Vulnerability CVE-2021-47115

Vulnerability CVE-2021-47115

Published: 2024-03-15

Description:

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

nfc: fix NULL ptr dereference in llcp_sock_getname() after failed connect

It's possible to trigger NULL pointer dereference by local unprivileged
user, when calling getsockname() after failed bind() (e.g. the bind
fails because LLCP_SAP_MAX used as SAP):

BUG: kernel NULL pointer dereference, address: 0000000000000000
CPU: 1 PID: 426 Comm: llcp_sock_getna Not tainted 5.13.0-rc2-next-20210521+ #9
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1 04/01/2014
Call Trace:
llcp_sock_getname+0xb1/0xe0
__sys_getpeername+0x95/0xc0
? lockdep_hardirqs_on_prepare+0xd5/0x180
? syscall_enter_from_user_mode+0x1c/0x40
__x64_sys_getpeername+0x11/0x20
do_syscall_64+0x36/0x70
entry_SYSCALL_64_after_hwframe+0x44/0xae

This can be reproduced with Syzkaller C repro (bind followed by
getpeername):
https://syzkaller.appspot.com/x/repro.c?x=14def446e00000

References:

https://git.kernel.org/stable/c/eb6875d48590d8e564092e831ff07fa384d7e477

https://git.kernel.org/stable/c/39c15bd2e5d11bcf7f4c3dba2aad9e1e110a5d94

https://git.kernel.org/stable/c/ffff05b9ee5c74c04bba2801c1f99b31975d74d9

https://git.kernel.org/stable/c/93e4ac2a9979a9a4ecc158409ed9c3044dc0ae1f

https://git.kernel.org/stable/c/5d4c4b06ed9fb7a69d0b2e2a73fc73226d25ab70

https://git.kernel.org/stable/c/48ee0db61c8299022ec88c79ad137f290196cac2

https://git.kernel.org/stable/c/0c4559736d9a4ec1ca58ba98ca34e7c4da4c422b

https://git.kernel.org/stable/c/4ac06a1e013cf5fdd963317ffd3b968560f33bba

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