CVE-2021-47497
Description
In the Linux kernel, the following vulnerability has been resolved: nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0); will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we subtract one from that making a large number that is then shifted more than the number of bits that fit into an unsigned long. UBSAN reports this problem: UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8 shift exponent 64 is too large for 64-bit type 'unsigned long' CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9 Hardware name: Google Lazor (rev3+) with KB Backlight (DT) Workqueue: events_unbound deferred_probe_work_func Call trace: dump_backtrace+0x0/0x170 show_stack+0x24/0x30 dump_stack_lvl+0x64/0x7c dump_stack+0x18/0x38 ubsan_epilogue+0x10/0x54 __ubsan_handle_shift_out_of_bounds+0x180/0x194 __nvmem_cell_read+0x1ec/0x21c nvmem_cell_read+0x58/0x94 nvmem_cell_read_variable_common+0x4c/0xb0 nvmem_cell_read_variable_le_u32+0x40/0x100 a6xx_gpu_init+0x170/0x2f4 adreno_bind+0x174/0x284 component_bind_all+0xf0/0x264 msm_drm_bind+0x1d8/0x7a0 try_to_bring_up_master+0x164/0x1ac __component_add+0xbc/0x13c component_add+0x20/0x2c dp_display_probe+0x340/0x384 platform_probe+0xc0/0x100 really_probe+0x110/0x304 __driver_probe_device+0xb8/0x120 driver_probe_device+0x4c/0xfc __device_attach_driver+0xb0/0x128 bus_for_each_drv+0x90/0xdc __device_attach+0xc8/0x174 device_initial_probe+0x20/0x2c bus_probe_device+0x40/0xa4 deferred_probe_work_func+0x7c/0xb8 process_one_work+0x128/0x21c process_scheduled_works+0x40/0x54 worker_thread+0x1ec/0x2a8 kthread+0x138/0x158 ret_from_fork+0x10/0x20 Fix it by making sure there are any bits to mask out.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
Description kernel: nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells CVSS v3: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H) Errata / fixed releases ProductPackageAdvisoryReleased Red Hat Enterprise Linux 8kernel-rt-0:4.18.0-553.22.1.rt7.363.el8_10RHSA-2024:70012024-09-24T00:00:00Z Red Hat Enterprise Linux 8kernel-0:4.18.0-553.22.1.el8_10RHSA-2024:70002024-09-24T00:00:00Z Red Hat…
Description
kernel: nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells
CVSS v3: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)
Errata / fixed releases
| Product | Package | Advisory | Released |
|---|---|---|---|
| Red Hat Enterprise Linux 8 | kernel-rt-0:4.18.0-553.22.1.rt7.363.el8_10 | RHSA-2024:7001 | 2024-09-24T00:00:00Z |
| Red Hat Enterprise Linux 8 | kernel-0:4.18.0-553.22.1.el8_10 | RHSA-2024:7000 | 2024-09-24T00:00:00Z |
| Red Hat Enterprise Linux 9 | kernel-0:5.14.0-503.11.1.el9_5 | RHSA-2024:9315 | 2024-11-12T00:00:00Z |
| Red Hat Enterprise Linux 9 | kernel-0:5.14.0-503.11.1.el9_5 | RHSA-2024:9315 | 2024-11-12T00:00:00Z |
| Red Hat Enterprise Linux 9.4 Extended Update Support | kernel-0:5.14.0-427.59.1.el9_4 | RHSA-2025:2490 | 2025-03-10T00:00:00Z |
Package state
| Product | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected |
| Red Hat Enterprise Linux 7 | kernel | Out of support scope |
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope |
| Red Hat Enterprise Linux 9 | kernel-rt | Affected |
Apply commands
yum update -y kernel-rt
# or:
dnf upgrade -y kernel-rtAffected
| Vendor | Product | Version |
|---|---|---|
| redhat | Red Hat Enterprise Linux 6 | Not affected |
| redhat | Red Hat Enterprise Linux 9 | Affected |
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| rhel | 9 | fixed | |
| rocky | 8 | fixed | |
| sles | affected | | |
| debian | bookworm | fixed | 5.14.16-1 |
| debian | bullseye | fixed | 5.10.84-1 |
| debian | forky | fixed | 5.14.16-1 |
| debian | sid | fixed | 5.14.16-1 |
| debian | trixie | fixed | 5.14.16-1 |
| almalinux | 8 | fixed | kernel-abi-stablelists-4.18.0-553.22.1.el8_10.noarch.rpm |
References
- https://access.redhat.com/errata/RHSA-2024:9315
- https://errata.rockylinux.org/RLSA-2024:7000
- https://errata.rockylinux.org/RLSA-2024:7001
- https://www.suse.com/security/cve/CVE-2021-47497.html
- https://security-tracker.debian.org/tracker/CVE-2021-47497
- https://access.redhat.com/errata/RHSA-2024:7000
- https://bugzilla.redhat.com/2258012
- https://bugzilla.redhat.com/2258013
- https://bugzilla.redhat.com/2260038
- https://bugzilla.redhat.com/2265799
- https://bugzilla.redhat.com/2265838
- https://bugzilla.redhat.com/2266358
- https://bugzilla.redhat.com/2266750
- https://bugzilla.redhat.com/2267036
- https://bugzilla.redhat.com/2267041
- https://bugzilla.redhat.com/2267795
- https://bugzilla.redhat.com/2267916
- https://bugzilla.redhat.com/2267925
- https://bugzilla.redhat.com/2268295
- https://bugzilla.redhat.com/2270103
- https://bugzilla.redhat.com/2271648
- https://bugzilla.redhat.com/2271796
- https://bugzilla.redhat.com/2272793
- https://bugzilla.redhat.com/2273141
- https://bugzilla.redhat.com/2273148
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Verify integrity in audit chain (admin only). AS-IS.