ghsa-vgjx-6ccw-c3f6
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2021-47497"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-22T09:15:11Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvmem: Fix shift-out-of-bound (UBSAN) with byte size cells\n\nIf a cell has \u0027nbits\u0027 equal to a multiple of BITS_PER_BYTE the logic\n\n *p \u0026= GENMASK((cell-\u003enbits%BITS_PER_BYTE) - 1, 0);\n\nwill become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we\nsubtract one from that making a large number that is then shifted more than the\nnumber of bits that fit into an unsigned long.\n\nUBSAN reports this problem:\n\n UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8\n shift exponent 64 is too large for 64-bit type \u0027unsigned long\u0027\n CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9\n Hardware name: Google Lazor (rev3+) with KB Backlight (DT)\n Workqueue: events_unbound deferred_probe_work_func\n Call trace:\n dump_backtrace+0x0/0x170\n show_stack+0x24/0x30\n dump_stack_lvl+0x64/0x7c\n dump_stack+0x18/0x38\n ubsan_epilogue+0x10/0x54\n __ubsan_handle_shift_out_of_bounds+0x180/0x194\n __nvmem_cell_read+0x1ec/0x21c\n nvmem_cell_read+0x58/0x94\n nvmem_cell_read_variable_common+0x4c/0xb0\n nvmem_cell_read_variable_le_u32+0x40/0x100\n a6xx_gpu_init+0x170/0x2f4\n adreno_bind+0x174/0x284\n component_bind_all+0xf0/0x264\n msm_drm_bind+0x1d8/0x7a0\n try_to_bring_up_master+0x164/0x1ac\n __component_add+0xbc/0x13c\n component_add+0x20/0x2c\n dp_display_probe+0x340/0x384\n platform_probe+0xc0/0x100\n really_probe+0x110/0x304\n __driver_probe_device+0xb8/0x120\n driver_probe_device+0x4c/0xfc\n __device_attach_driver+0xb0/0x128\n bus_for_each_drv+0x90/0xdc\n __device_attach+0xc8/0x174\n device_initial_probe+0x20/0x2c\n bus_probe_device+0x40/0xa4\n deferred_probe_work_func+0x7c/0xb8\n process_one_work+0x128/0x21c\n process_scheduled_works+0x40/0x54\n worker_thread+0x1ec/0x2a8\n kthread+0x138/0x158\n ret_from_fork+0x10/0x20\n\nFix it by making sure there are any bits to mask out.",
"id": "GHSA-vgjx-6ccw-c3f6",
"modified": "2024-05-22T09:31:47Z",
"published": "2024-05-22T09:31:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47497"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0594f1d048d8dc338eb9a240021b1d00ae1eb082"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0e822e5413da1af28cca350cb1cb42b6133bdcae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2df6c023050205c4d04ffc121bc549f65cb8d1df"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/57e48886401b14cd351423fabfec2cfd18df4f66"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5d388fa01fa6eb310ac023a363a6cb216d9d8fe9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/60df06bbdf497e37ed25ad40572c362e5b0998df"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/abcb8d33e4d2215ccde5ab5ccf9f730a59d79d97"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eb0fc8e7170e61eaf65d28dee4a8baf4e86b19ca"
}
],
"schema_version": "1.4.0",
"severity": []
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
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