{ "schema_version": "1.6.1", "id": "RPI-CVE-2025-38101", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2025-38101" ], "published": "2025-07-03T08:36:23Z", "summary": "ring-buffer: Fix buffer locking in ring_buffer_subbuf_order_set()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nring-buffer: Fix buffer locking in ring_buffer_subbuf_order_set()\n\nEnlarge the critical section in ring_buffer_subbuf_order_set() to\nensure that error handling takes place with per-buffer mutex held,\nthus preventing list corruption and other concurrency-related issues.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.20-1+rpt1~bpo12+1", "1:6.12.25-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.20+rpt-rpi-2712", "binary_version": "1:6.12.20-1+rpt1~bpo12+1" }, { 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"upstream_version": "6.12.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" }, "1:6.12.25-1+rpt1": { "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16", "upstream_version": "6.12.25", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.19-1+rpt1~bpo12+1", "1:6.12.19-1+rpt1", "1:6.12.20-1+rpt1", "1:6.12.25-1+rpt1+trixie" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.19+rpt-rpi-2712", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v6", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v7", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v7l", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v8", "binary_version": 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"binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v6", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v7", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v8", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v8-rt", "binary_version": "1:6.12.25-1+rpt1+trixie" } ] }, "database_specific": { "per_version": { "1:6.12.19-1+rpt1~bpo12+1": { "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0", "upstream_version": "6.12.19", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" }, "1:6.12.19-1+rpt1": { "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0", "upstream_version": "6.12.19", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" }, "1:6.12.20-1+rpt1": { "linux_commit": "cd231d4775b14f228606c09f219b48308f6ab3aa", "upstream_version": "6.12.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" }, "1:6.12.25-1+rpt1+trixie": { "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16", "upstream_version": "6.12.25", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.34" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2025-38101" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e09c0600beea469b3ebf974464e526a02d59ad62" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/0fc9a295cd8e59c3636e97395e7c74a9c89fee42" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/40ee2afafc1d9fe3aa44a6fbe440d78a5c96a72e" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T12:19:11Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The vulnerable function is reached only through a local `write()` to the tracefs file `buffer_subbuf_size_kb` (via `buffer_subbuf_size_write()`), with the error path armed by a local `mmap()` of `per_cpu/cpuN/trace_pipe_raw`. No remote or network-supplied data reaches `ring_buffer_subbuf_order_set()`.\nAC:L - The attacker owns both sides of the race \u2014 two threads writing `buffer_subbuf_size_kb` concurrently, with no `trace_types_lock` serializing `buffer_subbuf_size_write()` \u2014 and deterministically forces the unlocked `error:` path by mmap'ing a later CPU's `trace_pipe_raw` so `cpu_buffer->mapped` yields `-EBUSY` after earlier CPUs already allocated `new_pages`. The window spans a sleeping GFP_KERNEL allocation loop and a multi-page free loop whose length the attacker sets via `buffer_size_kb` and CPU count, and the attempt can be retried indefinitely.\nPR:L - No capability check exists anywhere on the path \u2014 `tracing_check_open_get_tr()` only tests `LOCKDOWN_TRACEFS` and `tracing_disabled` \u2014 so access is governed purely by tracefs DAC, which Android (`shell`, `traced_probes`/Perfetto), ChromeOS and observability/embedded deployments routinely delegate to ordinary non-root accounts and tracing groups. This matches the CNA's existing tracefs precedent (CVE-2025-38267, CVE-2025-68329, both PR:L).\nUI:N - The attacker performs the `mmap()` of `trace_pipe_raw` and both concurrent writes to `buffer_subbuf_size_kb` entirely from its own threads. No victim action, mount, or file open by another user is involved.\nS:U - The list corruption and freed-page reuse occur in the kernel's own ring-buffer allocations and stay within the host kernel's security authority. No VM, IOMMU, container, or sandbox boundary is crossed.\nC:H - The race leaves the live `cpu_buffer->pages` list pointing at `struct buffer_page` objects and order-N data pages that the other thread has already handed back via `kfree()`/`free_pages()`, so the ring buffer keeps reading from memory that the slab and page allocators have reissued to other kernel users. Reading `trace` or `trace_pipe_raw` then discloses the contents of those reallocated kernel objects.\nI:H - Concurrent `list_del_init()` against a re-initialized head produces list corruption plus double-free of both a kmalloc'd `struct buffer_page` and its `free_pages()` backing allocation \u2014 a classic heap-corruption primitive. Because `trace_marker` writes attacker-chosen bytes directly into ring-buffer data pages, the attacker can overwrite the freed-and-reallocated memory with controlled content, giving a write primitive usable for control-flow hijack.\nA:H - The corrupted linked list and double-free reliably oops the kernel \u2014 immediately under `CONFIG_DEBUG_LIST`, which turns the bad `__list_del_entry()` into a BUG, and otherwise through the subsequent `rb_check_pages()`/`rb_head_page_deactivate()` walk over freed pages. This was the syzbot-reported failure mode and the attacker can repeat it at will." } } }