{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53846","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-12-09T01:27:17.827Z","datePublished":"2025-12-09T01:30:09.202Z","dateUpdated":"2026-08-05T09:16:23.337Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T09:16:23.337Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on direct node in truncate_dnode()\n\nsyzbot reports below bug:\n\nBUG: KASAN: slab-use-after-free in f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574\nRead of size 4 at addr ffff88802a25c000 by task syz-executor148/5000\n\nCPU: 1 PID: 5000 Comm: syz-executor148 Not tainted 6.4.0-rc7-syzkaller-00041-ge660abd551f1 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023\nCall Trace:\n <TASK>\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106\n print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351\n print_report mm/kasan/report.c:462 [inline]\n kasan_report+0x11c/0x130 mm/kasan/report.c:572\n f2fs_truncate_data_blocks_range+0x122a/0x14c0 fs/f2fs/file.c:574\n truncate_dnode+0x229/0x2e0 fs/f2fs/node.c:944\n f2fs_truncate_inode_blocks+0x64b/0xde0 fs/f2fs/node.c:1154\n f2fs_do_truncate_blocks+0x4ac/0xf30 fs/f2fs/file.c:721\n f2fs_truncate_blocks+0x7b/0x300 fs/f2fs/file.c:749\n f2fs_truncate.part.0+0x4a5/0x630 fs/f2fs/file.c:799\n f2fs_truncate include/linux/fs.h:825 [inline]\n f2fs_setattr+0x1738/0x2090 fs/f2fs/file.c:1006\n notify_change+0xb2c/0x1180 fs/attr.c:483\n do_truncate+0x143/0x200 fs/open.c:66\n handle_truncate fs/namei.c:3295 [inline]\n do_open fs/namei.c:3640 [inline]\n path_openat+0x2083/0x2750 fs/namei.c:3791\n do_filp_open+0x1ba/0x410 fs/namei.c:3818\n do_sys_openat2+0x16d/0x4c0 fs/open.c:1356\n do_sys_open fs/open.c:1372 [inline]\n __do_sys_creat fs/open.c:1448 [inline]\n __se_sys_creat fs/open.c:1442 [inline]\n __x64_sys_creat+0xcd/0x120 fs/open.c:1442\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe root cause is, inodeA references inodeB via inodeB's ino, once inodeA\nis truncated, it calls truncate_dnode() to truncate data blocks in inodeB's\nnode page, it traverse mapping data from node->i.i_addr[0] to\nnode->i.i_addr[ADDRS_PER_BLOCK() - 1], result in out-of-boundary access.\n\nThis patch fixes to add sanity check on dnode page in truncate_dnode(),\nso that, it can help to avoid triggering such issue, and once it encounters\nsuch issue, it will record newly introduced ERROR_INVALID_NODE_REFERENCE\nerror into superblock, later fsck can detect such issue and try repairing.\n\nAlso, it removes f2fs_truncate_data_blocks() for cleanup due to the\nfunction has only one caller, and uses f2fs_truncate_data_blocks_range()\ninstead."}],"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 bug is reached through local syscalls (`creat`/`truncate`/`ftruncate`) on a file in a mounted f2fs image; there is no network-facing path into `truncate_dnode()`. Attack requires local system access to mount the crafted image and operate on it.\nAC:L - The corrupted node reference is fully attacker-controlled on-disk data, and syzbot has a deterministic reproducer — a single truncate on the crafted inode reliably drives the loop past the end of the inode page. No race or uncontrollable state is involved.\nPR:L - An unprivileged local user can get an arbitrary f2fs image mounted on common deployments (udisks2/systemd-mount removable-media policy for active sessions, Android vold adoptable storage), and triggering the truncate afterward needs only ordinary write access to a file. No root in the initial namespace is required in these configurations.\nUI:N - The same unprivileged attacker performs both the mount (via the removable-media auto-mount path) and the truncate syscall; no separate victim action is needed once the image is attached.\nS:U - The out-of-bounds access and any resulting corruption stay within the kernel's own security authority — this is a standard in-kernel memory-safety flaw with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The loop performs an out-of-bounds read of ~84 four-byte words past the end of the node page (KASAN reports it as slab-use-after-free), and those adjacent-page values are consumed as block addresses that get invalidated and reflected in the extent cache and block accounting, disclosing adjacent kernel heap contents.\nI:H - Every non-zero out-of-bounds word triggers `f2fs_set_data_blkaddr()` → `__set_data_blkaddr()`, writing a 4-byte zero through the same OOB pointer — an out-of-bounds write into the neighbouring physical page, plus corruption of SIT/valid-block accounting and freeing of blocks belonging to other inodes.\nA:H - The out-of-bounds access reliably produces a KASAN slab-use-after-free splat and can panic the kernel, and the bogus block addresses and inflated free counts drive `f2fs_invalidate_blocks()`/`dec_valid_block_count()` into `f2fs_bug_on()` conditions."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/f2fs/f2fs.h","fs/f2fs/file.c","fs/f2fs/node.c","include/linux/f2fs_fs.h"],"versions":[{"version":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4","lessThan":"af0f716ad3b039cab9d426da63a5ee6c88751185","status":"affected","versionType":"git"},{"version":"98e4da8ca301e062d79ae168c67e56f3c3de3ce4","lessThan":"a6ec83786ab9f13f25fb18166dee908845713a95","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/f2fs.h","fs/f2fs/file.c","fs/f2fs/node.c","include/linux/f2fs_fs.h"],"versions":[{"version":"3.8","status":"affected"},{"version":"0","lessThan":"3.8","status":"unaffected","versionType":"semver"},{"version":"6.4.10","lessThanOrEqual":"6.4.*","status":"unaffected","versionType":"semver"},{"version":"6.5","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":"6.4.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.8","versionEndExcluding":"6.5"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/af0f716ad3b039cab9d426da63a5ee6c88751185"},{"url":"https://git.kernel.org/stable/c/a6ec83786ab9f13f25fb18166dee908845713a95"}],"title":"f2fs: fix to do sanity check on direct node in truncate_dnode()","x_generator":{"engine":"bippy-1.2.0"}}}}