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Thu, 23 May 2024 19:39:51 +0800 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Thu, 23 May 2024 19:39:51 +0800 From: dicken.ding To: Thomas Gleixner , Matthias Brugger , AngeloGioacchino Del Regno CC: , , , , , , , dicken.ding Subject: [PATCH 1/1] irq: Fix uaf issue in irq_find_at_or_after Date: Thu, 23 May 2024 19:39:49 +0800 Message-ID: <20240523113949.10444-1-dicken.ding@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-TM-AS-Product-Ver: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-AS-Result: No-10-4.177400-8.000000 X-TMASE-MatchedRID: 2aTVZGXuTB8ff24atxvqbrMjW/sniEQKuoYFb0nRiqNx1e3NhjX9AiX5 3Srl2nNUxo7ed0Rl0pgsXpgfc4uq3GF9INTZ2jjMSHCU59h5KrGkWoMjFfK3XtSVUkz9BPXe7j8 sAI9BuGov53aacJHWeJ+Db2Vym711hCZu5goHpcabYgXsVVm7zEJfxXUWJFGS31GU/N5W5BB3Hs 0YS1IA83Apm8RB2n0t42WC8ffme7UfE8yM4pjsD23U7j2vVURrxEHRux+uk8jQ9TRN0mhS13wZJ S/5YqMnXVKv7/WG8TXYQnlb38PjIG0VCOqEk9p23uBhPc05NEF4Zvr17pnQUPueCzBmgUWhUuPw TjND/xoICtGLeyfJS46H7DI0GsVcMmI24qiENwrMpIbcl3IoA+q1XYAYw09quxzcuGDedhg= X-TM-AS-User-Approved-Sender: No X-TM-AS-User-Blocked-Sender: No X-TMASE-Result: 10-4.177400-8.000000 X-TMASE-Version: SMEX-14.0.0.3152-9.1.1006-23728.005 X-TM-SNTS-SMTP: FE9282E63577086F736FFDFCA4986544633F2DCF74F2105A3F1396C83B7110892000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240523_044002_552236_D2B3265C X-CRM114-Status: GOOD ( 11.59 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The function "irq_find_at_or_after" is at the risk of use-after-free due to the race condition between the functions "delayer_free_desc" and "irq_desc_get_irq". The function "delayer_free_desc" could be called between "mt_find" and "irq_desc_get_irq" due to the absence of any locks to ensure atomic operations on the "irq_desc" structure. In this patch, we introduce a pair of locks, namely "rcu_read_lock" and "rcu_read_unlock" to prevent the occurrence of use-after-free in "irq_find_at_or_after". Call trace: dump_backtrace+0xec/0x138 show_stack+0x18/0x24 dump_stack_lvl+0x50/0x6c print_report+0x1b0/0x714 kasan_report+0xc4/0x124 __do_kernel_fault+0xc0/0x368 do_bad_area+0x30/0xdc do_tag_check_fault+0x20/0x34 do_mem_abort+0x58/0x118 el1_abort+0x3c/0x5c el1h_64_sync_handler+0x54/0x90 el1h_64_sync+0x68/0x6c irq_get_next_irq+0x58/0x84 show_stat+0x638/0x824 seq_read_iter+0x158/0x4ec proc_reg_read_iter+0x94/0x12c vfs_read+0x1e0/0x2c8 __arm64_sys_pread64+0x84/0xcc invoke_syscall+0x58/0x114 el0_svc_common+0x80/0xe0 do_el0_svc+0x1c/0x28 el0_svc+0x38/0x68 el0t_64_sync_handler+0x68/0xbc el0t_64_sync+0x1a8/0x1ac Freed by task 4471: kasan_save_stack+0x40/0x70 save_stack_info+0x34/0x128 kasan_save_free_info+0x18/0x28 ____kasan_slab_free+0x254/0x25c __kasan_slab_free+0x10/0x20 slab_free_freelist_hook+0x174/0x1e0 __kmem_cache_free+0xa4/0x1dc kfree+0x64/0x128 irq_kobj_release+0x28/0x3c kobject_put+0xcc/0x1e0 delayed_free_desc+0x14/0x2c rcu_do_batch+0x214/0x720 rcu_core+0x1b0/0x408 rcu_core_si+0x10/0x20 __do_softirq+0x154/0x470 Signed-off-by: dicken.ding --- kernel/irq/irqdesc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 88ac3652fcf2..14124e1bcb03 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -160,9 +160,15 @@ static int irq_find_free_area(unsigned int from, unsigned int cnt) static unsigned int irq_find_at_or_after(unsigned int offset) { unsigned long index = offset; + unsigned int irq = nr_irqs; + + rcu_read_lock(); struct irq_desc *desc = mt_find(&sparse_irqs, &index, nr_irqs); + if (desc) + irq = irq_desc_get_irq(desc); + rcu_read_unlock(); - return desc ? irq_desc_get_irq(desc) : nr_irqs; + return irq; } static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)