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fix: sanitize DNS preference inputs #32

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Merged
hawkff merged 2 commits into from
Jun 19, 2026
Merged

fix: sanitize DNS preference inputs #32

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3498fef
fix: sanitize DNS preference inputs
hawkff Jun 19, 2026
5e2876c
fix: type DNS sanitizing listeners
hawkff Jun 19, 2026
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8 changes: 6 additions & 2 deletions app/src/main/java/io/nekohasekai/sagernet/fmt/ConfigBuilder.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,10 @@ import moe.matsuri.nb4a.utils.Util
import moe.matsuri.nb4a.utils.listByLineOrComma
import okhttp3.HttpUrl.Companion.toHttpUrlOrNull

private fun sanitizeDnsEntry(value: String): String {
return value.filterNot { it.isISOControl() }.trim()
}

const val TAG_MIXED = "mixed-in"

const val TAG_PROXY = "proxy"
Expand Down Expand Up @@ -144,9 +148,9 @@ fun buildConfig(
val isVPN = DataStore.serviceMode == Key.MODE_VPN
val bind = if (!forTest && DataStore.allowAccess) "0.0.0.0" else LOCALHOST
val remoteDns = DataStore.remoteDns.split("\n")
.mapNotNull { dns -> dns.trim().takeIf { it.isNotBlank() && !it.startsWith("#") } }
.mapNotNull { dns -> sanitizeDnsEntry(dns).takeIf { it.isNotBlank() && !it.startsWith("#") } }
val directDNS = DataStore.directDns.split("\n")
.mapNotNull { dns -> dns.trim().takeIf { it.isNotBlank() && !it.startsWith("#") } }
.mapNotNull { dns -> sanitizeDnsEntry(dns).takeIf { it.isNotBlank() && !it.startsWith("#") } }
val enableDnsRouting = DataStore.enableDnsRouting
val useFakeDns = DataStore.enableFakeDns && !forTest
val needSniff = DataStore.trafficSniffing > 0
Expand Down
28 changes: 26 additions & 2 deletions app/src/main/java/io/nekohasekai/sagernet/ui/SettingsPreferenceFragment.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,26 @@ class SettingsPreferenceFragment : PreferenceFragmentCompat() {
true
}

private fun sanitizeDnsPreferenceValue(value: String): String {
return value.lines().joinToString("\n") { line ->
line.filterNot { it.isISOControl() }.trim()
}
}

private fun dnsReloadListener(preference: Preference, newValue: Any?): Boolean {
val rawValue = newValue as? String ?: return reloadListener.onPreferenceChange(preference, newValue)
val sanitizedValue = sanitizeDnsPreferenceValue(rawValue)
if (sanitizedValue != rawValue) {
if (preference is EditTextPreference) {
preference.text = sanitizedValue
}
needReload()
return false
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greptile-apps[bot] marked this conversation as resolved.
}
needReload()
return true
}

@greptile-apps greptile-apps Bot Jun 19, 2026

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P2 needReload() is called unconditionally in both branches of the if/else, so it can be hoisted before the conditional to remove the duplication.

Suggested change
private fun dnsReloadListener(preference: Preference, newValue: Any?): Boolean {
val rawValue = newValue as? String ?: return reloadListener.onPreferenceChange(preference, newValue)
val sanitizedValue = sanitizeDnsPreferenceValue(rawValue)
if (sanitizedValue != rawValue) {
if (preference is EditTextPreference) {
preference.text = sanitizedValue
}
needReload()
return false
}
needReload()
return true
}
private fun dnsReloadListener(preference: Preference, newValue: Any?): Boolean {
val rawValue = newValue as? String ?: return reloadListener.onPreferenceChange(preference, newValue)
val sanitizedValue = sanitizeDnsPreferenceValue(rawValue)
needReload()
if (sanitizedValue != rawValue) {
if (preference is EditTextPreference) {
preference.text = sanitizedValue
}
return false
}
return true
}

Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!


override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
preferenceManager.preferenceDataStore = DataStore.configurationStore
DataStore.initGlobal()
Expand Down Expand Up @@ -203,8 +223,12 @@ class SettingsPreferenceFragment : PreferenceFragmentCompat() {
concurrentDial.onPreferenceChangeListener = reloadListener

enableFakeDns.onPreferenceChangeListener = reloadListener
remoteDns.onPreferenceChangeListener = reloadListener
directDns.onPreferenceChangeListener = reloadListener
remoteDns.onPreferenceChangeListener = Preference.OnPreferenceChangeListener { preference, newValue ->
dnsReloadListener(preference, newValue)
}
directDns.onPreferenceChangeListener = Preference.OnPreferenceChangeListener { preference, newValue ->
dnsReloadListener(preference, newValue)
}
enableDnsRouting.onPreferenceChangeListener = reloadListener

ipv6Mode.onPreferenceChangeListener = reloadListener
Expand Down
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