findRoots(): Add 'censor' parameter

This is less brittle than filtering paths after the fact in
nix-daemon.
This commit is contained in:
Eelco Dolstra 2019-03-14 13:50:07 +01:00
parent a3f37d87ea
commit 53522cb6ac
No known key found for this signature in database
GPG key ID: 8170B4726D7198DE
7 changed files with 40 additions and 53 deletions

View file

@ -129,7 +129,7 @@ Path LocalFSStore::addPermRoot(const Path & _storePath,
check if the root is in a directory in or linked from the
gcroots directory. */
if (settings.checkRootReachability) {
Roots roots = findRoots();
Roots roots = findRoots(false);
if (roots[storePath].count(gcRoot) == 0)
printError(
format(
@ -197,7 +197,10 @@ void LocalStore::addTempRoot(const Path & path)
}
void LocalStore::findTempRoots(FDs & fds, Roots & tempRoots)
static std::string censored = "{censored}";
void LocalStore::findTempRoots(FDs & fds, Roots & tempRoots, bool censor)
{
/* Read the `temproots' directory for per-process temporary root
files. */
@ -248,7 +251,7 @@ void LocalStore::findTempRoots(FDs & fds, Roots & tempRoots)
Path root(contents, pos, end - pos);
debug("got temporary root '%s'", root);
assertStorePath(root);
tempRoots[root].emplace(fmt("{temp:%d}", pid));
tempRoots[root].emplace(censor ? censored : fmt("{temp:%d}", pid));
pos = end + 1;
}
@ -317,7 +320,7 @@ void LocalStore::findRoots(const Path & path, unsigned char type, Roots & roots)
}
void LocalStore::findRootsNoTemp(Roots & roots)
void LocalStore::findRootsNoTemp(Roots & roots, bool censor)
{
/* Process direct roots in {gcroots,profiles}. */
findRoots(stateDir + "/" + gcRootsDir, DT_UNKNOWN, roots);
@ -327,17 +330,17 @@ void LocalStore::findRootsNoTemp(Roots & roots)
NIX_ROOT_FINDER environment variable. This is typically used
to add running programs to the set of roots (to prevent them
from being garbage collected). */
findRuntimeRoots(roots);
findRuntimeRoots(roots, censor);
}
Roots LocalStore::findRoots()
Roots LocalStore::findRoots(bool censor)
{
Roots roots;
findRootsNoTemp(roots);
findRootsNoTemp(roots, censor);
FDs fds;
findTempRoots(fds, roots);
findTempRoots(fds, roots, censor);
return roots;
}
@ -381,7 +384,7 @@ static void readFileRoots(const char * path, Roots & roots)
}
}
void LocalStore::findRuntimeRoots(Roots & roots)
void LocalStore::findRuntimeRoots(Roots & roots, bool censor)
{
Roots unchecked;
@ -467,6 +470,9 @@ void LocalStore::findRuntimeRoots(Roots & roots)
Path path = toStorePath(target);
if (isStorePath(path) && isValidPath(path)) {
debug(format("got additional root '%1%'") % path);
if (censor)
roots[path].insert(censored);
else
roots[path].insert(links.begin(), links.end());
}
}
@ -739,7 +745,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
printError(format("finding garbage collector roots..."));
Roots rootMap;
if (!options.ignoreLiveness)
findRootsNoTemp(rootMap);
findRootsNoTemp(rootMap, true);
for (auto & i : rootMap) state.roots.insert(i.first);
@ -748,7 +754,7 @@ void LocalStore::collectGarbage(const GCOptions & options, GCResults & results)
can be added to the set of temporary roots. */
FDs fds;
Roots tempRoots;
findTempRoots(fds, tempRoots);
findTempRoots(fds, tempRoots, true);
for (auto & root : tempRoots)
state.tempRoots.insert(root.first);
state.roots.insert(state.tempRoots.begin(), state.tempRoots.end());

View file

@ -180,11 +180,11 @@ private:
typedef std::shared_ptr<AutoCloseFD> FDPtr;
typedef list<FDPtr> FDs;
void findTempRoots(FDs & fds, Roots & roots);
void findTempRoots(FDs & fds, Roots & roots, bool censor);
public:
Roots findRoots() override;
Roots findRoots(bool censor) override;
void collectGarbage(const GCOptions & options, GCResults & results) override;
@ -267,9 +267,9 @@ private:
void findRoots(const Path & path, unsigned char type, Roots & roots);
void findRootsNoTemp(Roots & roots);
void findRootsNoTemp(Roots & roots, bool censor);
void findRuntimeRoots(Roots & roots);
void findRuntimeRoots(Roots & roots, bool censor);
void removeUnusedLinks(const GCState & state);

View file

@ -596,7 +596,7 @@ void RemoteStore::syncWithGC()
}
Roots RemoteStore::findRoots()
Roots RemoteStore::findRoots(bool censor)
{
auto conn(getConnection());
conn->to << wopFindRoots;

View file

@ -82,7 +82,7 @@ public:
void syncWithGC() override;
Roots findRoots() override;
Roots findRoots(bool censor) override;
void collectGarbage(const GCOptions & options, GCResults & results) override;

View file

@ -484,8 +484,10 @@ public:
/* Find the roots of the garbage collector. Each root is a pair
(link, storepath) where `link' is the path of the symlink
outside of the Nix store that point to `storePath'. */
virtual Roots findRoots()
outside of the Nix store that point to `storePath'. If
'censor' is true, privacy-sensitive information about roots
found in /proc is censored. */
virtual Roots findRoots(bool censor)
{ unsupported("findRoots"); }
/* Perform a garbage collection. */

View file

@ -475,40 +475,19 @@ static void performOp(TunnelLogger * logger, ref<Store> store,
case wopFindRoots: {
logger->startWork();
Roots roots = store->findRoots();
Roots roots = store->findRoots(true);
logger->stopWork();
// Pre-compute roots length using same algo as below.
size_t total_length = 0;
bool hasMemoryLink;
for (auto & root : roots) {
hasMemoryLink = false;
for (auto & link : root.second) {
if (link.rfind("{memory:", 0) == 0) {
if (hasMemoryLink) continue;
++total_length;
hasMemoryLink = true;
} else {
++total_length;
}
}
}
size_t size = 0;
for (auto & i : roots)
size += i.second.size();
to << total_length;
int n = 0;
for (auto & [target, links] : roots) {
bool hasMemoryLink = false;
for (auto & link : links) {
// Obfuscate 'memory' roots as they expose information about other users,
if (link.rfind("{memory:", 0) == 0) {
if (hasMemoryLink) continue;
to << fmt("{memory:%d}", n++) << target;
hasMemoryLink = true;
} else {
to << size;
for (auto & [target, links] : roots)
for (auto & link : links)
to << link << target;
}
}
}
break;
}

View file

@ -427,7 +427,7 @@ static void opQuery(Strings opFlags, Strings opArgs)
maybeUseOutputs(store->followLinksToStorePath(i), useOutput, forceRealise),
referrers, true, settings.gcKeepOutputs, settings.gcKeepDerivations);
}
Roots roots = store->findRoots();
Roots roots = store->findRoots(false);
for (auto & [target, links] : roots)
if (referrers.find(target) != referrers.end())
for (auto & link : links)
@ -591,7 +591,7 @@ static void opGC(Strings opFlags, Strings opArgs)
if (!opArgs.empty()) throw UsageError("no arguments expected");
if (printRoots) {
Roots roots = store->findRoots();
Roots roots = store->findRoots(false);
for (auto & [target, links] : roots)
for (auto & link : links)
cout << link << " -> " << target << std::endl;