{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-44941", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-08-21T05:34:56.665Z", "datePublished": "2024-08-26T11:20:45.678Z", "dateUpdated": "2026-08-05T11:37:10.547Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:37:10.547Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to cover read extent cache access with lock\n\nsyzbot reports a f2fs bug as below:\n\nBUG: KASAN: slab-use-after-free in sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\nRead of size 4 at addr ffff8880739ab220 by task syz-executor200/5097\n\nCPU: 0 PID: 5097 Comm: syz-executor200 Not tainted 6.9.0-rc6-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024\nCall Trace:\n \n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x169/0x550 mm/kasan/report.c:488\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n sanity_check_extent_cache+0x370/0x410 fs/f2fs/extent_cache.c:46\n do_read_inode fs/f2fs/inode.c:509 [inline]\n f2fs_iget+0x33e1/0x46e0 fs/f2fs/inode.c:560\n f2fs_nfs_get_inode+0x74/0x100 fs/f2fs/super.c:3237\n generic_fh_to_dentry+0x9f/0xf0 fs/libfs.c:1413\n exportfs_decode_fh_raw+0x152/0x5f0 fs/exportfs/expfs.c:444\n exportfs_decode_fh+0x3c/0x80 fs/exportfs/expfs.c:584\n do_handle_to_path fs/fhandle.c:155 [inline]\n handle_to_path fs/fhandle.c:210 [inline]\n do_handle_open+0x495/0x650 fs/fhandle.c:226\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nWe missed to cover sanity_check_extent_cache() w/ extent cache lock,\nso, below race case may happen, result in use after free issue.\n\n- f2fs_iget\n - do_read_inode\n - f2fs_init_read_extent_tree\n : add largest extent entry in to cache\n\t\t\t\t\t- shrink\n\t\t\t\t\t - f2fs_shrink_read_extent_tree\n\t\t\t\t\t - __shrink_extent_tree\n\t\t\t\t\t - __detach_extent_node\n\t\t\t\t\t : drop largest extent entry\n - sanity_check_extent_cache\n : access et->largest w/o lock\n\nlet's refactor sanity_check_extent_cache() to avoid extent cache access\nand call it before f2fs_init_read_extent_tree() to fix this issue." } ], "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 vulnerable code is reached through ordinary VFS syscalls (`open`/`stat`/`open_by_handle_at`) that instantiate an f2fs inode via `f2fs_iget()`->`do_read_inode()`, requiring a local account with access to a mounted f2fs filesystem. There is no remote or adjacent-network protocol handler on the path.\nAC:L - The attacker controls both sides of the race: they force the shrinker side by inflating extent-cache memory past the `f2fs_available_free_memory(READ_EXTENT_CACHE)` watermark so `f2fs_balance_fs_bg()`/`f2fs_shrink_scan()` run `f2fs_shrink_read_extent_tree()` continuously, and drive the iget side by repeatedly evicting and re-instantiating inodes. syzbot reproduced it in default configuration (`READ_EXTENT_CACHE` is set by `default_options()`).\nPR:L - No capability, owner, or privilege check exists anywhere on the `f2fs_lookup`/`f2fs_iget`/`do_read_inode`/`sanity_check_extent_cache ` path — any unprivileged user who can look up a file on an f2fs mount reaches it (e.g. any app on Android's f2fs `/data`).\nUI:N - The attacker performs the entire sequence with their own file operations and memory pressure against an already-mounted filesystem; no victim action is required.\nS:U - The corruption and its consequences are confined to the kernel's own memory and the local system's security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - This is a slab-use-after-free read of a freed `extent_tree`; the attacker can groom the freed slot with controlled data, and the leaked `largest` extent is then installed as the inode's read-extent mapping, redirecting file reads to arbitrary data blocks and disclosing other files' contents, while the `f2fs_warn` also prints freed heap contents to the log.\nI:H - Beyond the read, the `CP_ERROR_FLAG` branch writes into the freed object (`ei->len = 0; et->largest_updated = true;`), giving a write primitive into a reallocated slab object, and the poisoned extent mapping causes subsequent I/O to be directed at attacker-influenced block addresses — a UAF of this shape is leverageable for control-flow hijack.\nA:H - The confirmed KASAN slab-use-after-free crashes the kernel, and the garbage `largest.blk` additionally drives `f2fs_is_valid_blkaddr()` failure paths (`f2fs_handle_error`, `SBI_NEED_FSCK`, `dump_stack`) that panic the system under `errors=panic`/`CONFIG_F2FS_CHECK_FS`, and can be retriggered at will." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/extent_cache.c", "fs/f2fs/f2fs.h", "fs/f2fs/inode.c" ], "versions": [ { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "263df78166d3a9609b97d28c34029bd01874cbb8", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "323ef20b5558b9d9fd10c1224327af6f11a8177d", "status": "affected", "versionType": "git" }, { "version": "98e4da8ca301e062d79ae168c67e56f3c3de3ce4", "lessThan": "d7409b05a64f212735f0d33f5f1602051a886eab", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/extent_cache.c", "fs/f2fs/f2fs.h", "fs/f2fs/inode.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.47", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.10.6", "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": "3.8", "versionEndExcluding": "6.6.47" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.10.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "6.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/263df78166d3a9609b97d28c34029bd01874cbb8" }, { "url": "https://git.kernel.org/stable/c/323ef20b5558b9d9fd10c1224327af6f11a8177d" }, { "url": "https://git.kernel.org/stable/c/d7409b05a64f212735f0d33f5f1602051a886eab" } ], "title": "f2fs: fix to cover read extent cache access with lock", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2024-44941", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-09-10T15:27:29.159607Z" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-09-12T17:33:04.422Z" } } ] } }