Researching CVE published originally by longterm.io
Big thank you to all the other security research people publishing their work,\
allowing others to learn, and do independent research.
Resources:
Original exploit article via longterm.io:\
https://www.longterm.io/cve-2020-0423.html
Repo from Github user 20000s, also looking into 2020-0423:\
https://github.com/20000s/android_cve/tree/main
Typhoon Black Hat presentation, documenting 2020-0423 as well:\
https://i.blackhat.com/USA21/Wednesday-Handouts/us-21-Typhoon-Mangkhut-One-Click-Remote-Universal-Root-Formed-With-Two-Vulnerabilities.pdf
Currently:
- Re-created KASAN crash with emulator
**TODO:**
- Next steps add heap groom, and achieve double free.
```
#######################
# KASAN CVE-2020-0423 #
#######################
EMULATOR CONSOLE OUTPUT:
[ 603.405298] binder: undelivered TRANSACTION_COMPLETE
[ 603.414687] ==================================================================
[ 603.419847] BUG: KASAN: use-after-free in binder_release_work+0x7e/0x1b7
[ 603.420120] binder: undelivered TRANSACTION_COMPLETE
[ 603.424408] Read of size 4 at addr ffff888055eaf3d8 by task crash/6106
[ 603.432171]
[ 603.433018] CPU: 1 PID: 6106 Comm: crash Not tainted 4.14.150+ #2
[ 603.436710] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014
[ 603.441990] binder: undelivered TRANSACTION_COMPLETE
[ 603.444149] Call Trace:
[ 603.444263] dump_stack+0x93/0xcc
[ 603.444405] print_address_description+0x67/0x22a
[ 603.444431] ? binder_release_work+0x7e/0x1b7
[ 603.444447] __kasan_report+0x13b/0x181
[ 603.444465] ? binder_release_work+0x7e/0x1b7
[ 603.444487] kasan_report+0x16/0x1b
[ 603.444505] __asan_report_load4_noabort+0x18/0x1a
[ 603.444541] binder_release_work+0x7e/0x1b7
[ 603.462842] binder: undelivered TRANSACTION_COMPLETE
[ 603.465411] binder_thread_release+0x3d5/0x3ef
[ 603.465449] binder_ioctl+0xa13/0x1097
[ 603.465481] ? binder_thread_write+0x27fa/0x27fa
[ 603.465598] ? selinux_bprm_set_creds+0x8d8/0x8d8
[ 603.465657] ? __fsnotify_update_child_dentry_flags+0x2c9/0x2c9
[ 603.465698] ? fsnotify_perm+0x10e/0x11d
[ 603.465731] ? __fcheck_files+0xc5/0xd1
[ 603.465766] ? security_file_ioctl+0x67/0xa4
[ 603.465793] ? security_file_ioctl+0x95/0xa4
[ 603.465825] ? binder_thread_write+0x27fa/0x27fa
[ 603.465884] compat_SyS_ioctl+0x773/0x1f8e
[ 603.465979] ? fdput_pos.isra.0+0x36/0x3c
[ 603.471241] binder: undelivered TRANSACTION_COMPLETE
[ 603.471533] ? do_ioctl+0x52/0x52
[ 603.479034] binder: undelivered TRANSACTION_COMPLETE
[ 603.480270] ? syscall_return_slowpath+0x20b/0x217
[ 603.480317] do_fast_syscall_32+0x38c/0x4af
[ 603.491999] binder: undelivered TRANSACTION_COMPLETE
[ 603.492460] ? do_ioctl+0x52/0x52
[ 603.497958] binder: undelivered TRANSACTION_COMPLETE
[ 603.499648] entry_SYSENTER_compat+0x7f/0x8e
[ 603.515820] binder: undelivered TRANSACTION_COMPLETE
[ 603.515997] RIP: 0023:0xed87da69
[ 603.516016] RSP: 002b:00000000ecff414c EFLAGS: 00200292 ORIG_RAX: 0000000000000036
[ 603.516046] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000040046208
[ 603.516056] RDX: 0000000000000000 RSI: 00000000ed569140 RDI: 00000000ecff4230
[ 603.516072] RBP: 00000000ecff4198 R08: 0000000000000000 R09: 0000000000000000
[ 603.516090] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 603.516105] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 603.516137]
[ 603.541399] binder: undelivered TRANSACTION_COMPLETE
[ 603.541767] Allocated by task 6106:
[ 603.546639] binder: undelivered TRANSACTION_COMPLETE
[ 603.550587] save_stack_trace+0x1a/0x1c
[ 603.550621] save_stack+0x44/0xab
[ 603.550670] __kasan_kmalloc.constprop.0+0x8f/0xa1
[ 603.571263] binder: undelivered TRANSACTION_COMPLETE
[ 603.577168] kasan_kmalloc+0xd/0xf
[ 603.577215] __kmalloc+0x172/0x19b
[ 603.579423] binder: undelivered TRANSACTION_COMPLETE
[ 603.582212] kzalloc.constprop.0+0x1c/0x1e
[ 603.582239] binder_new_node+0x26/0x651
[ 603.582264] binder_transaction+0x2f8f/0x558f
[ 603.582289] binder_thread_write+0x1217/0x27fa
[ 603.582312] binder_ioctl+0x483/0x1097
[ 603.582361] compat_SyS_ioctl+0x773/0x1f8e
[ 603.594137] binder: unexpected work type, 4, not freed
[ 603.594780] do_fast_syscall_32+0x38c/0x4af
[ 603.597924] binder: undelivered TRANSACTION_COMPLETE
[ 603.600009] entry_SYSENTER_compat+0x7f/0x8e
[ 603.603516] binder: unexpected work type, 4, not freed
[ 603.605772] 0xffffffffffffffff
[ 603.605795]
[ 603.609444] binder: undelivered TRANSACTION_COMPLETE
[ 603.611140] Freed by task 1848:
[ 603.611167] save_stack_trace+0x1a/0x1c
[ 603.611186] save_stack+0x44/0xab
[ 603.611205] __kasan_slab_free+0x10b/0x12e
[ 603.611224] kasan_slab_free+0x12/0x14
[ 603.611240] slab_free_freelist_hook+0xb9/0x105
[ 603.611255] kfree+0x102/0x196
[ 603.611294] binder_free_node+0x17/0x23
[ 603.617318] binder: unexpected work type, 4, not freed
[ 603.619637] binder_free_ref+0x47/0x84
[ 603.619683] binder_update_ref_for_handle+0x4bf/0x4d4
[ 603.622439] binder: undelivered TRANSACTION_COMPLETE
[ 603.625653] binder_transaction_buffer_release+0x49f/0x7a7
[ 603.625669] binder_thread_write+0x115a/0x27fa
[ 603.625683] binder_ioctl+0x483/0x1097
[ 603.625714] compat_SyS_ioctl+0x773/0x1f8e
[ 603.635322] binder: unexpected work type, 4, not freed
[ 603.637686] do_fast_syscall_32+0x38c/0x4af
[ 603.639943] binder: undelivered TRANSACTION_COMPLETE
[ 603.641551] entry_SYSENTER_compat+0x7f/0x8e
[ 603.641563] 0xffffffffffffffff
[ 603.641567]
[ 603.641610] The buggy address belongs to the object at ffff888055eaf3c0
[ 603.641610] which belongs to the cache kmalloc-128 of size 128
[ 603.641625] The buggy address is located 24 bytes inside of
[ 603.641625] 128-byte region [ffff888055eaf3c0, ffff888055eaf440)
[ 603.641630] The buggy address belongs to the page:
[ 603.641672] page:ffffea000157abc0 count:1 mapcount:0 mapping: (null) index:0x0
[ 603.658184] binder: unexpected work type, 4, not freed
[ 603.661778] binder: undelivered TRANSACTION_COMPLETE
[ 603.664121] flags: 0x4000000000000200(slab)
[ 603.671362] binder: undelivered TRANSACTION_COMPLETE
[ 603.672867] raw: 4000000000000200 0000000000000000 0000000000000000 0000000100150015
[ 603.698824] binder: undelivered TRANSACTION_COMPLETE
[ 603.701565] raw: 0000000000000000 0000000300000001 ffff888059003340 0000000000000000
[ 603.701580] page dumped because: kasan: bad access detected
[ 603.701585]
[ 603.701593] Memory state around the buggy address:
[ 603.701628] ffff888055eaf280: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
[ 603.708474] binder: undelivered TRANSACTION_COMPLETE
[ 603.708974] ffff888055eaf300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
[ 603.720795] binder: undelivered TRANSACTION_COMPLETE
[ 603.725813] >ffff888055eaf380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
[ 603.750163] binder: undelivered TRANSACTION_COMPLETE
[ 603.751975] ^
[ 603.760701] binder: unexpected work type, 4, not freed
[ 603.760817] ffff888055eaf400: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[ 603.764683] binder: undelivered TRANSACTION_COMPLETE
[ 603.765591] ffff888055eaf480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 603.781882] binder: undelivered TRANSACTION_COMPLETE
[ 603.781981] ==================================================================
[ 603.788061] binder: undelivered TRANSACTION_COMPLETE
[ 603.789080] Disabling lock debugging due to kernel taint
[ 603.800441] binder: undelivered TRANSACTION_COMPLETE
[ 603.821838] binder: unexpected work type, 4, not freed
[ 603.841384] binder: undelivered TRANSACTION_COMPLETE
[ 603.850458] binder: unexpected work type, 4, not freed
[ 603.854205] binder: unexpected work type, 4, not freed
DMESG OUTPUT EMULATOR:
[ 603.379559] binder: undelivered TRANSACTION_COMPLETE
[ 603.386711] binder: unexpected work type, 4, not freed
[ 603.389963] binder: undelivered TRANSACTION_COMPLETE
[ 603.393125] binder: undelivered TRANSACTION_COMPLETE
[ 603.399327] binder: unexpected work type, 4, not freed
[ 603.399486] binder: undelivered TRANSACTION_COMPLETE
[ 603.405298] binder: undelivered TRANSACTION_COMPLETE
[ 603.419847] BUG: KASAN: use-after-free in binder_release_work+0x7e/0x1b7
[ 603.420120] binder: undelivered TRANSACTION_COMPLETE
[ 603.441990] binder: undelivered TRANSACTION_COMPLETE
[ 603.444431] ? binder_release_work+0x7e/0x1b7
[ 603.444465] ? binder_release_work+0x7e/0x1b7
[ 603.444541] binder_release_work+0x7e/0x1b7
[ 603.462842] binder: undelivered TRANSACTION_COMPLETE
[ 603.465411] binder_thread_release+0x3d5/0x3ef
[ 603.465449] binder_ioctl+0xa13/0x1097
[ 603.465481] ? binder_thread_write+0x27fa/0x27fa
[ 603.465825] ? binder_thread_write+0x27fa/0x27fa
[ 603.471241] binder: undelivered TRANSACTION_COMPLETE
[ 603.479034] binder: undelivered TRANSACTION_COMPLETE
[ 603.491999] binder: undelivered TRANSACTION_COMPLETE
[ 603.497958] binder: undelivered TRANSACTION_COMPLETE
[ 603.515820] binder: undelivered TRANSACTION_COMPLETE
[ 603.541399] binder: undelivered TRANSACTION_COMPLETE
[ 603.546639] binder: undelivered TRANSACTION_COMPLETE
[ 603.571263] binder: undelivered TRANSACTION_COMPLETE
[ 603.579423] binder: undelivered TRANSACTION_COMPLETE
[ 603.582239] binder_new_node+0x26/0x651
[ 603.582264] binder_transaction+0x2f8f/0x558f
[ 603.582289] binder_thread_write+0x1217/0x27fa
[ 603.582312] binder_ioctl+0x483/0x1097
[ 603.594137] binder: unexpected work type, 4, not freed
[ 603.597924] binder: undelivered TRANSACTION_COMPLETE
[ 603.603516] binder: unexpected work type, 4, not freed
[ 603.609444] binder: undelivered TRANSACTION_COMPLETE
[ 603.611294] binder_free_node+0x17/0x23
[ 603.617318] binder: unexpected work type, 4, not freed
[ 603.619637] binder_free_ref+0x47/0x84
[ 603.619683] binder_update_ref_for_handle+0x4bf/0x4d4
[ 603.622439] binder: undelivered TRANSACTION_COMPLETE
[ 603.625653] binder_transaction_buffer_release+0x49f/0x7a7
[ 603.625669] binder_thread_write+0x115a/0x27fa
[ 603.625683] binder_ioctl+0x483/0x1097
[ 603.635322] binder: unexpected work type, 4, not freed
[ 603.639943] binder: undelivered TRANSACTION_COMPLETE
[ 603.658184] binder: unexpected work type, 4, not freed
[ 603.661778] binder: undelivered TRANSACTION_COMPLETE
[ 603.671362] binder: undelivered TRANSACTION_COMPLETE
```
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