Description Preview
In the Linux kernel CIFS implementation, processing of symlinks could overflow a destination buffer because link_len was derived from sscanf() without proper validation. Smatch reported a warning in arch/x86/crypto/poly1305_glue.c around poly1305_update_arch() showing a memcpy destination being too small, but the root cause is in fs/cifs/link.c where link_len could exceed the allocated link_str buffer. The resolution adds a guard to ensure link_len does not exceed the size of the link_str buffer before performing memory copies, preventing potential memory corruption or kernel instability. The vulnerability has been addressed in updated kernel releases and backports.
Overview
This vulnerability concerns the CIFS (Common Internet File System) path in the Linux kernel, where symlink handling could trigger a buffer overflow if an untrusted length value is copied without proper bounds checking. The underlying issue stems from unvalidated data originating from sscanf(), enabling an unchecked copy operation in the CIFS link handling code. A fix was implemented to validate that the length of the link path does not exceed the allocated buffer size, thereby preventing an overflow. The problem was identified through Smatch reporting and has since been resolved in the affected kernels.
Remediation
- Upgrade the kernel to a version that includes the CIFS symlink handling fix (or apply the upstream patch/backport provided by your distribution) to ensure link_len is validated against the link string buffer before copying.
- If patching manually, modify the CIFS code (fs/cifs/link.c) to add a bounds check on link_len, e.g., if (link_len > sizeof(link_str)) return an error; otherwise safely copy data.
- Rebuild and deploy the kernel and related modules, and perform targeted tests of CIFS symlink operations under representative workloads.
- After patching or upgrading, monitor for advisories or updated kernel releases and perform follow-up verification to confirm the vulnerability is mitigated.
References
- CVE-2022-49058 - Mitre CVE Entry
- Stable commit addressing the issue: 3e582749e742e662a8e9bb37cffac62dccaaa1e2
- Stable commit addressing the issue: 1316c28569a80ab3596eeab05bf5e01991e7e739
- Stable commit addressing the issue: eb5f51756944735ac70cd8bb38637cc202e29c91
- Stable commit addressing the issue: 22d658c6c5affed10c8907e67160cef0b6c92186
- Stable commit addressing the issue: 4e166a41180be2f1e66bbb6d46448e80a9a5ec05
- Stable commit addressing the issue: 9901b07ba42b39266b34a888e48d7306fd707bee
- Stable commit addressing the issue: 515e7ba11ef043d6febe69389949c8ef5f25e9d0
- Stable commit addressing the issue: 64c4a37ac04eeb43c42d272f6e6c8c12bfcf4304
Industry ExposureMost to leastThis section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
This section illustrates the prevalence of a specific Common Vulnerabilities and Exposures (CVE) across various industries based on customer reports. The ranking displays industries from the most to least affected by this particular vulnerability, offering valuable insight into where this CVE has been most frequently observed. This information can help organizations within these sectors prioritize their security efforts, understand their relative risk exposure compared to their peers, and focus remediation strategies where they are most needed. By understanding the industry-specific impact, organizations can make more informed decisions regarding patching, resource allocation, and overall risk management related to this CVE.
- ManufacturingManufacturing: Medium
- Health Care & Social AssistanceHealth Care & Social Assistance: Medium
- Public AdministrationPublic Administration: Medium
- Finance and InsuranceFinance and Insurance: Medium
- Professional, Scientific, & Technical ServicesProfessional, Scientific, & Technical Services: Medium
- Retail TradeRetail Trade: Medium
- Transportation & WarehousingTransportation & Warehousing: Low
- Educational ServicesEducational Services: Low
- Arts, Entertainment & RecreationArts, Entertainment & Recreation: Low
- Other Services (except Public Administration)Other Services (except Public Administration): Low
- UtilitiesUtilities: Low
- Management of Companies & EnterprisesManagement of Companies & Enterprises: Low
- Agriculture, Forestry Fishing & HuntingAgriculture, Forestry Fishing & Hunting: Low
- InformationInformation: Low
- Real Estate Rental & LeasingReal Estate Rental & Leasing: Low
- Accommodation & Food ServicesAccommodation & Food Services: Low
- Administrative, Support, Waste Management & Remediation ServicesAdministrative, Support, Waste Management & Remediation Services: Low
- ConstructionConstruction: Low
- MiningMining: Low
- Wholesale TradeWholesale Trade: Low
