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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=+JJbAZWlkVU1tOxB6NfR448daaaJ9VSQN9pfa39B6NU=; b=qs0NTtP013QpukVbasliZCLW2jFx2aP861ObnNl+SPC+i7vp56OKh7xIFQwgoTPdIF FGgHqFX6dR75lE/GambcADy6vTU7ExTqEgzkmS9MqXlGEgctdFRQT/NUMRsc9cKBJZC4 OU1oBTT5ZagpcnQYjxBH3z98q0q518X9m5vCLb98ThTbh9Yr/wZuiCYUZ0g7p0RTJe4l CCTmWBhKBetct8PHG/GC4/Uyq1IWvNimJh7uoWuitqJffCCqpQ9NUh5JXPjp7k+eUKG8 lAv071et5BR0GxBLH0ECI7AlDkcEHGAvvIkSzvuqMAgv8TMiyfYjIoU5gMJ8jz1D5c6M 0Q8Q== X-Gm-Message-State: AOAM531rEZmmDYZIZ2e2jgyu8GfY93qTphL99aUX8a6LD+xXtQdIpcXR e+sz0+ba05ererv+C9qc2uIT+Kg0Mw3m4gPdBHktvA== X-Google-Smtp-Source: ABdhPJzy851qkPJ6xDuGKCL2T4Cit+ZW0MdHRdTOhPX/tT5vMtmh3iNyHOiWQRiYPVjgLqVx3z8gj1NWO4lo39y2Hk0= X-Received: by 2002:a37:9301:: with SMTP id v1mr3987157qkd.350.1602664054983; Wed, 14 Oct 2020 01:27:34 -0700 (PDT) MIME-Version: 1.0 References: <0000000000002954fa05b02468d7@google.com> <300c32a1-a0de-4f05-b467-0822b3d21733n@googlegroups.com> In-Reply-To: Date: Wed, 14 Oct 2020 10:27:23 +0200 Message-ID: To: Fox Chen Cc: linux-kernel-mentees@lists.linuxfoundation.org, syzkaller-bugs Subject: Re: [Linux-kernel-mentees] KASAN: slab-out-of-bounds Read in squashfs_get_id X-BeenThere: linux-kernel-mentees@lists.linuxfoundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Dmitry Vyukov via Linux-kernel-mentees Reply-To: Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-kernel-mentees-bounces@lists.linuxfoundation.org Sender: "Linux-kernel-mentees" On Wed, Oct 14, 2020 at 10:02 AM Fox Chen wrote: > > Oh, Thank you, Dmitry! > > I firstly replied to this from > https://groups.google.com/g/syzkaller-bugs/c/SPtlDDI7jmw/m/BtgjaCcDAwAJ. > I don't know why "reply all" only replies to syzkaller-bugs and I > didn't notice that. > > Sorry about that. Oh, from groups. Yes, that won't work for the kernel. That also generated an HTML email, which is generally not welcome on kernel mailing lists. > On Wed, Oct 14, 2020 at 3:57 PM Dmitry Vyukov wrote: > > > > FYI Gmail has a setting of making Replay All the default button. > > > > > > On Wed, Oct 14, 2020 at 9:39 AM Fox Chen wrote: > >> > >> Hi, > >> > >> I found this bug was caused by either uid/gid info in superblocks or id_index_table is corrupted. The uid/gid index is larger than the size of msblk->id_table. > >> > >> Should I add a sanity check to squashfs_get_id?? > >> > >> > >> The complete solution is to record the size of msblk->id_table in msblk and check uid/gid index each time in squashfs_get_id. However, this requires a change to msblk struct. > >> > >> A simple solution is to calculate the max available room for uid/gid table by doing msblk->xattr_table - msblk->id_table[0] and check if index is larger than this. While this provides some sort of check, it is imperfect because id_table can be smaller than that. > >> > >> Both of them work out for this bug. > >> > >> > >> thanks, > >> fox > >> > >> On Friday, September 25, 2020 at 10:48:18 PM UTC+8 syzbot wrote: > >>> > >>> Hello, > >>> > >>> syzbot found the following issue on: > >>> > >>> HEAD commit: 171d4ff7 Merge tag 'mmc-v5.9-rc4-2' of git://git.kernel.or.. > >>> git tree: upstream > >>> console output: https://syzkaller.appspot.com/x/log.txt?x=1597ead3900000 > >>> kernel config: https://syzkaller.appspot.com/x/.config?x=af502ec9a451c9fc > >>> dashboard link: https://syzkaller.appspot.com/bug?extid=8e28bba73ed1772a6802 > >>> compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) > >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=172ff481900000 > >>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17c3e6c5900000 > >>> > >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: > >>> Reported-by: syzbot+8e28bb...@syzkaller.appspotmail.com > >>> > >>> ================================================================== > >>> BUG: KASAN: slab-out-of-bounds in squashfs_get_id+0xb9/0x1c0 fs/squashfs/id.c:38 > >>> Read of size 8 at addr ffff8880a9684b98 by task syz-executor329/6836 > >>> > >>> CPU: 1 PID: 6836 Comm: syz-executor329 Not tainted 5.9.0-rc6-syzkaller #0 > >>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > >>> Call Trace: > >>> __dump_stack lib/dump_stack.c:77 [inline] > >>> dump_stack+0x1d6/0x29e lib/dump_stack.c:118 > >>> print_address_description+0x66/0x620 mm/kasan/report.c:383 > >>> __kasan_report mm/kasan/report.c:513 [inline] > >>> kasan_report+0x132/0x1d0 mm/kasan/report.c:530 > >>> squashfs_get_id+0xb9/0x1c0 fs/squashfs/id.c:38 > >>> squashfs_new_inode fs/squashfs/inode.c:51 [inline] > >>> squashfs_read_inode+0x155/0x2170 fs/squashfs/inode.c:120 > >>> squashfs_fill_super+0x1478/0x1790 fs/squashfs/super.c:310 > >>> get_tree_bdev+0x3e9/0x5f0 fs/super.c:1342 > >>> vfs_get_tree+0x88/0x270 fs/super.c:1547 > >>> do_new_mount fs/namespace.c:2875 [inline] > >>> path_mount+0x179d/0x29e0 fs/namespace.c:3192 > >>> do_mount fs/namespace.c:3205 [inline] > >>> __do_sys_mount fs/namespace.c:3413 [inline] > >>> __se_sys_mount+0x126/0x180 fs/namespace.c:3390 > >>> do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 > >>> entry_SYSCALL_64_after_hwframe+0x44/0xa9 > >>> RIP: 0033:0x446d1a > >>> Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00 > >>> RSP: 002b:00007ffd7dd4f8b8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5 > >>> RAX: ffffffffffffffda RBX: 00007ffd7dd4f910 RCX: 0000000000446d1a > >>> RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffd7dd4f8d0 > >>> RBP: 00007ffd7dd4f8d0 R08: 00007ffd7dd4f910 R09: 00007ffd00000015 > >>> R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 > >>> R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003 > >>> > >>> Allocated by task 3913: > >>> kasan_save_stack mm/kasan/common.c:48 [inline] > >>> kasan_set_track mm/kasan/common.c:56 [inline] > >>> __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 > >>> kmalloc_node include/linux/slab.h:577 [inline] > >>> __vmalloc_area_node mm/vmalloc.c:2429 [inline] > >>> __vmalloc_node_range+0x2c7/0x870 mm/vmalloc.c:2511 > >>> module_alloc+0x7e/0x90 arch/x86/kernel/module.c:75 > >>> bpf_jit_binary_alloc+0x123/0x230 kernel/bpf/core.c:871 > >>> bpf_int_jit_compile+0x7995/0x8920 arch/x86/net/bpf_jit_comp.c:1911 > >>> bpf_prog_select_runtime+0x76d/0xa60 kernel/bpf/core.c:1807 > >>> bpf_migrate_filter net/core/filter.c:1290 [inline] > >>> bpf_prepare_filter+0xec2/0x1140 net/core/filter.c:1338 > >>> bpf_prog_create_from_user+0x2ad/0x3e0 net/core/filter.c:1432 > >>> seccomp_prepare_filter kernel/seccomp.c:567 [inline] > >>> seccomp_prepare_user_filter kernel/seccomp.c:604 [inline] > >>> seccomp_set_mode_filter kernel/seccomp.c:1546 [inline] > >>> do_seccomp+0x852/0x20b0 kernel/seccomp.c:1661 > >>> do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 > >>> entry_SYSCALL_64_after_hwframe+0x44/0xa9 > >>> > >>> The buggy address belongs to the object at ffff8880a9684b80 > >>> which belongs to the cache kmalloc-32 of size 32 > >>> The buggy address is located 24 bytes inside of > >>> 32-byte region [ffff8880a9684b80, ffff8880a9684ba0) > >>> The buggy address belongs to the page: > >>> page:00000000f697ca3d refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a9684fc1 pfn:0xa9684 > >>> flags: 0xfffe0000000200(slab) > >>> raw: 00fffe0000000200 ffffea0002a5d5c8 ffffea0002a98588 ffff8880aa440100 > >>> raw: ffff8880a9684fc1 ffff8880a9684000 000000010000003f 0000000000000000 > >>> page dumped because: kasan: bad access detected > >>> > >>> Memory state around the buggy address: > >>> ffff8880a9684a80: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc > >>> ffff8880a9684b00: 00 fc fc fc fc fc fc fc fa fb fb fb fc fc fc fc > >>> >ffff8880a9684b80: 00 fc fc fc fc fc fc fc fa fb fb fb fc fc fc fc > >>> ^ > >>> ffff8880a9684c00: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc > >>> ffff8880a9684c80: 00 00 01 fc fc fc fc fc fa fb fb fb fc fc fc fc > >>> ================================================================== > >>> > >>> > >>> --- > >>> This report is generated by a bot. It may contain errors. > >>> See https://goo.gl/tpsmEJ for more information about syzbot. > >>> syzbot engineers can be reached at syzk...@googlegroups.com. > >>> > >>> syzbot will keep track of this issue. See: > >>> https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > >>> syzbot can test patches for this issue, for details see: > >>> https://goo.gl/tpsmEJ#testing-patches > >> > >> -- > >> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > >> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > >> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/300c32a1-a0de-4f05-b467-0822b3d21733n%40googlegroups.com. _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees