| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
drm/ttm: Don't leak a resource on swapout move error
If moving the bo to system for swapout failed, we were leaking
a resource. Fix. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: Add preempt_count_{sub,add} into btf id deny list
The recursion check in __bpf_prog_enter* and __bpf_prog_exit*
leave preempt_count_{sub,add} unprotected. When attaching trampoline to
them we get panic as follows,
[ 867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28)
[ 867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI
[ 867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4
[ 867.843100] Call Trace:
[ 867.843101] <TASK>
[ 867.843104] asm_exc_int3+0x3a/0x40
[ 867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0
[ 867.843135] __bpf_prog_enter_recur+0x17/0x90
[ 867.843148] bpf_trampoline_6442468108_0+0x2e/0x1000
[ 867.843154] ? preempt_count_sub+0x1/0xa0
[ 867.843157] preempt_count_sub+0x5/0xa0
[ 867.843159] ? migrate_enable+0xac/0xf0
[ 867.843164] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843168] bpf_trampoline_6442468108_0+0x55/0x1000
...
[ 867.843788] preempt_count_sub+0x5/0xa0
[ 867.843793] ? migrate_enable+0xac/0xf0
[ 867.843829] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35)
[ 867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c)
[ 867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec)
[ 867.843842] bpf_trampoline_6442468108_0+0x55/0x1000
...
That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are
called after prog->active is decreased.
Fixing this by adding these two functions into btf ids deny list. |
| In the Linux kernel, the following vulnerability has been resolved:
ubi: Fix possible null-ptr-deref in ubi_free_volume()
It willl cause null-ptr-deref in the following case:
uif_init()
ubi_add_volume()
cdev_add() -> if it fails, call kill_volumes()
device_register()
kill_volumes() -> if ubi_add_volume() fails call this function
ubi_free_volume()
cdev_del()
device_unregister() -> trying to delete a not added device,
it causes null-ptr-deref
So in ubi_free_volume(), it delete devices whether they are added
or not, it will causes null-ptr-deref.
Handle the error case whlie calling ubi_add_volume() to fix this
problem. If add volume fails, set the corresponding vol to null,
so it can not be accessed in kill_volumes() and release the
resource in ubi_add_volume() error path. |
| In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: Fix slab-out-of-bounds in r_page
When PAGE_SIZE is 64K, if read_log_page is called by log_read_rst for
the first time, the size of *buffer would be equal to
DefaultLogPageSize(4K).But for *buffer operations like memcpy,
if the memory area size(n) which being assigned to buffer is larger
than 4K (log->page_size(64K) or bytes(64K-page_off)), it will cause
an out of boundary error.
Call trace:
[...]
kasan_report+0x44/0x130
check_memory_region+0xf8/0x1a0
memcpy+0xc8/0x100
ntfs_read_run_nb+0x20c/0x460
read_log_page+0xd0/0x1f4
log_read_rst+0x110/0x75c
log_replay+0x1e8/0x4aa0
ntfs_loadlog_and_replay+0x290/0x2d0
ntfs_fill_super+0x508/0xec0
get_tree_bdev+0x1fc/0x34c
[...]
Fix this by setting variable r_page to NULL in log_read_rst. |
| In the Linux kernel, the following vulnerability has been resolved:
devlink: report devlink_port_type_warn source device
devlink_port_type_warn is scheduled for port devlink and warning
when the port type is not set. But from this warning it is not easy
found out which device (driver) has no devlink port set.
[ 3709.975552] Type was not set for devlink port.
[ 3709.975579] WARNING: CPU: 1 PID: 13092 at net/devlink/leftover.c:6775 devlink_port_type_warn+0x11/0x20
[ 3709.993967] Modules linked in: openvswitch nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nfnetlink bluetooth rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs vhost_net vhost vhost_iotlb tap tun bridge stp llc qrtr intel_rapl_msr intel_rapl_common i10nm_edac nfit libnvdimm x86_pkg_temp_thermal mlx5_ib intel_powerclamp coretemp dell_wmi ledtrig_audio sparse_keymap ipmi_ssif kvm_intel ib_uverbs rfkill ib_core video kvm iTCO_wdt acpi_ipmi intel_vsec irqbypass ipmi_si iTCO_vendor_support dcdbas ipmi_devintf mei_me ipmi_msghandler rapl mei intel_cstate isst_if_mmio isst_if_mbox_pci dell_smbios intel_uncore isst_if_common i2c_i801 dell_wmi_descriptor wmi_bmof i2c_smbus intel_pch_thermal pcspkr acpi_power_meter xfs libcrc32c sd_mod sg nvme_tcp mgag200 i2c_algo_bit nvme_fabrics drm_shmem_helper drm_kms_helper nvme syscopyarea ahci sysfillrect sysimgblt nvme_core fb_sys_fops crct10dif_pclmul libahci mlx5_core sfc crc32_pclmul nvme_common drm
[ 3709.994030] crc32c_intel mtd t10_pi mlxfw libata tg3 mdio megaraid_sas psample ghash_clmulni_intel pci_hyperv_intf wmi dm_multipath sunrpc dm_mirror dm_region_hash dm_log dm_mod be2iscsi bnx2i cnic uio cxgb4i cxgb4 tls libcxgbi libcxgb qla4xxx iscsi_boot_sysfs iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi fuse
[ 3710.108431] CPU: 1 PID: 13092 Comm: kworker/1:1 Kdump: loaded Not tainted 5.14.0-319.el9.x86_64 #1
[ 3710.108435] Hardware name: Dell Inc. PowerEdge R750/0PJ80M, BIOS 1.8.2 09/14/2022
[ 3710.108437] Workqueue: events devlink_port_type_warn
[ 3710.108440] RIP: 0010:devlink_port_type_warn+0x11/0x20
[ 3710.108443] Code: 84 76 fe ff ff 48 c7 03 20 0e 1a ad 31 c0 e9 96 fd ff ff 66 0f 1f 44 00 00 0f 1f 44 00 00 48 c7 c7 18 24 4e ad e8 ef 71 62 ff <0f> 0b c3 cc cc cc cc 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f6 87
[ 3710.108445] RSP: 0018:ff3b6d2e8b3c7e90 EFLAGS: 00010282
[ 3710.108447] RAX: 0000000000000000 RBX: ff366d6580127080 RCX: 0000000000000027
[ 3710.108448] RDX: 0000000000000027 RSI: 00000000ffff86de RDI: ff366d753f41f8c8
[ 3710.108449] RBP: ff366d658ff5a0c0 R08: ff366d753f41f8c0 R09: ff3b6d2e8b3c7e18
[ 3710.108450] R10: 0000000000000001 R11: 0000000000000023 R12: ff366d753f430600
[ 3710.108451] R13: ff366d753f436900 R14: 0000000000000000 R15: ff366d753f436905
[ 3710.108452] FS: 0000000000000000(0000) GS:ff366d753f400000(0000) knlGS:0000000000000000
[ 3710.108453] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3710.108454] CR2: 00007f1c57bc74e0 CR3: 000000111d26a001 CR4: 0000000000773ee0
[ 3710.108456] PKRU: 55555554
[ 3710.108457] Call Trace:
[ 3710.108458] <TASK>
[ 3710.108459] process_one_work+0x1e2/0x3b0
[ 3710.108466] ? rescuer_thread+0x390/0x390
[ 3710.108468] worker_thread+0x50/0x3a0
[ 3710.108471] ? rescuer_thread+0x390/0x390
[ 3710.108473] kthread+0xdd/0x100
[ 3710.108477] ? kthread_complete_and_exit+0x20/0x20
[ 3710.108479] ret_from_fork+0x1f/0x30
[ 3710.108485] </TASK>
[ 3710.108486] ---[ end trace 1b4b23cd0c65d6a0 ]---
After patch:
[ 402.473064] ice 0000:41:00.0: Type was not set for devlink port.
[ 402.473064] ice 0000:41:00.1: Type was not set for devlink port. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/msm: fix NULL-deref on snapshot tear down
In case of early initialisation errors and on platforms that do not use
the DPU controller, the deinitilisation code can be called with the kms
pointer set to NULL.
Patchwork: https://patchwork.freedesktop.org/patch/525099/ |
| In the Linux kernel, the following vulnerability has been resolved:
iio: adc: ina2xx: avoid NULL pointer dereference on OF device match
The affected lines were resulting in a NULL pointer dereference on our
platform because the device tree contained the following list of
compatible strings:
power-sensor@40 {
compatible = "ti,ina232", "ti,ina231";
...
};
Since the driver doesn't declare a compatible string "ti,ina232", the OF
matching succeeds on "ti,ina231". But the I2C device ID info is
populated via the first compatible string, cf. modalias population in
of_i2c_get_board_info(). Since there is no "ina232" entry in the legacy
I2C device ID table either, the struct i2c_device_id *id pointer in the
probe function is NULL.
Fix this by using the already populated type variable instead, which
points to the proper driver data. Since the name is also wanted, add a
generic one to the ina2xx_config table. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: ath11k: Fix qmi_msg_handler data structure initialization
qmi_msg_handler is required to be null terminated by QMI module.
There might be a case where a handler for a msg id is not present in the
handlers array which can lead to infinite loop while searching the handler
and therefore out of bound access in qmi_invoke_handler().
Hence update the initialization in qmi_msg_handler data structure.
Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-01100-QCAHKSWPL_SILICONZ-1 |
| In the Linux kernel, the following vulnerability has been resolved:
ARM: OMAP2+: Fix memory leak in realtime_counter_init()
The "sys_clk" resource is malloced by clk_get(),
it is not released when the function return. |
| In the Linux kernel, the following vulnerability has been resolved:
virtio_pmem: add the missing REQ_OP_WRITE for flush bio
When doing mkfs.xfs on a pmem device, the following warning was
------------[ cut here ]------------
WARNING: CPU: 2 PID: 384 at block/blk-core.c:751 submit_bio_noacct
Modules linked in:
CPU: 2 PID: 384 Comm: mkfs.xfs Not tainted 6.4.0-rc7+ #154
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:submit_bio_noacct+0x340/0x520
......
Call Trace:
<TASK>
? submit_bio_noacct+0xd5/0x520
submit_bio+0x37/0x60
async_pmem_flush+0x79/0xa0
nvdimm_flush+0x17/0x40
pmem_submit_bio+0x370/0x390
__submit_bio+0xbc/0x190
submit_bio_noacct_nocheck+0x14d/0x370
submit_bio_noacct+0x1ef/0x520
submit_bio+0x55/0x60
submit_bio_wait+0x5a/0xc0
blkdev_issue_flush+0x44/0x60
The root cause is that submit_bio_noacct() needs bio_op() is either
WRITE or ZONE_APPEND for flush bio and async_pmem_flush() doesn't assign
REQ_OP_WRITE when allocating flush bio, so submit_bio_noacct just fail
the flush bio.
Simply fix it by adding the missing REQ_OP_WRITE for flush bio. And we
could fix the flush order issue and do flush optimization later. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/client: Fix memory leak in drm_client_target_cloned
dmt_mode is allocated and never freed in this function.
It was found with the ast driver, but most drivers using generic fbdev
setup are probably affected.
This fixes the following kmemleak report:
backtrace:
[<00000000b391296d>] drm_mode_duplicate+0x45/0x220 [drm]
[<00000000e45bb5b3>] drm_client_target_cloned.constprop.0+0x27b/0x480 [drm]
[<00000000ed2d3a37>] drm_client_modeset_probe+0x6bd/0xf50 [drm]
[<0000000010e5cc9d>] __drm_fb_helper_initial_config_and_unlock+0xb4/0x2c0 [drm_kms_helper]
[<00000000909f82ca>] drm_fbdev_client_hotplug+0x2bc/0x4d0 [drm_kms_helper]
[<00000000063a69aa>] drm_client_register+0x169/0x240 [drm]
[<00000000a8c61525>] ast_pci_probe+0x142/0x190 [ast]
[<00000000987f19bb>] local_pci_probe+0xdc/0x180
[<000000004fca231b>] work_for_cpu_fn+0x4e/0xa0
[<0000000000b85301>] process_one_work+0x8b7/0x1540
[<000000003375b17c>] worker_thread+0x70a/0xed0
[<00000000b0d43cd9>] kthread+0x29f/0x340
[<000000008d770833>] ret_from_fork+0x1f/0x30
unreferenced object 0xff11000333089a00 (size 128): |
| In the Linux kernel, the following vulnerability has been resolved:
net: prevent skb corruption on frag list segmentation
Ian reported several skb corruptions triggered by rx-gro-list,
collecting different oops alike:
[ 62.624003] BUG: kernel NULL pointer dereference, address: 00000000000000c0
[ 62.631083] #PF: supervisor read access in kernel mode
[ 62.636312] #PF: error_code(0x0000) - not-present page
[ 62.641541] PGD 0 P4D 0
[ 62.644174] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 62.648629] CPU: 1 PID: 913 Comm: napi/eno2-79 Not tainted 6.4.0 #364
[ 62.655162] Hardware name: Supermicro Super Server/A2SDi-12C-HLN4F, BIOS 1.7a 10/13/2022
[ 62.663344] RIP: 0010:__udp_gso_segment (./include/linux/skbuff.h:2858
./include/linux/udp.h:23 net/ipv4/udp_offload.c:228 net/ipv4/udp_offload.c:261
net/ipv4/udp_offload.c:277)
[ 62.687193] RSP: 0018:ffffbd3a83b4f868 EFLAGS: 00010246
[ 62.692515] RAX: 00000000000000ce RBX: 0000000000000000 RCX: 0000000000000000
[ 62.699743] RDX: ffffa124def8a000 RSI: 0000000000000079 RDI: ffffa125952a14d4
[ 62.706970] RBP: ffffa124def8a000 R08: 0000000000000022 R09: 00002000001558c9
[ 62.714199] R10: 0000000000000000 R11: 00000000be554639 R12: 00000000000000e2
[ 62.721426] R13: ffffa125952a1400 R14: ffffa125952a1400 R15: 00002000001558c9
[ 62.728654] FS: 0000000000000000(0000) GS:ffffa127efa40000(0000)
knlGS:0000000000000000
[ 62.736852] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 62.742702] CR2: 00000000000000c0 CR3: 00000001034b0000 CR4: 00000000003526e0
[ 62.749948] Call Trace:
[ 62.752498] <TASK>
[ 62.779267] inet_gso_segment (net/ipv4/af_inet.c:1398)
[ 62.787605] skb_mac_gso_segment (net/core/gro.c:141)
[ 62.791906] __skb_gso_segment (net/core/dev.c:3403 (discriminator 2))
[ 62.800492] validate_xmit_skb (./include/linux/netdevice.h:4862
net/core/dev.c:3659)
[ 62.804695] validate_xmit_skb_list (net/core/dev.c:3710)
[ 62.809158] sch_direct_xmit (net/sched/sch_generic.c:330)
[ 62.813198] __dev_queue_xmit (net/core/dev.c:3805 net/core/dev.c:4210)
net/netfilter/core.c:626)
[ 62.821093] br_dev_queue_push_xmit (net/bridge/br_forward.c:55)
[ 62.825652] maybe_deliver (net/bridge/br_forward.c:193)
[ 62.829420] br_flood (net/bridge/br_forward.c:233)
[ 62.832758] br_handle_frame_finish (net/bridge/br_input.c:215)
[ 62.837403] br_handle_frame (net/bridge/br_input.c:298
net/bridge/br_input.c:416)
[ 62.851417] __netif_receive_skb_core.constprop.0 (net/core/dev.c:5387)
[ 62.866114] __netif_receive_skb_list_core (net/core/dev.c:5570)
[ 62.871367] netif_receive_skb_list_internal (net/core/dev.c:5638
net/core/dev.c:5727)
[ 62.876795] napi_complete_done (./include/linux/list.h:37
./include/net/gro.h:434 ./include/net/gro.h:429 net/core/dev.c:6067)
[ 62.881004] ixgbe_poll (drivers/net/ethernet/intel/ixgbe/ixgbe_main.c:3191)
[ 62.893534] __napi_poll (net/core/dev.c:6498)
[ 62.897133] napi_threaded_poll (./include/linux/netpoll.h:89
net/core/dev.c:6640)
[ 62.905276] kthread (kernel/kthread.c:379)
[ 62.913435] ret_from_fork (arch/x86/entry/entry_64.S:314)
[ 62.917119] </TASK>
In the critical scenario, rx-gro-list GRO-ed packets are fed, via a
bridge, both to the local input path and to an egress device (tun).
The segmentation of such packets unsafely writes to the cloned skbs
with shared heads.
This change addresses the issue by uncloning as needed the
to-be-segmented skbs. |
| In the Linux kernel, the following vulnerability has been resolved:
can: j1939: j1939_tp_tx_dat_new(): fix out-of-bounds memory access
In the j1939_tp_tx_dat_new() function, an out-of-bounds memory access
could occur during the memcpy() operation if the size of skb->cb is
larger than the size of struct j1939_sk_buff_cb. This is because the
memcpy() operation uses the size of skb->cb, leading to a read beyond
the struct j1939_sk_buff_cb.
Updated the memcpy() operation to use the size of struct
j1939_sk_buff_cb instead of the size of skb->cb. This ensures that the
memcpy() operation only reads the memory within the bounds of struct
j1939_sk_buff_cb, preventing out-of-bounds memory access.
Additionally, add a BUILD_BUG_ON() to check that the size of skb->cb
is greater than or equal to the size of struct j1939_sk_buff_cb. This
ensures that the skb->cb buffer is large enough to hold the
j1939_sk_buff_cb structure.
[mkl: rephrase commit message] |
| In the Linux kernel, the following vulnerability has been resolved:
powerpc/iommu: Fix notifiers being shared by PCI and VIO buses
fail_iommu_setup() registers the fail_iommu_bus_notifier struct to both
PCI and VIO buses. struct notifier_block is a linked list node, so this
causes any notifiers later registered to either bus type to also be
registered to the other since they share the same node.
This causes issues in (at least) the vgaarb code, which registers a
notifier for PCI buses. pci_notify() ends up being called on a vio
device, converted with to_pci_dev() even though it's not a PCI device,
and finally makes a bad access in vga_arbiter_add_pci_device() as
discovered with KASAN:
BUG: KASAN: slab-out-of-bounds in vga_arbiter_add_pci_device+0x60/0xe00
Read of size 4 at addr c000000264c26fdc by task swapper/0/1
Call Trace:
dump_stack_lvl+0x1bc/0x2b8 (unreliable)
print_report+0x3f4/0xc60
kasan_report+0x244/0x698
__asan_load4+0xe8/0x250
vga_arbiter_add_pci_device+0x60/0xe00
pci_notify+0x88/0x444
notifier_call_chain+0x104/0x320
blocking_notifier_call_chain+0xa0/0x140
device_add+0xac8/0x1d30
device_register+0x58/0x80
vio_register_device_node+0x9ac/0xce0
vio_bus_scan_register_devices+0xc4/0x13c
__machine_initcall_pseries_vio_device_init+0x94/0xf0
do_one_initcall+0x12c/0xaa8
kernel_init_freeable+0xa48/0xba8
kernel_init+0x64/0x400
ret_from_kernel_thread+0x5c/0x64
Fix this by creating separate notifier_block structs for each bus type.
[mpe: Add #ifdef to fix CONFIG_IBMVIO=n build] |
| In the Linux kernel, the following vulnerability has been resolved:
soundwire: fix enumeration completion
The soundwire subsystem uses two completion structures that allow
drivers to wait for soundwire device to become enumerated on the bus and
initialised by their drivers, respectively.
The code implementing the signalling is currently broken as it does not
signal all current and future waiters and also uses the wrong
reinitialisation function, which can potentially lead to memory
corruption if there are still waiters on the queue.
Not signalling future waiters specifically breaks sound card probe
deferrals as codec drivers can not tell that the soundwire device is
already attached when being reprobed. Some codec runtime PM
implementations suffer from similar problems as waiting for enumeration
during resume can also timeout despite the device already having been
enumerated. |
| In the Linux kernel, the following vulnerability has been resolved:
regulator: stm32-pwr: fix of_iomap leak
Smatch reports:
drivers/regulator/stm32-pwr.c:166 stm32_pwr_regulator_probe() warn:
'base' from of_iomap() not released on lines: 151,166.
In stm32_pwr_regulator_probe(), base is not released
when devm_kzalloc() fails to allocate memory or
devm_regulator_register() fails to register a new regulator device,
which may cause a leak.
To fix this issue, replace of_iomap() with
devm_platform_ioremap_resource(). devm_platform_ioremap_resource()
is a specialized function for platform devices.
It allows 'base' to be automatically released whether the probe
function succeeds or fails.
Besides, use IS_ERR(base) instead of !base
as the return value of devm_platform_ioremap_resource()
can either be a pointer to the remapped memory or
an ERR_PTR() encoded error code if the operation fails. |
| In the Linux kernel, the following vulnerability has been resolved:
wifi: rtl818x: Fix potential memory leaks in rtl8180_init_rx_ring()
In rtl8180_init_rx_ring(), memory is allocated for skb packets and DMA
allocations in a loop. When an allocation fails, the previously
successful allocations are not freed on exit.
Fix that by jumping to err_free_rings label on error, which calls
rtl8180_free_rx_ring() to free the allocations. Remove the free of
rx_ring in rtl8180_init_rx_ring() error path, and set the freed
priv->rx_buf entry to null, to avoid double free. |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/amd: Fix potential out-of-bounds read in iommu_mmio_show
In iommu_mmio_write(), it validates the user-provided offset with the
check: `iommu->dbg_mmio_offset > iommu->mmio_phys_end - 4`.
This assumes a 4-byte access. However, the corresponding
show handler, iommu_mmio_show(), uses readq() to perform an 8-byte
(64-bit) read.
If a user provides an offset equal to `mmio_phys_end - 4`, the check
passes, and will lead to a 4-byte out-of-bounds read.
Fix this by adjusting the boundary check to use sizeof(u64), which
corresponds to the size of the readq() operation. |
| CLUSTERPRO X for Linux 4.0, 4.1, 4.2, 5.0, 5.1 and 5.2 and EXPRESSCLUSTER X for Linux 4.0, 4.1, 4.2, 5.0, 5.1 and 5.2, CLUSTERPRO X SingleServerSafe for Linux 4.0, 4.1, 4.2, 5.0, 5.1 and 5.2, EXPRESSCLUSTER X SingleServerSafe for Linux 4.0, 4.1, 4.2, 5.0, 5.1 and 5.2 allows an attacker sends specially crafted network packets to the product, arbitrary OS commands may be executed without authentication. |
| In the Linux kernel, the following vulnerability has been resolved:
fs: Protect reconfiguration of sb read-write from racing writes
The reconfigure / remount code takes a lot of effort to protect
filesystem's reconfiguration code from racing writes on remounting
read-only. However during remounting read-only filesystem to read-write
mode userspace writes can start immediately once we clear SB_RDONLY
flag. This is inconvenient for example for ext4 because we need to do
some writes to the filesystem (such as preparation of quota files)
before we can take userspace writes so we are clearing SB_RDONLY flag
before we are fully ready to accept userpace writes and syzbot has found
a way to exploit this [1]. Also as far as I'm reading the code
the filesystem remount code was protected from racing writes in the
legacy mount path by the mount's MNT_READONLY flag so this is relatively
new problem. It is actually fairly easy to protect remount read-write
from racing writes using sb->s_readonly_remount flag so let's just do
that instead of having to workaround these races in the filesystem code.
[1] https://lore.kernel.org/all/00000000000006a0df05f6667499@google.com/T/ |
