| From bippy-7c5fe7eed585 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-2025-21943: gpio: aggregator: protect driver attr handlers against module unload |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| gpio: aggregator: protect driver attr handlers against module unload |
| |
| Both new_device_store and delete_device_store touch module global |
| resources (e.g. gpio_aggregator_lock). To prevent race conditions with |
| module unload, a reference needs to be held. |
| |
| Add try_module_get() in these handlers. |
| |
| For new_device_store, this eliminates what appears to be the most dangerous |
| scenario: if an id is allocated from gpio_aggregator_idr but |
| platform_device_register has not yet been called or completed, a concurrent |
| module unload could fail to unregister/delete the device, leaving behind a |
| dangling platform device/GPIO forwarder. This can result in various issues. |
| The following simple reproducer demonstrates these problems: |
| |
| #!/bin/bash |
| while :; do |
| # note: whether 'gpiochip0 0' exists or not does not matter. |
| echo 'gpiochip0 0' > /sys/bus/platform/drivers/gpio-aggregator/new_device |
| done & |
| while :; do |
| modprobe gpio-aggregator |
| modprobe -r gpio-aggregator |
| done & |
| wait |
| |
| Starting with the following warning, several kinds of warnings will appear |
| and the system may become unstable: |
| |
| ------------[ cut here ]------------ |
| list_del corruption, ffff888103e2e980->next is LIST_POISON1 (dead000000000100) |
| WARNING: CPU: 1 PID: 1327 at lib/list_debug.c:56 __list_del_entry_valid_or_report+0xa3/0x120 |
| [...] |
| RIP: 0010:__list_del_entry_valid_or_report+0xa3/0x120 |
| [...] |
| Call Trace: |
| <TASK> |
| ? __list_del_entry_valid_or_report+0xa3/0x120 |
| ? __warn.cold+0x93/0xf2 |
| ? __list_del_entry_valid_or_report+0xa3/0x120 |
| ? report_bug+0xe6/0x170 |
| ? __irq_work_queue_local+0x39/0xe0 |
| ? handle_bug+0x58/0x90 |
| ? exc_invalid_op+0x13/0x60 |
| ? asm_exc_invalid_op+0x16/0x20 |
| ? __list_del_entry_valid_or_report+0xa3/0x120 |
| gpiod_remove_lookup_table+0x22/0x60 |
| new_device_store+0x315/0x350 [gpio_aggregator] |
| kernfs_fop_write_iter+0x137/0x1f0 |
| vfs_write+0x262/0x430 |
| ksys_write+0x60/0xd0 |
| do_syscall_64+0x6c/0x180 |
| entry_SYSCALL_64_after_hwframe+0x76/0x7e |
| [...] |
| </TASK> |
| ---[ end trace 0000000000000000 ]--- |
| |
| The Linux kernel CVE team has assigned CVE-2025-21943 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 5.10.235 with commit fd6aa1f8cbe0979eb66ac32ebc231bf0b10a2117 |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 5.15.179 with commit 807789018186cf508ceb3a1f8f02935cd195717b |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 6.1.131 with commit 9334c88fc2fbc6836b307d269fcc1744c69701c0 |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 6.6.83 with commit d99dc8f7ea01ee1b21306e0eda8eb18a4af80db6 |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 6.12.19 with commit 8fb07fb1bba91d45846ed8605c3097fe67a7d54c |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 6.13.7 with commit 56281a76b805b5ac61feb5d580139695a22f87f0 |
| Issue introduced in 5.8 with commit 828546e24280f721350a7a0dcc92416e917b4382 and fixed in 6.14 with commit 12f65d1203507f7db3ba59930fe29a3b8eee9945 |
| |
| 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-2025-21943 |
| 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/gpio/gpio-aggregator.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/fd6aa1f8cbe0979eb66ac32ebc231bf0b10a2117 |
| https://git.kernel.org/stable/c/807789018186cf508ceb3a1f8f02935cd195717b |
| https://git.kernel.org/stable/c/9334c88fc2fbc6836b307d269fcc1744c69701c0 |
| https://git.kernel.org/stable/c/d99dc8f7ea01ee1b21306e0eda8eb18a4af80db6 |
| https://git.kernel.org/stable/c/8fb07fb1bba91d45846ed8605c3097fe67a7d54c |
| https://git.kernel.org/stable/c/56281a76b805b5ac61feb5d580139695a22f87f0 |
| https://git.kernel.org/stable/c/12f65d1203507f7db3ba59930fe29a3b8eee9945 |
