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6 daysguix gc: Adjust size suffix based on the amount of data.Efraim Flashner
* guix/ui.scm (number->size): New procedure. * guix/scripts/gc.scm (guix-gc)[actions]: Display the amount of collected-garbage using more specific units. [ensure-free-space]: Display the size using an appropriate size unit. * nix/libstore/gc.cc (deletePathRecursive, removeUnusedLinks): Same. * nix/libstore/optimise-store.cc (showBytes): Move function ... * nix/libstore/misc.cc: ... to here. Expand to adjust the output based on the amount of bytes received. Change-Id: Idceb1a13f8e45f959d327f53d1a8accb29d2678b
2025-07-16daemon: Consider the current user as trusted.Ludovic Courtès
This allows use of ‘guix gc --verify=repair’ when running guix-daemon as an unprivileged user. * nix/nix-daemon/nix-daemon.cc (acceptConnection): Consider the current user as trusted. Reported-by: David Elsing <david.elsing@posteo.net> Change-Id: I559e56cf0640e8dc9bbc510317aa2bdc024ff681
2025-07-16daemon: Use std::string or std::vector instead of variable-length array (VLA).Congcong Kuo
* libutil/util.h (waitForMessage): Use std::string instead of char* to unify coding style. * libutil/util.cc (waitForMessage): Use std::string instead of variable-length array (VLA). (readLink, copyFileRecursively, expect): Use std::vector instead of VLA. * libutil/hash.cc (printHash): Use std::vector instead of VLA. Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-07-04daemon: Gracefully handle target mount point already existing.Reepca Russelstein
Fixes guix/guix#903. * nix/libutil/spawn.cc (bindMount): in the "regular file" case, only create a placeholder file if one doesn't already exist. Change-Id: Ie46b2fef2cea5b2a052c4ec48d00e97bfc1ee506 Reported-by: Hilton Chain <hako@ultrarare.space> Signed-off-by: Ludovic Courtès <ludo@gnu.org>
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>
2025-06-26daemon: Fix build of spawn.cc for non-Linux and newer GCC.Reepca Russelstein
* nix/libutil/spawn.cc: Include <fcntl.h> and <cstdint>. (cloneChild): Wrap body in #if CLONE_ENABLED. Change-Id: I0be7e6dbe80ac2f7022793149472270a4e49d23c Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2025-06-25daemon: Fix build with gcc-14.Andreas Enge
* nix/libutil/seccomp.hh: Include cstdint. Change-Id: I454c7abd56abbe4cf03a5bc8ebc402678e07a0f0
2025-06-24daemon: Protect ‘copyFileRecursively’ from race conditions.Ludovic Courtès
Previously, if an attacker managed to introduce a hard link or a symlink on one of the destination file names before it is opened, ‘copyFileRecursively’ would overwrite the symlink’s target or the hard link’s content. This kind of attack could be carried out while guix-daemon is copying the output or the chroot directory of a failed fixed-output derivation build, possibly allowing the attacker to escalate to the privileges of the build user. * nix/libutil/util.cc (copyFileRecursively): In the ‘S_ISREG’ case, open ‘destination’ with O_NOFOLLOW | O_EXCL. In the ‘S_ISDIR’ case, open ‘destination’ with O_NOFOLLOW. Reported-by: Reepca Russelstein <reepca@russelstein.xyz> Change-Id: I94273efe4e92c1a4270a98c5ec47bd098e9227c9 Signed-off-by: John Kehayias <john.kehayias@protonmail.com>
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>
2025-06-24daemon: Implement ‘deletePath’ in terms of the *at functions.Reepca Russelstein
deletePath needs to be able to operate securely in unfriendly environments, where adversaries may be concurrently modifying the files being operated on. For example, directories that we are currently recursing through may be replaced with symbolic links. We err on the side of early failure here: if a file or directory is concurrently modified in a way that causes one of the system calls to fail, we throw an exception immediately instead of trying to adapt to the change. Note that we use fstat instead of fstatat for verifying the directory's st_mode field because AT_EMPTY_PATH is linux-specific. * nix/libutil/util.cc (_deletePathAt): new procedure. (_deletePath): use it. Change-Id: I7ccfe6f1f74dbab95617b24034494e0f63030582 Signed-off-by: Ludovic Courtès <ludo@gnu.org> 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>
2025-05-28daemon: Remove ‘AutoDeleteArray’.Congcong Kuo
* libutil/util.hh (AutoDeleteArray): Remove. * libutil/util.cc (readString, readStrings): Use ‘std::vector’ instead of ‘AutoDeleteArray’. * libutil/serialise.cc (readFile): Likewise. Change-Id: I45362998dbb8226874f66b77cd19f071f7bb2ab3 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
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>
2025-05-14build: Fix substitutions for .service files.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/78318>. This is a followup to 107eb8ee8f5f9192c795abeb47885b49a57bacd4. * nix/local.mk (etc/guix-%.service): Add ‘g’ for ‘@localstatedir@’ substitution. Substitute ‘@storedir@’. Reported-by: Ido Yariv <yarivido@gmail.com> Change-Id: I9b53d3a6d713a000bc0a7a57f667badc00d2dff8
2025-05-12daemon: Replace ‘random_shuffle’ with ‘shuffle’.Congcong Kuo
‘std::random_shuffle’ was removed in C++14. * nix/libstore/gc.cc (LocalStore::collectGarbage): Use ‘std::random’ and ‘std::shuffle’. Change-Id: If91ed3ec3596a419ae7c87d7ce677e0970853e9f 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
2025-04-14daemon: Catch SIGINT, SIGTERM, and SIGHUP for proper termination.Ludovic Courtès
Previously the daemon would not install handlers for these signals. It would thus terminate abruptly when receiving them, without properly closing the SQLite database. Consequently, the database’s WAL file, which is normally deleted by the last client closing the database (via ‘sqlite3_close’), would not be deleted when the guix-daemon process is terminated; instead, it would persist and possibly keep growing beyond reason. This patch fixes that. * nix/nix-daemon/nix-daemon.cc (handleSignal, setTerminationSignalHandler): New functions. (processConnection): Call it. Reported-by: Christopher Baines <mail@cbaines.net> Change-Id: I07e510a1242e92b6a629d60eb840e029c0f921be
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: Create /var/guix/profiles/per-user unconditionally.Ludovic Courtès
* nix/libstore/local-store.cc (LocalStore::LocalStore): Create ‘perUserDir’ unconditionally. Change-Id: I5188320f9630a81d16f79212d0fffabd55d94abe
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
2025-03-26daemon: Close the read end of the logging pipe.Ludovic Courtès
* nix/libutil/util.cc (commonChildInit): Close ‘logPipe.readSide’. Reported-by: Reepca Russelstein <reepca@russelstein.xyz> Change-Id: Ia9e48d1afb85d7af52770e016f2b6832792044dd
2025-03-26daemon: Use ‘close_range’ where available.Ludovic Courtès
* nix/libutil/util.cc (closeMostFDs) [HAVE_CLOSE_RANGE]: Use ‘close_range’ when ‘exceptions’ is empty. * config-daemon.ac: Check for <linux/close_range.h> and the ‘close_range’ symbol. Change-Id: I12fa3bde58b003fcce5ea5a1fee1dcf9a92c0359
2025-03-02nix: Install guix-gc systemd timer.Efraim Flashner
* nix/local.mk (nodist_systemdservice_DATA): Add etc/guix-gc.timer. (etc/guix-gc.timer): Add rule to generate file. (EXTRA_DIST): Add guix-gc.timer.in, remove guix-gc.timer. * gitignore: Add etc/guix-gc.timer. Change-Id: I361aef660fe7d9803f58f4e31e16d8db595d1853
2025-03-02Revert "nix: Install guix-gc systemd timer."Efraim Flashner
This reverts commit 3355de608cb2267435c2592fc7dc76a1dcc5c02d. This commit does the opposite of what it was supposed to do.
2025-02-26nix: Install guix-gc systemd timer.Efraim Flashner
* nix/local.mk (nodist_systemdservice_DATA): Add etc/guix-gc.timer. Change-Id: I6f71d68f77ff07976f9ec16c37dba99ebedd9b9d
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>
2024-12-09daemon: Fix linking gcrypt when --as-needed linker arg is usedDoğan Çeçen
This is a followup to 8a7bd211d21f06c1234fbb82bb905d202d58f598. As it is mentioned in autoconf manual that library names should be specified in LIBS, not LDFLAGS. See: https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.72/html_node/Preset-Output-Variables.html#index-LDFLAGS-2 This change also brings back the save_* vars trick that was there before. I missed in my earlier change that nix/local.mk was referring LIBGCRYPT_* vars directly. And, instead of CXXFLAGS, CPPFLAGS is used since the latter is probably more correct as this is used for include dirs, therefore using preprocessor flags. Tested with ./configure LDFLAGS="-Wl,--as-needed" --with-libgcrypt-prefix=... combinations. * config-daemon.ac: Set ‘LIBGCRYPT_CPPFLAGS’ instead of ‘LIBGCRYPT_CXXFLAGS’. Set ‘LIBGCRYPT_LIBS’ in addition to ‘LIBGCRYPT_LDFLAGS’. Save and restore ‘CPPFLAGS’, ‘LDFLAGS’, and ‘LIBS’ around test. * nix/local.mk (libutil_a_CPPFLAGS): Add $(LIBGCRYPT_CPPFLAGS). (libstore_a_CXXFLAGS): Remove $(LIBGCRYPT_CFLAGS). (guix_daemon_LDFLAGS): New variable. Change-Id: Iadb10e1994c9a78e2927847af2cfe5e096fbb2a8 Signed-off-by: Ludovic Courtès <ludo@gnu.org>
2024-11-17daemon: Improve error message in ‘checkStoreName’.Brennan Vincent
* nix/libstore/store-api.cc (checkStoreName): Clarify message when NAME starts with a dot. Change-Id: I045a663bc6cd9844677c65b38a31d3941cf212b5 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>
2024-06-26etc: Add explicit ‘--substitute-urls’ in guix-daemon service files.Ludovic Courtès
Having substitute URLs explicitly listed in the service startup file makes it clearer what should be modified to permanently change the list of substitute URLs. * config-daemon.ac: Rename ‘guix_substitute_urls’ to ‘GUIX_SUBSTITUTE_URLS’ and substitute it. * nix/local.mk (etc/guix-%.service, etc/init.d/guix-daemon) (etc/guix-%.conf): Substitute it. * etc/guix-daemon.conf.in, etc/guix-daemon.service.in, etc/init.d/guix-daemon.in: Add an explicit ‘--substitute-urls’ option. Change-Id: Ie491b7fab5c42e54dca582801c03805a85de2bf9
2024-05-13daemon: Loop over ‘copy_file_range’ upon short writes.Ludovic Courtès
Fixes <https://issues.guix.gnu.org/70877>. * nix/libutil/util.cc (copyFile): Loop over ‘copy_file_range’ instead of throwing upon short write. Reported-by: Ricardo Wurmus <rekado@elephly.net> Change-Id: Id7b8a65ea59006c2d91bc23732309a68665b9ca0
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
2024-01-05daemon: Change default ‘timeout’ and ‘max-silent-time’ values.Ludovic Courtès
Having a timeout seems generally preferable as it makes sure build slots are not kept busy for no good reason (few package builds, if any, are expected to exceed these values). * nix/libstore/globals.cc (Settings::Settings): Change ‘maxSilentTime’ and ‘buildTimeout’. * gnu/services/base.scm (<guix-configuration>)[max-silent-time] [timeout]: Change default values. * doc/guix.texi (Invoking guix-daemon, Base Services): Adjust accordingly. Change-Id: I25c50893f3f7fcca451b8f093d9d4d1a15fa58d8
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
2023-12-11daemon: Implement ‘substitute-urls’ RPC.Ludovic Courtès
* nix/libstore/worker-protocol.hh (PROTOCOL_VERSION): Bump. (WorkerOp): Add ‘wopSubstituteURLs’. * nix/nix-daemon/nix-daemon.cc (performOp): Implement it. * guix/store.scm (%protocol-version): Bump. (operation-id): Add ‘substitute-urls’. (substitute-urls): New procedure. * tests/store.scm ("substitute-urls, default") ("substitute-urls, client-specified URLs") ("substitute-urls, disabled"): New tests. Change-Id: I2c0119500c3a1eecfa5ebf32463ffb0f173161de
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
2023-09-24Revert "build: Add missing guix-gc.timer file to binary tarball."Tobias Geerinckx-Rice
This reverts commit 69f6edc1a8596d2cb4c67e0435d35633af6f3cbc. The intention is good, but nodist_systemdservice_DATA are meant to be disposable artefacts generated from corresponding ‘.in’ files. etc/guix-gc.timer doesn't fit that description, breaking builds: $ make clean && make … make[2]: *** No rule to make target 'etc/guix-gc.timer', needed by 'all-am'. Stop.