CVE-2021-47488

一、漏洞信息
 漏洞编号：[CVE-2021-47488](https://nvd.nist.gov/vuln/detail/CVE-2021-47488)
 漏洞归属组件：[kernel](https://gitee.com/src-openeuler/kernel)
 漏洞归属的版本：4.19.140,4.19.194,4.19.90,5.10.0
 CVSS V3.0分值：
  BaseScore：0.0 None
  Vector：CVSS：3.0/
 漏洞简述：
  A vulnerability has been found in Linux Kernel up to 5.10.76/5.14.15 (Operating System) and classified as critical.The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.As an impact it is known to affect availability.Upgrading to version 5.10.77 or 5.14.16 eliminates this vulnerability. Applying the patch 01599bf7cc2b/b529f88d9388/04f8ef5643bc is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.
 漏洞公开时间：2024-05-22 00:00:00
 漏洞创建时间：2024-05-22 09:32:42
 漏洞详情参考链接：
  https://nvd.nist.gov/vuln/detail/CVE-2021-47488
<details>
<summary>更多参考(点击展开)</summary>

| 参考来源 | 参考链接 | 来源链接 |
| ------- | -------- | -------- |
|  | https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed |  |
|  | https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba |  |
|  | https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d |  |
|  | https://www.cve.org/CVERecord?id=CVE-2021-47488 |  |
|  | https://git.kernel.org/linus/04f8ef5643bcd8bcde25dfdebef998aea480b2ba |  |

</details>

漏洞分析指导链接：
  https://gitee.com/openeuler/cve-manager/blob/master/cve-vulner-manager/doc/md/manual.md
 漏洞数据来源:
  openBrain开源漏洞感知系统
 漏洞补丁信息：
  <details>
<summary>详情(点击展开)</summary>

| 影响的包 | 修复版本 | 修复补丁 | 问题引入补丁 | 来源  |
| ------- | -------- | ------- | -------- | --------- |
|  | https://github.com/torvalds/linux/commit/04f8ef5643bcd8bcde25dfd | https://github.com/torvalds/linux/commit/04f8ef5643bcd8bcde25dfdebef998aea480b2ba.patch |  | ljqc |

</details>

二、漏洞分析结构反馈
 影响性分析说明：
          In the Linux kernel, the following vulnerability has been resolved:cgroup: Fix memory leak caused by missing cgroup_bpf_offlineWhen enabling CONFIG_CGROUP_BPF, kmemleak can be observed by runningthe command as below:    $mount -t cgroup -o none,name=foo cgroup cgroup/    $umount cgroup/unreferenced object 0xc3585c40 (size 64):  comm  mount , pid 425, jiffies 4294959825 (age 31.990s)  hex dump (first 32 bytes):    01 00 00 80 84 8c 28 c0 00 00 00 00 00 00 00 00  ......(.........    00 00 00 00 00 00 00 00 6c 43 a0 c3 00 00 00 00  ........lC......  backtrace:    [<e95a2f9e>] cgroup_bpf_inherit+0x44/0x24c    [<1f03679c>] cgroup_setup_root+0x174/0x37c    [<ed4b0ac5>] cgroup1_get_tree+0x2c0/0x4a0    [<f85b12fd>] vfs_get_tree+0x24/0x108    [<f55aec5c>] path_mount+0x384/0x988    [<e2d5e9cd>] do_mount+0x64/0x9c    [<208c9cfe>] sys_mount+0xfc/0x1f4    [<06dd06e0>] ret_fast_syscall+0x0/0x48    [<a8308cb3>] 0xbeb4daa8This is because that since the commit 2b0d3d3e4fcf ( percpu_ref: reducememory footprint of percpu_ref in fast path ) root_cgrp->bpf.refcnt.datais allocated by the function percpu_ref_init in cgroup_bpf_inherit whichis called by cgroup_setup_root when mounting, but not freed along withroot_cgrp when umounting. Adding cgroup_bpf_offline which callspercpu_ref_kill to cgroup_kill_sb can free root_cgrp->bpf.refcnt.data inumount path.This patch also fixes the commit 4bfc0bb2c60e ( bpf: decouple the lifetimeof cgroup_bpf from cgroup itself ). A cgroup_bpf_offline is needed to do acleanup that frees the resources which are allocated by cgroup_bpf_inheritin cgroup_setup_root.And inside cgroup_bpf_offline, cgroup_get() is at the beginning andcgroup_put is at the end of cgroup_bpf_release which is called bycgroup_bpf_offline. So cgroup_bpf_offline can keep the balance ofcgroup s refcount.    
 openEuler评分：
  5.5
 Vector：CVSS：3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N
 受影响版本排查(受影响/不受影响)：
  1.openEuler-22.03-LTS-SP1:受影响
2.openEuler-22.03-LTS-SP3:受影响
3.openEuler-20.03-LTS-SP1:不受影响
4.openEuler-20.03-LTS-SP4:不受影响
5.openEuler-22.03-LTS:不受影响
6.openEuler-22.03-LTS-SP2:不受影响
7.master:不受影响
8.openEuler-22.03-LTS-Next:不受影响
9.openEuler-24.03-LTS:不受影响
10.openEuler-24.03-LTS-Next:不受影响

修复是否涉及abi变化(是/否)：
  1.openEuler-20.03-LTS-SP1:否
2.openEuler-20.03-LTS-SP4:否
3.openEuler-22.03-LTS:否
4.openEuler-22.03-LTS-SP1:否
5.openEuler-22.03-LTS-SP2:否
6.openEuler-22.03-LTS-SP3:否
7.master:否
8.openEuler-22.03-LTS-Next:否
9.openEuler-24.03-LTS:否
10.openEuler-24.03-LTS-Next:否

原因说明：
  1.master:
2.openEuler-20.03-LTS-SP4:
3.openEuler-22.03-LTS-SP1:
4.openEuler-22.03-LTS-SP3:
5.openEuler-22.03-LTS-SP4:
6.openEuler-24.03-LTS:
7.openEuler-24.03-LTS-Next:
8.openEuler-24.03-LTS-SP1:

@yangyingliang ,@jiaoff ,@guohaocs2c ,@hanjun-guo ,@woqidaideshi ,@newbeats ,@zhangyi089 ,@colyli ,@thundertown ,@htforge ,@chiqijun ,@lengchao ,@zhujianwei001 ,@kylin-mayukun ,@wangxiongfeng ,@wkfxxx ,@SuperSix173 ,@jentlestea ,@oskernel0719 ,@gasonchen 
**issue处理注意事项:** 
**1. 当前issue受影响的分支提交pr时, 须在pr描述中填写当前issue编号进行关联, 否则无法关闭当前issue;**
**2. 模板内容需要填写完整, 无论是受影响或者不受影响都需要填写完整内容,未引入的分支不需要填写, 否则无法关闭当前issue;**
**3. 以下为模板中需要填写完整的内容, 请复制到评论区回复, 注: 内容的标题名称(影响性分析说明, openEuler评分, 受影响版本排查(受影响/不受影响), 修复是否涉及abi变化(是/否))不能省略,省略后cve-manager将无法正常解析填写内容.**
************************************************************************
影响性分析说明:

openEuler评分: (评分和向量)

受影响版本排查(受影响/不受影响): 
1.master(6.1.0):
2.openEuler-20.03-LTS-SP1(4.19.90):
3.openEuler-20.03-LTS-SP4(4.19.90):
4.openEuler-22.03-LTS(5.10.0):
5.openEuler-22.03-LTS-Next(5.10.0):
6.openEuler-22.03-LTS-SP1(5.10.0):
7.openEuler-22.03-LTS-SP2(5.10.0):
8.openEuler-22.03-LTS-SP3(5.10.0):
9.openEuler-22.03-LTS-SP4:
10.openEuler-24.03-LTS:
11.openEuler-24.03-LTS-Next:

修复是否涉及abi变化(是/否)：
1.master(6.1.0):
2.openEuler-20.03-LTS-SP1(4.19.90):
3.openEuler-20.03-LTS-SP4(4.19.90):
4.openEuler-22.03-LTS(5.10.0):
5.openEuler-22.03-LTS-Next(5.10.0):
6.openEuler-22.03-LTS-SP1(5.10.0):
7.openEuler-22.03-LTS-SP2(5.10.0):
8.openEuler-22.03-LTS-SP3(5.10.0):
9.openEuler-22.03-LTS-SP4:
10.openEuler-24.03-LTS:
11.openEuler-24.03-LTS-Next:

-----------------------------------------------------------------------
issue处理具体操作请参考: 
https://gitee.com/openeuler/cve-manager/blob/master/cve-vulner-manager/doc/md/manual.md
pr关联issue具体操作请参考:
https://gitee.com/help/articles/4142

<table><tr><th white-space: nowrap;>参考网址</th> <th white-space: nowrap;>关联pr</th> <th white-space: nowrap;>状态</th> <th white-space: nowrap;>补丁链接</th></tr><tr><td rowspan="1">https://nvd.nist.gov/vuln/detail/CVE-2021-47488</td><td>None</td><td>None</td><td><a href=https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba>https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba</a><br /><a href=https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed>https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed</a><br /><a href=https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d>https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d</a></td></tr><tr><td rowspan="1">https://ubuntu.com/security/CVE-2021-47488</td><td>None</td><td>None</td><td><a href=https://discourse.ubuntu.com/c/ubuntu-pro>https://discourse.ubuntu.com/c/ubuntu-pro</a></td></tr><tr><td rowspan="1">https://www.opencve.io/cve/CVE-2021-47488</td><td>None</td><td>None</td><td><a href=https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba>https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba</a><br /><a href=https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed>https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed</a><br /><a href=https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d>https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d</a></td></tr><tr><td>https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2021-47488</td><td></td><td></td><td></td></tr><tr><td rowspan="1">https://security-tracker.debian.org/tracker/CVE-2021-47488</td><td>None</td><td>None</td><td><a href=https://git.kernel.org/linus/04f8ef5643bcd8bcde25dfdebef998aea480b2ba>https://git.kernel.org/linus/04f8ef5643bcd8bcde25dfdebef998aea480b2ba</a></td></tr></table>

> 说明：补丁链接仅供初步排查参考，实际可用性请人工再次确认，补丁下载验证可使用[CVE补丁工具](https://gitee.com/openeuler/cve-manager/blob/master/cve-agency-manager/cve_tracking/README.md)。
若补丁不准确，烦请在此issue下评论 '/report-patch 参考网址 补丁链接1,补丁链接2' 反馈正确信息，便于我们不断优化工具，不胜感激。
如 /report-patch https://security-tracker.debian.org/tracker/CVE-2021-3997 https://github.com/systemd/systemd/commit/5b1cf7a9be37e20133c0208005274ce4a5b5c6a1

CVE-2021-47488

影响性分析说明：
In the Linux kernel, the following vulnerability has been resolved:

cgroup: Fix memory leak caused by missing cgroup_bpf_offline

When enabling CONFIG_CGROUP_BPF, kmemleak can be observed by running
the command as below:

$mount -t cgroup -o none,name=foo cgroup cgroup/
    $umount cgroup/

unreferenced object 0xc3585c40 (size 64):
  comm "mount", pid 425, jiffies 4294959825 (age 31.990s)
  hex dump (first 32 bytes):
    01 00 00 80 84 8c 28 c0 00 00 00 00 00 00 00 00  ......(.........
    00 00 00 00 00 00 00 00 6c 43 a0 c3 00 00 00 00  ........lC......
  backtrace:
    [<e95a2f9e>] cgroup_bpf_inherit+0x44/0x24c
    [<1f03679c>] cgroup_setup_root+0x174/0x37c
    [<ed4b0ac5>] cgroup1_get_tree+0x2c0/0x4a0
    [<f85b12fd>] vfs_get_tree+0x24/0x108
    [<f55aec5c>] path_mount+0x384/0x988
    [<e2d5e9cd>] do_mount+0x64/0x9c
    [<208c9cfe>] sys_mount+0xfc/0x1f4
    [<06dd06e0>] ret_fast_syscall+0x0/0x48
    [<a8308cb3>] 0xbeb4daa8

This is because that since the commit 2b0d3d3e4fcf ("percpu_ref: reduce
memory footprint of percpu_ref in fast path") root_cgrp->bpf.refcnt.data
is allocated by the function percpu_ref_init in cgroup_bpf_inherit which
is called by cgroup_setup_root when mounting, but not freed along with
root_cgrp when umounting. Adding cgroup_bpf_offline which calls
percpu_ref_kill to cgroup_kill_sb can free root_cgrp->bpf.refcnt.data in
umount path.

This patch also fixes the commit 4bfc0bb2c60e ("bpf: decouple the lifetime
of cgroup_bpf from cgroup itself"). A cgroup_bpf_offline is needed to do a
cleanup that frees the resources which are allocated by cgroup_bpf_inherit
in cgroup_setup_root.

And inside cgroup_bpf_offline, cgroup_get() is at the beginning and
cgroup_put is at the end of cgroup_bpf_release which is called by
cgroup_bpf_offline. So cgroup_bpf_offline can keep the balance of
cgroup's refcount.

openEuler评分:(评分和向量)
5.5
CVSS: 3.0/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:N

受影响版本排查(受影响/不受影响):
1.openEuler-20.03-LTS-SP1:不受影响
2.openEuler-20.03-LTS-SP4:不受影响
3.openEuler-22.03-LTS:受影响
4.openEuler-22.03-LTS-SP1:受影响
5.openEuler-22.03-LTS-SP2:受影响
6.openEuler-22.03-LTS-SP3:受影响
7.master(6.1.0):不受影响
8.openEuler-22.03-LTS-Next:不受影响
9.openEuler-24.03-LTS:不受影响
10.openEuler-24.03-LTS-Next:不受影响

修复是否涉及abi变化(是/否)：
1.openEuler-20.03-LTS-SP1(4.19.90):否
2.openEuler-20.03-LTS-SP4:否
3.openEuler-22.03-LTS:否
4.openEuler-22.03-LTS-SP1:否
5.openEuler-22.03-LTS-SP2:否
6.openEuler-22.03-LTS-SP3:否
7.master(6.1.0):否
8.openEuler-22.03-LTS-Next:否
9.openEuler-24.03-LTS:否
10.openEuler-24.03-LTS-Next:否