From d6da646d879a1b7f0ea2d09db2b266e3b6d0f3fa Mon Sep 17 00:00:00 2001
From: ouwou <26526779+ouwou@users.noreply.github.com>
Date: Wed, 29 Dec 2021 22:15:04 -0500
Subject: validate iso8601 when parsing to snowflake

---
 src/discord/discord.cpp   | 6 +++---
 src/discord/snowflake.cpp | 8 +++++---
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/discord/discord.cpp b/src/discord/discord.cpp
index 8c5ec93..7b0db38 100644
--- a/src/discord/discord.cpp
+++ b/src/discord/discord.cpp
@@ -1923,7 +1923,7 @@ void DiscordClient::HandleGatewayUserGuildSettingsUpdate(const GatewayMessage &m
         if (override.Muted) {
             if (override.MuteConfig.EndTime.has_value()) {
                 const auto end = Snowflake::FromISO8601(*override.MuteConfig.EndTime);
-                if (end > now)
+                if (end.IsValid() && end > now)
                     now_muted_channels.insert(override.ChannelID);
             } else {
                 now_muted_channels.insert(override.ChannelID);
@@ -2325,7 +2325,7 @@ void DiscordClient::HandleReadyGuildSettings(const ReadyEventData &data) {
         if (entry.Muted) {
             if (entry.MuteConfig.EndTime.has_value()) {
                 const auto end = Snowflake::FromISO8601(*entry.MuteConfig.EndTime);
-                if (end > now)
+                if (end.IsValid() && end > now)
                     m_muted_guilds.insert(entry.GuildID);
             } else {
                 m_muted_guilds.insert(entry.GuildID);
@@ -2335,7 +2335,7 @@ void DiscordClient::HandleReadyGuildSettings(const ReadyEventData &data) {
             if (override.Muted) {
                 if (override.MuteConfig.EndTime.has_value()) {
                     const auto end = Snowflake::FromISO8601(*override.MuteConfig.EndTime);
-                    if (end > now)
+                    if (end.IsValid() && end > now)
                         m_muted_channels.insert(override.ChannelID);
                 } else {
                     m_muted_channels.insert(override.ChannelID);
diff --git a/src/discord/snowflake.cpp b/src/discord/snowflake.cpp
index 32f9f4f..8f470a7 100644
--- a/src/discord/snowflake.cpp
+++ b/src/discord/snowflake.cpp
@@ -42,9 +42,11 @@ Snowflake Snowflake::FromNow() {
 Snowflake Snowflake::FromISO8601(std::string_view ts) {
     int yr, mon, day, hr, min, sec, tzhr, tzmin;
     float milli;
-    std::sscanf(ts.data(), "%d-%d-%dT%d:%d:%d%f+%d:%d",
-                &yr, &mon, &day, &hr, &min, &sec, &milli, &tzhr, &tzmin);
-    return SecondsInterval * (util::TimeToEpoch(yr, mon, day, hr, min, sec) - DiscordEpochSeconds) + static_cast<uint64_t>(milli * static_cast<float>(SecondsInterval));
+    if (std::sscanf(ts.data(), "%d-%d-%dT%d:%d:%d%f+%d:%d",
+                    &yr, &mon, &day, &hr, &min, &sec, &milli, &tzhr, &tzmin) != 9) return Snowflake::Invalid;
+    const auto epoch = util::TimeToEpoch(yr, mon, day, hr, min, sec);
+    if (epoch < DiscordEpochSeconds) return Snowflake::Invalid;
+    return SecondsInterval * (epoch - DiscordEpochSeconds) + static_cast<uint64_t>(milli * static_cast<float>(SecondsInterval));
 }
 
 bool Snowflake::IsValid() const {
-- 
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