high
7.8
CWE
416
Advisory Published
CVE Published
Updated

CVE-2022-1011: Use After Free

First published: Mon Mar 07 2022(Updated: )

A flaw in the Linux Kernel found. If unprivileged users can mount FUSE filesystems, then can trigger use after free (UAF) that reads of write() buffers, allowing theft of (partial) /etc/shadow hashes or any other data from filesystem. FUSE allows the userspace filesystem to specify on FUSE_OPEN whether the file should use the normal kernel pagecache for handling read()/write() or just send FUSE_READ/FUSE_WRITE requests directly to the userspace filesystem (using the flag FOPEN_DIRECT_IO in fuse_open_out::open_flags). In FOPEN_DIRECT_IO mode, fuse_file_write_iter() calls fuse_direct_write_iter(), which normally calls fuse_direct_io(), which then imports the write buffer with fuse_get_user_pages(), which uses iov_iter_get_pages() to grab references to userspace pages instead of actually copying memory. On the filesystem device side, these pages can then either be read to userspace (via fuse_dev_read()), or splice()d over into a pipe using fuse_dev_splice_read() as pipe buffers with &nosteal_pipe_buf_ops. This is wrong because after fuse_dev_do_read() unlocks the FUSE request, the userspace filesystem can mark the request as completed, causing write() to return. At that point, the write buffer may be reused for other purposes, and the userspace filesystem should no longer have access to it.

Credit: secalert@redhat.com

Affected SoftwareAffected VersionHow to fix
redhat/kernel-rt<0:4.18.0-372.9.1.rt7.166.el8
0:4.18.0-372.9.1.rt7.166.el8
redhat/kernel<0:4.18.0-372.9.1.el8
0:4.18.0-372.9.1.el8
redhat/Linux kernel<5.16
5.16
Linux Kernel<5.17
Linux Kernel=5.17
Linux Kernel=5.17-rc1
Linux Kernel=5.17-rc2
Linux Kernel=5.17-rc3
Linux Kernel=5.17-rc4
Linux Kernel=5.17-rc7
Red Hat Fedora=34
Red Hat Fedora=35
Red Hat Quarkus=2.0
Red Hat Developer Tools=1.0
Red Hat Enterprise Linux=6.0
Red Hat Enterprise Linux=7.0
Red Hat Enterprise Linux=8.0
Red Hat Enterprise Linux Server EUS=8.6
Red Hat Enterprise Linux for IBM Z Systems=8.0
Red Hat Enterprise Linux for IBM Z Systems (s390x)=8.6
Red Hat Enterprise Linux for Power, little endian=8.0
Red Hat Enterprise Linux for Power, little endian - Extended Update Support=8.6
Red Hat Enterprise Linux for Real Time=8
Red Hat Enterprise Linux for Real Time for NFV=8
Red Hat Enterprise Linux for Real Time for NFV=8.6
Red Hat Enterprise Linux for Real Time=8.6
Red Hat Enterprise Linux Server=8.6
Red Hat Enterprise Linux for SAP Applications for Power, little endian - Extended Update Support=8.6
Red Hat Enterprise Linux Server=8.6
Red Hat Enterprise Linux Server Update Services for SAP Solutions=8.6
All of
Red Hat Virtualization Host EUS=4.0
Red Hat Enterprise Linux=8.0
All of
Red Hat CodeReady Linux Builder
Any of
Red Hat Enterprise Linux=8.0
Red Hat Enterprise Linux=8.6
Red Hat Enterprise Linux Server EUS=8.6
Red Hat Enterprise Linux for Power, little endian=8.0
Red Hat Enterprise Linux for Power, little endian - Extended Update Support=8.6
All of
NetApp H300S Firmware
NetApp H300S Firmware
All of
NetApp H500e Firmware
NetApp H500e Firmware
All of
NetApp H700S
NetApp H700S
All of
NetApp H300E
NetApp H300E Firmware
All of
NetApp H500S Firmware
NetApp H500e Firmware
All of
NetApp H700E
NetApp H700E
All of
NetApp H410S
NetApp H410S Firmware
All of
NetApp H410C
NetApp H410C Firmware
Debian Linux=9.0
Debian Linux=10.0
Oracle Communications Cloud Native Core Binding Support Function=22.1.3
Red Hat Virtualization Host EUS=4.0
Red Hat Enterprise Linux=8.0
Red Hat CodeReady Linux Builder
Red Hat Enterprise Linux=8.6
Red Hat Enterprise Linux Server EUS=8.6
Red Hat Enterprise Linux for Power, little endian=8.0
Red Hat Enterprise Linux for Power, little endian - Extended Update Support=8.6
NetApp H300S Firmware
NetApp H300S Firmware
NetApp H500e Firmware
NetApp H500e Firmware
NetApp H700S
NetApp H700S
NetApp H300E
NetApp H300E Firmware
NetApp H500S Firmware
NetApp H500e Firmware
NetApp H700E
NetApp H700E
NetApp H410S
NetApp H410S Firmware
NetApp H410C
NetApp H410C Firmware
debian/linux
5.10.223-1
5.10.234-1
6.1.129-1
6.1.128-1
6.12.20-1
6.12.21-1

Remedy

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

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Reference Links

Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is the severity of CVE-2022-1011?

    CVE-2022-1011 is considered a medium severity vulnerability due to its potential to allow unauthorized access to sensitive files.

  • How do I fix CVE-2022-1011?

    To remediate CVE-2022-1011, upgrade to the fixed versions of the Linux kernel as specified in the patches provided by your distribution.

  • What systems are affected by CVE-2022-1011?

    CVE-2022-1011 affects specific versions of the Linux kernel including Red Hat kernel versions 4.18.0-372.9.1 and 5.16, among others.

  • What type of vulnerability is CVE-2022-1011?

    CVE-2022-1011 is a use after free (UAF) vulnerability that can lead to information disclosure.

  • Who is impacted by CVE-2022-1011?

    Unprivileged users who can mount FUSE filesystems on affected systems are at risk from CVE-2022-1011.

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