{"id":"CVE-2024-44941","title":"f2fs: fix to cover read extent cache access with lock","summary":"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/…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 9bd5d5e3244242e7be26e86025b74eff3cf20d8c","Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 263df78166d3a9609b97d28c34029bd01874cbb8","Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 323ef20b5558b9d9fd10c1224327af6f11a8177d","Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < d7409b05a64f212735f0d33f5f1602051a886eab","Linux 3.8"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-09-10T15:27:29.159607Z"},"published":"2024-08-26","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:19:08.713Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-44941","references":[{"url":"https://git.kernel.org/stable/c/9bd5d5e3244242e7be26e86025b74eff3cf20d8c"},{"url":"https://git.kernel.org/stable/c/263df78166d3a9609b97d28c34029bd01874cbb8"},{"url":"https://git.kernel.org/stable/c/323ef20b5558b9d9fd10c1224327af6f11a8177d"},{"url":"https://git.kernel.org/stable/c/d7409b05a64f212735f0d33f5f1602051a886eab"}],"tags":["cve.org"],"epss":0.00211,"epssPercentile":0.11361,"ingestedAt":"2026-11-03T13:45:42.688Z","slug":"CVE-2024-44941","body":"## Overview\n\nIn 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 <TASK>\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.\n\n## Affected\n\n- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 9bd5d5e3244242e7be26e86025b74eff3cf20d8c`\n- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 263df78166d3a9609b97d28c34029bd01874cbb8`\n- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < 323ef20b5558b9d9fd10c1224327af6f11a8177d`\n- `Linux >= 98e4da8ca301e062d79ae168c67e56f3c3de3ce4 < d7409b05a64f212735f0d33f5f1602051a886eab`\n- `Linux 3.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}