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2026-03-29daemon: Dereference symlinks for /etc/services & co.Ludovic Courtès
Fixes a regression on Guix System introduced in c4298638ca27717be4a83cb033dcbfecdea88093 (from guix/guix#4178) where files in /etc, such as /etc/services, would be symlinks. Consequently, the chroot of fixed-output derivations would contain a dangling symlink for /etc/services, leading to name resolution failures in the chroot. This also relates to 82f84f5e7fb34cc719ed6ea538a3d1ca7516f23d. * nix/libstore/build.cc (DerivationGoal::startBuilder): Add call to ‘canonPath’. Change-Id: If34c8e74447ffc03d9fa81a1ea6bc0aef7c4d0b3 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2026-03-19daemon: Resolve symlinks in /etc/resolv.conf for slirp4netns chroot.Roman Scherer
* nix/libstore/build.cc (prepareSlirpChrootAction): Use canonPath(i, true) to resolve symlinks when adding /etc/resolv.conf and /etc/hosts to the slirp4netns chroot, so that bindMount receives a regular file path instead of a symlink. On systems using systemd-resolved, /etc/resolv.conf is typically a symlink: /etc/resolv.conf -> /run/systemd/resolve/stub-resolv.conf The slirp4netns chroot creates an empty /run/ directory, so when bindMount copies the symlink verbatim (spawn.cc line 537-542), the target does not exist and slirp4netns cannot determine the upstream DNS server. This causes all DNS resolution to fail for fixed-output derivations that use the Guile-based git-fetch builder (e.g. git-fetch/lfs), since they rely on slirp4netns for network access in the build chroot. Derivations using builtin:git-download are unaffected because they run in the daemon process itself, which has full network access. Change-Id: Ib73e69a8760e74eb8141dd0408c27aa8b3001e37 Signed-off-by: Ludovic Courtès <ludo@gnu.org> Merges: #6959
2025-12-26daemon: Fix typo in format string.Ludovic Courtès
* nix/libstore/build.cc (Worker::waitForInput): Fix typo in format string. Change-Id: I0a39ada8a347c8c8daddd9f34292cbbb03ba0076
2025-11-12daemon: Use inline functions and variables instead of externCongcong Kuo
Avoid separate declarations and definitions for so-called 'global' objects. * nix/libstore/derivations.{cc, hh} (drvHashes): Use inline instead of separate declaration and definition. * nix/libstore/globals.{cc, hh} (settings, nixVersion): Same. * nix/libstore/local-store.hh (drvsLogDir, deduplicationMinSize): Same. * nix/libstore/optimise-store.cc (deduplicationMinSize): Same. * nix/libstore/store-api.{cc, hh} (store): Same. * nix/libutil/archive.{cc, hh} (defaultPathFilter): Same. * nix/libutil/hash.{cc, hh} (base32Chars): Same and modify header files. * nix/libutil/util.{cc, hh} (logType, verbosity, _writeToStderr, _isInterrupted): Same. * nix/local.mk: Modified according to the rename of shared.hh. * nix/nix-daemon/guix-daemon.cc (blockInt, argvSaved, run): Same and modify header files. * nix/nix-daemon/nix-daemon.cc: Modify header files. * nix/nix-daemon/shared.hh: Renamed to nix-daemon.hh Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-11-04daemon: Fix compilation error while using Zig (LLVM)Congcong Kuo
* nix/libstore/build.cc (guestUID, guestGID): Rename to 'defaultGuestUID' and 'defaultGuestGID' respectively. (initializeUserNamespace, DerivationGoal::startBuilder): Rename references to variables accordingly. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-11-03daemon: Use starts_with() and ends_with() instead of string() or hasSuffix()Congcong Kuo
* nix/libstore/build.cc (DerivationGoal::tryBuildHook): Use starts_with instead of string() * nix/libstore/builtins.cc (lookupBuiltinBuilder): Same. * nix/libstore/builtins.hh (isBuiltin): Same and fix indentation of the file. * nix/libstore/derivations.cc (DerivationOutput::parseHashInfo, isDerivation): Same and clean header files. * nix/libstore/gc.cc (addPermRoot, LocalStore::isActiveTempFile): Same. * nix/libstore/globals.cc: Same. * nix/libstore/local-store.cc: Same. * nix/libstore/misc.cc: Same. * nix/libstore/store-api.cc (checkStoreName): Same. * nix/libutil/affinity.cc: Same. * nix/libutil/archive.cc: Same. * nix/libutil/spawn.cc: Same. * nix/libutil/util.{cc, hh} (hasSuffix): Removed. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-10-19daemon: Bump to C++20 and use ‘std::format’ instead of ‘boost::format’.Congcong Kuo
* nix/boost: This directory and all files inside it are removed. * nix/libstore/build.cc (Goal::trace): Use ‘std::string’ instead of ‘const format &’. (DerivationGoal::startBuilder, ...): Use ‘std::format’ or ‘std::vformat’ instead of ‘boost::format’. * nix/libstore/builtins.cc (builtinDownload): Same. * nix/libstore/derivations.cc (DerivationOutput::parseHashInfo, ...): Same. * nix/libstore/gc.cc (LocalStore::openGCLock, ...): Same. * nix/libstore/globals.cc (Settings::_get): Same. * nix/libstore/local-store.cc: (checkStoreNotSymlink, ...): Same. * nix/libstore/misc.cc (dfsVisit, showBytes): Same * nix/libstore/optimise-store.cc (makeWritable, ...): Same. * nix/libstore/pathlocks.cc (openLockFile, ...): Same. * nix/libstore/references.cc (search, scanForReferences): Same. * nix/libstore/sqlite.hh (throwSQLiteError): Use ‘std::string’ instead of ‘const format &’. * nix/libstore/sqlite.cc (throwSQLiteError): Use ‘std::string’ instead of ‘const format &’. * nix/libstore/store-api.cc (assertStorePath, ...): Use ‘std::format’ instead of ‘boost::format’. * nix/libutil/affinity.cc (setAffinityTo): Same. * nix/libutil/archive.cc (dumpContents, ...): Same. * nix/libutil/hash.cc (parseHash, parseHash32, parseHash16or32, hashFile): Same. * nix/libutil/hash.hh (parseHash, parseHash32, parseHash16or32, isHash): Same. * nix/libutil/serialise.cc : Add ‘<cassert>’ header file. * nix/libutil/spawn.cc (addPhaseAfter, ...): Use ‘std::format’ instead of ‘boost::format’. * nix/libutil/types.hh (FormatOrString): Removed. (BaseError, BaseError::addPrefix, SysError, MakeError): Use ‘std::string or std::string_view’ instead of ‘FormatOrString’. * nix/libutil/util.hh (Nest::open, printMsg_, warnOnce, expect): Same. * nix/libutil/util.cc (BaseError::BaseError, ...): Same. (writeToStderr, _interrupted): Use std::uncaught_exceptions() instead of std::uncaught_exception() * nix/nix-daemon/nix-daemon.cc (performOp, ...): Same. * nix/nix-daemon/guix-daemon.cc (string_to_bool, ...): Same. * nix/local.mk: Remove ‘libformat.a’ from ‘noinst_LIBRARIES’, remove ‘libformat_a_SOURCES’ and ‘libformat_headers’, remove ‘libformat_a_CPPFLAGS’ from ‘libutil_a_CPPFLAGS’ and ‘guix_daemon_LDADD’, update ‘AM_CXXFLAGS’ to ‘-std=c++20’. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-10-16daemon: Attempt to map the “kvm” group inside the build user namespace.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/77862>. Previously, the ‘guix-daemon’ account (for unprivileged execution) would typically have “kvm” as a supplementary group, but that group would not be mapped in the build user namespace. Consequently, attempts to ‘chown’ a file to that supplementary group would fail with EINVAL. The test suites of Coreutils, Python, and Go (among others) exercise this chown-to-supplementary-group behavior, so they would all fail when started by the unprivileged ‘guix-daemon’ even though they succeed when started by ‘guix-daemon’ running as root. Thanks to keinflue <keinflue@posteo.net> and Reepca Russelstein <reepca@russelstein.xyz> for helping out. * nix/libstore/build.cc (initializeUserNamespace): Add ‘extraGIDs’ and ‘haveCapSetGID’ parameters. Invoke ‘newgidmap’ when ‘extraGIDs’ is non-empty and ‘haveCapSetGID’ is false. Honor ‘extraGIDs’ when ‘haveCapSetGID’ is true. (maxGroups, guestKVMGID): New variables. (kvmGIDMapping): New function. (DerivationGoal::startBuilder): Set ‘ctx.lockMountsMapAll’ in the CLONE_NEWUSER case. Pass ‘extraGIDs’ to ‘initializeUserNamespace’. * tests/store.scm ("kvm GID is mapped"): New test. Change-Id: I10ba710fc1b9ca1e3cd3122be1ec8ede5df18b40
2025-09-23daemon: Restore post-canonicalization permissions after moving.Reepca Russelstein
At this point the value of 'st.st_mode' is from before canonicalization, so restoring to that will undo the permissions aspect of the canonicalization for a top-level directory store item. Fixes #1104, introduced in ae18b3d9e6 (https://codeberg.org/guix/guix/commit/ae18b3d9e6bd0c184505a094851448d08555e23e). * nix/libstore/build.cc (DerivationGoal::registerOutputs): update 'st' with post-canonicalization permissions before making actualPath temporarily-writable. * tests/store.scm ("build outputs aren't writable"): new test. Change-Id: I5e5eaa79fa6b7f81e1d12fd285883c762a22ce5a Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-08-23daemon: Tolerate pipes and sockets in failed build trees.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/78919>. Fixes guix/guix#471. Fixes a bug introduced in ae18b3d9e6bd0c184505a094851448d08555e23e whereby interrupting ‘guix build -K hello’ would leave a build directory with root ownership due ‘secureFilePerms’ bailing out due to the presence of FIFOs in the temporary build directory. * nix/libstore/build.cc (secureFilePerms): Add ‘allowSpecialFiles’ parameter; honor it and pass it in recursive call. (DerivationGoal::deleteTmpDir): Pass true as the second argument to ‘secureFilePerms’. Reported-by: Janneke Nieuwenhuizen <janneke@gnu.org> Reported-by: David Elsing <david.elsing@posteo.net> Change-Id: I638a4ee909a2b5022f9153e1cbb832bfb2e15263
2025-06-30daemon: Conditionally disable seccomp filter on ‘socketcall’ systems.Reepca Russelstein
glibc currently will insist on using 'socketcall' on i686-linux unless built with '--enable-kernel=4.3.0' or above, even on systems that have dedicated system calls available for all the socket-related functionality. This behavior breaks the assumption that socketcall can be safely blocked without impacting functionality in slirp4netns, rendering the seccomp filter unusable with those glibcs. This change makes the slirp4netns seccomp filter opt-in on systems with a 'socketcall' system call. It can either be opted-into at compile-time or at runtime using the NO_SOCKETCALL_LIBC preprocessor define or the GUIX_FORCE_SECCOMP environment variable, respectively. The seccomp filter being disabled on these systems means that it is possible for a compromised slirp4netns to access abstract unix domain sockets in the root network namespace. It does not affect any of the other mechanisms used to isolate slirp4netns (e.g. chroot, namespaces, etc). Fixes guix/guix#808. * nix/libstore/build.cc (spawnSlirp4netns) [__NR_socketcall]: Do not add seccomp filter, unless ‘GUIX_FORCE_SECCOMP’ is set. Change-Id: Ibfe8becc9431f5aff11a21f06858b20496f9cb4a Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-06-24daemon: add seccomp filter for slirp4netns.Reepca Russelstein
The container that slirp4netns runs in should already be quite difficult to do anything malicious in beyond basic denial of service or sending of network traffic. There is, however, one hole remaining in the case in which there is an adversary able to run code locally: abstract unix sockets. Because these are governed by network namespaces, not IPC namespaces, and slirp4netns is in the root network namespace, any process in the root network namespace can cooperate with the slirp4netns process to take over its user. To close this, we use seccomp to block the creation of unix-domain sockets by slirp4netns. This requires some finesse, since slirp4netns absolutely needs to be able to create other types of sockets - at minimum AF_INET and AF_INET6 Seccomp has many, many pitfalls. To name a few: 1. Seccomp provides you with an "arch" field, but this does not uniquely determine the ABI being used; the actual meaning of a system call number depends on both the number (which is often the result of ORing a related system call with a flag for an alternate ABI) and the architecture. 2. Seccomp provides no direct way of knowing what the native value for the arch field should be; the user must do configure/compile-time testing for every architecture+ABI combination they want to support. Amusingly enough, the linux-internal header files have this exact information (SECCOMP_ARCH_NATIVE), but they aren't sharing it. 3. The only system call numbers we naturally have are the native ones in asm/unistd.h. __NR_socket will always refer to the system call number for the target system's ABI. 4. Seccomp can only manipulate 32-bit words, but represents every system call argument as a uint64. 5. New system call numbers with as-yet-unknown semantics can be added to the kernel at any time. 6. Based on this comment in arch/x86/entry/syscalls/syscall_32.tbl: # 251 is available for reuse (was briefly sys_set_zone_reclaim) previously-invalid system call numbers may later be reused for new system calls. 7. Most architecture+ABI combinations have system call tables with many gaps in them. arm-eabi, for example, has 35 such gaps (note: this is just the number of distinct gaps, not the number of system call numbers contained in those gaps). 8. Seccomp's BPF filters require a fully-acyclic control flow graph. Any operation on a data structure must therefore first be fully unrolled before it can be run. 9. Seccomp cannot dereference pointers. Only the raw bits provided to the system calls can be inspected. 10. Some architecture+ABI combos have multiplexer system calls. For example, socketcall can perform any socket-related system call. The arguments to the multiplexed system call are passed indirectly, via a pointer to user memory. They therefore cannot be inspected by seccomp. 11. Some valid system calls are not listed in any table in the kernel source. For example, __ARM_NR_cacheflush is an "ARM private" system call. It does not appear in any *.tbl file. 12. Conditional branches are limited to relative jumps of at most 256 instructions forward. 13. Prior to Linux 4.8, any process able to spawn another process and call ptrace could bypass seccomp restrictions. To address (1), (2), and (3), we include preprocessor checks to identify the native architecture value, and reject all system calls that don't use the native architecture. To address (4), we use the AC_C_BIGENDIAN autoconf check to conditionally define WORDS_BIGENDIAN, and match up the proper portions of any uint64 we test for with the value in the accumulator being tested against. To address (5) and (6), we use system call pinning. That is, we hardcode a snapshot of all the valid system call numbers at the time of writing, and reject any system call numbers not in the recorded set. A set is recorded for every architecture+ABI combo, and the native one is chosen at compile-time. This ensures that not only are non-native architectures rejected, but so are non-native ABIs. For the sake of conciseness, we represent these sets as sets of disjoint ranges. Due to (7), checking each range in turn could add a lot of overhead to each system call, so we instead binary search through the ranges. Due to (8), this binary search has to be fully unrolled, so we do that too. It can be tedious and error-prone to manually produce the syscall ranges by looking at linux's *.tbl files, since the gaps are often small and uncommented. To address this, a script, build-aux/extract-syscall-ranges.sh, is added that will produce them given a *.tbl filename and an ABI regex (some tables seem to abuse the ABI field with strange values like "memfd_secret"). Note that producing the final values still requires looking at the proper asm/unistd.h file to find any private numbers and to identify any offsets and ABI variants used. (10) used to have no good solution, but in the past decade most architectures have gained dedicated system call alternatives to at least socketcall, so we can (hopefully) just block it entirely. To address (13), we block ptrace also. * build-aux/extract-syscall-ranges.sh: new script. * Makefile.am (EXTRA_DIST): register it. * config-daemon.ac: use AC_C_BIGENDIAN. * nix/libutil/spawn.cc (setNoNewPrivsAction, addSeccompFilterAction): new functions. * nix/libutil/spawn.hh (setNoNewPrivsAction, addSeccompFilterAction): new declarations. (SpawnContext)[setNoNewPrivs, addSeccompFilter]: new fields. * nix/libutil/seccomp.hh: new header file. * nix/libutil/seccomp.cc: new file. * nix/local.mk (libutil_a_SOURCES, libutil_headers): register them. * nix/libstore/build.cc (slirpSeccompFilter, writeSeccompFilterDot): new functions. (spawnSlirp4netns): use them, set seccomp filter for slirp4netns. Change-Id: Ic92c7f564ab12596b87ed0801b22f88fbb543b95 Signed-off-by: John Kehayias <john.kehayias@protonmail.com>
2025-06-24daemon: Use slirp4netns to provide networking to fixed-output derivations.Reepca Russelstein
Previously, the builder of a fixed-output derivation could communicate with an external process via an abstract Unix-domain socket. In particular, it could send an open file descriptor to the store, granting write access to some of its output files in the store provided the derivation build fails—the fix for CVE-2024-27297 did not address this specific case. It could also send an open file descriptor to a setuid program, which could then be executed using execveat to gain the privileges of the build user. With this change, fixed-output derivations other than “builtin:download” and “builtin:git-download” always run in a separate network namespace and have network access provided by a TAP device backed by slirp4netns, thereby closing the abstract Unix-domain socket channel. * nix/libstore/globals.hh (Settings)[useHostLoopback, slirp4netns]: new fields. * config-daemon.ac (SLIRP4NETNS): new C preprocessor definition. * nix/libstore/globals.cc (Settings::Settings): initialize them to defaults. * nix/nix-daemon/guix-daemon.cc (options): add --isolate-host-loopback option. * doc/guix.texi: document it. * nix/libstore/build.cc (DerivationGoal)[slirp]: New field. (setupTap, setupTapAction, waitForSlirpReadyAction, enableRouteLocalnetAction, prepareSlirpChrootAction, spawnSlirp4netns, haveGlobalIPv6Address, remapIdsTo0Action): New functions. (initializeUserNamespace): allow the guest UID and GID to be specified. (DerivationGoal::killChild): When ‘slirp’ is not -1, call ‘kill’. (DerivationGoal::startBuilder): Unconditionally add CLONE_NEWNET to FLAGS. When ‘fixedOutput’ is true, spawn ‘slirp4netns’. When ‘fixedOutput’ and ‘useChroot’ are true, add setupTapAction, waitForSlirpReadyAction, and enableRouteLocalnetAction to builder setup phases. Create a /etc/resolv.conf for fixed-output derivations that directs them to slirp4netns's dns address. When settings.useHostLoopback is true, supply fixed-output derivations with a /etc/hosts that resolves "localhost" to slirp4netns's address for accessing the host loopback. * nix/libutil/util.cc (keepOnExec, decodeOctalEscaped, sendFD, receiveFD, findProgram): New functions. * nix/libutil/util.hh (keepOnExec, decodeOctalEscaped, sendFD, receiveFD, findProgram): New declarations. * gnu/packages/package-management.scm (guix): add slirp4netns input for linux targets. * tests/derivations.scm (builder-network-isolated?): new variable. ("fixed-output derivation, network access, localhost", "fixed-output derivation, network access, external host"): skip test case if fixed output derivations are isolated from the network. Change-Id: Ia3fea2ab7add56df66800071cf15cdafe7bfab96 Signed-off-by: John Kehayias <john.kehayias@protonmail.com>
2025-06-24daemon: add and use spawn.cc and spawn.hh.Reepca Russelstein
This adds a mechanism for manipulating and running "spawn phases" similarly to how builder-side code manipulates "build phases". The main difference is that spawn phases take a (reference to a) single structure that they can both read from and write to, with their writes being visible to subsequent phases. The base structure type for this is SpawnContext. It also adds some predefined phase sequences, namely basicSpawnPhases and cloneSpawnPhases, and exposes each of the actions performed by these phases. Finally, it modifies build.cc to replace runChild() with use of this new code. * nix/libutil/util.cc (keepOnExec, waitForMessage): new functions. * nix/libutil.util.hh (keepOnExec, waitForMessage): add prototypes. * nix/libutil/spawn.cc, nix/libutil/spawn.hh: new files. (addPhaseAfter, addPhaseBefore, prependPhase, appendPhase, deletePhase, replacePhase, reset_writeToStderrAction, restoreAffinityAction, setsidAction, earlyIOSetupAction, dropAmbientCapabilitiesAction, chrootAction, chdirAction, closeMostFDsAction, setPersonalityAction, oomSacrificeAction, setIDsAction, restoreSIGPIPEAction, setupSuccessAction, execAction, getBasicSpawnPhases, usernsInitSyncAction, usernsSetIDsAction, initLoopbackAction, setHostAndDomainAction, makeFilesystemsPrivateAction, makeChrootSeparateFilesystemAction, statfsToMountFlags, bindMount, mountIntoChroot, mountIntoChrootAction, mountProcAction, mountDevshmAction, mountDevptsAction, pivotRootAction, lockMountsAction, getCloneSpawnPhases, runChildSetup, runChildSetupEntry, cloneChild, idMapToIdentityMap, unshareAndInitUserns): new procedures. * nix/local.mk (libutil_a_SOURCES): add spawn.cc. (libutil_headers): add spawn.hh. * nix/libstore/build.cc (restoreSIGPIPE, DerivationGoal::runChild, childEntry): removed procedures. (DerivationGoal::{dirsInChroot,env,readiness}): removed. (execBuilderOrBuiltin, execBuilderOrBuiltinAction, clearRootWritePermsAction): new procedures. (DerivationGoal::startBuilder): modified to use a CloneSpawnContext if chroot builds are available, otherwise a SpawnContext. Change-Id: Ifd50110de077378ee151502eda62b99973d083bf Change-Id: I76e10d3f928cc30566e1e6ca79077196972349f8 spawn.cc, util.cc, util.hh changes Change-Id: I287320e63197cb4f65665ee5b3fdb3a0e125ebac Signed-off-by: John Kehayias <john.kehayias@protonmail.com>
2025-06-09daemon: Remove ‘foreach’ and ‘foreach_reverse’Congcong Kuo
‘foreach_reverse’ is not used anywhere * nix/libutil/util.hh (foreach, foreach_reverse): Remove. * nix/libstore/build.cc (addToWeakGoals): Use ‘std::none_of’ instead of macro ‘foreach’. (Goal::waiteeDone, Goal::amDone, UserLock::acquire, rewriteHashes, DerivationGoal::addWantedOutputs, DerivationGoal::haveDerivation, DerivationGoal::outputsSubstituted, DerivationGoal::repairClosure, DerivationGoal::inputsRealised, DerivationGoal::tryToBuild, DerivationGoal::buildDone, DerivationGoal::tryBuildHook, DerivationGoal::startBuilder, DerivationGoal::runChild, parseReferenceSpecifiers, DerivationGoal::registerOutputs, DerivationGoal::checkPathValidity, SubstitutionGoal::tryNext, SubstitutionGoal::referencesValid, Worker::removeGoal, Worker::childTerminated, Worker::run, Worker::waitForInput): Use range-based ‘for’ instead of macro ‘foreach’. * nix/libstore/derivations.cc (writeDerivation, unparseDerivation, hashDerivationModulo): Likewise. * nix/libstore/gc.cc (addAdditionalRoots, LocalStore::deletePathRecursive, LocalStore::canReachRoot, LocalStore::collectGarbage): Likewise. * nix/libstore/globals.cc (Settings::pack): Likewise. * nix/libstore/local-store.cc (checkDerivationOutputs, queryValidPaths, querySubstitutablePaths, querySubstitutablePathInfos, registerValidPaths, verifyStore, verifyPath): Likewise. * nix/libstore/misc.cc (computeFSClosure, dfsVisit, topoSortPaths): Likewise. * nix/libstore/optimise-store.cc (LocalStore::optimisePath_, LocalStore::optimiseStore): Likewise. * nix/libstore/pathlocks.cc (PathLocks::lockPaths, PathLocks::~PathLocks): Likewise. * nix/libstore/references.cc (search, scanForReferences): Likewise. * nix/libstore/store-api.cc (checkStoreName, computeStorePathForText, StoreAPI::makeValidityRegistration, showPaths, readStorePaths): Likewise. * nix/libutil/serialise.cc (writeStrings): Likewise. * nix/libutil/util.cc (concatStringsSep): Likewise. * nix/nix-daemon/nix-daemon.cc (performOp): Likewise. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-06-03daemon: Remove ‘singleton’ and replace ‘typedef’ with ‘using’ in ↵Congcong Kuo
‘types.hh’ * nix/libutil/util.hh (singleton): Remove. * nix/libstore/build.cc (DerivationGoal::startBuilder) (SubstitutionGoal::tryNext, SubstitutionGoal::tryToRun) (LocalStore::ensurePath, LocalStore::repairPath): Use normal construction function instead of ‘singleton’. * nix/libstore/local-store.cc (LocalStore::addToStoreFromDump) (LocalStore::addTextToStore, LocalStore::importPath): Likewise. * nix/nix-daemon/nix-daemon.cc (performOp): Likewise. Change-Id: If0d929407c09482f3b506a1c51dfda70e29696dd Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-06-01daemon: Fix build failure with gcc@15.wrobell
* nix/libstore/build.cc (CompareGoalPtrs::operator): Add const keyword. * nix/libstore/store-api.hh: Add missing include for uint64_t. Change-Id: I56368da9eb10dc376f7e6eeae6a61746bb36c9cf Signed-off-by: Andreas Enge <andreas@enge.fr>
2025-05-25daemon: Remove ‘defined’ in macro definition.Congcong Kuo
Closes #6. * nix/libstore/build.cc (CHROOT_ENABLED, CLONE_ENABLED): Wrap in #ifdefs. Change-Id: I217e46fc2cac579a199fcd7c28ef5a8155a12750 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-04-25daemon: Use the guest GID in /etc/group.Ludovic Courtès
Partly fixes <https://issues.guix.gnu.org/77862>. Fixes a bug whereby, when running guix-daemon unprivileged, /etc/group would contain the wrong GID for the “nixbld” group. This inconsistency would lead to failures in the Coreutils test suite, for instance. * nix/libstore/build.cc (DerivationGoal::startBuilder): Use ‘guestGID’ when writing /etc/group. * tests/store.scm ("/etc/passwd and /etc/group"): New test. Reported-by: keinflue <keinflue@posteo.net> Change-Id: I739bc96c4c935fd9015a45e2bfe5b3e3f90554a9
2025-04-11daemon: Do not make chroot root directory read-only.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/77570>. Commit 40f69b586a440d0397fa3dfe03b95a0f44e4d242 made chroot root directory read-only; as a consequence, build processes attempting to write to the root directory would now get EROFS instead of EACCES. It turns out that a number of test suites (Go, Ruby, SCons, Shepherd) would fail because of this observable difference. To restore previous behavior in build environments while still preventing build processes from exposing their root directory to outside processes, this patch (1) keeps the root writable but #o555 by default, thereby restoring the EACCES behavior, and (2) ensures that the parent of the chroot root directory is itself user-accessible only. * nix/libstore/build.cc (class DerivationGoal)[chrootRootTop]: New field. (DerivationGoal::startBuilder): Initialize ‘chrootRootTop’ and make it ‘AutoDelete’. Replace ‘mount’ call that made the root directory read-only by a mere ‘chmod_’ call. * tests/store.scm ("build root cannot be made world-readable"): Remove. ("writing to build root leads to EACCES"): New test. Reported-by: Ada Stevenson <adanskana@gmail.com> Reported-by: keinflue <keinflue@posteo.net> Suggested-by: Reepca Russelstein <reepca@russelstein.xyz> Change-Id: I5912e8b3b293f8242a010cfc79255fc981314445
2025-03-26daemon: Move comments where they belong.Ludovic Courtès
* nix/libstore/build.cc (DerivationGoal::startBuilder): Shuffle comments for clarity. Change-Id: I6557c103ade4a3ab046354548ea193c68f8c9c05
2025-03-26daemon: Drop Linux ambient capabilities before executing builder.Ludovic Courtès
* config-daemon.ac: Check for <sys/prctl.h>. * nix/libstore/build.cc (DerivationGoal::runChild): When ‘useChroot’ is true, call ‘prctl’ to drop all ambient capabilities. Change-Id: If34637fc508e5fb6d278167f5df7802fc595284f
2025-03-26daemon: Allow running as non-root with unprivileged user namespaces.Ludovic Courtès
Many thanks to Reepca Russelstein for their review and guidance on these changes. * nix/libstore/build.cc (guestUID, guestGID): New variables. (DerivationGoal)[readiness]: New field. (initializeUserNamespace): New function. (DerivationGoal::runChild): When ‘readiness.readSide’ is positive, read from it. (DerivationGoal::startBuilder): Call ‘chown’ only when ‘buildUser.enabled()’ is true. Pass CLONE_NEWUSER to ‘clone’ when ‘buildUser.enabled()’ is false or not running as root. Retry ‘clone’ without CLONE_NEWUSER upon EPERM. (DerivationGoal::registerOutputs): Make ‘actualPath’ writable before ‘rename’. (DerivationGoal::deleteTmpDir): Catch ‘SysError’ around ‘_chown’ call. * nix/libstore/local-store.cc (LocalStore::createUser): Do nothing if ‘dirs’ already exists. Warn instead of failing when failing to chown ‘dir’. * guix/substitutes.scm (%narinfo-cache-directory): Check for ‘_NIX_OPTIONS’ rather than getuid() == 0 to determine the cache location. * doc/guix.texi (Build Environment Setup): Reorganize a bit. Add section headings “Daemon Running as Root” and “The Isolated Build Environment”. Add “Daemon Running Without Privileges” subsection. Remove paragraph about ‘--disable-chroot’. (Invoking guix-daemon): Warn against ‘--disable-chroot’ and explain why. * tests/derivations.scm ("builder is outside the store"): New test. Reviewed-by: Reepca Russelstein <reepca@russelstein.xyz>
2025-03-26daemon: Remount root directory as read-only.Ludovic Courtès
* nix/libstore/build.cc (DerivationGoal::runChild): Bind-mount the store and /tmp under ‘chrootRootDir’ to themselves as read-write. Remount / as read-only. Change-Id: I79565094c8ec8448401897c720aad75304fd1948
2025-03-26daemon: Remount inputs as read-only.Ludovic Courtès
* nix/libstore/build.cc (DerivationGoal::runChild): Remount ‘target’ as read-only. Reported-by: Reepca Russelstein <reepca@russelstein.xyz> Change-Id: Ib7201bcf4363be566f205d23d17fe2f55d3ad666
2025-03-26daemon: Bind-mount all the inputs, not just directories.Ludovic Courtès
* nix/libstore/build.cc (DerivationGoal::startBuilder): Add all of ‘inputPaths’ to ‘dirsInChroot’ instead of hard-linking regular files. Special-case symlinks. (DerivationGoal)[regularInputPaths]: Remove. Reported-by: Reepca Russelstein <reepca@russelstein.xyz> Change-Id: I070987f92d73f187f7826a975bee9ee309d67f56
2025-03-26daemon: Bind-mount /etc/nsswitch.conf & co. only if it exists.Ludovic Courtès
Those files may be missing in some contexts, for instance within the build environment. * nix/libstore/build.cc (DerivationGoal::runChild): Add /etc/resolv.conf and related files to ‘ss’ only if they exist. Change-Id: Ie19664a86c8101a1dc82cf39ad4b7abb10f8250a
2024-12-30daemon: Explicitly unlock output path in the has-become-valid case.Reepca Russelstein
Fixes <https://issues.guix.gnu.org/31785>. Similar to <https://github.com/NixOS/nix/issues/178>, fixed in <https://github.com/NixOS/nix/commit/29cde917fe6b8f2e669c8bf10b38f640045c83b8>. We can't rely on Goal deletion to release our locks in a timely manner. In the case in which multiple guix-daemon processes simultaneously try producing an output path path1, the one that gets there first (P1) will get the lock, and the second one (P2) will continue trying to acquire the lock until it is released. Once it has acquired the lock, it checks to see whether the path has already become valid in the meantime, and if so it reports success to those Goals waiting on its completion and finishes. Unfortunately, it fails to release the locks it holds first, so those stay held until that Goal gets deleted. Suppose we have the following store path dependency graph: path4 / | \ path1 path2 path3 P2 is now sitting on path1's lock, and will continue to do so until path4 is completed. Suppose there is also a P3, and it has been blocked while P1 builds path2. Now P3 is sitting on path2's lock, and can't acquire path1's lock to determine that it has been completed. Likewise P2 is sitting on path1's lock, and now can't acquire path2's lock to determine that it has been completed. Finally, P3 completes path3 while P2 is blocked. Now: - P1 knows that path1 and path2 are complete, and holds no locks, but can't determine that path3 is complete - P2 knows that path1 and path3 are complete, and holds locks on path1 and path3, but can't determine that path2 is complete - P3 knows that path2 and path3 are complete, and holds a lock on path2, but can't determine that path1 is complete And none of these locks will be released until path4 is complete. Thus, we have a deadlock. To resolve this, we should explicitly release these locks as soon as they should be released. * nix/libstore/build.cc (DerivationGoal::tryToBuild, SubstitutionGoal::tryToRun): Explicitly release locks in the has-become-valid case. * tests/store-deadlock.scm: New file. * Makefile.am (SCM_TESTS): Add it. Change-Id: Ie510f84828892315fe6776c830db33d0f70bcef8 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2024-10-21daemon: Sanitize successful build outputs prior to exposing them.Reepca Russelstein
There is currently a window of time between when the build outputs are exposed and when their metadata is canonicalized. * nix/libstore/build.cc (DerivationGoal::registerOutputs): wait until after metadata canonicalization to move successful build outputs to the store. Change-Id: Ia995136f3f965eaf7b0e1d92af964b816f3fb276 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2024-10-21daemon: Sanitize failed build outputs prior to exposing them.Reepca Russelstein
The only thing keeping a rogue builder and a local user from collaborating to usurp control over the builder's user during the build is the fact that whatever files the builder may produce are not accessible to any other users yet. If we're going to make them accessible, we should probably do some sanity checking to ensure that sort of collaborating can't happen. Currently this isn't happening when failed build outputs are moved from the chroot as an aid to debugging. * nix/libstore/build.cc (secureFilePerms): new function. (DerivationGoal::buildDone): use it. Change-Id: I9dce1e3d8813b31cabd87a0e3219bf9830d8be96 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2024-03-12daemon: Address shortcoming in previous security fix for CVE-2024-27297.Ludovic Courtès
This is a followup to 8f4ffb3fae133bb21d7991e97c2f19a7108b1143. Commit 8f4ffb3fae133bb21d7991e97c2f19a7108b1143 fell short in two ways: (1) it didn’t have any effet for fixed-output derivations performed in a chroot, which is the case for all of them except those using “builtin:download” and “builtin:git-download”, and (2) it did not preserve ownership when copying, leading to “suspicious ownership or permission […] rejecting this build output” errors. * nix/libstore/build.cc (DerivationGoal::buildDone): Account for ‘chrootRootDir’ when copying ‘drv.outputs’. * nix/libutil/util.cc (copyFileRecursively): Add ‘fchown’ and ‘fchownat’ calls to preserve file ownership; this is necessary for chrooted fixed-output derivation builds. * nix/libutil/util.hh: Update comment. Change-Id: Ib59f040e98fed59d1af81d724b874b592cbef156
2024-03-11daemon: Protect against FD escape when building fixed-output derivations ↵Ludovic Courtès
(CVE-2024-27297). This fixes a security issue (CVE-2024-27297) whereby a fixed-output derivation build process could open a writable file descriptor to its output, send it to some outside process for instance over an abstract AF_UNIX socket, which would then allow said process to modify the file in the store after it has been marked as “valid”. Vulnerability discovered by puck <https://github.com/puckipedia>. Nix security advisory: https://github.com/NixOS/nix/security/advisories/GHSA-2ffj-w4mj-pg37 Nix fix: https://github.com/NixOS/nix/commit/244f3eee0bbc7f11e9b383a15ed7368e2c4becc9 * nix/libutil/util.cc (readDirectory): Add variants that take a DIR* and a file descriptor. Rewrite the ‘Path’ variant accordingly. (copyFile, copyFileRecursively): New functions. * nix/libutil/util.hh (copyFileRecursively): New declaration. * nix/libstore/build.cc (DerivationGoal::buildDone): When ‘fixedOutput’ is true, call ‘copyFileRecursively’ followed by ‘rename’ on each output. Change-Id: I7952d41093eed26e123e38c14a4c1424be1ce1c4 Reported-by: Picnoir <picnoir@alternativebit.fr>, Théophane Hufschmitt <theophane.hufschmitt@tweag.io> Change-Id: Idb5f2757f35af86b032a9851cecb19b70227bd88
2023-12-17daemon: Fix my own whitespace errors.Tobias Geerinckx-Rice
This follows up on commit d993ed43b2bae8717437aa27d9d33fd223a6411f and was entirely predictable. The noise, sorry for it. Change-Id: I8ddb8cfe33db3864949f6589cc091616a90ebc5b
2023-12-10daemon: Sacrifice builders on OOM.Tobias Geerinckx-Rice
* nix/libstore/build.cc (DerivationGoal::runChild): Maximise our OOM score adjustment. Change-Id: I418c763b499ca16e1ffe3c6033319112b9744f51
2023-12-04daemon: Simplify “empty status” substitute error message.Ludovic Courtès
* nix/libstore/build.cc (SubstitutionGoal::finished): Don’t show what the empty status looks like. Change-Id: Ie898432aeb047aff3d59024de6ed6d18f68903c4
2022-12-18daemon: Make "opening file" error messages distinguishable.Ludovic Courtès
* nix/libstore/build.cc (DerivationGoal::openLogFile): Customize "opening file" error message. * nix/libutil/hash.cc (hashFile): Likewise. * nix/libutil/util.cc (readFile, writeFile): Likewise.
2022-06-05daemon: Quote consistently within a string.Tobias Geerinckx-Rice
* nix/libstore/build.cc (DerivationGoal::registerOutput): ‘’ → `'.
2022-05-29daemon: Clarify ‘--check’ error when outputs are missing.Tobias Geerinckx-Rice
Drop the confusing ‘invalid’ jargon and display a hint like we do for ‘--fallback’. * nix/libstore/build.cc (DerivationGoal::outputsSubstituted): Rewrite error message.
2022-05-18daemon: runChild() is forbidden to talk during environment set upyarl-baudig@mailoo.org
DerivationGoal::startBuilder() is waiting for an empty line as a check that the environment set up is fine. Fixes <https://issues.guix.gnu.org/55324>. * nix/libstore/build.cc (DerivationGoal::runChild): Remove 'debug' statement corresponding to bind mounts. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2021-11-25daemon: Read substitute nar size as 'unsigned long long'.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/46212>. Reported by Christopher Baines <mail@cbaines.net>. Previously, the nar size returned by 'guix substitute' would be read as an 'int'; thus, values above 2^31 - 1 would be read and then stored as negative integers in the database. Regression introduced in 9dfa20a22ae0be3d3b01a7b3d422af97428c627e. * nix/libstore/build.cc (SubstitutionGoal::finished): Use templatized 'string2Int' instead of 'std::atoi' to get an 'unsigned long long', which is the type of 'hash.second'. * tests/store.scm ("substitute and large size"): New test.
2021-04-09daemon: 'guix substitute' replies on FD 4.Ludovic Courtès
This avoids the situation where error messages would unintentionally go to stderr and be wrongfully interpreted as a reply by the daemon. Fixes <https://bugs.gnu.org/46362>. This is a followup to ee3226e9d54891c7e696912245e4904435be191c. * guix/scripts/substitute.scm (display-narinfo-data): Add 'port' parameter and honor it. (process-query): Likewise. (process-substitution): Likewise. (%error-to-file-descriptor-4?, with-redirected-error-port): Remove. (%reply-file-descriptor): New variable. (guix-substitute): Remove use of 'with-redirected-error-port'. Define 'reply-port' and pass it to 'process-query' and 'process-substitution'. * nix/libstore/build.cc (SubstitutionGoal::handleChildOutput): Swap 'builderOut' and 'fromAgent'. * nix/libstore/local-store.cc (LocalStore::getLineFromSubstituter): Likewise. * tests/substitute.scm <top level>: Set '%reply-file-descriptor' rather than '%error-to-file-descriptor-4?'.
2021-03-18daemon: Prevent privilege escalation with '--keep-failed' [security].Ludovic Courtès
Fixes <https://bugs.gnu.org/47229>. Reported by Nathan Nye of WhiteBeam Security. * nix/libstore/build.cc (DerivationGoal::startBuilder): When 'useChroot' is true, add "/top" to 'tmpDir'. (DerivationGoal::deleteTmpDir): Adjust accordingly. When 'settings.keepFailed' is true, chown in two steps: first the "/top" sub-directory, and then rename "/top" to its parent.
2020-12-19daemon: Delegate deduplication to 'guix substitute'.Ludovic Courtès
This removes the main source of latency between subsequent downloads. * nix/libstore/build.cc (SubstitutionGoal::tryToRun): Add a "deduplicate" key to ENV. (SubstitutionGoal::finished): Remove call to 'optimisePath'. * guix/scripts/substitute.scm (process-substitution)[destination-in-store?] [dump-file/deduplicate*]: New variables. Pass #:dump-file to 'restore-file'. * guix/scripts/substitute.scm (guix-substitute)[deduplicate?]: New variable. Pass #:deduplicate? to 'process-substitution'. * guix/serialization.scm (dump-file): Export and augment 'dump-file'.
2020-12-19daemon: Do not reset timestamps and permissions on substituted items.Ludovic Courtès
'guix substitute' now takes care of it via 'restore-file'. * nix/libstore/build.cc (SubstitutionGoal::finished): Remove call to 'canonicalisePathMetaData'.
2020-12-19daemon: Let 'guix substitute' perform hash checks.Ludovic Courtès
This way, the hash of the store item can be computed as it is restored, thereby avoiding an additional file tree traversal ('hashPath' call) later on in the daemon. Consequently, it should reduce latency between subsequent substitute downloads. This is a followup to 5ff521452b9ec2aae9ed8e4bb7bdc250a581f203. * guix/scripts/substitute.scm (narinfo-hash-algorithm+value): New procedure. (process-substitution): Wrap INPUT into a hash input port, 'hashed', and read from it. Compare the actual and expected hashes, and print a "hash-mismatch" status line when they differ. When they match, print not just "success" but also the nar hash and size. * nix/libstore/build.cc (class SubstitutionGoal)[expectedHashStr]: Remove. (SubstitutionGoal::finished): Tokenize 'status'. Parse it and handle "success" and "hash-mismatch" accordingly. Call 'hashPath' only when the returned hash is not SHA256. (SubstitutionGoal::handleChildOutput): Remove 'expectedHashStr' handling. * tests/substitute.scm ("substitute, invalid hash"): Rename to... ("substitute, invalid narinfo hash"): ... this. ("substitute, invalid hash"): New test.
2020-12-08daemon: Raise an error if substituter doesn't send the expected hash.Ludovic Courtès
It was already impossible in practice for 'expectedHashStr' to be empty if 'status' == "success". * nix/libstore/build.cc (SubstitutionGoal::finished): Throw 'SubstError' when 'expectedHashStr' is empty.
2020-12-08substitute: Cache and reuse connections while substituting.Ludovic Courtès
That way, when fetching a series of substitutes from the same server(s), the connection is reused instead of being closed/opened for each substitutes, which saves on network round trips and TLS handshakes. * guix/http-client.scm (http-fetch): Add #:keep-alive? and honor it. * guix/progress.scm (progress-report-port): Add #:close? parameter and honor it. * guix/scripts/substitute.scm (at-most): Return the tail as a second value. (fetch): Add #:port and #:keep-alive? and honor them. (%max-cached-connections): New variable. (open-connection-for-uri/cached, call-with-cached-connection): New procedures. (with-cached-connection): New macro. (process-substitution): Wrap 'fetch' call in 'with-cached-connection'. Pass #:close? to 'progress-report-port'.
2020-12-08daemon: Run 'guix substitute --substitute' as an agent.Ludovic Courtès
This avoids spawning one substitute process per substitution. * nix/libstore/build.cc (class Worker)[substituter]: New field. [outPipe, logPipe, pid]: Remove. (class SubstitutionGoal)[expectedHashStr, status, substituter]: New fields. (SubstitutionGoal::timedOut): Adjust to check 'substituter'. (SubstitutionGoal::tryToRun): Remove references to 'outPipe' and 'logPipe'. Run "guix substitute --substitute" as an 'Agent'. Send the request with 'writeLine'. (SubstitutionGoal::finished): Likewise. (SubstitutionGoal::handleChildOutput): Change to fill in 'expectedHashStr' and 'status'. (SubstitutionGoal::handleEOF): Call 'wakeUp' unconditionally. (SubstitutionGoal::~SubstitutionGoal): Adjust to check 'substituter'. * guix/scripts/substitute.scm (process-substitution): Write "success\n" to stdout upon success. (%error-to-file-descriptor-4?): New variable. (guix-substitute): Set 'current-error-port' to file descriptor 4 unless (%error-to-file-descriptor-4?) is false. Remove "--substitute" arguments. Loop reading line from stdin. * tests/substitute.scm <top level>: Call '%error-to-file-descriptor-4?'. (request-substitution): New procedure. ("substitute, no signature") ("substitute, invalid hash") ("substitute, unauthorized key") ("substitute, authorized key") ("substitute, unauthorized narinfo comes first") ("substitute, unsigned narinfo comes first") ("substitute, first narinfo is unsigned and has wrong hash") ("substitute, first narinfo is unsigned and has wrong refs") ("substitute, two invalid narinfos") ("substitute, narinfo with several URLs"): Adjust to new "guix substitute --substitute" calling convention.
2020-12-08daemon: Use 'Agent' to spawn 'guix substitute --query'.Ludovic Courtès
* nix/libstore/local-store.hh (RunningSubstituter): Remove. (LocalStore)[runningSubstituter]: Change to unique_ptr<Agent>. [setSubstituterEnv, didSetSubstituterEnv]: Remove. [getLineFromSubstituter, getIntLineFromSubstituter]: Take an 'Agent'. * nix/libstore/local-store.cc (LocalStore::~LocalStore): Remove reference to 'runningSubstituter'. (LocalStore::setSubstituterEnv, LocalStore::startSubstituter): Remove. (LocalStore::getLineFromSubstituter): Adjust to 'run' being an 'Agent'. (LocalStore::querySubstitutablePaths): Spawn substituter agent if needed. Adjust to 'Agent' interface. (LocalStore::querySubstitutablePathInfos): Likewise. * nix/libstore/build.cc (SubstitutionGoal::tryToRun): Remove call to 'setSubstituterEnv' and add 'setenv' call for "_NIX_OPTIONS" instead. (SubstitutionGoal::finished): Remove 'readLine' call for 'dummy'. * guix/scripts/substitute.scm (%allow-unauthenticated-substitutes?): Remove second argument to 'make-parameter'. (process-query): Call 'warn-about-missing-authentication' when (%allow-unauthenticated-substitutes?) is #t. (guix-substitute): Wrap body in 'parameterize'. Set 'guix-warning-port' too. No longer exit when 'substitute-urls' returns the empty list. No longer print newline initially. * tests/substitute.scm (test-quit): Parameterize 'current-error-port' to account for the port changes in 'guix-substitute'.
2020-12-01daemon: Remove unneeded forward declaration.Ludovic Courtès
This is a followup to ee9dff34f9317509cb2b833d07a0d5e01a36a4ae. * nix/libstore/build.cc: Remove 'struct Agent' forward declaration.