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Merge 5.4.106 into android11-5.4-lts
Changes in 5.4.106
uapi: nfnetlink_cthelper.h: fix userspace compilation error
powerpc/pseries: Don't enforce MSI affinity with kdump
ethernet: alx: fix order of calls on resume
ath9k: fix transmitting to stations in dynamic SMPS mode
net: Fix gro aggregation for udp encaps with zero csum
net: check if protocol extracted by virtio_net_hdr_set_proto is correct
net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0
sh_eth: fix TRSCER mask for SH771x
can: skb: can_skb_set_owner(): fix ref counting if socket was closed before setting skb ownership
can: flexcan: assert FRZ bit in flexcan_chip_freeze()
can: flexcan: enable RX FIFO after FRZ/HALT valid
can: flexcan: invoke flexcan_chip_freeze() to enter freeze mode
can: tcan4x5x: tcan4x5x_init(): fix initialization - clear MRAM before entering Normal Mode
tcp: add sanity tests to TCP_QUEUE_SEQ
netfilter: nf_nat: undo erroneous tcp edemux lookup
netfilter: x_tables: gpf inside xt_find_revision()
selftests/bpf: No need to drop the packet when there is no geneve opt
selftests/bpf: Mask bpf_csum_diff() return value to 16 bits in test_verifier
samples, bpf: Add missing munmap in xdpsock
ibmvnic: always store valid MAC address
mt76: dma: do not report truncated frames to mac80211
powerpc/603: Fix protection of user pages mapped with PROT_NONE
mount: fix mounting of detached mounts onto targets that reside on shared mounts
cifs: return proper error code in statfs(2)
Revert "mm, slub: consider rest of partial list if acquire_slab() fails"
net: enetc: don't overwrite the RSS indirection table when initializing
net/mlx4_en: update moderation when config reset
net: stmmac: fix incorrect DMA channel intr enable setting of EQoS v4.10
nexthop: Do not flush blackhole nexthops when loopback goes down
net: sched: avoid duplicates in classes dump
net: usb: qmi_wwan: allow qmimux add/del with master up
netdevsim: init u64 stats for 32bit hardware
cipso,calipso: resolve a number of problems with the DOI refcounts
net: lapbether: Remove netif_start_queue / netif_stop_queue
net: davicom: Fix regulator not turned off on failed probe
net: davicom: Fix regulator not turned off on driver removal
net: qrtr: fix error return code of qrtr_sendmsg()
ixgbe: fail to create xfrm offload of IPsec tunnel mode SA
net: stmmac: stop each tx channel independently
net: stmmac: fix watchdog timeout during suspend/resume stress test
selftests: forwarding: Fix race condition in mirror installation
perf traceevent: Ensure read cmdlines are null terminated.
net: hns3: fix query vlan mask value error for flow director
net: hns3: fix bug when calculating the TCAM table info
s390/cio: return -EFAULT if copy_to_user() fails again
bnxt_en: reliably allocate IRQ table on reset to avoid crash
drm/compat: Clear bounce structures
drm/shmem-helper: Check for purged buffers in fault handler
drm/shmem-helper: Don't remove the offset in vm_area_struct pgoff
drm: meson_drv add shutdown function
s390/cio: return -EFAULT if copy_to_user() fails
s390/crypto: return -EFAULT if copy_to_user() fails
qxl: Fix uninitialised struct field head.surface_id
sh_eth: fix TRSCER mask for R7S9210
media: usbtv: Fix deadlock on suspend
media: v4l: vsp1: Fix uif null pointer access
media: v4l: vsp1: Fix bru null pointer access
media: rc: compile rc-cec.c into rc-core
net: hns3: fix error mask definition of flow director
net: enetc: initialize RFS/RSS memories for unused ports too
net: phy: fix save wrong speed and duplex problem if autoneg is on
i2c: rcar: faster irq code to minimize HW race condition
i2c: rcar: optimize cacheline to minimize HW race condition
udf: fix silent AED tagLocation corruption
mmc: mxs-mmc: Fix a resource leak in an error handling path in 'mxs_mmc_probe()'
mmc: mediatek: fix race condition between msdc_request_timeout and irq
Platform: OLPC: Fix probe error handling
powerpc/pci: Add ppc_md.discover_phbs()
spi: stm32: make spurious and overrun interrupts visible
powerpc: improve handling of unrecoverable system reset
powerpc/perf: Record counter overflow always if SAMPLE_IP is unset
HID: logitech-dj: add support for the new lightspeed connection iteration
powerpc/64: Fix stack trace not displaying final frame
iommu/amd: Fix performance counter initialization
sparc32: Limit memblock allocation to low memory
sparc64: Use arch_validate_flags() to validate ADI flag
Input: applespi - don't wait for responses to commands indefinitely.
PCI: xgene-msi: Fix race in installing chained irq handler
PCI: mediatek: Add missing of_node_put() to fix reference leak
kbuild: clamp SUBLEVEL to 255
PCI: Fix pci_register_io_range() memory leak
i40e: Fix memory leak in i40e_probe
s390/smp: __smp_rescan_cpus() - move cpumask away from stack
sysctl.c: fix underflow value setting risk in vm_table
scsi: libiscsi: Fix iscsi_prep_scsi_cmd_pdu() error handling
scsi: target: core: Add cmd length set before cmd complete
scsi: target: core: Prevent underflow for service actions
ALSA: usb: Add Plantronics C320-M USB ctrl msg delay quirk
ALSA: hda/hdmi: Cancel pending works before suspend
ALSA: hda/ca0132: Add Sound BlasterX AE-5 Plus support
ALSA: hda: Drop the BATCH workaround for AMD controllers
ALSA: hda: Flush pending unsolicited events before suspend
ALSA: hda: Avoid spurious unsol event handling during S3/S4
ALSA: usb-audio: Fix "cannot get freq eq" errors on Dell AE515 sound bar
ALSA: usb-audio: Apply the control quirk to Plantronics headsets
Revert 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities")
arm64: kasan: fix page_alloc tagging with DEBUG_VIRTUAL
s390/dasd: fix hanging DASD driver unbind
s390/dasd: fix hanging IO request during DASD driver unbind
software node: Fix node registration
mmc: core: Fix partition switch time for eMMC
mmc: cqhci: Fix random crash when remove mmc module/card
Goodix Fingerprint device is not a modem
USB: gadget: u_ether: Fix a configfs return code
usb: gadget: f_uac2: always increase endpoint max_packet_size by one audio slot
usb: gadget: f_uac1: stop playback on function disable
usb: dwc3: qcom: Add missing DWC3 OF node refcount decrement
usb: dwc3: qcom: Honor wakeup enabled/disabled state
USB: usblp: fix a hang in poll() if disconnected
usb: renesas_usbhs: Clear PIPECFG for re-enabling pipe with other EPNUM
usb: xhci: do not perform Soft Retry for some xHCI hosts
xhci: Improve detection of device initiated wake signal.
usb: xhci: Fix ASMedia ASM1042A and ASM3242 DMA addressing
xhci: Fix repeated xhci wake after suspend due to uncleared internal wake state
USB: serial: io_edgeport: fix memory leak in edge_startup
USB: serial: ch341: add new Product ID
USB: serial: cp210x: add ID for Acuity Brands nLight Air Adapter
USB: serial: cp210x: add some more GE USB IDs
usbip: fix stub_dev to check for stream socket
usbip: fix vhci_hcd to check for stream socket
usbip: fix vudc to check for stream socket
usbip: fix stub_dev usbip_sockfd_store() races leading to gpf
usbip: fix vhci_hcd attach_store() races leading to gpf
usbip: fix vudc usbip_sockfd_store races leading to gpf
misc/pvpanic: Export module FDT device table
misc: fastrpc: restrict user apps from sending kernel RPC messages
staging: rtl8192u: fix ->ssid overflow in r8192_wx_set_scan()
staging: rtl8188eu: prevent ->ssid overflow in rtw_wx_set_scan()
staging: rtl8712: unterminated string leads to read overflow
staging: rtl8188eu: fix potential memory corruption in rtw_check_beacon_data()
staging: ks7010: prevent buffer overflow in ks_wlan_set_scan()
staging: rtl8712: Fix possible buffer overflow in r8712_sitesurvey_cmd
staging: rtl8192e: Fix possible buffer overflow in _rtl92e_wx_set_scan
staging: comedi: addi_apci_1032: Fix endian problem for COS sample
staging: comedi: addi_apci_1500: Fix endian problem for command sample
staging: comedi: adv_pci1710: Fix endian problem for AI command data
staging: comedi: das6402: Fix endian problem for AI command data
staging: comedi: das800: Fix endian problem for AI command data
staging: comedi: dmm32at: Fix endian problem for AI command data
staging: comedi: me4000: Fix endian problem for AI command data
staging: comedi: pcl711: Fix endian problem for AI command data
staging: comedi: pcl818: Fix endian problem for AI command data
sh_eth: fix TRSCER mask for R7S72100
arm64/mm: Fix pfn_valid() for ZONE_DEVICE based memory
SUNRPC: Set memalloc_nofs_save() for sync tasks
NFS: Don't revalidate the directory permissions on a lookup failure
NFS: Don't gratuitously clear the inode cache when lookup failed
NFSv4.2: fix return value of _nfs4_get_security_label()
block: rsxx: fix error return code of rsxx_pci_probe()
configfs: fix a use-after-free in __configfs_open_file
arm64: mm: use a 48-bit ID map when possible on 52-bit VA builds
hrtimer: Update softirq_expires_next correctly after __hrtimer_get_next_event()
stop_machine: mark helpers __always_inline
include/linux/sched/mm.h: use rcu_dereference in in_vfork()
zram: fix return value on writeback_store
sched/membarrier: fix missing local execution of ipi_sync_rq_state()
powerpc/64s: Fix instruction encoding for lis in ppc_function_entry()
binfmt_misc: fix possible deadlock in bm_register_write
x86/unwind/orc: Disable KASAN checking in the ORC unwinder, part 2
KVM: arm64: Fix exclusive limit for IPA size
nvme: unlink head after removing last namespace
nvme: release namespace head reference on error
KVM: arm64: Ensure I-cache isolation between vcpus of a same VM
KVM: arm64: Reject VM creation when the default IPA size is unsupported
xen/events: reset affinity of 2-level event when tearing it down
xen/events: don't unmask an event channel when an eoi is pending
xen/events: avoid handling the same event on two cpus at the same time
Linux 5.4.106
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I14a7c69a857d6b64e7cf72003120c99610279bae
commit ee2e3f50629f17b0752b55b2566c15ce8dafb557 upstream.
Creating a series of detached mounts, attaching them to the filesystem,
and unmounting them can be used to trigger an integer overflow in
ns->mounts causing the kernel to block any new mounts in count_mounts()
and returning ENOSPC because it falsely assumes that the maximum number
of mounts in the mount namespace has been reached, i.e. it thinks it
can't fit the new mounts into the mount namespace anymore.
Depending on the number of mounts in your system, this can be reproduced
on any kernel that supportes open_tree() and move_mount() by compiling
and running the following program:
/* SPDX-License-Identifier: LGPL-2.1+ */
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <unistd.h>
/* open_tree() */
#ifndef OPEN_TREE_CLONE
#define OPEN_TREE_CLONE 1
#endif
#ifndef OPEN_TREE_CLOEXEC
#define OPEN_TREE_CLOEXEC O_CLOEXEC
#endif
#ifndef __NR_open_tree
#if defined __alpha__
#define __NR_open_tree 538
#elif defined _MIPS_SIM
#if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */
#define __NR_open_tree 4428
#endif
#if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */
#define __NR_open_tree 6428
#endif
#if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */
#define __NR_open_tree 5428
#endif
#elif defined __ia64__
#define __NR_open_tree (428 + 1024)
#else
#define __NR_open_tree 428
#endif
#endif
/* move_mount() */
#ifndef MOVE_MOUNT_F_EMPTY_PATH
#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
#endif
#ifndef __NR_move_mount
#if defined __alpha__
#define __NR_move_mount 539
#elif defined _MIPS_SIM
#if _MIPS_SIM == _MIPS_SIM_ABI32 /* o32 */
#define __NR_move_mount 4429
#endif
#if _MIPS_SIM == _MIPS_SIM_NABI32 /* n32 */
#define __NR_move_mount 6429
#endif
#if _MIPS_SIM == _MIPS_SIM_ABI64 /* n64 */
#define __NR_move_mount 5429
#endif
#elif defined __ia64__
#define __NR_move_mount (428 + 1024)
#else
#define __NR_move_mount 429
#endif
#endif
static inline int sys_open_tree(int dfd, const char *filename, unsigned int flags)
{
return syscall(__NR_open_tree, dfd, filename, flags);
}
static inline int sys_move_mount(int from_dfd, const char *from_pathname, int to_dfd,
const char *to_pathname, unsigned int flags)
{
return syscall(__NR_move_mount, from_dfd, from_pathname, to_dfd, to_pathname, flags);
}
static bool is_shared_mountpoint(const char *path)
{
bool shared = false;
FILE *f = NULL;
char *line = NULL;
int i;
size_t len = 0;
f = fopen("/proc/self/mountinfo", "re");
if (!f)
return 0;
while (getline(&line, &len, f) > 0) {
char *slider1, *slider2;
for (slider1 = line, i = 0; slider1 && i < 4; i++)
slider1 = strchr(slider1 + 1, ' ');
if (!slider1)
continue;
slider2 = strchr(slider1 + 1, ' ');
if (!slider2)
continue;
*slider2 = '\0';
if (strcmp(slider1 + 1, path) == 0) {
/* This is the path. Is it shared? */
slider1 = strchr(slider2 + 1, ' ');
if (slider1 && strstr(slider1, "shared:")) {
shared = true;
break;
}
}
}
fclose(f);
free(line);
return shared;
}
static void usage(void)
{
const char *text = "mount-new [--recursive] <base-dir>\n";
fprintf(stderr, "%s", text);
_exit(EXIT_SUCCESS);
}
#define exit_usage(format, ...) \
({ \
fprintf(stderr, format "\n", ##__VA_ARGS__); \
usage(); \
})
#define exit_log(format, ...) \
({ \
fprintf(stderr, format "\n", ##__VA_ARGS__); \
exit(EXIT_FAILURE); \
})
static const struct option longopts[] = {
{"help", no_argument, 0, 'a'},
{ NULL, no_argument, 0, 0 },
};
int main(int argc, char *argv[])
{
int exit_code = EXIT_SUCCESS, index = 0;
int dfd, fd_tree, new_argc, ret;
char *base_dir;
char *const *new_argv;
char target[PATH_MAX];
while ((ret = getopt_long_only(argc, argv, "", longopts, &index)) != -1) {
switch (ret) {
case 'a':
/* fallthrough */
default:
usage();
}
}
new_argv = &argv[optind];
new_argc = argc - optind;
if (new_argc < 1)
exit_usage("Missing base directory\n");
base_dir = new_argv[0];
if (*base_dir != '/')
exit_log("Please specify an absolute path");
/* Ensure that target is a shared mountpoint. */
if (!is_shared_mountpoint(base_dir))
exit_log("Please ensure that \"%s\" is a shared mountpoint", base_dir);
dfd = open(base_dir, O_RDONLY | O_DIRECTORY | O_CLOEXEC);
if (dfd < 0)
exit_log("%m - Failed to open base directory \"%s\"", base_dir);
ret = mkdirat(dfd, "detached-move-mount", 0755);
if (ret < 0)
exit_log("%m - Failed to create required temporary directories");
ret = snprintf(target, sizeof(target), "%s/detached-move-mount", base_dir);
if (ret < 0 || (size_t)ret >= sizeof(target))
exit_log("%m - Failed to assemble target path");
/*
* Having a mount table with 10000 mounts is already quite excessive
* and shoult account even for weird test systems.
*/
for (size_t i = 0; i < 10000; i++) {
fd_tree = sys_open_tree(dfd, "detached-move-mount",
OPEN_TREE_CLONE |
OPEN_TREE_CLOEXEC |
AT_EMPTY_PATH);
if (fd_tree < 0) {
fprintf(stderr, "%m - Failed to open %d(detached-move-mount)", dfd);
exit_code = EXIT_FAILURE;
break;
}
ret = sys_move_mount(fd_tree, "", dfd, "detached-move-mount", MOVE_MOUNT_F_EMPTY_PATH);
if (ret < 0) {
if (errno == ENOSPC)
fprintf(stderr, "%m - Buggy mount counting");
else
fprintf(stderr, "%m - Failed to attach mount to %d(detached-move-mount)", dfd);
exit_code = EXIT_FAILURE;
break;
}
close(fd_tree);
ret = umount2(target, MNT_DETACH);
if (ret < 0) {
fprintf(stderr, "%m - Failed to unmount %s", target);
exit_code = EXIT_FAILURE;
break;
}
}
(void)unlinkat(dfd, "detached-move-mount", AT_REMOVEDIR);
close(dfd);
exit(exit_code);
}
and wait for the kernel to refuse any new mounts by returning ENOSPC.
How many iterations are needed depends on the number of mounts in your
system. Assuming you have something like 50 mounts on a standard system
it should be almost instantaneous.
The root cause of this is that detached mounts aren't handled correctly
when source and target mount are identical and reside on a shared mount
causing a broken mount tree where the detached source itself is
propagated which propagation prevents for regular bind-mounts and new
mounts. This ultimately leads to a miscalculation of the number of
mounts in the mount namespace.
Detached mounts created via
open_tree(fd, path, OPEN_TREE_CLONE)
are essentially like an unattached new mount, or an unattached
bind-mount. They can then later on be attached to the filesystem via
move_mount() which calls into attach_recursive_mount(). Part of
attaching it to the filesystem is making sure that mounts get correctly
propagated in case the destination mountpoint is MS_SHARED, i.e. is a
shared mountpoint. This is done by calling into propagate_mnt() which
walks the list of peers calling propagate_one() on each mount in this
list making sure it receives the propagation event.
The propagate_one() functions thereby skips both new mounts and bind
mounts to not propagate them "into themselves". Both are identified by
checking whether the mount is already attached to any mount namespace in
mnt->mnt_ns. The is what the IS_MNT_NEW() helper is responsible for.
However, detached mounts have an anonymous mount namespace attached to
them stashed in mnt->mnt_ns which means that IS_MNT_NEW() doesn't
realize they need to be skipped causing the mount to propagate "into
itself" breaking the mount table and causing a disconnect between the
number of mounts recorded as being beneath or reachable from the target
mountpoint and the number of mounts actually recorded/counted in
ns->mounts ultimately causing an overflow which in turn prevents any new
mounts via the ENOSPC issue.
So teach propagation to handle detached mounts by making it aware of
them. I've been tracking this issue down for the last couple of days and
then verifying that the fix is correct by
unmounting everything in my current mount table leaving only /proc and
/sys mounted and running the reproducer above overnight verifying the
number of mounts counted in ns->mounts. With this fix the counts are
correct and the ENOSPC issue can't be reproduced.
This change will only have an effect on mounts created with the new
mount API since detached mounts cannot be created with the old mount API
so regressions are extremely unlikely.
Link: https://lore.kernel.org/r/20210306101010.243666-1-christian.brauner@ubuntu.com
Fixes: 2db154b3ea ("vfs: syscall: Add move_mount(2) to move mounts around")
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: <stable@vger.kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge 5.4.87 into android11-5.4-lts
Changes in 5.4.87
net/sched: sch_taprio: reset child qdiscs before freeing them
md/raid10: initialize r10_bio->read_slot before use.
thermal/drivers/cpufreq_cooling: Update cpufreq_state only if state has changed
ext4: prevent creating duplicate encrypted filenames
ubifs: prevent creating duplicate encrypted filenames
f2fs: prevent creating duplicate encrypted filenames
fscrypt: add fscrypt_is_nokey_name()
fscrypt: remove kernel-internal constants from UAPI header
vfio/pci: Move dummy_resources_list init in vfio_pci_probe()
btrfs: fix race when defragmenting leads to unnecessary IO
ext4: don't remount read-only with errors=continue on reboot
KVM: x86: avoid incorrect writes to host MSR_IA32_SPEC_CTRL
KVM: SVM: relax conditions for allowing MSR_IA32_SPEC_CTRL accesses
KVM: x86: reinstate vendor-agnostic check on SPEC_CTRL cpuid bits
powerpc/bitops: Fix possible undefined behaviour with fls() and fls64()
jffs2: Allow setting rp_size to zero during remounting
jffs2: Fix NULL pointer dereference in rp_size fs option parsing
scsi: block: Fix a race in the runtime power management code
uapi: move constants from <linux/kernel.h> to <linux/const.h>
tools headers UAPI: Sync linux/const.h with the kernel headers
null_blk: Fix zone size initialization
of: fix linker-section match-table corruption
cgroup: Fix memory leak when parsing multiple source parameters
scsi: cxgb4i: Fix TLS dependency
Bluetooth: hci_h5: close serdev device and free hu in h5_close
reiserfs: add check for an invalid ih_entry_count
misc: vmw_vmci: fix kernel info-leak by initializing dbells in vmci_ctx_get_chkpt_doorbells()
media: gp8psk: initialize stats at power control logic
f2fs: fix shift-out-of-bounds in sanity_check_raw_super()
ALSA: seq: Use bool for snd_seq_queue internal flags
ALSA: rawmidi: Access runtime->avail always in spinlock
bfs: don't use WARNING: string when it's just info.
fcntl: Fix potential deadlock in send_sig{io, urg}()
rtc: sun6i: Fix memleak in sun6i_rtc_clk_init
module: set MODULE_STATE_GOING state when a module fails to load
quota: Don't overflow quota file offsets
rtc: pl031: fix resource leak in pl031_probe
powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe()
i3c master: fix missing destroy_workqueue() on error in i3c_master_register
NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode
f2fs: avoid race condition for shrinker count
module: delay kobject uevent until after module init call
fs/namespace.c: WARN if mnt_count has become negative
um: ubd: Submit all data segments atomically
tick/sched: Remove bogus boot "safety" check
ALSA: pcm: Clear the full allocated memory at hw_params
dm verity: skip verity work if I/O error when system is shutting down
Linux 5.4.87
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
[EB: fixed fs/crypto/ merge resolution]
Signed-off-by: Eric Biggers <ebiggers@google.com>
Change-Id: I383fa03a6d3c025d167ab57faebf0d3a59919a00
[ Upstream commit edf7ddbf1c5eb98b720b063b73e20e8a4a1ce673 ]
Missing calls to mntget() (or equivalently, too many calls to mntput())
are hard to detect because mntput() delays freeing mounts using
task_work_add(), then again using call_rcu(). As a result, mnt_count
can often be decremented to -1 without getting a KASAN use-after-free
report. Such cases are still bugs though, and they point to real
use-after-frees being possible.
For an example of this, see the bug fixed by commit 1b0b9cc8d3
("vfs: fsmount: add missing mntget()"), discussed at
https://lkml.kernel.org/linux-fsdevel/20190605135401.GB30925@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#u.
This bug *should* have been trivial to find. But actually, it wasn't
found until syzkaller happened to use fchdir() to manipulate the
reference count just right for the bug to be noticeable.
Address this by making mntput_no_expire() issue a WARN if mnt_count has
become negative.
Suggested-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This starts to add private data associated directly
to mount points. The intent is to give filesystems
a sense of where they have come from, as a means of
letting a filesystem take different actions based on
this information.
Bug: 62094374
Bug: 120446149
Bug: 122428178
Change-Id: Ie769d7b3bb2f5972afe05c1bf16cf88c91647ab2
Signed-off-by: Daniel Rosenberg <drosen@google.com>
[astrachan: Folded 89a54ed3bf68 ("ANDROID: mnt: Fix next_descendent")
into this patch]
[drosen: Folded 138993ea820 ("Android: mnt: Propagate remount
correctly") into this patch, integrated fs_context things
Now has update_mnt_data instead of needing remount2
Signed-off-by: Alistair Strachan <astrachan@google.com>
Based on 1 normalized pattern(s):
released under gpl v2
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 15 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528171438.895196075@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ever since mount propagation was introduced in cases where a mount in
propagated to parent mount mountpoint pair that is already in use the
code has placed the new mount behind the old mount in the mount hash
table.
This implementation detail is problematic as it allows creating
arbitrary length mount hash chains.
Furthermore it invalidates the constraint maintained elsewhere in the
mount code that a parent mount and a mountpoint pair will have exactly
one mount upon them. Making it hard to deal with and to talk about
this special case in the mount code.
Modify mount propagation to notice when there is already a mount at
the parent mount and mountpoint where a new mount is propagating to
and place that preexisting mount on top of the new mount.
Modify unmount propagation to notice when a mount that is being
unmounted has another mount on top of it (and no other children), and
to replace the unmounted mount with the mount on top of it.
Move the MNT_UMUONT test from __lookup_mnt_last into
__propagate_umount as that is the only call of __lookup_mnt_last where
MNT_UMOUNT may be set on any mount visible in the mount hash table.
These modifications allow:
- __lookup_mnt_last to be removed.
- attach_shadows to be renamed __attach_mnt and its shadow
handling to be removed.
- commit_tree to be simplified
- copy_tree to be simplified
The result is an easier to understand tree of mounts that does not
allow creation of arbitrary length hash chains in the mount hash table.
The result is also a very slight userspace visible difference in semantics.
The following two cases now behave identically, where before order
mattered:
case 1: (explicit user action)
B is a slave of A
mount something on A/a , it will propagate to B/a
and than mount something on B/a
case 2: (tucked mount)
B is a slave of A
mount something on B/a
and than mount something on A/a
Histroically umount A/a would fail in case 1 and succeed in case 2.
Now umount A/a succeeds in both configurations.
This very small change in semantics appears if anything to be a bug
fix to me and my survey of userspace leads me to believe that no programs
will notice or care of this subtle semantic change.
v2: Updated to mnt_change_mountpoint to not call dput or mntput
and instead to decrement the counts directly. It is guaranteed
that there will be other references when mnt_change_mountpoint is
called so this is safe.
v3: Moved put_mountpoint under mount_lock in attach_recursive_mnt
As the locking in fs/namespace.c changed between v2 and v3.
v4: Reworked the logic in propagate_mount_busy and __propagate_umount
that detects when a mount completely covers another mount.
v5: Removed unnecessary tests whose result is alwasy true in
find_topper and attach_recursive_mnt.
v6: Document the user space visible semantic difference.
Cc: stable@vger.kernel.org
Fixes: b90fa9ae8f ("[PATCH] shared mount handling: bind and rbind")
Tested-by: Andrei Vagin <avagin@virtuozzo.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
CAI Qian <caiqian@redhat.com> pointed out that the semantics
of shared subtrees make it possible to create an exponentially
increasing number of mounts in a mount namespace.
mkdir /tmp/1 /tmp/2
mount --make-rshared /
for i in $(seq 1 20) ; do mount --bind /tmp/1 /tmp/2 ; done
Will create create 2^20 or 1048576 mounts, which is a practical problem
as some people have managed to hit this by accident.
As such CVE-2016-6213 was assigned.
Ian Kent <raven@themaw.net> described the situation for autofs users
as follows:
> The number of mounts for direct mount maps is usually not very large because of
> the way they are implemented, large direct mount maps can have performance
> problems. There can be anywhere from a few (likely case a few hundred) to less
> than 10000, plus mounts that have been triggered and not yet expired.
>
> Indirect mounts have one autofs mount at the root plus the number of mounts that
> have been triggered and not yet expired.
>
> The number of autofs indirect map entries can range from a few to the common
> case of several thousand and in rare cases up to between 30000 and 50000. I've
> not heard of people with maps larger than 50000 entries.
>
> The larger the number of map entries the greater the possibility for a large
> number of active mounts so it's not hard to expect cases of a 1000 or somewhat
> more active mounts.
So I am setting the default number of mounts allowed per mount
namespace at 100,000. This is more than enough for any use case I
know of, but small enough to quickly stop an exponential increase
in mounts. Which should be perfect to catch misconfigurations and
malfunctioning programs.
For anyone who needs a higher limit this can be changed by writing
to the new /proc/sys/fs/mount-max sysctl.
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
rmdir mntpoint will result in an infinite loop when there is
a mount locked on the mountpoint in another mount namespace.
This is because the logic to test to see if a mount should
be disconnected in umount_tree is buggy.
Move the logic to decide if a mount should remain connected to
it's mountpoint into it's own function disconnect_mount so that
clarity of expression instead of terseness of expression becomes
a virtue.
When the conditions where it is invalid to leave a mount connected
are first ruled out, the logic for deciding if a mount should
be disconnected becomes much clearer and simpler.
Fixes: e0c9c0afd2 mnt: Update detach_mounts to leave mounts connected
Fixes: ce07d891a0 mnt: Honor MNT_LOCKED when detaching mounts
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Modify umount(MNT_DETACH) to keep mounts in the hash table that are
locked to their parent mounts, when the parent is lazily unmounted.
In mntput_no_expire detach the children from the hash table, depending
on mnt_pin_kill in cleanup_mnt to decrement the mnt_count of the children.
In __detach_mounts if there are any mounts that have been unmounted
but still are on the list of mounts of a mountpoint, remove their
children from the mount hash table and those children to the unmounted
list so they won't linger potentially indefinitely waiting for their
final mntput, now that the mounts serve no purpose.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
If the first mount in shared subtree is locked don't unmount the
shared subtree.
This is ensured by walking through the mounts parents before children
and marking a mount as unmountable if it is not locked or it is locked
but it's parent is marked.
This allows recursive mount detach to propagate through a set of
mounts when unmounting them would not reveal what is under any locked
mount.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
A prerequisite of calling umount_tree is that the point where the tree
is mounted at is valid to unmount.
If we are propagating the effect of the unmount clear MNT_LOCKED in
every instance where the same filesystem is mounted on the same
mountpoint in the mount tree, as we know (by virtue of the fact
that umount_tree was called) that it is safe to reveal what
is at that mountpoint.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
umount_tree builds a list of mounts that need to be unmounted.
Utilize mnt_list for this purpose instead of mnt_hash. This begins to
allow keeping a mount on the mnt_hash after it is unmounted, which is
necessary for a properly functioning MNT_LOCKED implementation.
The fact that mnt_list is an ordinary list makding available list_move
is nice bonus.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
- Remove the unneeded declaration from pnode.h
- Mark umount_tree static as it has no callers outside of namespace.c
- Define an enumeration of umount_tree's flags.
- Pass umount_tree's flags in by name
This removes the magic numbers 0, 1 and 2 making the code a little
clearer and makes it possible for there to be lazy unmounts that don't
propagate. Which is what __detach_mounts actually wants for example.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The current mainline has copies propagated to *all* nodes, then
tears down the copies we made for nodes that do not contain
counterparts of the desired mountpoint. That sets the right
propagation graph for the copies (at teardown time we move
the slaves of removed node to a surviving peer or directly
to master), but we end up paying a fairly steep price in
useless allocations. It's fairly easy to create a situation
where N calls of mount(2) create exactly N bindings, with
O(N^2) vfsmounts allocated and freed in process.
Fortunately, it is possible to avoid those allocations/freeings.
The trick is to create copies in the right order and find which
one would've eventually become a master with the current algorithm.
It turns out to be possible in O(nodes getting propagation) time
and with no extra allocations at all.
One part is that we need to make sure that eventual master will be
created before its slaves, so we need to walk the propagation
tree in a different order - by peer groups. And iterate through
the peers before dealing with the next group.
Another thing is finding the (earlier) copy that will be a master
of one we are about to create; to do that we are (temporary) marking
the masters of mountpoints we are attaching the copies to.
Either we are in a peer of the last mountpoint we'd dealt with,
or we have the following situation: we are attaching to mountpoint M,
the last copy S_0 had been attached to M_0 and there are sequences
S_0...S_n, M_0...M_n such that S_{i+1} is a master of S_{i},
S_{i} mounted on M{i} and we need to create a slave of the first S_{k}
such that M is getting propagation from M_{k}. It means that the master
of M_{k} will be among the sequence of masters of M. On the
other hand, the nearest marked node in that sequence will either
be the master of M_{k} or the master of M_{k-1} (the latter -
in the case if M_{k-1} is a slave of something M gets propagation
from, but in a wrong peer group).
So we go through the sequence of masters of M until we find
a marked one (P). Let N be the one before it. Then we go through
the sequence of masters of S_0 until we find one (say, S) mounted
on a node D that has P as master and check if D is a peer of N.
If it is, S will be the master of new copy, if not - the master of S
will be.
That's it for the hard part; the rest is fairly simple. Iterator
is in next_group(), handling of one prospective mountpoint is
propagate_one().
It seems to survive all tests and gives a noticably better performance
than the current mainline for setups that are seriously using shared
subtrees.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fixes RCU bug - walking through hlist is safe in face of element moves,
since it's self-terminating. Cyclic lists are not - if we end up jumping
to another hash chain, we'll loop infinitely without ever hitting the
original list head.
[fix for dumb braino folded]
Spotted by: Max Kellermann <mk@cm4all.com>
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Don't copy bind mounts of /proc/<pid>/ns/mnt between namespaces.
These files hold references to a mount namespace and copying them
between namespaces could result in a reference counting loop.
The current mnt_ns_loop test prevents loops on the assumption that
mounts don't cross between namespaces. Unfortunately unsharing a
mount namespace and shared substrees can both cause mounts to
propogate between mount namespaces.
Add two flags CL_COPY_UNBINDABLE and CL_COPY_MNT_NS_FILE are added to
control this behavior, and CL_COPY_ALL is redefined as both of them.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
As a matter of policy MNT_READONLY should not be changable if the
original mounter had more privileges than creator of the mount
namespace.
Add the flag CL_UNPRIVILEGED to note when we are copying a mount from
a mount namespace that requires more privileges to a mount namespace
that requires fewer privileges.
When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT
if any of the mnt flags that should never be changed are set.
This protects both mount propagation and the initial creation of a less
privileged mount namespace.
Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Sharing mount subtress with mount namespaces created by unprivileged
users allows unprivileged mounts created by unprivileged users to
propagate to mount namespaces controlled by privileged users.
Prevent nasty consequences by changing shared subtrees to slave
subtress when an unprivileged users creates a new mount namespace.
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
a) mount --move is checking that ->mnt_parent is non-NULL before
looking if that parent happens to be shared; ->mnt_parent is never
NULL and it's not even an misspelled !mnt_has_parent()
b) pivot_root open-codes is_path_reachable(), poorly.
c) so does path_is_under(), while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
vfsmounts have ->mnt_parent pointing either to a different vfsmount
or to itself; it's never NULL and termination condition in loops
traversing the tree towards root is mnt == mnt->mnt_parent. At least
one place (see the next patch) is confused about what's going on;
let's add an explicit helper checking it right way and use it in
all places where we need it. Not that there had been too many,
but...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
some stuff in there can actually become static; some belongs to pnode.h
as it's a private interface between namespace.c and pnode.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The handling of mount flags in set_mnt_shared() got a little tangled
up during previous cleanups, with the following problems:
* MNT_PNODE_MASK is defined as a literal constant when it should be a
bitwise xor of other MNT_* flags
* set_mnt_shared() clears and then sets MNT_SHARED (part of MNT_PNODE_MASK)
* MNT_PNODE_MASK could use a comment in mount.h
* MNT_PNODE_MASK is a terrible name, change to MNT_SHARED_MASK
This patch fixes these problems.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
First of all, get_source() never results in CL_PROPAGATION
alone. We either get CL_MAKE_SHARED (for the continuation
of peer group) or CL_SLAVE (slave that is not shared) or both
(beginning of peer group among slaves). Massage the code to
make that explicit, kill CL_PROPAGATION test in clone_mnt()
(nothing sets CL_MAKE_SHARED without CL_PROPAGATION and in
clone_mnt() we are checking CL_PROPAGATION after we'd found
that there's no CL_SLAVE, so the check for CL_MAKE_SHARED
would do just as well).
Fix comments, while we are at it...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Show peer group ID of nearest dominating group that has intersection
with the mount's namespace.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Get a snapshot of a subtree, creating private clones of vfsmounts
for all its components and release such snapshot resp.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Rename 'struct namespace' to 'struct mnt_namespace' to avoid confusion with
other namespaces being developped for the containers : pid, uts, ipc, etc.
'namespace' variables and attributes are also renamed to 'mnt_ns'
Signed-off-by: Kirill Korotaev <dev@sw.ru>
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
An unbindable mount does not forward or receive propagation. Also
unbindable mount disallows bind mounts. The semantics is as follows.
Bind semantics:
It is invalid to bind mount an unbindable mount.
Move semantics:
It is invalid to move an unbindable mount under shared mount.
Clone-namespace semantics:
If a mount is unbindable in the parent namespace, the corresponding
cloned mount in the child namespace becomes unbindable too. Note:
there is subtle difference, unbindable mounts cannot be bind mounted
but can be cloned during clone-namespace.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A slave mount always has a master mount from which it receives
mount/umount events. Unlike shared mount the event propagation does not
flow from the slave mount to the master.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
An unmount of a mount creates a umount event on the parent. If the
parent is a shared mount, it gets propagated to all mounts in the peer
group.
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement handling of MS_BIND in presense of shared mounts (see
Documentation/sharedsubtree.txt in the end of patch series for detailed
description).
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
