4.7

CVE-2021-47507

nfsd: Fix nsfd startup race (again)

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

nfsd: Fix nsfd startup race (again)

Commit bd5ae9288d64 ("nfsd: register pernet ops last, unregister first")
has re-opened rpc_pipefs_event() race against nfsd_net_id registration
(register_pernet_subsys()) which has been fixed by commit bb7ffbf29e76
("nfsd: fix nsfd startup race triggering BUG_ON").

Restore the order of register_pernet_subsys() vs register_cld_notifier().
Add WARN_ON() to prevent a future regression.

Crash info:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000012
CPU: 8 PID: 345 Comm: mount Not tainted 5.4.144-... #1
pc : rpc_pipefs_event+0x54/0x120 [nfsd]
lr : rpc_pipefs_event+0x48/0x120 [nfsd]
Call trace:
 rpc_pipefs_event+0x54/0x120 [nfsd]
 blocking_notifier_call_chain
 rpc_fill_super
 get_tree_keyed
 rpc_fs_get_tree
 vfs_get_tree
 do_mount
 ksys_mount
 __arm64_sys_mount
 el0_svc_handler
 el0_svc
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.4.102 < 5.4.165
Linux ≫ Linux Kernel Version >= 5.10.20 < 5.10.85
Linux ≫ Linux Kernel Version >= 5.11.3 < 5.15.8
Linux ≫ Linux Kernel Version5.16 Updaterc1
Linux ≫ Linux Kernel Version5.16 Updaterc2
Linux ≫ Linux Kernel Version5.16 Updaterc3
Linux ≫ Linux Kernel Version5.16 Updaterc4
VulnDex Vulnerability Enrichment
Diese Information steht angemeldeten Benutzern zur Verfügung. Login Login
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.19% 0.083
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 4.7 1 3.6
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

https://git.kernel.org/stable/c/8bf902fee5893cfc2f04a698abab47629699ae9a
Patch
https://git.kernel.org/stable/c/b10252c7ae9c9d7c90552f88b544a44ee773af64
Patch
https://git.kernel.org/stable/c/c520943a00ad5015704969ad3304c956bcd49d25
Patch
https://git.kernel.org/stable/c/f5734b1714ca355703e9ea8fb61d04beff1790b9
Patch