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CVE-2022-50323

net: do not sense pfmemalloc status in skb_append_pagefrags()

CVSS score

5.5

EPSS probability

%0.2

Risk score

0.0

Published

1 y ago

Official patch verified

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Vulnerability description

DayBreach CVE AI Research

CVE-2022-50323 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

In the Linux kernel, the following vulnerability has been resolved: net: do not sense pfmemalloc status in skb_append_pagefrags() skb_append_pagefrags() is used by af_unix and udp sendpage() implementation so far. In commit 326140063946 ("tcp: TX zerocopy should not sense pfmemalloc status") we explained why we should not sense pfmemalloc status for pages owned by user space. We should also use skb_fill_page_desc_noacc() in skb_append_pagefrags() to avoid following KCSAN report: BUG: KCSAN: data-race in lru_add_fn / skb_append_pagefrags write to 0xffffea00058fc1c8 of 8 bytes by task 17319 on cpu 0: __list_add include/linux/list.h:73 [inline] list_add include/linux/list.h:88 [inline] lruvec_add_folio include/linux/mm_inline.h:323 [inline] lru_add_fn+0x327/0x410 mm/swap.c:228 folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246 lru_add_drain_cpu+0x73/0x250 mm/swap.c:669 lru_add_drain+0x21/0x60 mm/swap.c:773 free_pages_and_swap_cache+0x16/0x70 mm/swap_state.c:311 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline] tlb_flush_mmu_free mm/mmu_gather.c:256 [inline] tlb_flush_mmu+0x5b2/0x640 mm/mmu_gather.c:263 tlb_finish_mmu+0x86/0x100 mm/mmu_gather.c:363 exit_mmap+0x190/0x4d0 mm/mmap.c:3098 __mmput+0x27/0x1b0 kernel/fork.c:1185 mmput+0x3d/0x50 kernel/fork.c:1207 copy_process+0x19fc/0x2100 kernel/fork.c:2518 kernel_clone+0x166/0x550 kernel/fork.c:2671 __do_sys_clone kernel/fork.c:2812 [inline] __se_sys_clone kernel/fork.c:2796 [inline] __x64_sys_clone+0xc3/0xf0 kernel/fork.c:2796 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffffea00058fc1c8 of 8 bytes by task 17325 on cpu 1: page_is_pfmemalloc include/linux/mm.h:1817 [inline] __skb_fill_page_desc include/linux/skbuff.h:2432 [inline] skb_fill_page_desc include/linux/skbuff.h:2453 [inline] skb_append_pagefrags+0x210/0x600 net/core/skbuff.c:3974 unix_stream_sendpage+0x45e/0x990 net/unix/af_unix.c:2338 kernel_sendpage+0x184/0x300 net/socket.c:3561 sock_sendpage+0x5a/0x70 net/socket.c:1054 pipe_to_sendpage+0x128/0x160 fs/splice.c:361 splice_from_pipe_feed fs/splice.c:415 [inline] __splice_from_pipe+0x222/0x4d0 fs/splice.c:559 splice_from_pipe fs/splice.c:594 [inline] generic_splice_sendpage+0x89/0xc0 fs/splice.c:743 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:931 splice_direct_to_actor+0x305/0x620 fs/splice.c:886 do_splice_direct+0xfb/0x180 fs/splice.c:974 do_sendfile+0x3bf/0x910 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x0000000000000000 -> 0xffffea00058fc188 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 17325 Comm: syz-executor.0 Not tainted 6.1.0-rc1-syzkaller-00158-g440b7895c990-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2022-50323 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
3linuxlinux kernel View
4linuxlinux kernel View
5linuxlinux kernel View
6linuxlinux kernel View
7linuxlinux kernel View
Total affected vendors: 1|Products: 7

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
5.5CVSS V31MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

3 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
nvd

NVD tarafından Patch olarak etiketlenmiş referans

Open source
Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Apply the official update named in the evidence only to the matching product and version.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2022-50323 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2022-50323 weaknesses.

Attack Vector and Accessibility

ExposureYerel erişim
PermissionsLow
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

5.5 / 10
Attack VectorLocalComplexityLowPrivilegesLowUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack VectorLocal
Attack ComplexityLow
Privileges RequiredLow privileges
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama doğrulandı

3 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

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CVE-2022-50323 · net: do not sense pfmemalloc status in…