cafkafk/lix
cafkafk/lix
1
0
Fork 0
Code Issues Pull requests 1 Projects Releases Packages Wiki Activity Actions

Don't allow writing to /etc

Browse source
This commit is contained in:
Yorick van Pelt 2023-02-14 12:03:34 +01:00
parent df9a71f6ea
commit db41f74af3
No known key found for this signature in database
GPG key ID: A36E70F9DC014A15
2 changed files with 6 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
src/libstore/build/local-derivation-goal.cc
View file

@ -670,7 +670,6 @@ void LocalDerivationGoal::startBuilder()
nobody account. The latter is kind of a hack to support
Samba-in-QEMU. */
createDirs(chrootRootDir + "/etc");
chownToBuilder(chrootRootDir + "/etc");
if (parsedDrv->useUidRange() && (!buildUser || buildUser->getUIDCount() < 65536))
throw Error("feature 'uid-range' requires the setting '%s' to be enabled", settings.autoAllocateUids.name);
@ -970,6 +969,9 @@ void LocalDerivationGoal::startBuilder()
"nobody:x:65534:65534:Nobody:/:/noshell\n",
sandboxUid(), sandboxGid(), settings.sandboxBuildDir));
/* Make /etc unwritable */
chmod_(chrootRootDir + "/etc", 0555);
/* Save the mount- and user namespace of the child. We have to do this
*before* the child does a chroot. */
sandboxMountNamespace = open(fmt("/proc/%d/ns/mnt", (pid_t) pid).c_str(), O_RDONLY);

3
tests/linux-sandbox.sh
View file

@ -37,3 +37,6 @@ nix-build check.nix -A nondeterministic --sandbox-paths /nix/store --no-out-link
(! nix-build check.nix -A nondeterministic --sandbox-paths /nix/store --no-out-link --check -K 2> $TEST_ROOT/log)
if grep -q 'error: renaming' $TEST_ROOT/log; then false; fi
grep -q 'may not be deterministic' $TEST_ROOT/log
# Test that sandboxed builds cannot write to /etc easily
(! nix-build -E 'with import ./config.nix; mkDerivation { name = "etc-write"; buildCommand = "echo > /etc/test"; }' --no-out-link --sandbox-paths /nix/store)