUTES_DIGIT_2: char_to_digit(current_char, args->current_digit); args->offset_minutes = args->offset_minutes * 10 + args->current_digit; if (args->offset_minutes < 0 || args->offset_minutes > 23) { return PARSE_ERROR; } return FINISHED; default: return PARSE_ERROR; } } int s2n_asn1_time_to_nano_since_epoch_ticks(const char *asn1_time, uint32_t len, uint64_t *ticks) { /* figure out if we are on something other than UTC since timegm is not supported everywhere. */ long gmt_offset_current = 0; int is_dst = 0; get_current_timesettings(&gmt_offset_current, &is_dst); uint32_t str_len = len; parser_state state = ON_YEAR_DIGIT_1; struct parser_args args = { .time = {.tm_hour = 0, .tm_isdst = -1, .tm_mday = 0, .tm_min = 0, .tm_mon = 0, .tm_sec = 0, .tm_wday = 0, .tm_yday = 0, .tm_year = 0, }, .current_digit = 0, .local_time_assumed = 1, .offset_hours = 0, .offset_minutes = 0, .offset_negative = 0 }; size_t current_pos = 0; while (state < FINISHED && current_pos < str_len) { char current_char = asn1_time[current_pos]; state = process_state(state, current_char, &args); current_pos++; } /* state on subsecond means no timezone info was found and we assume local time */ if (state == FINISHED || state == ON_SUBSECOND) { time_t clock_data = 0; /* ASN1 + and - is in format HHMM. We need to convert it to seconds for the adjustment */ long gmt_offset = (args.offset_hours * 3600) + (args.offset_minutes * 60); if (args.offset_negative) { gmt_offset = 0 - gmt_offset; } clock_data = mktime(&args.time); /* if we detected UTC is being used (please always use UTC), we need to add the detected timezone on the local * machine back to the offset. Also, the offset includes an offset for daylight savings time. When the time being parsed * and the local time are on different sides of the dst barrier, the offset has to be adjusted to account for it. */ if (!args.local_time_assumed) { gmt_offset -= gmt_offset_current; gmt_offset -= args.time.tm_isdst != is_dst ? (args.time.tm_isdst - is_dst) * 3600 : 0; } /* convert to nanoseconds and add the timezone offset. */ if (clock_data > 0) { *ticks = ((uint64_t) clock_data - gmt_offset) * 1000000000; return 0; } } return -1; }