| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47441: mlxsw: thermal: Fix out-of-bounds memory accesses |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mlxsw: thermal: Fix out-of-bounds memory accesses |
| |
| Currently, mlxsw allows cooling states to be set above the maximum |
| cooling state supported by the driver: |
| |
| # cat /sys/class/thermal/thermal_zone2/cdev0/type |
| mlxsw_fan |
| # cat /sys/class/thermal/thermal_zone2/cdev0/max_state |
| 10 |
| # echo 18 > /sys/class/thermal/thermal_zone2/cdev0/cur_state |
| # echo $? |
| 0 |
| |
| This results in out-of-bounds memory accesses when thermal state |
| transition statistics are enabled (CONFIG_THERMAL_STATISTICS=y), as the |
| transition table is accessed with a too large index (state) [1]. |
| |
| According to the thermal maintainer, it is the responsibility of the |
| driver to reject such operations [2]. |
| |
| Therefore, return an error when the state to be set exceeds the maximum |
| cooling state supported by the driver. |
| |
| To avoid dead code, as suggested by the thermal maintainer [3], |
| partially revert commit a421ce088ac8 ("mlxsw: core: Extend cooling |
| device with cooling levels") that tried to interpret these invalid |
| cooling states (above the maximum) in a special way. The cooling levels |
| array is not removed in order to prevent the fans going below 20% PWM, |
| which would cause them to get stuck at 0% PWM. |
| |
| [1] |
| BUG: KASAN: slab-out-of-bounds in thermal_cooling_device_stats_update+0x271/0x290 |
| Read of size 4 at addr ffff8881052f7bf8 by task kworker/0:0/5 |
| |
| CPU: 0 PID: 5 Comm: kworker/0:0 Not tainted 5.15.0-rc3-custom-45935-gce1adf704b14 #122 |
| Hardware name: Mellanox Technologies Ltd. "MSN2410-CB2FO"/"SA000874", BIOS 4.6.5 03/08/2016 |
| Workqueue: events_freezable_power_ thermal_zone_device_check |
| Call Trace: |
| dump_stack_lvl+0x8b/0xb3 |
| print_address_description.constprop.0+0x1f/0x140 |
| kasan_report.cold+0x7f/0x11b |
| thermal_cooling_device_stats_update+0x271/0x290 |
| __thermal_cdev_update+0x15e/0x4e0 |
| thermal_cdev_update+0x9f/0xe0 |
| step_wise_throttle+0x770/0xee0 |
| thermal_zone_device_update+0x3f6/0xdf0 |
| process_one_work+0xa42/0x1770 |
| worker_thread+0x62f/0x13e0 |
| kthread+0x3ee/0x4e0 |
| ret_from_fork+0x1f/0x30 |
| |
| Allocated by task 1: |
| kasan_save_stack+0x1b/0x40 |
| __kasan_kmalloc+0x7c/0x90 |
| thermal_cooling_device_setup_sysfs+0x153/0x2c0 |
| __thermal_cooling_device_register.part.0+0x25b/0x9c0 |
| thermal_cooling_device_register+0xb3/0x100 |
| mlxsw_thermal_init+0x5c5/0x7e0 |
| __mlxsw_core_bus_device_register+0xcb3/0x19c0 |
| mlxsw_core_bus_device_register+0x56/0xb0 |
| mlxsw_pci_probe+0x54f/0x710 |
| local_pci_probe+0xc6/0x170 |
| pci_device_probe+0x2b2/0x4d0 |
| really_probe+0x293/0xd10 |
| __driver_probe_device+0x2af/0x440 |
| driver_probe_device+0x51/0x1e0 |
| __driver_attach+0x21b/0x530 |
| bus_for_each_dev+0x14c/0x1d0 |
| bus_add_driver+0x3ac/0x650 |
| driver_register+0x241/0x3d0 |
| mlxsw_sp_module_init+0xa2/0x174 |
| do_one_initcall+0xee/0x5f0 |
| kernel_init_freeable+0x45a/0x4de |
| kernel_init+0x1f/0x210 |
| ret_from_fork+0x1f/0x30 |
| |
| The buggy address belongs to the object at ffff8881052f7800 |
| which belongs to the cache kmalloc-1k of size 1024 |
| The buggy address is located 1016 bytes inside of |
| 1024-byte region [ffff8881052f7800, ffff8881052f7c00) |
| The buggy address belongs to the page: |
| page:0000000052355272 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1052f0 |
| head:0000000052355272 order:3 compound_mapcount:0 compound_pincount:0 |
| flags: 0x200000000010200(slab|head|node=0|zone=2) |
| raw: 0200000000010200 ffffea0005034800 0000000300000003 ffff888100041dc0 |
| raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 |
| page dumped because: kasan: bad access detected |
| |
| Memory state around the buggy address: |
| ffff8881052f7a80: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc |
| ffff8881052f7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| >ffff8881052f7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ^ |
| ffff8881052f7c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| ffff8881052f7c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc |
| |
| [2] https://lore.kernel.org/linux-pm/9aca37cb-1629-5c67-1895-1fdc45c0244e@linaro.org/ |
| [3] https://lore.kernel.org/linux-pm/af9857f2-578e-de3a-e62b-6baff7e69fd4@linaro.org/ |
| |
| The Linux kernel CVE team has assigned CVE-2021-47441 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.10 with commit a50c1e35650b929500bd89be61c89d95a267ce56 and fixed in 5.4.155 with commit ae0993739e14a102d506aa09e11b0065f3144f10 |
| Issue introduced in 4.10 with commit a50c1e35650b929500bd89be61c89d95a267ce56 and fixed in 5.10.75 with commit e59d839743b50cb1d3f42a786bea48cc5621d254 |
| Issue introduced in 4.10 with commit a50c1e35650b929500bd89be61c89d95a267ce56 and fixed in 5.14.14 with commit df8e58716afb3bee2b59de66b1ba1033f2e26303 |
| Issue introduced in 4.10 with commit a50c1e35650b929500bd89be61c89d95a267ce56 and fixed in 5.15 with commit 332fdf951df8b870e3da86b122ae304e2aabe88c |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47441 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/net/ethernet/mellanox/mlxsw/core_thermal.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/ae0993739e14a102d506aa09e11b0065f3144f10 |
| https://git.kernel.org/stable/c/e59d839743b50cb1d3f42a786bea48cc5621d254 |
| https://git.kernel.org/stable/c/df8e58716afb3bee2b59de66b1ba1033f2e26303 |
| https://git.kernel.org/stable/c/332fdf951df8b870e3da86b122ae304e2aabe88c |
