Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1000 CNY

100.0%
Buy Us a Coffee

CVE-2021-47089— kfence: fix memory leak when cat kfence objects

EPSS 0.02% · P4
Get alerts for future matching vulnerabilitiesLog in to subscribe

I. Basic Information for CVE-2021-47089

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
kfence: fix memory leak when cat kfence objects
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: kfence: fix memory leak when cat kfence objects Hulk robot reported a kmemleak problem: unreferenced object 0xffff93d1d8cc02e8 (size 248): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 unreferenced object 0xffff93d419854000 (size 4096): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12- backtrace: seq_read_iter+0x313/0x440 seq_read+0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 I find that we can easily reproduce this problem with the following commands: cat /sys/kernel/debug/kfence/objects echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak The leaked memory is allocated in the stack below: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---> alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse ---> alloc seq_buf And it should have been released in the following process: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---> free here However, the release function corresponding to file_operations is not implemented in kfence. As a result, a memory leak occurs. Therefore, the solution to this problem is to implement the corresponding release function.
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel 存在安全漏洞，该漏洞源于kfence中的cat kfence存在内存泄漏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux 0ce20dd840897b12ae70869c69f1ba34d6d16965 ~ 2f06c8293d27f6337f907042c602c9c953988c48 -
LinuxLinux 5.12 -

II. Public POCs for CVE-2021-47089

#POC DescriptionSource LinkShenlong Link
AI-Generated POCPremium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2021-47089

请登录查看更多情报信息。

Same Patch Batch · Linux · 2024-03-04 · 26 CVEs total

CVE-2021-47096ALSA: rawmidi - fix the uninitalized user_pversion
CVE-2021-47108drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf
CVE-2021-47107NFSD: Fix READDIR buffer overflow
CVE-2021-47106netfilter: nf_tables: fix use-after-free in nft_set_catchall_destroy()
CVE-2021-47105ice: xsk: return xsk buffers back to pool when cleaning the ring
CVE-2021-47104IB/qib: Fix memory leak in qib_user_sdma_queue_pkts()
CVE-2021-47103inet: fully convert sk->sk_rx_dst to RCU rules
CVE-2021-47102net: marvell: prestera: fix incorrect structure access
CVE-2021-47101asix: fix uninit-value in asix_mdio_read()
CVE-2021-47100ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module
CVE-2021-47099veth: ensure skb entering GRO are not cloned.
CVE-2021-47098hwmon: (lm90) Prevent integer overflow/underflow in hysteresis calculations
CVE-2021-47097Input: elantech - fix stack out of bound access in elantech_change_report_id()
CVE-2024-26622tomoyo: fix UAF write bug in tomoyo_write_control()
CVE-2021-47095ipmi: ssif: initialize ssif_info->client early
CVE-2021-47094KVM: x86/mmu: Don't advance iterator after restart due to yielding
CVE-2021-47093platform/x86: intel_pmc_core: fix memleak on registration failure
CVE-2021-47092KVM: VMX: Always clear vmx->fail on emulation_required
CVE-2021-47091mac80211: fix locking in ieee80211_start_ap error path
CVE-2021-47090mm/hwpoison: clear MF_COUNT_INCREASED before retrying get_any_page()

Showing top 20 of 26 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47089

No comments yet

Leave a comment