{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-45024", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-08-21T05:34:56.684Z", "datePublished": "2024-09-11T15:13:57.076Z", "dateUpdated": "2026-08-05T11:37:49.139Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:37:49.139Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/hugetlb: fix hugetlb vs. core-mm PT locking\n\nWe recently made GUP's common page table walking code to also walk hugetlb\nVMAs without most hugetlb special-casing, preparing for the future of\nhaving less hugetlb-specific page table walking code in the codebase. \nTurns out that we missed one page table locking detail: page table locking\nfor hugetlb folios that are not mapped using a single PMD/PUD.\n\nAssume we have hugetlb folio that spans multiple PTEs (e.g., 64 KiB\nhugetlb folios on arm64 with 4 KiB base page size). GUP, as it walks the\npage tables, will perform a pte_offset_map_lock() to grab the PTE table\nlock.\n\nHowever, hugetlb that concurrently modifies these page tables would\nactually grab the mm->page_table_lock: with USE_SPLIT_PTE_PTLOCKS, the\nlocks would differ. Something similar can happen right now with hugetlb\nfolios that span multiple PMDs when USE_SPLIT_PMD_PTLOCKS.\n\nThis issue can be reproduced [1], for example triggering:\n\n[ 3105.936100] ------------[ cut here ]------------\n[ 3105.939323] WARNING: CPU: 31 PID: 2732 at mm/gup.c:142 try_grab_folio+0x11c/0x188\n[ 3105.944634] Modules linked in: [...]\n[ 3105.974841] CPU: 31 PID: 2732 Comm: reproducer Not tainted 6.10.0-64.eln141.aarch64 #1\n[ 3105.980406] Hardware name: QEMU KVM Virtual Machine, BIOS edk2-20240524-4.fc40 05/24/2024\n[ 3105.986185] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)\n[ 3105.991108] pc : try_grab_folio+0x11c/0x188\n[ 3105.994013] lr : follow_page_pte+0xd8/0x430\n[ 3105.996986] sp : ffff80008eafb8f0\n[ 3105.999346] x29: ffff80008eafb900 x28: ffffffe8d481f380 x27: 00f80001207cff43\n[ 3106.004414] x26: 0000000000000001 x25: 0000000000000000 x24: ffff80008eafba48\n[ 3106.009520] x23: 0000ffff9372f000 x22: ffff7a54459e2000 x21: ffff7a546c1aa978\n[ 3106.014529] x20: ffffffe8d481f3c0 x19: 0000000000610041 x18: 0000000000000001\n[ 3106.019506] x17: 0000000000000001 x16: ffffffffffffffff x15: 0000000000000000\n[ 3106.024494] x14: ffffb85477fdfe08 x13: 0000ffff9372ffff x12: 0000000000000000\n[ 3106.029469] x11: 1fffef4a88a96be1 x10: ffff7a54454b5f0c x9 : ffffb854771b12f0\n[ 3106.034324] x8 : 0008000000000000 x7 : ffff7a546c1aa980 x6 : 0008000000000080\n[ 3106.038902] x5 : 00000000001207cf x4 : 0000ffff9372f000 x3 : ffffffe8d481f000\n[ 3106.043420] x2 : 0000000000610041 x1 : 0000000000000001 x0 : 0000000000000000\n[ 3106.047957] Call trace:\n[ 3106.049522] try_grab_folio+0x11c/0x188\n[ 3106.051996] follow_pmd_mask.constprop.0.isra.0+0x150/0x2e0\n[ 3106.055527] follow_page_mask+0x1a0/0x2b8\n[ 3106.058118] __get_user_pages+0xf0/0x348\n[ 3106.060647] faultin_page_range+0xb0/0x360\n[ 3106.063651] do_madvise+0x340/0x598\n\nLet's make huge_pte_lockptr() effectively use the same PT locks as any\ncore-mm page table walker would. Add ptep_lockptr() to obtain the PTE\npage table lock using a pte pointer -- unfortunately we cannot convert\npte_lockptr() because virt_to_page() doesn't work with kmap'ed page tables\nwe can have with CONFIG_HIGHPTE.\n\nHandle CONFIG_PGTABLE_LEVELS correctly by checking in reverse order, such\nthat when e.g., CONFIG_PGTABLE_LEVELS==2 with\nPGDIR_SIZE==P4D_SIZE==PUD_SIZE==PMD_SIZE will work as expected. Document\nwhy that works.\n\nThere is one ugly case: powerpc 8xx, whereby we have an 8 MiB hugetlb\nfolio being mapped using two PTE page tables. While hugetlb wants to take\nthe PMD table lock, core-mm would grab the PTE table lock of one of both\nPTE page tables. In such corner cases, we have to make sure that both\nlocks match, which is (fortunately!) currently guaranteed for 8xx as it\ndoes not support SMP and consequently doesn't use split PT locks.\n\n[1] https://lore.kernel.org/all/1bbfcc7f-f222-45a5-ac44-c5a1381c596d@redhat.com/" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The race is driven entirely through local syscalls on the attacker's own address space (mmap/madvise/munmap/move_pages, plus GUP consumers such as vmsplice, process_vm_readv and io_uring). No network or remote-peer data is involved.\nAC:L - The attacker owns both sides of the race — one thread drives slow GUP over the hugetlb range while another unmaps/COWs/migrates the same PTEs — and can retry indefinitely across CPUs over an arbitrarily large mapping, with no condition outside its control; the affected hugetlb sizes (arm64 CONT_PTE/CONT_PMD/PUD) are default-registered hstates on stock distro kernels.\nPR:L - Only an ordinary unprivileged local user is required: MAP_HUGETLB/memfd_create(MFD_HUGETLB) and the madvise/munmap/GUP paths involve no capability check whatsoever.\nUI:N - The attacker's own threads perform every step; no victim action or interaction is needed.\nS:U - The corruption and its consequences stay within the kernel's own security authority — no VM, IOMMU, or sandbox boundary is crossed.\nC:H - GUP can pin a hugetlb folio that hugetlb concurrently freed, so after the folio is returned to the pool and reallocated the attacker retains a kernel-held reference and can read another process's — or the kernel's — memory through the pin (e.g. via vmsplice or process_vm_readv).\nI:H - The same stale pin taken with FOLL_WRITE gives a write primitive into a reallocated folio, and racing hugetlb_wp lets a write land on a page that is still shared, providing arbitrary-write/COW-break capability exploitable for privilege escalation.\nA:H - The race is demonstrated to hit an already-freed folio (WARN at mm/gup.c:142, fatal under panic_on_warn), and the resulting use-after-free on hugetlb folios and page tables readily causes kernel oops or panic." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/hugetlb.h", "include/linux/mm.h" ], "versions": [ { "version": "9cb28da54643ad464c47585cd5866c30b0218e67", "lessThan": "7300dadba49e531af2d890ae4e34c9b115384a62", "status": "affected", "versionType": "git" }, { "version": "9cb28da54643ad464c47585cd5866c30b0218e67", "lessThan": "5f75cfbd6bb02295ddaed48adf667b6c828ce07b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/hugetlb.h", "include/linux/mm.h" ], "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.7", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.11", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.10.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7300dadba49e531af2d890ae4e34c9b115384a62" }, { "url": "https://git.kernel.org/stable/c/5f75cfbd6bb02295ddaed48adf667b6c828ce07b" } ], "title": "mm/hugetlb: fix hugetlb vs. core-mm PT locking", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-09-29T15:47:11.835460Z", "id": "CVE-2024-45024", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-29T15:47:26.113Z" } } ] } }