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-rw-r--r--server/FirewallController.cpp215
1 files changed, 5 insertions, 210 deletions
diff --git a/server/FirewallController.cpp b/server/FirewallController.cpp
index 35fd1e20..31e34b35 100644
--- a/server/FirewallController.cpp
+++ b/server/FirewallController.cpp
@@ -37,24 +37,10 @@
#include "bpf/BpfUtils.h"
using android::base::Join;
-using android::base::ReadFileToString;
-using android::base::Split;
using android::base::StringAppendF;
using android::base::StringPrintf;
using android::net::gCtls;
-namespace {
-
-// Default maximum valid uid in a normal root user namespace. The maximum valid uid is used in
-// rules that exclude all possible UIDs in the namespace in order to match packets that have
-// no socket associated with them.
-constexpr const uid_t kDefaultMaximumUid = UID_MAX - 1; // UID_MAX defined as UINT_MAX
-
-// Proc file containing the uid mapping for the user namespace of the current process.
-const char kUidMapProcFile[] = "/proc/self/uid_map";
-
-} // namespace
-
namespace android {
namespace net {
@@ -83,25 +69,14 @@ const char* FirewallController::ICMPV6_TYPES[] = {
"redirect",
};
-FirewallController::FirewallController(void) : mMaxUid(discoverMaximumValidUid(kUidMapProcFile)) {
+FirewallController::FirewallController(void) {
// If no rules are set, it's in DENYLIST mode
mFirewallType = DENYLIST;
mIfaceRules = {};
}
int FirewallController::setupIptablesHooks(void) {
- int res = flushRules();
-
- // mUseBpfOwnerMatch should be removed, but it is still depended upon by test code.
- mUseBpfOwnerMatch = true;
- if (mUseBpfOwnerMatch) {
- return res;
- }
- res |= createChain(LOCAL_DOZABLE, getFirewallType(DOZABLE));
- res |= createChain(LOCAL_STANDBY, getFirewallType(STANDBY));
- res |= createChain(LOCAL_POWERSAVE, getFirewallType(POWERSAVE));
- res |= createChain(LOCAL_RESTRICTED, getFirewallType(RESTRICTED));
- return res;
+ return flushRules();
}
int FirewallController::setFirewallType(FirewallType ftype) {
@@ -146,36 +121,7 @@ int FirewallController::resetFirewall(void) {
}
int FirewallController::enableChildChains(ChildChain chain, bool enable) {
- int res = 0;
- const char* name;
- switch(chain) {
- case DOZABLE:
- name = LOCAL_DOZABLE;
- break;
- case STANDBY:
- name = LOCAL_STANDBY;
- break;
- case POWERSAVE:
- name = LOCAL_POWERSAVE;
- break;
- case RESTRICTED:
- name = LOCAL_RESTRICTED;
- break;
- default:
- return res;
- }
-
- if (mUseBpfOwnerMatch) {
- return gCtls->trafficCtrl.toggleUidOwnerMap(chain, enable);
- }
-
- std::string command = "*filter\n";
- for (const char *parent : { LOCAL_INPUT, LOCAL_OUTPUT }) {
- StringAppendF(&command, "%s %s -j %s\n", (enable ? "-A" : "-D"), parent, name);
- }
- StringAppendF(&command, "COMMIT\n");
-
- return execIptablesRestore(V4V6, command);
+ return gCtls->trafficCtrl.toggleUidOwnerMap(chain, enable);
}
int FirewallController::isFirewallEnabled(void) {
@@ -235,57 +181,8 @@ FirewallType FirewallController::getFirewallType(ChildChain chain) {
}
int FirewallController::setUidRule(ChildChain chain, int uid, FirewallRule rule) {
- const char* op;
- const char* target;
FirewallType firewallType = getFirewallType(chain);
- if (firewallType == ALLOWLIST) {
- target = "RETURN";
- // When adding, insert RETURN rules at the front, before the catch-all DROP at the end.
- op = (rule == ALLOW)? "-I" : "-D";
- } else { // DENYLIST mode
- target = "DROP";
- // When adding, append DROP rules at the end, after the RETURN rule that matches TCP RSTs.
- op = (rule == DENY)? "-A" : "-D";
- }
-
- std::vector<std::string> chainNames;
- switch(chain) {
- case DOZABLE:
- chainNames = {LOCAL_DOZABLE};
- break;
- case STANDBY:
- chainNames = {LOCAL_STANDBY};
- break;
- case POWERSAVE:
- chainNames = {LOCAL_POWERSAVE};
- break;
- case RESTRICTED:
- chainNames = {LOCAL_RESTRICTED};
- break;
- case NONE:
- chainNames = {LOCAL_INPUT, LOCAL_OUTPUT};
- break;
- default:
- ALOGW("Unknown child chain: %d", chain);
- return -EINVAL;
- }
- if (mUseBpfOwnerMatch) {
- return gCtls->trafficCtrl.changeUidOwnerRule(chain, uid, rule, firewallType);
- }
-
- std::string command = "*filter\n";
- for (const std::string& chainName : chainNames) {
- StringAppendF(&command, "%s %s -m owner --uid-owner %d -j %s\n",
- op, chainName.c_str(), uid, target);
- }
- StringAppendF(&command, "COMMIT\n");
-
- return (execIptablesRestore(V4V6, command) == 0) ? 0 : -EREMOTEIO;
-}
-
-int FirewallController::createChain(const char* chain, FirewallType type) {
- static const std::vector<int32_t> NO_UIDS;
- return replaceUidChain(chain, type == ALLOWLIST, NO_UIDS);
+ return gCtls->trafficCtrl.changeUidOwnerRule(chain, uid, rule, firewallType);
}
/* static */
@@ -301,111 +198,9 @@ std::string FirewallController::makeCriticalCommands(IptablesTarget target, cons
return commands;
}
-std::string FirewallController::makeUidRules(IptablesTarget target, const char* name,
- bool isAllowlist, const std::vector<int32_t>& uids) {
- std::string commands;
- StringAppendF(&commands, "*filter\n:%s -\n", name);
-
- // Allowlist chains have UIDs at the beginning, and new UIDs are added with '-I'.
- if (isAllowlist) {
- for (auto uid : uids) {
- StringAppendF(&commands, "-A %s -m owner --uid-owner %d -j RETURN\n", name, uid);
- }
-
- // Always allowlist system UIDs.
- StringAppendF(&commands,
- "-A %s -m owner --uid-owner %d-%d -j RETURN\n", name, 0, MAX_SYSTEM_UID);
-
- // This rule inverts the match for all UIDs; ie, if there is no UID match here,
- // there is no socket to be found
- StringAppendF(&commands,
- "-A %s -m owner ! --uid-owner %d-%u -j RETURN\n", name, 0, mMaxUid);
-
- // Always allowlist traffic with protocol ESP, or no known socket - required for IPSec
- StringAppendF(&commands, "-A %s -p esp -j RETURN\n", name);
- }
-
- // Always allow networking on loopback.
- StringAppendF(&commands, "-A %s -i lo -j RETURN\n", name);
- StringAppendF(&commands, "-A %s -o lo -j RETURN\n", name);
-
- // Allow TCP RSTs so we can cleanly close TCP connections of apps that no longer have network
- // access. Both incoming and outgoing RSTs are allowed.
- StringAppendF(&commands, "-A %s -p tcp --tcp-flags RST RST -j RETURN\n", name);
-
- if (isAllowlist) {
- commands.append(makeCriticalCommands(target, name));
- }
-
- // Denylist chains have UIDs at the end, and new UIDs are added with '-A'.
- if (!isAllowlist) {
- for (auto uid : uids) {
- StringAppendF(&commands, "-A %s -m owner --uid-owner %d -j DROP\n", name, uid);
- }
- }
-
- // If it's an allowlist chain, add a default DROP at the end. This is not necessary for a
- // denylist chain, because all user-defined chains implicitly RETURN at the end.
- if (isAllowlist) {
- StringAppendF(&commands, "-A %s -j DROP\n", name);
- }
-
- StringAppendF(&commands, "COMMIT\n");
-
- return commands;
-}
-
int FirewallController::replaceUidChain(const std::string& name, bool isAllowlist,
const std::vector<int32_t>& uids) {
- if (mUseBpfOwnerMatch) {
- return gCtls->trafficCtrl.replaceUidOwnerMap(name, isAllowlist, uids);
- }
- std::string commands4 = makeUidRules(V4, name.c_str(), isAllowlist, uids);
- std::string commands6 = makeUidRules(V6, name.c_str(), isAllowlist, uids);
- return execIptablesRestore(V4, commands4.c_str()) | execIptablesRestore(V6, commands6.c_str());
-}
-
-/* static */
-uid_t FirewallController::discoverMaximumValidUid(const std::string& fileName) {
- std::string content;
- if (!ReadFileToString(fileName, &content, false)) {
- // /proc/self/uid_map only exists if a uid mapping has been set.
- ALOGD("Could not read %s, max uid defaulting to %u", fileName.c_str(), kDefaultMaximumUid);
- return kDefaultMaximumUid;
- }
-
- std::vector<std::string> lines = Split(content, "\n");
- if (lines.empty()) {
- ALOGD("%s was empty, max uid defaulting to %u", fileName.c_str(), kDefaultMaximumUid);
- return kDefaultMaximumUid;
- }
-
- uint32_t maxUid = 0;
- for (const auto& line : lines) {
- if (line.empty()) {
- continue;
- }
-
- // Choose the end of the largest range found in the file.
- uint32_t start;
- uint32_t ignored;
- uint32_t rangeLength;
- int items = sscanf(line.c_str(), "%u %u %u", &start, &ignored, &rangeLength);
- if (items != 3) {
- // uid_map lines must have 3 items, see the man page of 'user_namespaces' for details.
- ALOGD("Format of %s unrecognized, max uid defaulting to %u", fileName.c_str(),
- kDefaultMaximumUid);
- return kDefaultMaximumUid;
- }
- maxUid = std::max(maxUid, start + rangeLength - 1);
- }
-
- if (maxUid == 0) {
- ALOGD("No max uid found, max uid defaulting to %u", kDefaultMaximumUid);
- return kDefaultMaximumUid;
- }
-
- return maxUid;
+ return gCtls->trafficCtrl.replaceUidOwnerMap(name, isAllowlist, uids);
}
} // namespace net
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-21 07:57:26 +0000