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CVE-2021-46974— bpf: Fix masking negation logic upon negative dst register

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

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 off_reg 位于 dst 寄存器中的情况的否定逻辑不正确。

CVSS 7.1 · High EPSS 0.25% · P15

Affected Version Matrix 20

VendorProduct Version RangeStatus
Linux Linux ae03b6b1c880a03d4771257336dc3bca156dd51b< 4d542ddb88fb2f39bf7f14caa2902f3e8d06f6ba affected
f92a819b4cbef8c9527d9797110544b2055a4b96< 0e2dfdc74a7f4036127356d42ea59388f153f42c affected
979d63d50c0c0f7bc537bf821e056cc9fe5abd38< 53e0db429b37a32b8fc706d0d90eb4583ad13848 affected
979d63d50c0c0f7bc537bf821e056cc9fe5abd38< 2cfa537674cd1051a3b8111536d77d0558f33d5d affected
979d63d50c0c0f7bc537bf821e056cc9fe5abd38< 6eba92a4d4be8feb4dc33976abac544fa99d6ecc affected
979d63d50c0c0f7bc537bf821e056cc9fe5abd38< 7cf64d8679ca1cb20cf57d6a88bfee79a0922a66 affected
979d63d50c0c0f7bc537bf821e056cc9fe5abd38< b9b34ddbe2076ade359cd5ce7537d5ed019e9807 affected
078da99d449f64ca04d459cdbdcce513b64173cd affected
… +12 more rows
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I. Basic Information for CVE-2021-46974

Vulnerability Information
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Vulnerability Title
bpf: Fix masking negation logic upon negative dst register
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix masking negation logic upon negative dst register The negation logic for the case where the off_reg is sitting in the dst register is not correct given then we cannot just invert the add to a sub or vice versa. As a fix, perform the final bitwise and-op unconditionally into AX from the off_reg, then move the pointer from the src to dst and finally use AX as the source for the original pointer arithmetic operation such that the inversion yields a correct result. The single non-AX mov in between is possible given constant blinding is retaining it as it's not an immediate based operation.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
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 off_reg 位于 dst 寄存器中的情况的否定逻辑不正确。
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

Vendor Product Affected Versions CPE Subscribe
Linux Linux ae03b6b1c880a03d4771257336dc3bca156dd51b ~ 4d542ddb88fb2f39bf7f14caa2902f3e8d06f6ba -
Linux Linux 5.0 -

II. Public POCs for CVE-2021-46974

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III. Intelligence Information for CVE-2021-46974

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Patches & Fixes for CVE-2021-46974 (1)

Other References for CVE-2021-46974 (5)

Same Patch Batch · Linux · 2024-02-27 · 67 CVEs total

CVE-2021-46911 9.8 CRITICAL ch_ktls: Fix kernel panic
CVE-2021-46955 8.2 HIGH openvswitch: fix stack OOB read while fragmenting IPv4 packets
CVE-2021-46967 7.8 HIGH vhost-vdpa: fix vm_flags for virtqueue doorbell mapping
CVE-2021-46913 7.8 HIGH netfilter: nftables: clone set element expression template
CVE-2021-46969 7.8 HIGH bus: mhi: core: Fix invalid error returning in mhi_queue
CVE-2021-46973 7.8 HIGH net: qrtr: Avoid potential use after free in MHI send
CVE-2021-46922 7.8 HIGH KEYS: trusted: Fix TPM reservation for seal/unseal
CVE-2021-46921 7.8 HIGH locking/qrwlock: Fix ordering in queued_write_lock_slowpath()
CVE-2021-46925 7.8 HIGH net/smc: fix kernel panic caused by race of smc_sock
CVE-2021-46963 7.8 HIGH scsi: qla2xxx: Fix crash in qla2xxx_mqueuecommand()
CVE-2021-46929 7.8 HIGH sctp: use call_rcu to free endpoint
CVE-2021-46958 7.8 HIGH btrfs: fix race between transaction aborts and fsyncs leading to use-after-free
CVE-2021-46933 7.8 HIGH usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear.
CVE-2021-46936 7.8 HIGH net: fix use-after-free in tw_timer_handler
CVE-2021-46960 7.5 HIGH cifs: Return correct error code from smb2_get_enc_key
CVE-2021-46948 7.5 HIGH sfc: farch: fix TX queue lookup in TX event handling
CVE-2021-46912 7.3 HIGH net: Make tcp_allowed_congestion_control readonly in non-init netns
CVE-2021-46908 7.1 HIGH bpf: Use correct permission flag for mixed signed bounds arithmetic
CVE-2021-46910 7.0 HIGH ARM: 9063/1: mm: reduce maximum number of CPUs if DEBUG_KMAP_LOCAL is enabled
CVE-2021-46952 NFS: fs_context: validate UDP retrans to prevent shift out-of-bounds

Showing top 20 of 67 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-46974

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