Executive Summary



This vulnerability is currently undergoing analysis and not all information is available. Please check back soon to view the completed vulnerability summary
Informations
Name CVE-2022-49947 First vendor Publication 2025-06-18
Vendor Cve Last vendor Modification 2025-06-18

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score NA
Base Score NA Environmental Score NA
impact SubScore NA Temporal Score NA
Exploitabality Sub Score NA
 
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Security-Database Scoring CVSS v2

Cvss vector :
Cvss Base Score N/A Attack Range N/A
Cvss Impact Score N/A Attack Complexity N/A
Cvss Expoit Score N/A Authentication N/A
Calculate full CVSS 2.0 Vectors scores

Detail

In the Linux kernel, the following vulnerability has been resolved:

binder: fix alloc->vma_vm_mm null-ptr dereference

Syzbot reported a couple issues introduced by commit 44e602b4e52f ("binder_alloc: add missing mmap_lock calls when using the VMA"), in which we attempt to acquire the mmap_lock when alloc->vma_vm_mm has not been initialized yet.

This can happen if a binder_proc receives a transaction without having previously called mmap() to setup the binder_proc->alloc space in [1]. Also, a similar issue occurs via binder_alloc_print_pages() when we try to dump the debugfs binder stats file in [2].

Sample of syzbot's crash report:
==================================================================
KASAN: null-ptr-deref in range [0x0000000000000128-0x000000000000012f]
CPU: 0 PID: 3755 Comm: syz-executor229 Not tainted 6.0.0-rc1-next-20220819-syzkaller #0
syz-executor229[3755] cmdline: ./syz-executor2294415195
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
RIP: 0010:__lock_acquire+0xd83/0x56d0 kernel/locking/lockdep.c:4923
[...]
Call Trace:

lock_acquire kernel/locking/lockdep.c:5666 [inline]
lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631
down_read+0x98/0x450 kernel/locking/rwsem.c:1499
mmap_read_lock include/linux/mmap_lock.h:117 [inline]
binder_alloc_new_buf_locked drivers/android/binder_alloc.c:405 [inline]
binder_alloc_new_buf+0xa5/0x19e0 drivers/android/binder_alloc.c:593
binder_transaction+0x242e/0x9a80 drivers/android/binder.c:3199
binder_thread_write+0x664/0x3220 drivers/android/binder.c:3986
binder_ioctl_write_read drivers/android/binder.c:5036 [inline]
binder_ioctl+0x3470/0x6d00 drivers/android/binder.c:5323
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]
==================================================================

Fix these issues by setting up alloc->vma_vm_mm pointer during open() and caching directly from current->mm. This guarantees we have a valid reference to take the mmap_lock during scenarios described above.

[1] https://syzkaller.appspot.com/bug?extid=f7dc54e5be28950ac459 [2] https://syzkaller.appspot.com/bug?extid=a75ebe0452711c9e56d9

Original Source

Url : http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-49947

Sources (Detail)

https://git.kernel.org/stable/c/1da52815d5f1b654c89044db0cdc6adce43da1f1
https://git.kernel.org/stable/c/81203ab7a6ef843a2b904a0a494f28c457d44d27
https://git.kernel.org/stable/c/b2a97babb0a510f8921891f9e70c5a5ef33cadac
Source Url

Alert History

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Date Informations
2025-06-18 17:20:35
  • First insertion