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CVE-2026-80662

cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size The CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58 bytes (CXL_RAS_CAPABILITY_LENGTH); the Header Log occupies the trailing 64 bytes at offset 0x18. CXL_HEADERLOG_SIZE was defined as SZ_512, eight times the actual on-device size. header_log_copy() reads CXL_HEADERLOG_SIZE_U32 (128) dwords from the RAS capability iomap, overrunning the 88-byte mapping by 448 bytes. The cxl_aer_uncorrectable_error trace event memcpy()s CXL_HEADERLOG_SIZE (512) bytes from its source. For the CPER caller the source is struct cxl_ras_capability_regs::header_log[16] (64 bytes) embedded in a stack-local cxl_cper_prot_err_work_data, so the memcpy reads 448 bytes of kernel stack into the trace event ring buffer where userspace can read it via tracefs. Set CXL_HEADERLOG_SIZE to 64 and derive CXL_HEADERLOG_SIZE_U32 from it, bringing all iomap readers into agreement on 16 dwords. Userspace tools such as rasdaemon have grown a dependency on the buggy 512-byte (128 u32) header_log layout in the cxl_aer_uncorrectable_error trace event. Add CXL_HEADERLOG_TRACE_SIZE_U32 = 128 and use it for the trace event __array and its memcpy to preserve that ABI. Both callers now pass a zero-filled u32[CXL_HEADERLOG_TRACE_SIZE_U32] staging buffer with only the first CXL_HEADERLOG_SIZE_U32 (16) entries populated from hardware; the remaining 112 u32s are zero-padded, keeping the 512-byte trace ring buffer layout intact. [ dj: Replaced 64 with SZ_64 per RichardC ]

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 2905cb5236cba63a5dc8a83752dcc31f3cc819f9 before d031617045dc743764ea574432e5c2a3757b4e57; affected 2905cb5236cba63a5dc8a83752dcc31f3cc819f9 before e3e8f3b760bcf6a4b3aec412015b74b578729006; affected 2905cb5236cba63a5dc8a83752dcc31f3cc819f9 before 6fc1919a6f2ed541484dd1f6cd93374044f8fd3d; affected 2905cb5236cba63a5dc8a83752dcc31f3cc819f9 before fc5eb0962a5e50d64e711817cc24d67df2d90528; affected 2905cb5236cba63a5dc8a83752dcc31f3cc819f9 before c268f949e219f9e179558e836f457f6c5fbec416
Linux / Linuxaffected 6.2; unaffected 0 before 6.2; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.42 through 6.18.*; unaffected 7.1.5 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References