CVE-2022-50341 — linux / linux_kernel
In the Linux kernel, the following vulnerability has been resolved:
cifs: fix oops during encryption
When running xfstests against Azure the following oops occurred on an arm64 system
Unable to handle kernel write to read-only memory at virtual address ffff0001221cf000 Mem abort info: ESR = 0x9600004f EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x0f: level 3 permission fault Data abort info: ISV = 0, ISS = 0x0000004f CM = 0, WnR = 1 swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000294f3000 [ffff0001221cf000] pgd=18000001ffff8003, p4d=18000001ffff8003, pud=18000001ff82e003, pmd=18000001ff71d003, pte=00600001221cf787 Internal error: Oops: 9600004f [#1] PREEMPT SMP ... pstate: 80000005 (Nzcv daif -PAN -UAO -TCO BTYPE=--) pc : __memcpy+0x40/0x230 lr : scatterwalk_copychunks+0xe0/0x200 sp : ffff800014e92de0 x29: ffff800014e92de0 x28: ffff000114f9de80 x27: 0000000000000008 x26: 0000000000000008 x25: ffff800014e92e78 x24: 0000000000000008 x23: 0000000000000001 x22: 0000040000000000 x21: ffff000000000000 x20: 0000000000000001 x19: ffff0001037c4488 x18: 0000000000000014 x17: 235e1c0d6efa9661 x16: a435f9576b6edd6c x15: 0000000000000058 x14: 0000000000000001 x13: 0000000000000008 x12: ffff000114f2e590 x11: ffffffffffffffff x10: 0000040000000000 x9 : ffff8000105c3580 x8 : 2e9413b10000001a x7 : 534b4410fb86b005 x6 : 534b4410fb86b005 x5 : ffff0001221cf008 x4 : ffff0001037c4490 x3 : 0000000000000001 x2 : 0000000000000008 x1 : ffff0001037c4488 x0 : ffff0001221cf000 Call trace: __memcpy+0x40/0x230 scatterwalk_map_and_copy+0x98/0x100 crypto_ccm_encrypt+0x150/0x180 crypto_aead_encrypt+0x2c/0x40 crypt_message+0x750/0x880 smb3_init_transform_rq+0x298/0x340 smb_send_rqst.part.11+0xd8/0x180 smb_send_rqst+0x3c/0x100 compound_send_recv+0x534/0xbc0 smb2_query_info_compound+0x32c/0x440 smb2_set_ea+0x438/0x4c0 cifs_xattr_set+0x5d4/0x7c0
This is because in scatterwalk_copychunks(), we attempted to write to a buffer (@sign) that was allocated in the stack (vmalloc area) by crypt_message() and thus accessing its remaining 8 (x2) bytes ended up crossing a page boundary.
To simply fix it, we could just pass @sign kmalloc'd from crypt_message() and then we're done. Luckily, we don't seem to pass any other vmalloc'd buffers in smb_rqst::rq_iov...
Instead, let's map the correct pages and offsets from vmalloc buffers as well in cifs_sg_set_buf() and then avoiding such oopses.
| Software | From | Fixed in |
|---|---|---|
| linux / linux_kernel | - | 5.4.229 |
| linux / linux_kernel | 5.5 | 5.10.163 |
| linux / linux_kernel | 5.11 | 5.15.87 |
| linux / linux_kernel | 5.16 | 6.0.16 |
| linux / linux_kernel | 6.1 | 6.1.1 |
- https://git.kernel.org/stable/c/a13e51760703f71c25d5fc1f4a62dfa4b0cc80e9
- https://git.kernel.org/stable/c/bf0543b93740916ee91956f9a63da6fc0d79daaa
- https://git.kernel.org/stable/c/e8d16a54842d609fd4a3ed2d81d4333d6329aa94
- https://git.kernel.org/stable/c/e8e2861cc3258dbe407d01ea8c59bb5a53132301
- https://git.kernel.org/stable/c/f7f291e14dde32a07b1f0aa06921d28f875a7b54
- https://git.kernel.org/stable/c/fe6ea044c4f05706cb71040055b1c70c6c8275e0
Deep Security Visibility Without the Complexity
SynScan provides clear, real-time security insights so you can monitor your attack surface, spot risks early, and act fast—without extra complexity.
- No setup fees
- 5-min deployment
- Cancel anytime
Frequently Asked Questions
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.