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[34.83.65.128]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7390611bd23sm8770464b3a.96.2025.03.24.13.55.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Mar 2025 13:55:17 -0700 (PDT) Date: Mon, 24 Mar 2025 20:55:12 +0000 From: Carlos Llamas To: Dmitry Antipov Cc: Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Suren Baghdasaryan , Colin Ian King , linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org, syzbot+353d7b75658a95aa955a@syzkaller.appspotmail.com Subject: Re: [PATCH] binder: fix use-after-free in binderfs_evict_inode() Message-ID: References: <20250324132427.922495-1-dmantipov@yandex.ru> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250324132427.922495-1-dmantipov@yandex.ru> On Mon, Mar 24, 2025 at 04:24:27PM +0300, Dmitry Antipov wrote: > Running 'stress-ng --binderfs 16 --timeout 300' under KASAN-enabled > kernel, I've noticed the following: > > BUG: KASAN: slab-use-after-free in binderfs_evict_inode+0x1de/0x2d0 > Write of size 8 at addr ffff88807379bc08 by task stress-ng-binde/1699 > > CPU: 0 UID: 0 PID: 1699 Comm: stress-ng-binde Not tainted 6.14.0-rc7-g586de92313fc-dirty #13 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014 > Call Trace: > > dump_stack_lvl+0x1c2/0x2a0 > ? __pfx_dump_stack_lvl+0x10/0x10 > ? __pfx__printk+0x10/0x10 > ? __pfx_lock_release+0x10/0x10 > ? __virt_addr_valid+0x18c/0x540 > ? __virt_addr_valid+0x469/0x540 > print_report+0x155/0x840 > ? __virt_addr_valid+0x18c/0x540 > ? __virt_addr_valid+0x469/0x540 > ? __phys_addr+0xba/0x170 > ? binderfs_evict_inode+0x1de/0x2d0 > kasan_report+0x147/0x180 > ? binderfs_evict_inode+0x1de/0x2d0 > binderfs_evict_inode+0x1de/0x2d0 > ? __pfx_binderfs_evict_inode+0x10/0x10 > evict+0x524/0x9f0 > ? __pfx_lock_release+0x10/0x10 > ? __pfx_evict+0x10/0x10 > ? do_raw_spin_unlock+0x4d/0x210 > ? _raw_spin_unlock+0x28/0x50 > ? iput+0x697/0x9b0 > __dentry_kill+0x209/0x660 > ? shrink_kill+0x8d/0x2c0 > shrink_kill+0xa9/0x2c0 > shrink_dentry_list+0x2e0/0x5e0 > shrink_dcache_parent+0xa2/0x2c0 > ? __pfx_shrink_dcache_parent+0x10/0x10 > ? __pfx_lock_release+0x10/0x10 > ? __pfx_do_raw_spin_lock+0x10/0x10 > do_one_tree+0x23/0xe0 > shrink_dcache_for_umount+0xa0/0x170 > generic_shutdown_super+0x67/0x390 > kill_litter_super+0x76/0xb0 > binderfs_kill_super+0x44/0x90 > deactivate_locked_super+0xb9/0x130 > cleanup_mnt+0x422/0x4c0 > ? lockdep_hardirqs_on+0x9d/0x150 > task_work_run+0x1d2/0x260 > ? __pfx_task_work_run+0x10/0x10 > resume_user_mode_work+0x52/0x60 > syscall_exit_to_user_mode+0x9a/0x120 > do_syscall_64+0x103/0x210 > ? asm_sysvec_apic_timer_interrupt+0x1a/0x20 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0xcac57b > Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 > RSP: 002b:00007ffecf4226a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 > RAX: 0000000000000000 RBX: 00007ffecf422720 RCX: 0000000000cac57b > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffecf422850 > RBP: 00007ffecf422850 R08: 0000000028d06ab1 R09: 7fffffffffffffff > R10: 3fffffffffffffff R11: 0000000000000246 R12: 00007ffecf422718 > R13: 00007ffecf422710 R14: 00007f478f87b658 R15: 00007ffecf422830 > > > Allocated by task 1705: > kasan_save_track+0x3e/0x80 > __kasan_kmalloc+0x8f/0xa0 > __kmalloc_cache_noprof+0x213/0x3e0 > binderfs_binder_device_create+0x183/0xa80 > binder_ctl_ioctl+0x138/0x190 > __x64_sys_ioctl+0x120/0x1b0 > do_syscall_64+0xf6/0x210 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > Freed by task 1705: > kasan_save_track+0x3e/0x80 > kasan_save_free_info+0x46/0x50 > __kasan_slab_free+0x62/0x70 > kfree+0x194/0x440 > evict+0x524/0x9f0 > do_unlinkat+0x390/0x5b0 > __x64_sys_unlink+0x47/0x50 > do_syscall_64+0xf6/0x210 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > > This 'stress-ng' workload causes the concurrent deletions from > 'binder_devices' and so requires full-featured synchronization > to prevent list corruption. > > I've found this issue independently but pretty sure that syzbot did > the same, so Reported-by: and Closes: should be applicable here as well. > > Reported-by: syzbot+353d7b75658a95aa955a@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=353d7b75658a95aa955a > Fixes: e77aff5528a18 ("binderfs: fix use-after-free in binder_devices") > Signed-off-by: Dmitry Antipov > --- Thanks Dmitry, I was just running an almost identical fix. :) Acked-by: Carlos Llamas