CVE-2021-47169

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> serial: rp2: use &amp;#39;request_firmware&amp;#39; instead of &amp;#39;request_firmware_nowait&amp;#39;<br /> <br /> In &amp;#39;rp2_probe&amp;#39;, the driver registers &amp;#39;rp2_uart_interrupt&amp;#39; then calls<br /> &amp;#39;rp2_fw_cb&amp;#39; through &amp;#39;request_firmware_nowait&amp;#39;. In &amp;#39;rp2_fw_cb&amp;#39;, if the<br /> firmware don&amp;#39;t exists, function just return without initializing ports<br /> of &amp;#39;rp2_card&amp;#39;. But now the interrupt handler function has been<br /> registered, and when an interrupt comes, &amp;#39;rp2_uart_interrupt&amp;#39; may access<br /> those ports then causing NULL pointer dereference or other bugs.<br /> <br /> Because the driver does some initialization work in &amp;#39;rp2_fw_cb&amp;#39;, in<br /> order to make the driver ready to handle interrupts, &amp;#39;request_firmware&amp;#39;<br /> should be used instead of asynchronous &amp;#39;request_firmware_nowait&amp;#39;.<br /> <br /> This report reveals it:<br /> <br /> INFO: trying to register non-static key.<br /> the code is fine but needs lockdep annotation.<br /> turning off the locking correctness validator.<br /> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.19.177-gdba4159c14ef-dirty #45<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-<br /> gc9ba5276e321-prebuilt.qemu.org 04/01/2014<br /> Call Trace:<br /> <br /> __dump_stack lib/dump_stack.c:77 [inline]<br /> dump_stack+0xec/0x156 lib/dump_stack.c:118<br /> assign_lock_key kernel/locking/lockdep.c:727 [inline]<br /> register_lock_class+0x14e5/0x1ba0 kernel/locking/lockdep.c:753<br /> __lock_acquire+0x187/0x3750 kernel/locking/lockdep.c:3303<br /> lock_acquire+0x124/0x340 kernel/locking/lockdep.c:3907<br /> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]<br /> _raw_spin_lock+0x32/0x50 kernel/locking/spinlock.c:144<br /> spin_lock include/linux/spinlock.h:329 [inline]<br /> rp2_ch_interrupt drivers/tty/serial/rp2.c:466 [inline]<br /> rp2_asic_interrupt.isra.9+0x15d/0x990 drivers/tty/serial/rp2.c:493<br /> rp2_uart_interrupt+0x49/0xe0 drivers/tty/serial/rp2.c:504<br /> __handle_irq_event_percpu+0xfb/0x770 kernel/irq/handle.c:149<br /> handle_irq_event_percpu+0x79/0x150 kernel/irq/handle.c:189<br /> handle_irq_event+0xac/0x140 kernel/irq/handle.c:206<br /> handle_fasteoi_irq+0x232/0x5c0 kernel/irq/chip.c:725<br /> generic_handle_irq_desc include/linux/irqdesc.h:155 [inline]<br /> handle_irq+0x230/0x3a0 arch/x86/kernel/irq_64.c:87<br /> do_IRQ+0xa7/0x1e0 arch/x86/kernel/irq.c:247<br /> common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670<br /> <br /> RIP: 0010:native_safe_halt+0x28/0x30 arch/x86/include/asm/irqflags.h:61<br /> Code: 00 00 55 be 04 00 00 00 48 c7 c7 00 c2 2f 8c 48 89 e5 e8 fb 31 e7 f8<br /> 8b 05 75 af 8d 03 85 c0 7e 07 0f 00 2d 8a 61 65 00 fb f4 c3 90 90 90<br /> 90 90 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 41<br /> RSP: 0018:ffff88806b71fcc8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffde<br /> RAX: 0000000000000000 RBX: ffffffff8bde7e48 RCX: ffffffff88a21285<br /> RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff8c2fc200<br /> RBP: ffff88806b71fcc8 R08: fffffbfff185f840 R09: fffffbfff185f840<br /> R10: 0000000000000001 R11: fffffbfff185f840 R12: 0000000000000002<br /> R13: ffffffff8bea18a0 R14: 0000000000000000 R15: 0000000000000000<br /> arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]<br /> default_idle+0x6f/0x360 arch/x86/kernel/process.c:557<br /> arch_cpu_idle+0xf/0x20 arch/x86/kernel/process.c:548<br /> default_idle_call+0x3b/0x60 kernel/sched/idle.c:93<br /> cpuidle_idle_call kernel/sched/idle.c:153 [inline]<br /> do_idle+0x2ab/0x3c0 kernel/sched/idle.c:263<br /> cpu_startup_entry+0xcb/0xe0 kernel/sched/idle.c:369<br /> start_secondary+0x3b8/0x4e0 arch/x86/kernel/smpboot.c:271<br /> secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243<br /> BUG: unable to handle kernel NULL pointer dereference at 0000000000000010<br /> PGD 8000000056d27067 P4D 8000000056d27067 PUD 56d28067 PMD 0<br /> Oops: 0000 [#1] PREEMPT SMP KASAN PTI<br /> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.19.177-gdba4159c14ef-dirty #45<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-<br /> gc9ba5276e321-prebuilt.qemu.org 04/01/2014<br /> RIP: 0010:readl arch/x86/include/asm/io.h:59 [inline]<br /> RIP: 0010:rp2_ch_interrupt drivers/tty/serial/rp2.c:472 [inline]<br /> RIP: 0010:rp2_asic_interrupt.isra.9+0x181/0x990 drivers/tty/serial/rp2.c:<br /> 493<br /> Co<br /> ---truncated---