CVE-2024-35877

{"id": "CVE-2024-35877", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.5, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 1.8}]}, "published": "2024-05-19T09:15:08.990", "references": [{"url": "https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/04c35ab3bdae7fefbd7c7a7355f29fa03a035221", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/09e6bb53217bf388a0d2fd7fb21e74ab9dffc173", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/1341e4b32e1fb1b0acd002ccd56f07bd32f2abc6", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/51b7841f3fe84606ec0bd8da859d22e05e5419ec", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/7cfee26d1950250b14c5cb0a37b142f3fcc6396a", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/97e93367e82752e475a33839a80b33bdbef1209f", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/c2b2430b48f3c9eaccd2c3d2ad75bb540d4952f4", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://git.kernel.org/stable/c/f18681daaec9665a15c5e7e0f591aad5d0ac622b", "tags": ["Patch"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00017.html", "tags": ["Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}, {"url": "https://lists.debian.org/debian-lts-announce/2024/06/msg00020.html", "tags": ["Third Party Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-401"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nx86/mm/pat: fix VM_PAT handling in COW mappings\n\nPAT handling won't do the right thing in COW mappings: the first PTE (or,\nin fact, all PTEs) can be replaced during write faults to point at anon\nfolios. Reliably recovering the correct PFN and cachemode using\nfollow_phys() from PTEs will not work in COW mappings.\n\nUsing follow_phys(), we might just get the address+protection of the anon\nfolio (which is very wrong), or fail on swap/nonswap entries, failing\nfollow_phys() and triggering a WARN_ON_ONCE() in untrack_pfn() and\ntrack_pfn_copy(), not properly calling free_pfn_range().\n\nIn free_pfn_range(), we either wouldn't call memtype_free() or would call\nit with the wrong range, possibly leaking memory.\n\nTo fix that, let's update follow_phys() to refuse returning anon folios,\nand fallback to using the stored PFN inside vma->vm_pgoff for COW mappings\nif we run into that.\n\nWe will now properly handle untrack_pfn() with COW mappings, where we\ndon't need the cachemode. We'll have to fail fork()->track_pfn_copy() if\nthe first page was replaced by an anon folio, though: we'd have to store\nthe cachemode in the VMA to make this work, likely growing the VMA size.\n\nFor now, lets keep it simple and let track_pfn_copy() just fail in that\ncase: it would have failed in the past with swap/nonswap entries already,\nand it would have done the wrong thing with anon folios.\n\nSimple reproducer to trigger the WARN_ON_ONCE() in untrack_pfn():\n\n<--- C reproducer --->\n #include <stdio.h>\n #include <sys/mman.h>\n #include <unistd.h>\n #include <liburing.h>\n\n int main(void)\n {\n struct io_uring_params p = {};\n int ring_fd;\n size_t size;\n char *map;\n\n ring_fd = io_uring_setup(1, &p);\n if (ring_fd < 0) {\n perror(\"io_uring_setup\");\n return 1;\n }\n size = p.sq_off.array + p.sq_entries * sizeof(unsigned);\n\n /* Map the submission queue ring MAP_PRIVATE */\n map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE,\n ring_fd, IORING_OFF_SQ_RING);\n if (map == MAP_FAILED) {\n perror(\"mmap\");\n return 1;\n }\n\n /* We have at least one page. Let's COW it. */\n *map = 0;\n pause();\n return 0;\n }\n<--- C reproducer --->\n\nOn a system with 16 GiB RAM and swap configured:\n # ./iouring &\n # memhog 16G\n # killall iouring\n[ 301.552930] ------------[ cut here ]------------\n[ 301.553285] WARNING: CPU: 7 PID: 1402 at arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100\n[ 301.553989] Modules linked in: binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g\n[ 301.558232] CPU: 7 PID: 1402 Comm: iouring Not tainted 6.7.5-100.fc38.x86_64 #1\n[ 301.558772] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4\n[ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100\n[ 301.559893] Code: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b 6b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000\n[ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282\n[ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 000000010455e047\n[ 301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200\n[ 301.562628] RBP: 0000000000000000 R08: ffffba2c0377fab8 R09: 0000000000000000\n[ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000\n[ 301.563669] R13: 0000000000000000 R14: ffffba2c0377fc08 R15: 0000000000000000\n[ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000\n[ 301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0\n[ 301.565725] PKRU: 55555554\n[ 301.565944] Call Trace:\n[ 301.566148] <TASK>\n[ 301.566325] ? untrack_pfn+0xf4/0x100\n[ 301.566618] ? __warn+0x81/0x130\n[ 301.566876] ? untrack_pfn+0xf4/0x100\n[ 3\n---truncated---"}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: x86/mm/pat: corrige el manejo de VM_PAT en asignaciones COW El manejo de PAT no funcionar\u00e1 correctamente en las asignaciones COW: la primera PTE (o, de hecho, todas las PTE) pueden ser reemplazado durante fallos de escritura para se\u00f1alar folios an\u00f3nimos. Recuperar de manera confiable el PFN y el modo de cach\u00e9 correctos usando follow_phys() de las PTE no funcionar\u00e1 en las asignaciones COW. Usando follow_phys(), podr\u00edamos obtener la direcci\u00f3n+protecci\u00f3n de la publicaci\u00f3n an\u00f3nima (lo cual es muy incorrecto), o fallar en las entradas de intercambio/no intercambio, fallando en follow_phys() y activando un WARN_ON_ONCE() en untrack_pfn() y track_pfn_copy() , no llamando correctamente a free_pfn_range(). En free_pfn_range(), no llamar\u00edamos a memtype_free() o lo llamar\u00edamos con el rango incorrecto, posiblemente perdiendo memoria. Para solucionarlo, actualicemos follow_phys() para rechazar la devoluci\u00f3n de publicaciones an\u00f3nimas y recurramos al uso del PFN almacenado dentro de vma-&gt;vm_pgoff para asignaciones COW si nos encontramos con eso. Ahora manejaremos adecuadamente untrack_pfn() con asignaciones COW, donde no necesitamos el modo cach\u00e9. Sin embargo, tendremos que fallar fork()-&gt;track_pfn_copy() si la primera p\u00e1gina fue reemplazada por una publicaci\u00f3n an\u00f3nima: tendr\u00edamos que almacenar el modo de cach\u00e9 en el VMA para que esto funcione, probablemente aumentando el tama\u00f1o del VMA. Por ahora, manteng\u00e1moslo simple y dejemos que track_pfn_copy() simplemente falle en ese caso: ya habr\u00eda fallado en el pasado con entradas de intercambio/no intercambio, y habr\u00eda hecho algo incorrecto con folios an\u00f3nimos. Reproductor simple para activar WARN_ON_ONCE() en untrack_pfn(): &lt;--- Reproductor C ---&gt; #include #include #include #include int main(void) { struct io_uring_params p = {}; int anillo_fd; tama\u00f1o_t tama\u00f1o; carb\u00f3n *mapa; ring_fd = io_uring_setup(1, &amp;p); if (ring_fd &lt; 0) { perror(\"io_uring_setup\"); devolver 1; } tama\u00f1o = p.sq_off.array + p.sq_entries * tama\u00f1o de (sin firmar); /* Asigna el anillo de cola de env\u00edo MAP_PRIVATE */ map = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, ring_fd, IORING_OFF_SQ_RING); if (mapa == MAP_FAILED) { perror(\"mmap\"); devolver 1; } /* Tenemos al menos una p\u00e1gina. Vamos a acobardarnos. */ *mapa = 0; pausa(); devolver 0; } &lt;--- Reproductor C ---&gt; En un sistema con 16 GiB de RAM y swap configurado: # ./iouring &amp; # memhog 16G # killall iouring [ 301.552930] ------------[ cut aqu\u00ed ]------------ [ 301.553285] ADVERTENCIA: CPU: 7 PID: 1402 en arch/x86/mm/pat/memtype.c:1060 untrack_pfn+0xf4/0x100 [ 301.553989] M\u00f3dulos vinculados en : binfmt_misc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_g [ 301.558232] CPU: 7 PID: 1402 Comm: iouring No contaminado 6.7.5-100.fc38.x86_64 #1 [ 301.558772] Nombre del hardware: PC est\u00e1ndar QEMU (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebu4 [ 301.559569] RIP: 0010:untrack_pfn+0xf4/0x100 [ 301.559893] C\u00f3digo: 75 c4 eb cf 48 8b 43 10 8b a8 e8 00 00 00 3b b 28 74 b8 48 8b 7b 30 e8 ea 1a f7 000 [ 301.561189] RSP: 0018:ffffba2c0377fab8 EFLAGS: 00010282 [ 301.561590] RAX: 00000000ffffffea RBX: ffff9208c8ce9cc0 RCX: 455e047 [301.562105] RDX: 07fffffff0eb1e0a RSI: 0000000000000000 RDI: ffff9208c391d200 [301.562628] RBP: 0000000000000000 R08: 8 R09: 0000000000000000 [ 301.563145] R10: ffff9208d2292d50 R11: 0000000000000002 R12: 00007fea890e0000 [ 301.563669] R13: 00000 R14: ffffba2c0377fc08 R15: 00000000000000000 [ 301.564186] FS: 0000000000000000(0000) GS:ffff920c2fbc0000(0000) knlGS:0000000000000000 0 [301.564773] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 301.565197] CR2: 00007fea88ee8a20 CR3: 00000001033a8000 CR4: 0000000000750ef0 [ 301.565725] KRU: 55555554 [ 301.565944] Seguimiento de llamadas: [ 301.566148] [ 301.566325] ? untrack_pfn+0xf4/0x100 [301.566618]? __advertir+0x81/0x130 [ 301.566876] ? untrack_pfn+0xf4/0x100 [ 3 ---truncado---"}], "lastModified": "2025-12-23T19:33:10.590", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "FC6D429D-BBC0-45CE-BDD8-A62B2EF8F67A", "versionEndExcluding": "4.19.312", "versionStartIncluding": "2.6.29"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F45A0F3C-C16D-49C4-86D6-D021C3D4B834", "versionEndExcluding": "5.4.274", "versionStartIncluding": "4.20"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "9CD5894E-58E9-4B4A-B0F4-3E6BC134B8F5", "versionEndExcluding": "5.10.215", "versionStartIncluding": "5.5"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "F11B6314-A852-4FBD-AD84-ECE23F5C092B", "versionEndExcluding": "5.15.155", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "325665BF-2409-49D9-B391-39AD4566FDBD", "versionEndExcluding": "6.1.85", "versionStartIncluding": "5.16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "C520696A-A594-4FFC-A32D-12DA535CE911", "versionEndExcluding": "6.6.26", "versionStartIncluding": "6.2"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DBD6C99E-4250-4DFE-8447-FF2075939D10", "versionEndExcluding": "6.8.5", "versionStartIncluding": "6.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.9:rc1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "22BEDD49-2C6D-402D-9DBF-6646F6ECD10B"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.9:rc2:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DF73CB2A-DFFD-46FB-9BFE-AA394F27EA37"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}