{ "schema_version": "1.6.1", "id": "RPI-CVE-2025-40199", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2025-40199" ], "published": "2025-11-12T22:01:07Z", "summary": "page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\npage_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches\n\nHelge reported that the introduction of PP_MAGIC_MASK let to crashes on\nboot on his 32-bit parisc machine. The cause of this is the mask is set\ntoo wide, so the page_pool_page_is_pp() incurs false positives which\ncrashes the machine.\n\nJust disabling the check in page_pool_is_pp() will lead to the page_pool\ncode itself malfunctioning; so instead of doing this, this patch changes\nthe define for PP_DMA_INDEX_BITS to avoid mistaking arbitrary kernel\npointers for page_pool-tagged pages.\n\nThe fix relies on the kernel pointers that alias with the pp_magic field\nalways being above PAGE_OFFSET. With this assumption, we can use the\nlowest bit of the value of PAGE_OFFSET as the upper bound of the\nPP_DMA_INDEX_MASK, which should avoid the false positives.\n\nBecause we cannot rely on PAGE_OFFSET always being a compile-time\nconstant, nor on it always being >0, we fall back to disabling the\ndma_index storage when there are not enough bits available. This leaves\nus in the situation we were in before the patch in the Fixes tag, but\nonly on a subset of architecture configurations. This seems to be the\nbest we can do until the transition to page types in complete for\npage_pool pages.\n\nv2:\n- Make sure there's at least 8 bits available and that the PAGE_OFFSET\n bit calculation doesn't wrap", "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": [ "1:6.12.34-1+rpt1~bookworm", "1:6.12.47-1+rpt1~bookworm" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.34+rpt-rpi-2712", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v6", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v7", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v7l", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v6", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7l", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1~bookworm" } ] }, "database_specific": { "per_version": { "1:6.12.34-1+rpt1~bookworm": { "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd", "upstream_version": "6.12.34", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.54" }, "1:6.12.47-1+rpt1~bookworm": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.54" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.34-1+rpt1", "1:6.12.47-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.34+rpt-rpi-2712", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v6", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v7", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v6", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.34-1+rpt1": { "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd", "upstream_version": "6.12.34", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.54" }, "1:6.12.47-1+rpt1": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.54" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2025-40199" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/15b8a5b4cdc16e9a8bb2a548e12a0fd92997605a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/f62934cea32c8f7b11b747975d69bf5afe4264cf" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/95920c2ed02bde551ab654e9749c2ca7bc3100e0" } ], "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 broken `PP_MAGIC_MASK` is evaluated on every page free/alloc check and on every page_pool skb recycle, driven by ordinary local memory and I/O activity rather than by attacker-supplied packet content; an unprivileged local process reliably reaches `free_page_is_bad()`/`napi_pp_put_page()` through normal slab and socket buffer churn. No remote input influences the aliased pointer values, so Local is the accurate vector.\nAC:L - On an affected architecture (32-bit parisc/m68k/nommu targets whose default `PAGE_OFFSET < 0x40000000`) the false positive is deterministic and occurs with no special setup \u2014 it fires during boot on stock configuration, and any page-allocation churn reproduces it. No condition beyond the attacker's control is required.\nPR:L - Any unprivileged local user can drive slab page frees and network buffer recycling that funnel pages through `page_pool_page_is_pp()`/`netmem_is_pp()`; no capability, namespace privilege, or root is needed. The condition even manifests spontaneously under the init process during boot.\nUI:N - No victim action is required \u2014 the misidentification happens inside the page allocator and skb free paths during normal kernel operation.\nS:U - Both the flawed check and its consequences (page allocator state, page_pool/skb handling) live entirely within the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - A false positive in `netmem_is_pp()` causes `page->mapping` to be reinterpreted as a `struct page_pool *` and dereferenced throughout `page_pool_put_unrefed_netmem()`, giving a type-confusion read primitive over arbitrary kernel memory; `bad_page()` additionally dumps raw `struct page` contents and kernel pointers to the log.\nI:H - The same type confusion lets `page_pool_recycle_in_cache()`/`page_pool_recycle_in_ring()` write netmem values and update counters at offsets from an uncontrolled kernel pointer, and `skb_pp_frag_ref()` performs `atomic_long_inc()` on the `page->private`-aliased `pp_ref_count`, corrupting page-cache metadata \u2014 memory corruption leverageable for control-flow hijack.\nA:H - The reported symptom is a machine crash on boot: every affected slab page free triggers a \"BUG: Bad page state ... page_pool leak\" splat and permanently leaks the page, exhausting memory, while the network path oopses on a wild `page_pool` pointer dereference." } } }