Changes in 5.15.90
btrfs: fix trace event name typo for FLUSH_DELAYED_REFS
pNFS/filelayout: Fix coalescing test for single DS
selftests/bpf: check null propagation only neither reg is PTR_TO_BTF_ID
tools/virtio: initialize spinlocks in vring_test.c
virtio_pci: modify ENOENT to EINVAL
vduse: Validate vq_num in vduse_validate_config()
net/ethtool/ioctl: return -EOPNOTSUPP if we have no phy stats
r8169: move rtl_wol_enable_rx() and rtl_prepare_power_down()
RDMA/srp: Move large values to a new enum for gcc13
btrfs: always report error in run_one_delayed_ref()
x86/asm: Fix an assembler warning with current binutils
f2fs: let's avoid panic if extent_tree is not created
perf/x86/rapl: Treat Tigerlake like Icelake
fbdev: omapfb: avoid stack overflow warning
Bluetooth: hci_qca: Fix driver shutdown on closed serdev
wifi: brcmfmac: fix regression for Broadcom PCIe wifi devices
wifi: mac80211: sdata can be NULL during AMPDU start
Add exception protection processing for vd in axi_chan_handle_err function
zonefs: Detect append writes at invalid locations
nilfs2: fix general protection fault in nilfs_btree_insert()
efi: fix userspace infinite retry read efivars after EFI runtime services page fault
ALSA: hda/realtek: fix mute/micmute LEDs for a HP ProBook
ALSA: hda/realtek: fix mute/micmute LEDs don't work for a HP platform
drm/amdgpu: disable runtime pm on several sienna cichlid cards(v2)
drm/amd: Delay removal of the firmware framebuffer
hugetlb: unshare some PMDs when splitting VMAs
io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL
eventpoll: add EPOLL_URING_WAKE poll wakeup flag
eventfd: provide a eventfd_signal_mask() helper
io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups
io_uring: improve send/recv error handling
io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly
io_uring: add flag for disabling provided buffer recycling
io_uring: support MSG_WAITALL for IORING_OP_SEND(MSG)
io_uring: allow re-poll if we made progress
io_uring: fix async accept on O_NONBLOCK sockets
io_uring: ensure that cached task references are always put on exit
io_uring: remove duplicated calls to io_kiocb_ppos
io_uring: update kiocb->ki_pos at execution time
io_uring: do not recalculate ppos unnecessarily
io_uring/rw: defer fsnotify calls to task context
xhci-pci: set the dma max_seg_size
usb: xhci: Check endpoint is valid before dereferencing it
xhci: Fix null pointer dereference when host dies
xhci: Add update_hub_device override for PCI xHCI hosts
xhci: Add a flag to disable USB3 lpm on a xhci root port level.
usb: acpi: add helper to check port lpm capability using acpi _DSM
xhci: Detect lpm incapable xHC USB3 roothub ports from ACPI tables
prlimit: do_prlimit needs to have a speculation check
USB: serial: option: add Quectel EM05-G (GR) modem
USB: serial: option: add Quectel EM05-G (CS) modem
USB: serial: option: add Quectel EM05-G (RS) modem
USB: serial: option: add Quectel EC200U modem
USB: serial: option: add Quectel EM05CN (SG) modem
USB: serial: option: add Quectel EM05CN modem
staging: vchiq_arm: fix enum vchiq_status return types
USB: misc: iowarrior: fix up header size for USB_DEVICE_ID_CODEMERCS_IOW100
misc: fastrpc: Don't remove map on creater_process and device_release
misc: fastrpc: Fix use-after-free race condition for maps
usb: core: hub: disable autosuspend for TI TUSB8041
comedi: adv_pci1760: Fix PWM instruction handling
ACPI: PRM: Check whether EFI runtime is available
mmc: sunxi-mmc: Fix clock refcount imbalance during unbind
mmc: sdhci-esdhc-imx: correct the tuning start tap and step setting
btrfs: do not abort transaction on failure to write log tree when syncing log
btrfs: fix race between quota rescan and disable leading to NULL pointer deref
cifs: do not include page data when checking signature
thunderbolt: Use correct function to calculate maximum USB3 link rate
riscv: dts: sifive: fu740: fix size of pcie 32bit memory
bpf: restore the ebpf program ID for BPF_AUDIT_UNLOAD and PERF_BPF_EVENT_PROG_UNLOAD
staging: mt7621-dts: change some node hex addresses to lower case
tty: serial: qcom-geni-serial: fix slab-out-of-bounds on RX FIFO buffer
tty: fix possible null-ptr-defer in spk_ttyio_release
USB: gadgetfs: Fix race between mounting and unmounting
USB: serial: cp210x: add SCALANCE LPE-9000 device id
usb: cdns3: remove fetched trb from cache before dequeuing
usb: host: ehci-fsl: Fix module alias
usb: typec: tcpm: Fix altmode re-registration causes sysfs create fail
usb: typec: altmodes/displayport: Add pin assignment helper
usb: typec: altmodes/displayport: Fix pin assignment calculation
usb: gadget: g_webcam: Send color matching descriptor per frame
usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()
usb-storage: apply IGNORE_UAS only for HIKSEMI MD202 on RTL9210
dt-bindings: phy: g12a-usb2-phy: fix compatible string documentation
dt-bindings: phy: g12a-usb3-pcie-phy: fix compatible string documentation
serial: pch_uart: Pass correct sg to dma_unmap_sg()
dmaengine: lgm: Move DT parsing after initialization
dmaengine: tegra210-adma: fix global intr clear
dmaengine: idxd: Let probe fail when workqueue cannot be enabled
serial: amba-pl011: fix high priority character transmission in rs486 mode
serial: atmel: fix incorrect baudrate setup
gsmi: fix null-deref in gsmi_get_variable
mei: me: add meteor lake point M DID
drm/i915: re-disable RC6p on Sandy Bridge
drm/i915/display: Check source height is > 0
drm/amd/display: Fix set scaling doesn's work
drm/amd/display: Calculate output_color_space after pixel encoding adjustment
drm/amd/display: Fix COLOR_SPACE_YCBCR2020_TYPE matrix
drm/amdgpu: drop experimental flag on aldebaran
fs/ntfs3: Fix attr_punch_hole() null pointer derenference
arm64: efi: Execute runtime services from a dedicated stack
efi: rt-wrapper: Add missing include
Revert "drm/amdgpu: make display pinning more flexible (v2)"
x86/fpu: Use _Alignof to avoid undefined behavior in TYPE_ALIGN
tracing: Use alignof__(struct {type b;}) instead of offsetof()
io_uring: io_kiocb_update_pos() should not touch file for non -1 offset
io_uring/net: fix fast_iov assignment in io_setup_async_msg()
net/ulp: use consistent error code when blocking ULP
net/mlx5: fix missing mutex_unlock in mlx5_fw_fatal_reporter_err_work()
block: mq-deadline: Rename deadline_is_seq_writes()
Revert "wifi: mac80211: fix memory leak in ieee80211_if_add()"
soc: qcom: apr: Make qcom,protection-domain optional again
mm/khugepaged: fix collapse_pte_mapped_thp() to allow anon_vma
io_uring: Clean up a false-positive warning from GCC 9.3.0
io_uring: fix double poll leak on repolling
io_uring/rw: ensure kiocb_end_write() is always called
io_uring/rw: remove leftover debug statement
Linux 5.15.90
Change-Id: I5abc2e695f7183a1d3be9d8f62633bb1df8e8a48
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
commit 739790605705ddcf18f21782b9c99ad7d53a8c11 upstream.
do_prlimit() adds the user-controlled resource value to a pointer that
will subsequently be dereferenced. In order to help prevent this
codepath from being used as a spectre "gadget" a barrier needs to be
added after checking the range.
Reported-by: Jordy Zomer <jordyzomer@google.com>
Tested-by: Jordy Zomer <jordyzomer@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Changes in 5.15.25
drm/nouveau/pmu/gm200-: use alternate falcon reset sequence
fs/proc: task_mmu.c: don't read mapcount for migration entry
btrfs: zoned: cache reported zone during mount
scsi: lpfc: Fix mailbox command failure during driver initialization
HID:Add support for UGTABLET WP5540
Revert "svm: Add warning message for AVIC IPI invalid target"
parisc: Show error if wrong 32/64-bit compiler is being used
serial: parisc: GSC: fix build when IOSAPIC is not set
parisc: Drop __init from map_pages declaration
parisc: Fix data TLB miss in sba_unmap_sg
parisc: Fix sglist access in ccio-dma.c
mmc: block: fix read single on recovery logic
mm: don't try to NUMA-migrate COW pages that have other uses
HID: amd_sfh: Add illuminance mask to limit ALS max value
HID: i2c-hid: goodix: Fix a lockdep splat
HID: amd_sfh: Increase sensor command timeout
HID: amd_sfh: Correct the structure field name
PCI: hv: Fix NUMA node assignment when kernel boots with custom NUMA topology
parisc: Add ioread64_lo_hi() and iowrite64_lo_hi()
btrfs: send: in case of IO error log it
platform/x86: touchscreen_dmi: Add info for the RWC NANOTE P8 AY07J 2-in-1
platform/x86: ISST: Fix possible circular locking dependency detected
kunit: tool: Import missing importlib.abc
selftests: rtc: Increase test timeout so that all tests run
kselftest: signal all child processes
net: ieee802154: at86rf230: Stop leaking skb's
selftests/zram: Skip max_comp_streams interface on newer kernel
selftests/zram01.sh: Fix compression ratio calculation
selftests/zram: Adapt the situation that /dev/zram0 is being used
selftests: openat2: Print also errno in failure messages
selftests: openat2: Add missing dependency in Makefile
selftests: openat2: Skip testcases that fail with EOPNOTSUPP
selftests: skip mincore.check_file_mmap when fs lacks needed support
ax25: improve the incomplete fix to avoid UAF and NPD bugs
pinctrl: bcm63xx: fix unmet dependency on REGMAP for GPIO_REGMAP
vfs: make freeze_super abort when sync_filesystem returns error
quota: make dquot_quota_sync return errors from ->sync_fs
scsi: pm80xx: Fix double completion for SATA devices
kselftest: Fix vdso_test_abi return status
scsi: core: Reallocate device's budget map on queue depth change
scsi: pm8001: Fix use-after-free for aborted TMF sas_task
scsi: pm8001: Fix use-after-free for aborted SSP/STP sas_task
drm/amd: Warn users about potential s0ix problems
nvme: fix a possible use-after-free in controller reset during load
nvme-tcp: fix possible use-after-free in transport error_recovery work
nvme-rdma: fix possible use-after-free in transport error_recovery work
net: sparx5: do not refer to skb after passing it on
drm/amd: add support to check whether the system is set to s3
drm/amd: Only run s3 or s0ix if system is configured properly
drm/amdgpu: fix logic inversion in check
x86/Xen: streamline (and fix) PV CPU enumeration
Revert "module, async: async_synchronize_full() on module init iff async is used"
gcc-plugins/stackleak: Use noinstr in favor of notrace
random: wake up /dev/random writers after zap
KVM: x86/xen: Fix runstate updates to be atomic when preempting vCPU
KVM: x86: nSVM/nVMX: set nested_run_pending on VM entry which is a result of RSM
KVM: x86: SVM: don't passthrough SMAP/SMEP/PKE bits in !NPT && !gCR0.PG case
KVM: x86: nSVM: fix potential NULL derefernce on nested migration
KVM: x86: nSVM: mark vmcb01 as dirty when restoring SMM saved state
iwlwifi: fix use-after-free
drm/radeon: Fix backlight control on iMac 12,1
drm/atomic: Don't pollute crtc_state->mode_blob with error pointers
drm/amd/pm: correct the sequence of sending gpu reset msg
drm/amdgpu: skipping SDMA hw_init and hw_fini for S0ix.
drm/i915/opregion: check port number bounds for SWSCI display power state
drm/i915: Fix dbuf slice config lookup
drm/i915: Fix mbus join config lookup
vsock: remove vsock from connected table when connect is interrupted by a signal
drm/cma-helper: Set VM_DONTEXPAND for mmap
drm/i915/gvt: Make DRM_I915_GVT depend on X86
drm/i915/ttm: tweak priority hint selection
iwlwifi: pcie: fix locking when "HW not ready"
iwlwifi: pcie: gen2: fix locking when "HW not ready"
iwlwifi: mvm: don't send SAR GEO command for 3160 devices
selftests: netfilter: fix exit value for nft_concat_range
netfilter: nft_synproxy: unregister hooks on init error path
selftests: netfilter: disable rp_filter on router
ipv4: fix data races in fib_alias_hw_flags_set
ipv6: fix data-race in fib6_info_hw_flags_set / fib6_purge_rt
ipv6: mcast: use rcu-safe version of ipv6_get_lladdr()
ipv6: per-netns exclusive flowlabel checks
Revert "net: ethernet: bgmac: Use devm_platform_ioremap_resource_byname"
mac80211: mlme: check for null after calling kmemdup
brcmfmac: firmware: Fix crash in brcm_alt_fw_path
cfg80211: fix race in netlink owner interface destruction
net: dsa: lan9303: fix reset on probe
net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN
net: dsa: lantiq_gswip: fix use after free in gswip_remove()
net: dsa: lan9303: handle hwaccel VLAN tags
net: dsa: lan9303: add VLAN IDs to master device
net: ieee802154: ca8210: Fix lifs/sifs periods
ping: fix the dif and sdif check in ping_lookup
bonding: force carrier update when releasing slave
drop_monitor: fix data-race in dropmon_net_event / trace_napi_poll_hit
net_sched: add __rcu annotation to netdev->qdisc
bonding: fix data-races around agg_select_timer
libsubcmd: Fix use-after-free for realloc(..., 0)
net/smc: Avoid overwriting the copies of clcsock callback functions
net: phy: mediatek: remove PHY mode check on MT7531
atl1c: fix tx timeout after link flap on Mikrotik 10/25G NIC
tipc: fix wrong publisher node address in link publications
dpaa2-switch: fix default return of dpaa2_switch_flower_parse_mirror_key
dpaa2-eth: Initialize mutex used in one step timestamping path
net: bridge: multicast: notify switchdev driver whenever MC processing gets disabled
perf bpf: Defer freeing string after possible strlen() on it
selftests/exec: Add non-regular to TEST_GEN_PROGS
arm64: Correct wrong label in macro __init_el2_gicv3
ALSA: usb-audio: revert to IMPLICIT_FB_FIXED_DEV for M-Audio FastTrack Ultra
ALSA: hda/realtek: Add quirk for Legion Y9000X 2019
ALSA: hda/realtek: Fix deadlock by COEF mutex
ALSA: hda: Fix regression on forced probe mask option
ALSA: hda: Fix missing codec probe on Shenker Dock 15
ASoC: ops: Fix stereo change notifications in snd_soc_put_volsw()
ASoC: ops: Fix stereo change notifications in snd_soc_put_volsw_range()
ASoC: ops: Fix stereo change notifications in snd_soc_put_volsw_sx()
ASoC: ops: Fix stereo change notifications in snd_soc_put_xr_sx()
cifs: fix set of group SID via NTSD xattrs
powerpc/603: Fix boot failure with DEBUG_PAGEALLOC and KFENCE
powerpc/lib/sstep: fix 'ptesync' build error
mtd: rawnand: gpmi: don't leak PM reference in error path
smb3: fix snapshot mount option
tipc: fix wrong notification node addresses
scsi: ufs: Remove dead code
scsi: ufs: Fix a deadlock in the error handler
ASoC: tas2770: Insert post reset delay
ASoC: qcom: Actually clear DMA interrupt register for HDMI
block/wbt: fix negative inflight counter when remove scsi device
NFS: Remove an incorrect revalidation in nfs4_update_changeattr_locked()
NFS: LOOKUP_DIRECTORY is also ok with symlinks
NFS: Do not report writeback errors in nfs_getattr()
tty: n_tty: do not look ahead for EOL character past the end of the buffer
block: fix surprise removal for drivers calling blk_set_queue_dying
mtd: rawnand: qcom: Fix clock sequencing in qcom_nandc_probe()
mtd: parsers: qcom: Fix kernel panic on skipped partition
mtd: parsers: qcom: Fix missing free for pparts in cleanup
mtd: phram: Prevent divide by zero bug in phram_setup()
mtd: rawnand: brcmnand: Fixed incorrect sub-page ECC status
HID: elo: fix memory leak in elo_probe
mtd: rawnand: ingenic: Fix missing put_device in ingenic_ecc_get
Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj
KVM: x86/pmu: Refactoring find_arch_event() to pmc_perf_hw_id()
KVM: x86/pmu: Don't truncate the PerfEvtSeln MSR when creating a perf event
KVM: x86/pmu: Use AMD64_RAW_EVENT_MASK for PERF_TYPE_RAW
ARM: OMAP2+: hwmod: Add of_node_put() before break
ARM: OMAP2+: adjust the location of put_device() call in omapdss_init_of
phy: usb: Leave some clocks running during suspend
staging: vc04_services: Fix RCU dereference check
phy: phy-mtk-tphy: Fix duplicated argument in phy-mtk-tphy
irqchip/sifive-plic: Add missing thead,c900-plic match string
x86/bug: Merge annotate_reachable() into _BUG_FLAGS() asm
netfilter: conntrack: don't refresh sctp entries in closed state
ksmbd: fix same UniqueId for dot and dotdot entries
ksmbd: don't align last entry offset in smb2 query directory
arm64: dts: meson-gx: add ATF BL32 reserved-memory region
arm64: dts: meson-g12: add ATF BL32 reserved-memory region
arm64: dts: meson-g12: drop BL32 region from SEI510/SEI610
pidfd: fix test failure due to stack overflow on some arches
selftests: fixup build warnings in pidfd / clone3 tests
mm: io_uring: allow oom-killer from io_uring_setup
ACPI: PM: Revert "Only mark EC GPE for wakeup on Intel systems"
kconfig: let 'shell' return enough output for deep path names
ata: libata-core: Disable TRIM on M88V29
soc: aspeed: lpc-ctrl: Block error printing on probe defer cases
xprtrdma: fix pointer derefs in error cases of rpcrdma_ep_create
drm/rockchip: dw_hdmi: Do not leave clock enabled in error case
tracing: Fix tp_printk option related with tp_printk_stop_on_boot
display/amd: decrease message verbosity about watermarks table failure
drm/amd/display: Cap pflip irqs per max otg number
drm/amd/display: fix yellow carp wm clamping
net: usb: qmi_wwan: Add support for Dell DW5829e
net: macb: Align the dma and coherent dma masks
kconfig: fix failing to generate auto.conf
scsi: lpfc: Fix pt2pt NVMe PRLI reject LOGO loop
EDAC: Fix calculation of returned address and next offset in edac_align_ptr()
ucounts: Handle wrapping in is_ucounts_overlimit
ucounts: In set_cred_ucounts assume new->ucounts is non-NULL
ucounts: Base set_cred_ucounts changes on the real user
ucounts: Enforce RLIMIT_NPROC not RLIMIT_NPROC+1
lib/iov_iter: initialize "flags" in new pipe_buffer
rlimit: Fix RLIMIT_NPROC enforcement failure caused by capability calls in set_user
ucounts: Move RLIMIT_NPROC handling after set_user
net: sched: limit TC_ACT_REPEAT loops
dmaengine: sh: rcar-dmac: Check for error num after setting mask
dmaengine: stm32-dmamux: Fix PM disable depth imbalance in stm32_dmamux_probe
dmaengine: sh: rcar-dmac: Check for error num after dma_set_max_seg_size
tests: fix idmapped mount_setattr test
i2c: qcom-cci: don't delete an unregistered adapter
i2c: qcom-cci: don't put a device tree node before i2c_add_adapter()
dmaengine: ptdma: Fix the error handling path in pt_core_init()
copy_process(): Move fd_install() out of sighand->siglock critical section
scsi: qedi: Fix ABBA deadlock in qedi_process_tmf_resp() and qedi_process_cmd_cleanup_resp()
ice: enable parsing IPSEC SPI headers for RSS
i2c: brcmstb: fix support for DSL and CM variants
lockdep: Correct lock_classes index mapping
Linux 5.15.25
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ib129a0e11f5e82d67563329a5de1b0aef1d87928
commit c923a8e7edb010da67424077cbf1a6f1396ebd2e upstream.
During set*id() which cred->ucounts to charge the the current process
to is not known until after set_cred_ucounts. So move the
RLIMIT_NPROC checking into a new helper flag_nproc_exceeded and call
flag_nproc_exceeded after set_cred_ucounts.
This is very much an arbitrary subset of the places where we currently
change the RLIMIT_NPROC accounting, designed to preserve the existing
logic.
Fixing the existing logic will be the subject of another series of
changes.
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20220216155832.680775-4-ebiederm@xmission.com
Fixes: 21d1c5e386 ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c16bdeb5a39ffa3f32b32f812831a2092d2a3061 upstream.
Solar Designer <solar@openwall.com> wrote:
> I'm not aware of anyone actually running into this issue and reporting
> it. The systems that I personally know use suexec along with rlimits
> still run older/distro kernels, so would not yet be affected.
>
> So my mention was based on my understanding of how suexec works, and
> code review. Specifically, Apache httpd has the setting RLimitNPROC,
> which makes it set RLIMIT_NPROC:
>
> https://httpd.apache.org/docs/2.4/mod/core.html#rlimitnproc
>
> The above documentation for it includes:
>
> "This applies to processes forked from Apache httpd children servicing
> requests, not the Apache httpd children themselves. This includes CGI
> scripts and SSI exec commands, but not any processes forked from the
> Apache httpd parent, such as piped logs."
>
> In code, there are:
>
> ./modules/generators/mod_cgid.c: ( (cgid_req.limits.limit_nproc_set) && ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC,
> ./modules/generators/mod_cgi.c: ((rc = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC,
> ./modules/filters/mod_ext_filter.c: rv = apr_procattr_limit_set(procattr, APR_LIMIT_NPROC, conf->limit_nproc);
>
> For example, in mod_cgi.c this is in run_cgi_child().
>
> I think this means an httpd child sets RLIMIT_NPROC shortly before it
> execs suexec, which is a SUID root program. suexec then switches to the
> target user and execs the CGI script.
>
> Before 2863643fb8, the setuid() in suexec would set the flag, and the
> target user's process count would be checked against RLIMIT_NPROC on
> execve(). After 2863643fb8, the setuid() in suexec wouldn't set the
> flag because setuid() is (naturally) called when the process is still
> running as root (thus, has those limits bypass capabilities), and
> accordingly execve() would not check the target user's process count
> against RLIMIT_NPROC.
In commit 2863643fb8 ("set_user: add capability check when
rlimit(RLIMIT_NPROC) exceeds") capable calls were added to set_user to
make it more consistent with fork. Unfortunately because of call site
differences those capable calls were checking the credentials of the
user before set*id() instead of after set*id().
This breaks enforcement of RLIMIT_NPROC for applications that set the
rlimit and then call set*id() while holding a full set of
capabilities. The capabilities are only changed in the new credential
in security_task_fix_setuid().
The code in apache suexec appears to follow this pattern.
Commit 909cc4ae86f3 ("[PATCH] Fix two bugs with process limits
(RLIMIT_NPROC)") where this check was added describes the targes of this
capability check as:
2/ When a root-owned process (e.g. cgiwrap) sets up process limits and then
calls setuid, the setuid should fail if the user would then be running
more than rlim_cur[RLIMIT_NPROC] processes, but it doesn't. This patch
adds an appropriate test. With this patch, and per-user process limit
imposed in cgiwrap really works.
So the original use case of this check also appears to match the broken
pattern.
Restore the enforcement of RLIMIT_NPROC by removing the bad capable
checks added in set_user. This unfortunately restores the
inconsistent state the code has been in for the last 11 years, but
dealing with the inconsistencies looks like a larger problem.
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20210907213042.GA22626@openwall.com/
Link: https://lkml.kernel.org/r/20220212221412.GA29214@openwall.com
Link: https://lkml.kernel.org/r/20220216155832.680775-1-ebiederm@xmission.com
Fixes: 2863643fb8 ("set_user: add capability check when rlimit(RLIMIT_NPROC) exceeds")
History-Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Reviewed-by: Solar Designer <solar@openwall.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Android uses vma names of up to 256 characters. Change the max limit
for anonymous vma names to support Android legacy use cases.
Bug: 120441514
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: Ia0126ab3919281ce4d5c597a43a47de80eadf71a
In many userspace applications, and especially in VM based applications
like Android uses heavily, there are multiple different allocators in
use. At a minimum there is libc malloc and the stack, and in many cases
there are libc malloc, the stack, direct syscalls to mmap anonymous
memory, and multiple VM heaps (one for small objects, one for big
objects, etc.). Each of these layers usually has its own tools to
inspect its usage; malloc by compiling a debug version, the VM through
heap inspection tools, and for direct syscalls there is usually no way
to track them.
On Android we heavily use a set of tools that use an extended version of
the logic covered in Documentation/vm/pagemap.txt to walk all pages
mapped in userspace and slice their usage by process, shared (COW) vs.
unique mappings, backing, etc. This can account for real physical
memory usage even in cases like fork without exec (which Android uses
heavily to share as many private COW pages as possible between
processes), Kernel SamePage Merging, and clean zero pages. It produces
a measurement of the pages that only exist in that process (USS, for
unique), and a measurement of the physical memory usage of that process
with the cost of shared pages being evenly split between processes that
share them (PSS).
If all anonymous memory is indistinguishable then figuring out the real
physical memory usage (PSS) of each heap requires either a pagemap
walking tool that can understand the heap debugging of every layer, or
for every layer's heap debugging tools to implement the pagemap walking
logic, in which case it is hard to get a consistent view of memory
across the whole system.
Tracking the information in userspace leads to all sorts of problems.
It either needs to be stored inside the process, which means every
process has to have an API to export its current heap information upon
request, or it has to be stored externally in a filesystem that somebody
needs to clean up on crashes. It needs to be readable while the process
is still running, so it has to have some sort of synchronization with
every layer of userspace. Efficiently tracking the ranges requires
reimplementing something like the kernel vma trees, and linking to it
from every layer of userspace. It requires more memory, more syscalls,
more runtime cost, and more complexity to separately track regions that
the kernel is already tracking.
This patch adds a field to /proc/pid/maps and /proc/pid/smaps to show a
userspace-provided name for anonymous vmas. The names of named
anonymous vmas are shown in /proc/pid/maps and /proc/pid/smaps as
[anon:<name>].
Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name)
Setting the name to NULL clears it. The name length limit is 80 bytes
including NUL-terminator and is checked to contain only printable ascii
characters (including space), except '[',']','\','$' and '`'.
Ascii strings are being used to have a descriptive identifiers for vmas,
which can be understood by the users reading /proc/pid/maps or
/proc/pid/smaps. Names can be standardized for a given system and they
can include some variable parts such as the name of the allocator or a
library, tid of the thread using it, etc.
The name is stored in a pointer in the shared union in vm_area_struct
that points to a null terminated string. Anonymous vmas with the same
name (equivalent strings) and are otherwise mergeable will be merged.
The name pointers are not shared between vmas even if they contain the
same name. The name pointer is stored in a union with fields that are
only used on file-backed mappings, so it does not increase memory usage.
CONFIG_ANON_VMA_NAME kernel configuration is introduced to enable this
feature. It keeps the feature disabled by default to prevent any
additional memory overhead and to avoid confusing procfs parsers on
systems which are not ready to support named anonymous vmas.
The patch is based on the original patch developed by Colin Cross, more
specifically on its latest version [1] posted upstream by Sumit Semwal.
It used a userspace pointer to store vma names. In that design, name
pointers could be shared between vmas. However during the last
upstreaming attempt, Kees Cook raised concerns [2] about this approach
and suggested to copy the name into kernel memory space, perform
validity checks [3] and store as a string referenced from
vm_area_struct.
One big concern is about fork() performance which would need to strdup
anonymous vma names. Dave Hansen suggested experimenting with
worst-case scenario of forking a process with 64k vmas having longest
possible names [4]. I ran this experiment on an ARM64 Android device
and recorded a worst-case regression of almost 40% when forking such a
process.
This regression is addressed in the followup patch which replaces the
pointer to a name with a refcounted structure that allows sharing the
name pointer between vmas of the same name. Instead of duplicating the
string during fork() or when splitting a vma it increments the refcount.
[1] https://lore.kernel.org/linux-mm/20200901161459.11772-4-sumit.semwal@linaro.org/
[2] https://lore.kernel.org/linux-mm/202009031031.D32EF57ED@keescook/
[3] https://lore.kernel.org/linux-mm/202009031022.3834F692@keescook/
[4] https://lore.kernel.org/linux-mm/5d0358ab-8c47-2f5f-8e43-23b89d6a8e95@intel.com/
Changes for prctl(2) manual page (in the options section):
PR_SET_VMA
Sets an attribute specified in arg2 for virtual memory areas
starting from the address specified in arg3 and spanning the
size specified in arg4. arg5 specifies the value of the attribute
to be set. Note that assigning an attribute to a virtual memory
area might prevent it from being merged with adjacent virtual
memory areas due to the difference in that attribute's value.
Currently, arg2 must be one of:
PR_SET_VMA_ANON_NAME
Set a name for anonymous virtual memory areas. arg5 should
be a pointer to a null-terminated string containing the
name. The name length including null byte cannot exceed
80 bytes. If arg5 is NULL, the name of the appropriate
anonymous virtual memory areas will be reset. The name
can contain only printable ascii characters (including
space), except '[',']','\','$' and '`'.
This feature is available only if the kernel is built with
the CONFIG_ANON_VMA_NAME option enabled.
[surenb@google.com: docs: proc.rst: /proc/PID/maps: fix malformed table]
Link: https://lkml.kernel.org/r/20211123185928.2513763-1-surenb@google.com
[surenb: rebased over v5.15-rc6, replaced userpointer with a kernel copy,
added input sanitization and CONFIG_ANON_VMA_NAME config. The bulk of the
work here was done by Colin Cross, therefore, with his permission, keeping
him as the author]
Link: https://lkml.kernel.org/r/20211019215511.3771969-2-surenb@google.com
Signed-off-by: Colin Cross <ccross@google.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Glauber <jan.glauber@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Landley <rob@landley.net>
Cc: "Serge E. Hallyn" <serge.hallyn@ubuntu.com>
Cc: Shaohua Li <shli@fusionio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 9a10064f5625d5572c3626c1516e0bebc6c9fe9b)
Bug: 120441514
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Change-Id: I53d56d551a7d62f75341304751814294b447c04e
Steps on the way to 5.15-rc1
Resolves merge conflict in:
fs/proc/base.c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ic554ca8447961e52fbc6f27d91470a816b59a771
Merge more updates from Andrew Morton:
"147 patches, based on 7d2a07b769.
Subsystems affected by this patch series: mm (memory-hotplug, rmap,
ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
selftests, ipc, and scripts"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
scripts: check_extable: fix typo in user error message
mm/workingset: correct kernel-doc notations
ipc: replace costly bailout check in sysvipc_find_ipc()
selftests/memfd: remove unused variable
Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
configs: remove the obsolete CONFIG_INPUT_POLLDEV
prctl: allow to setup brk for et_dyn executables
pid: cleanup the stale comment mentioning pidmap_init().
kernel/fork.c: unexport get_{mm,task}_exe_file
coredump: fix memleak in dump_vma_snapshot()
fs/coredump.c: log if a core dump is aborted due to changed file permissions
nilfs2: use refcount_dec_and_lock() to fix potential UAF
nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
nilfs2: fix NULL pointer in nilfs_##name##_attr_release
nilfs2: fix memory leak in nilfs_sysfs_create_device_group
trap: cleanup trap_init()
init: move usermodehelper_enable() to populate_rootfs()
...
Keno Fischer reported that when a binray loaded via ld-linux-x the
prctl(PR_SET_MM_MAP) doesn't allow to setup brk value because it lays
before mm:end_data.
For example a test program shows
| # ~/t
|
| start_code 401000
| end_code 401a15
| start_stack 7ffce4577dd0
| start_data 403e10
| end_data 40408c
| start_brk b5b000
| sbrk(0) b5b000
and when executed via ld-linux
| # /lib64/ld-linux-x86-64.so.2 ~/t
|
| start_code 7fc25b0a4000
| end_code 7fc25b0c4524
| start_stack 7fffcc6b2400
| start_data 7fc25b0ce4c0
| end_data 7fc25b0cff98
| start_brk 55555710c000
| sbrk(0) 55555710c000
This of course prevent criu from restoring such programs. Looking into
how kernel operates with brk/start_brk inside brk() syscall I don't see
any problem if we allow to setup brk/start_brk without checking for
end_data. Even if someone pass some weird address here on a purpose then
the worst possible result will be an unexpected unmapping of existing vma
(own vma, since prctl works with the callers memory) but test for
RLIMIT_DATA is still valid and a user won't be able to gain more memory in
case of expanding VMAs via new values shipped with prctl call.
Link: https://lkml.kernel.org/r/20210121221207.GB2174@grain
Fixes: bbdc6076d2 ("binfmt_elf: move brk out of mmap when doing direct loader exec")
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reported-by: Keno Fischer <keno@juliacomputing.com>
Acked-by: Andrey Vagin <avagin@gmail.com>
Tested-by: Andrey Vagin <avagin@gmail.com>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull MAP_DENYWRITE removal from David Hildenbrand:
"Remove all in-tree usage of MAP_DENYWRITE from the kernel and remove
VM_DENYWRITE.
There are some (minor) user-visible changes:
- We no longer deny write access to shared libaries loaded via legacy
uselib(); this behavior matches modern user space e.g. dlopen().
- We no longer deny write access to the elf interpreter after exec
completed, treating it just like shared libraries (which it often
is).
- We always deny write access to the file linked via /proc/pid/exe:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) will fail if write access to the
file cannot be denied, and write access to the file will remain
denied until the link is effectivel gone (exec, termination,
sys_prctl(PR_SET_MM_MAP/EXE_FILE)) -- just as if exec'ing the file.
Cross-compiled for a bunch of architectures (alpha, microblaze, i386,
s390x, ...) and verified via ltp that especially the relevant tests
(i.e., creat07 and execve04) continue working as expected"
* tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux:
fs: update documentation of get_write_access() and friends
mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()
mm: remove VM_DENYWRITE
binfmt: remove in-tree usage of MAP_DENYWRITE
kernel/fork: always deny write access to current MM exe_file
kernel/fork: factor out replacing the current MM exe_file
binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib()
Let's factor the main logic out into replace_mm_exe_file(), such that
all mm->exe_file logic is contained in kernel/fork.c.
While at it, perform some simple cleanups that are possible now that
we're simplifying the individual functions.
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
in copy_process(): non root users but with capability CAP_SYS_RESOURCE
or CAP_SYS_ADMIN will clean PF_NPROC_EXCEEDED flag even
rlimit(RLIMIT_NPROC) exceeds. Add the same capability check logic here.
Align the permission checks in copy_process() and set_user(). In
copy_process() CAP_SYS_RESOURCE or CAP_SYS_ADMIN capable users will be
able to circumvent and clear the PF_NPROC_EXCEEDED flag whereas they
aren't able to the same in set_user(). There's no obvious logic to this
and trying to unearth the reason in the thread didn't go anywhere.
The gist seems to be that this code wants to make sure that a program
can't successfully exec if it has gone through a set*id() transition
while exceeding its RLIMIT_NPROC.
A capable but non-INIT_USER caller getting PF_NPROC_EXCEEDED set during
a set*id() transition wouldn't be able to exec right away if they still
exceed their RLIMIT_NPROC at the time of exec. So their exec would fail
in fs/exec.c:
if ((current->flags & PF_NPROC_EXCEEDED) &&
is_ucounts_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
retval = -EAGAIN;
goto out_ret;
}
However, if the caller were to fork() right after the set*id()
transition but before the exec while still exceeding their RLIMIT_NPROC
then they would get PF_NPROC_EXCEEDED cleared (while the child would
inherit it):
retval = -EAGAIN;
if (is_ucounts_overlimit(task_ucounts(p), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
if (p->real_cred->user != INIT_USER &&
!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
goto bad_fork_free;
}
current->flags &= ~PF_NPROC_EXCEEDED;
which means a subsequent exec by the capable caller would now succeed
even though they could still exceed their RLIMIT_NPROC limit. This seems
inconsistent. Allow a CAP_SYS_ADMIN or CAP_SYS_RESOURCE capable user to
avoid PF_NPROC_EXCEEDED as they already can in copy_process().
Cc: peterz@infradead.org, tglx@linutronix.de, linux-kernel@vger.kernel.org, Ran Xiaokai <ran.xiaokai@zte.com.cn>, , ,
Link: https://lore.kernel.org/r/20210728072629.530435-1-ran.xiaokai@zte.com.cn
Cc: Neil Brown <neilb@suse.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: James Morris <jamorris@linux.microsoft.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Pull user namespace rlimit handling update from Eric Biederman:
"This is the work mainly by Alexey Gladkov to limit rlimits to the
rlimits of the user that created a user namespace, and to allow users
to have stricter limits on the resources created within a user
namespace."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
cred: add missing return error code when set_cred_ucounts() failed
ucounts: Silence warning in dec_rlimit_ucounts
ucounts: Set ucount_max to the largest positive value the type can hold
kselftests: Add test to check for rlimit changes in different user namespaces
Reimplement RLIMIT_MEMLOCK on top of ucounts
Reimplement RLIMIT_SIGPENDING on top of ucounts
Reimplement RLIMIT_MSGQUEUE on top of ucounts
Reimplement RLIMIT_NPROC on top of ucounts
Use atomic_t for ucounts reference counting
Add a reference to ucounts for each cred
Increase size of ucounts to atomic_long_t
One giant leap, all the way up to 5.13-rc1
Also take the opportunity to re-align (a.k.a. fix a couple of previous
merge conflict fix-up issues) which occurred during this merge-window.
Fixes: 4797acfb9c ("Merge 16b3d0cf5b Merge tag 'sched-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into android-mainline")
Fixes: 92f282f338 ("Merge 8ca5297e7e Merge tag 'kconfig-v5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild into android-mainline")
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Change-Id: Ie9389f595776e8f66bba6eaf0fa7a3587c6a5749
This patch provides support for setting and copying core scheduling
'task cookies' between threads (PID), processes (TGID), and process
groups (PGID).
The value of core scheduling isn't that tasks don't share a core,
'nosmt' can do that. The value lies in exploiting all the sharing
opportunities that exist to recover possible lost performance and that
requires a degree of flexibility in the API.
From a security perspective (and there are others), the thread,
process and process group distinction is an existent hierarchal
categorization of tasks that reflects many of the security concerns
about 'data sharing'. For example, protecting against cache-snooping
by a thread that can just read the memory directly isn't all that
useful.
With this in mind, subcommands to CREATE/SHARE (TO/FROM) provide a
mechanism to create and share cookies. CREATE/SHARE_TO specify a
target pid with enum pidtype used to specify the scope of the targeted
tasks. For example, PIDTYPE_TGID will share the cookie with the
process and all of it's threads as typically desired in a security
scenario.
API:
prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, tgtpid, pidtype, &cookie)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, tgtpid, pidtype, NULL)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, tgtpid, pidtype, NULL)
prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_FROM, srcpid, pidtype, NULL)
where 'tgtpid/srcpid == 0' implies the current process and pidtype is
kernel enum pid_type {PIDTYPE_PID, PIDTYPE_TGID, PIDTYPE_PGID, ...}.
For return values, EINVAL, ENOMEM are what they say. ESRCH means the
tgtpid/srcpid was not found. EPERM indicates lack of PTRACE permission
access to tgtpid/srcpid. ENODEV indicates your machines lacks SMT.
[peterz: complete rewrite]
Signed-off-by: Chris Hyser <chris.hyser@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123309.039845339@infradead.org
The rlimit counter is tied to uid in the user_namespace. This allows
rlimit values to be specified in userns even if they are already
globally exceeded by the user. However, the value of the previous
user_namespaces cannot be exceeded.
To illustrate the impact of rlimits, let's say there is a program that
does not fork. Some service-A wants to run this program as user X in
multiple containers. Since the program never fork the service wants to
set RLIMIT_NPROC=1.
service-A
\- program (uid=1000, container1, rlimit_nproc=1)
\- program (uid=1000, container2, rlimit_nproc=1)
The service-A sets RLIMIT_NPROC=1 and runs the program in container1.
When the service-A tries to run a program with RLIMIT_NPROC=1 in
container2 it fails since user X already has one running process.
We cannot use existing inc_ucounts / dec_ucounts because they do not
allow us to exceed the maximum for the counter. Some rlimits can be
overlimited by root or if the user has the appropriate capability.
Changelog
v11:
* Change inc_rlimit_ucounts() which now returns top value of ucounts.
* Drop inc_rlimit_ucounts_and_test() because the return code of
inc_rlimit_ucounts() can be checked.
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/c5286a8aa16d2d698c222f7532f3d735c82bc6bc.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
For RLIMIT_NPROC and some other rlimits the user_struct that holds the
global limit is kept alive for the lifetime of a process by keeping it
in struct cred. Adding a pointer to ucounts in the struct cred will
allow to track RLIMIT_NPROC not only for user in the system, but for
user in the user_namespace.
Updating ucounts may require memory allocation which may fail. So, we
cannot change cred.ucounts in the commit_creds() because this function
cannot fail and it should always return 0. For this reason, we modify
cred.ucounts before calling the commit_creds().
Changelog
v6:
* Fix null-ptr-deref in is_ucounts_overlimit() detected by trinity. This
error was caused by the fact that cred_alloc_blank() left the ucounts
pointer empty.
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/b37aaef28d8b9b0d757e07ba6dd27281bbe39259.1619094428.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This change introduces a prctl that allows the user program to control
which PAC keys are enabled in a particular task. The main reason
why this is useful is to enable a userspace ABI that uses PAC to
sign and authenticate function pointers and other pointers exposed
outside of the function, while still allowing binaries conforming
to the ABI to interoperate with legacy binaries that do not sign or
authenticate pointers.
The idea is that a dynamic loader or early startup code would issue
this prctl very early after establishing that a process may load legacy
binaries, but before executing any PAC instructions.
This change adds a small amount of overhead to kernel entry and exit
due to additional required instruction sequences.
On a DragonBoard 845c (Cortex-A75) with the powersave governor, the
overhead of similar instruction sequences was measured as 4.9ns when
simulating the common case where IA is left enabled, or 43.7ns when
simulating the uncommon case where IA is disabled. These numbers can
be seen as the worst case scenario, since in more realistic scenarios
a better performing governor would be used and a newer chip would be
used that would support PAC unlike Cortex-A75 and would be expected
to be faster than Cortex-A75.
On an Apple M1 under a hypervisor, the overhead of the entry/exit
instruction sequences introduced by this patch was measured as 0.3ns
in the case where IA is left enabled, and 33.0ns in the case where
IA is disabled.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Link: https://linux-review.googlesource.com/id/Ibc41a5e6a76b275efbaa126b31119dc197b927a5
Link: https://lore.kernel.org/r/d6609065f8f40397a4124654eb68c9f490b4d477.1616123271.git.pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Doing a
prctl(PR_SET_MM, PR_SET_MM_AUXV, addr, 1);
will copy 1 byte from userspace to (quite big) on-stack array
and then stash everything to mm->saved_auxv.
AT_NULL terminator will be inserted at the very end.
/proc/*/auxv handler will find that AT_NULL terminator
and copy original stack contents to userspace.
This devious scheme requires CAP_SYS_RESOURCE.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Steps on the way to 5.12-rc1
Resolves merge conflicts in:
drivers/dma-buf/dma-heap.c
drivers/dma-buf/heaps/cma_heap.c
drivers/dma-buf/heaps/system_heap.c
include/linux/dma-heap.h
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ibb32dbdba5183c9e19f5d1e94016cc1ae9616173
Steps on the way to 5.12-rc1.
Resolves conflicts in:
fs/overlayfs/inode.c
Note, incfs is broken here, will mark it as BROKEN in another patch to
make it more obvious.
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I95a5938fc3cfa27d521c5d4fd18b2adfb13a6d84
Pull Kbuild updates from Masahiro Yamada:
- Fix false-positive build warnings for ARCH=ia64 builds
- Optimize dictionary size for module compression with xz
- Check the compiler and linker versions in Kconfig
- Fix misuse of extra-y
- Support DWARF v5 debug info
- Clamp SUBLEVEL to 255 because stable releases 4.4.x and 4.9.x
exceeded the limit
- Add generic syscall{tbl,hdr}.sh for cleanups across arches
- Minor cleanups of genksyms
- Minor cleanups of Kconfig
* tag 'kbuild-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (38 commits)
initramfs: Remove redundant dependency of RD_ZSTD on BLK_DEV_INITRD
kbuild: remove deprecated 'always' and 'hostprogs-y/m'
kbuild: parse C= and M= before changing the working directory
kbuild: reuse this-makefile to define abs_srctree
kconfig: unify rule of config, menuconfig, nconfig, gconfig, xconfig
kconfig: omit --oldaskconfig option for 'make config'
kconfig: fix 'invalid option' for help option
kconfig: remove dead code in conf_askvalue()
kconfig: clean up nested if-conditionals in check_conf()
kconfig: Remove duplicate call to sym_get_string_value()
Makefile: Remove # characters from compiler string
Makefile: reuse CC_VERSION_TEXT
kbuild: check the minimum linker version in Kconfig
kbuild: remove ld-version macro
scripts: add generic syscallhdr.sh
scripts: add generic syscalltbl.sh
arch: syscalls: remove $(srctree)/ prefix from syscall tables
arch: syscalls: add missing FORCE and fix 'targets' to make if_changed work
gen_compile_commands: prune some directories
kbuild: simplify access to the kernel's version
...
Pull idmapped mounts from Christian Brauner:
"This introduces idmapped mounts which has been in the making for some
time. Simply put, different mounts can expose the same file or
directory with different ownership. This initial implementation comes
with ports for fat, ext4 and with Christoph's port for xfs with more
filesystems being actively worked on by independent people and
maintainers.
Idmapping mounts handle a wide range of long standing use-cases. Here
are just a few:
- Idmapped mounts make it possible to easily share files between
multiple users or multiple machines especially in complex
scenarios. For example, idmapped mounts will be used in the
implementation of portable home directories in
systemd-homed.service(8) where they allow users to move their home
directory to an external storage device and use it on multiple
computers where they are assigned different uids and gids. This
effectively makes it possible to assign random uids and gids at
login time.
- It is possible to share files from the host with unprivileged
containers without having to change ownership permanently through
chown(2).
- It is possible to idmap a container's rootfs and without having to
mangle every file. For example, Chromebooks use it to share the
user's Download folder with their unprivileged containers in their
Linux subsystem.
- It is possible to share files between containers with
non-overlapping idmappings.
- Filesystem that lack a proper concept of ownership such as fat can
use idmapped mounts to implement discretionary access (DAC)
permission checking.
- They allow users to efficiently changing ownership on a per-mount
basis without having to (recursively) chown(2) all files. In
contrast to chown (2) changing ownership of large sets of files is
instantenous with idmapped mounts. This is especially useful when
ownership of a whole root filesystem of a virtual machine or
container is changed. With idmapped mounts a single syscall
mount_setattr syscall will be sufficient to change the ownership of
all files.
- Idmapped mounts always take the current ownership into account as
idmappings specify what a given uid or gid is supposed to be mapped
to. This contrasts with the chown(2) syscall which cannot by itself
take the current ownership of the files it changes into account. It
simply changes the ownership to the specified uid and gid. This is
especially problematic when recursively chown(2)ing a large set of
files which is commong with the aforementioned portable home
directory and container and vm scenario.
- Idmapped mounts allow to change ownership locally, restricting it
to specific mounts, and temporarily as the ownership changes only
apply as long as the mount exists.
Several userspace projects have either already put up patches and
pull-requests for this feature or will do so should you decide to pull
this:
- systemd: In a wide variety of scenarios but especially right away
in their implementation of portable home directories.
https://systemd.io/HOME_DIRECTORY/
- container runtimes: containerd, runC, LXD:To share data between
host and unprivileged containers, unprivileged and privileged
containers, etc. The pull request for idmapped mounts support in
containerd, the default Kubernetes runtime is already up for quite
a while now: https://github.com/containerd/containerd/pull/4734
- The virtio-fs developers and several users have expressed interest
in using this feature with virtual machines once virtio-fs is
ported.
- ChromeOS: Sharing host-directories with unprivileged containers.
I've tightly synced with all those projects and all of those listed
here have also expressed their need/desire for this feature on the
mailing list. For more info on how people use this there's a bunch of
talks about this too. Here's just two recent ones:
https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdfhttps://fosdem.org/2021/schedule/event/containers_idmap/
This comes with an extensive xfstests suite covering both ext4 and
xfs:
https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts
It covers truncation, creation, opening, xattrs, vfscaps, setid
execution, setgid inheritance and more both with idmapped and
non-idmapped mounts. It already helped to discover an unrelated xfs
setgid inheritance bug which has since been fixed in mainline. It will
be sent for inclusion with the xfstests project should you decide to
merge this.
In order to support per-mount idmappings vfsmounts are marked with
user namespaces. The idmapping of the user namespace will be used to
map the ids of vfs objects when they are accessed through that mount.
By default all vfsmounts are marked with the initial user namespace.
The initial user namespace is used to indicate that a mount is not
idmapped. All operations behave as before and this is verified in the
testsuite.
Based on prior discussions we want to attach the whole user namespace
and not just a dedicated idmapping struct. This allows us to reuse all
the helpers that already exist for dealing with idmappings instead of
introducing a whole new range of helpers. In addition, if we decide in
the future that we are confident enough to enable unprivileged users
to setup idmapped mounts the permission checking can take into account
whether the caller is privileged in the user namespace the mount is
currently marked with.
The user namespace the mount will be marked with can be specified by
passing a file descriptor refering to the user namespace as an
argument to the new mount_setattr() syscall together with the new
MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern
of extensibility.
The following conditions must be met in order to create an idmapped
mount:
- The caller must currently have the CAP_SYS_ADMIN capability in the
user namespace the underlying filesystem has been mounted in.
- The underlying filesystem must support idmapped mounts.
- The mount must not already be idmapped. This also implies that the
idmapping of a mount cannot be altered once it has been idmapped.
- The mount must be a detached/anonymous mount, i.e. it must have
been created by calling open_tree() with the OPEN_TREE_CLONE flag
and it must not already have been visible in the filesystem.
The last two points guarantee easier semantics for userspace and the
kernel and make the implementation significantly simpler.
By default vfsmounts are marked with the initial user namespace and no
behavioral or performance changes are observed.
The manpage with a detailed description can be found here:
1d7b902e28
In order to support idmapped mounts, filesystems need to be changed
and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The
patches to convert individual filesystem are not very large or
complicated overall as can be seen from the included fat, ext4, and
xfs ports. Patches for other filesystems are actively worked on and
will be sent out separately. The xfstestsuite can be used to verify
that port has been done correctly.
The mount_setattr() syscall is motivated independent of the idmapped
mounts patches and it's been around since July 2019. One of the most
valuable features of the new mount api is the ability to perform
mounts based on file descriptors only.
Together with the lookup restrictions available in the openat2()
RESOLVE_* flag namespace which we added in v5.6 this is the first time
we are close to hardened and race-free (e.g. symlinks) mounting and
path resolution.
While userspace has started porting to the new mount api to mount
proper filesystems and create new bind-mounts it is currently not
possible to change mount options of an already existing bind mount in
the new mount api since the mount_setattr() syscall is missing.
With the addition of the mount_setattr() syscall we remove this last
restriction and userspace can now fully port to the new mount api,
covering every use-case the old mount api could. We also add the
crucial ability to recursively change mount options for a whole mount
tree, both removing and adding mount options at the same time. This
syscall has been requested multiple times by various people and
projects.
There is a simple tool available at
https://github.com/brauner/mount-idmapped
that allows to create idmapped mounts so people can play with this
patch series. I'll add support for the regular mount binary should you
decide to pull this in the following weeks:
Here's an example to a simple idmapped mount of another user's home
directory:
u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt
u1001@f2-vm:/$ ls -al /home/ubuntu/
total 28
drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 .
drwxr-xr-x 4 root root 4096 Oct 28 04:00 ..
-rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile
-rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ ls -al /mnt/
total 28
drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 .
drwxr-xr-x 29 root root 4096 Oct 28 22:01 ..
-rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history
-rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout
-rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc
-rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile
-rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful
-rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo
u1001@f2-vm:/$ touch /mnt/my-file
u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file
u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file
u1001@f2-vm:/$ ls -al /mnt/my-file
-rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file
u1001@f2-vm:/$ ls -al /home/ubuntu/my-file
-rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file
u1001@f2-vm:/$ getfacl /mnt/my-file
getfacl: Removing leading '/' from absolute path names
# file: mnt/my-file
# owner: u1001
# group: u1001
user::rw-
user:u1001:rwx
group::rw-
mask::rwx
other::r--
u1001@f2-vm:/$ getfacl /home/ubuntu/my-file
getfacl: Removing leading '/' from absolute path names
# file: home/ubuntu/my-file
# owner: ubuntu
# group: ubuntu
user::rw-
user:ubuntu:rwx
group::rw-
mask::rwx
other::r--"
* tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits)
xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl
xfs: support idmapped mounts
ext4: support idmapped mounts
fat: handle idmapped mounts
tests: add mount_setattr() selftests
fs: introduce MOUNT_ATTR_IDMAP
fs: add mount_setattr()
fs: add attr_flags_to_mnt_flags helper
fs: split out functions to hold writers
namespace: only take read lock in do_reconfigure_mnt()
mount: make {lock,unlock}_mount_hash() static
namespace: take lock_mount_hash() directly when changing flags
nfs: do not export idmapped mounts
overlayfs: do not mount on top of idmapped mounts
ecryptfs: do not mount on top of idmapped mounts
ima: handle idmapped mounts
apparmor: handle idmapped mounts
fs: make helpers idmap mount aware
exec: handle idmapped mounts
would_dump: handle idmapped mounts
...
Instead of storing the version in a single integer and having various
kernel (and userspace) code how it's constructed, export individual
(major, patchlevel, sublevel) components and simplify kernel code that
uses it.
This should also make it easier on userspace.
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Steps on the way to 5.11-rc1
Resolves merge conflicts in:
include/uapi/linux/prctl.h
kernel/sys.c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I85ea8cffcd22f93277b357872254fe21d68bd82c
Introduce a mechanism to quickly disable/enable syscall handling for a
specific process and redirect to userspace via SIGSYS. This is useful
for processes with parts that require syscall redirection and parts that
don't, but who need to perform this boundary crossing really fast,
without paying the cost of a system call to reconfigure syscall handling
on each boundary transition. This is particularly important for Windows
games running over Wine.
The proposed interface looks like this:
prctl(PR_SET_SYSCALL_USER_DISPATCH, <op>, <off>, <length>, [selector])
The range [<offset>,<offset>+<length>) is a part of the process memory
map that is allowed to by-pass the redirection code and dispatch
syscalls directly, such that in fast paths a process doesn't need to
disable the trap nor the kernel has to check the selector. This is
essential to return from SIGSYS to a blocked area without triggering
another SIGSYS from rt_sigreturn.
selector is an optional pointer to a char-sized userspace memory region
that has a key switch for the mechanism. This key switch is set to
either PR_SYS_DISPATCH_ON, PR_SYS_DISPATCH_OFF to enable and disable the
redirection without calling the kernel.
The feature is meant to be set per-thread and it is disabled on
fork/clone/execv.
Internally, this doesn't add overhead to the syscall hot path, and it
requires very little per-architecture support. I avoided using seccomp,
even though it duplicates some functionality, due to previous feedback
that maybe it shouldn't mix with seccomp since it is not a security
mechanism. And obviously, this should never be considered a security
mechanism, since any part of the program can by-pass it by using the
syscall dispatcher.
For the sysinfo benchmark, which measures the overhead added to
executing a native syscall that doesn't require interception, the
overhead using only the direct dispatcher region to issue syscalls is
pretty much irrelevant. The overhead of using the selector goes around
40ns for a native (unredirected) syscall in my system, and it is (as
expected) dominated by the supervisor-mode user-address access. In
fact, with SMAP off, the overhead is consistently less than 5ns on my
test box.
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20201127193238.821364-4-krisman@collabora.com
Steps on the way to 5.10-rc1
Resolves conflicts in:
fs/userfaultfd.c
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ie3fe3c818f1f6565cfd4fa551de72d2b72ef60af
tid_addr is not a "pointer to (pointer to int in userspace)"; it is in
fact a "pointer to (pointer to int in userspace) in userspace". So
sparse rightfully complains about passing a kernel pointer to
put_user().
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull SafeSetID updates from Micah Morton:
"The changes are mostly contained to within the SafeSetID LSM, with the
exception of a few 1-line changes to change some ns_capable() calls to
ns_capable_setid() -- causing a flag (CAP_OPT_INSETID) to be set that
is examined by SafeSetID code and nothing else in the kernel.
The changes to SafeSetID internally allow for setting up GID
transition security policies, as already existed for UIDs"
* tag 'safesetid-5.10' of git://github.com/micah-morton/linux:
LSM: SafeSetID: Fix warnings reported by test bot
LSM: SafeSetID: Add GID security policy handling
LSM: Signal to SafeSetID when setting group IDs
For SafeSetID to properly gate set*gid() calls, it needs to know whether
ns_capable() is being called from within a sys_set*gid() function or is
being called from elsewhere in the kernel. This allows SafeSetID to deny
CAP_SETGID to restricted groups when they are attempting to use the
capability for code paths other than updating GIDs (e.g. setting up
userns GID mappings). This is the identical approach to what is
currently done for CAP_SETUID.
NOTE: We also add signaling to SafeSetID from the setgroups() syscall,
as we have future plans to restrict a process' ability to set
supplementary groups in addition to what is added in this series for
restricting setting of the primary group.
Signed-off-by: Thomas Cedeno <thomascedeno@google.com>
Signed-off-by: Micah Morton <mortonm@chromium.org>
