| 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-2021-47497: nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47497 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 4.4.290 with commit abcb8d33e4d2215ccde5ab5ccf9f730a59d79d97 |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 4.9.288 with commit 60df06bbdf497e37ed25ad40572c362e5b0998df |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 4.14.252 with commit 2df6c023050205c4d04ffc121bc549f65cb8d1df |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 4.19.213 with commit eb0fc8e7170e61eaf65d28dee4a8baf4e86b19ca |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 5.4.155 with commit 0594f1d048d8dc338eb9a240021b1d00ae1eb082 |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 5.10.75 with commit 57e48886401b14cd351423fabfec2cfd18df4f66 |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 5.14.14 with commit 0e822e5413da1af28cca350cb1cb42b6133bdcae |
| Issue introduced in 4.3 with commit 69aba7948cbe53f2f1827e84e9dd0ae470a5072e and fixed in 5.15 with commit 5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 |
| |
| 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-2021-47497 |
| 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/nvmem/core.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/abcb8d33e4d2215ccde5ab5ccf9f730a59d79d97 |
| https://git.kernel.org/stable/c/60df06bbdf497e37ed25ad40572c362e5b0998df |
| https://git.kernel.org/stable/c/2df6c023050205c4d04ffc121bc549f65cb8d1df |
| https://git.kernel.org/stable/c/eb0fc8e7170e61eaf65d28dee4a8baf4e86b19ca |
| https://git.kernel.org/stable/c/0594f1d048d8dc338eb9a240021b1d00ae1eb082 |
| https://git.kernel.org/stable/c/57e48886401b14cd351423fabfec2cfd18df4f66 |
| https://git.kernel.org/stable/c/0e822e5413da1af28cca350cb1cb42b6133bdcae |
| https://git.kernel.org/stable/c/5d388fa01fa6eb310ac023a363a6cb216d9d8fe9 |
