{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49170", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-02-26T01:49:39.279Z", "datePublished": "2025-02-26T01:55:27.562Z", "dateUpdated": "2026-08-12T23:58:11.094Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-12T23:58:11.094Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to do sanity check on curseg->alloc_type\n\nAs Wenqing Liu reported in bugzilla:\n\nhttps://bugzilla.kernel.org/show_bug.cgi?id=215657\n\n- Overview\nUBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2 when mount and operate a corrupted image\n\n- Reproduce\ntested on kernel 5.17-rc4, 5.17-rc6\n\n1. mkdir test_crash\n2. cd test_crash\n3. unzip tmp2.zip\n4. mkdir mnt\n5. ./single_test.sh f2fs 2\n\n- Kernel dump\n[ 46.434454] loop0: detected capacity change from 0 to 131072\n[ 46.529839] F2FS-fs (loop0): Mounted with checkpoint version = 7548c2d9\n[ 46.738319] ================================================================================\n[ 46.738412] UBSAN: array-index-out-of-bounds in fs/f2fs/segment.c:3460:2\n[ 46.738475] index 231 is out of range for type 'unsigned int [2]'\n[ 46.738539] CPU: 2 PID: 939 Comm: umount Not tainted 5.17.0-rc6 #1\n[ 46.738547] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-1ubuntu1.1 04/01/2014\n[ 46.738551] Call Trace:\n[ 46.738556] \n[ 46.738563] dump_stack_lvl+0x47/0x5c\n[ 46.738581] ubsan_epilogue+0x5/0x50\n[ 46.738592] __ubsan_handle_out_of_bounds+0x68/0x80\n[ 46.738604] f2fs_allocate_data_block+0xdff/0xe60 [f2fs]\n[ 46.738819] do_write_page+0xef/0x210 [f2fs]\n[ 46.738934] f2fs_do_write_node_page+0x3f/0x80 [f2fs]\n[ 46.739038] __write_node_page+0x2b7/0x920 [f2fs]\n[ 46.739162] f2fs_sync_node_pages+0x943/0xb00 [f2fs]\n[ 46.739293] f2fs_write_checkpoint+0x7bb/0x1030 [f2fs]\n[ 46.739405] kill_f2fs_super+0x125/0x150 [f2fs]\n[ 46.739507] deactivate_locked_super+0x60/0xc0\n[ 46.739517] deactivate_super+0x70/0xb0\n[ 46.739524] cleanup_mnt+0x11a/0x200\n[ 46.739532] __cleanup_mnt+0x16/0x20\n[ 46.739538] task_work_run+0x67/0xa0\n[ 46.739547] exit_to_user_mode_prepare+0x18c/0x1a0\n[ 46.739559] syscall_exit_to_user_mode+0x26/0x40\n[ 46.739568] do_syscall_64+0x46/0xb0\n[ 46.739584] entry_SYSCALL_64_after_hwframe+0x44/0xae\n\nThe root cause is we missed to do sanity check on curseg->alloc_type,\nresult in out-of-bound accessing on sbi->block_count[] array, fix it." } ], "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 only through the local f2fs mount/VFS path (mount crafted image → write/sync/umount → f2fs_allocate_data_block → stat_inc_block_count), not via network protocol handlers or packet processing.\nAC:L - A crafted checkpoint with an invalid curseg alloc_type (unsigned char, attacker-chosen) deterministically causes an out-of-bounds increment of sbi->block_count[] once allocation runs; CONFIG_F2FS_STAT_FS defaults to y and no attacker-uncontrollable race is required.\nPR:L - After the malicious f2fs volume is mounted (Android/udisks automount of removable media, or shared workstation), an unprivileged local user can trigger allocation via ordinary writes/sync; CAP_SYS_ADMIN is not required on that path (f2fs is not FS_USERNS_MOUNT, but mount itself is not required once the image is already mounted).\nUI:N - Once the crafted image is present and mounted via automount or delegated mount rights, the attacker drives block allocation themselves through write/sync/umount with no further separate victim action.\nS:U - Corruption and crash remain within the host kernel’s f2fs/sbi memory authority; this is standard local kernel impact, not a VM escape, IOMMU bypass, or other cross-boundary break.\nC:H - Attacker-controlled alloc_type indexes past block_count[2] into adjacent f2fs_sb_info fields (pointers, kobjects, locks), which is out-of-bounds memory corruption leverageable for kernel information disclosure under the overestimate-severity rule.\nI:H - The same OOB is a write primitive (block_count[idx]++), and repeated allocations let the attacker increment a chosen offset many times into critical sbi fields, enabling heap/metadata corruption and control-flow impact.\nA:H - The reported UBSAN out-of-bounds access in f2fs_allocate_data_block on umount/writeback can oops or panic the kernel when the corrupted sbi fields are later used, yielding a full denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/f2fs/segment.c" ], "versions": [ { "version": "351df4b201157351c7d26bf12c3eeb9dbce98854", "lessThan": "498b7088db71f9707359448cd6800bbb1882f4c3", "status": "affected", "versionType": "git" }, { "version": "351df4b201157351c7d26bf12c3eeb9dbce98854", "lessThan": "f68caedf264a95c0b02dfd0d9f92ac2637d5848a", "status": "affected", "versionType": "git" }, { "version": "351df4b201157351c7d26bf12c3eeb9dbce98854", "lessThan": "0748a0f7dcb9d9dddc80302d73ebcecef6782ef0", "status": "affected", "versionType": "git" }, { "version": "351df4b201157351c7d26bf12c3eeb9dbce98854", "lessThan": "c12765e3f129b144421c80d3383df885f85ee290", "status": "affected", "versionType": "git" }, { "version": "351df4b201157351c7d26bf12c3eeb9dbce98854", "lessThan": "f41ee8b91c00770d718be2ff4852a80017ae9ab3", "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/segment.c" ], "versions": [ { "version": "3.8", "status": "affected" }, { "version": "0", "lessThan": "3.8", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.110", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.33", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16.19", "lessThanOrEqual": "5.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.17.2", "lessThanOrEqual": "5.17.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.18", "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": "5.10.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.15.33" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.16.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.17.2" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.8", "versionEndExcluding": "5.18" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/498b7088db71f9707359448cd6800bbb1882f4c3" }, { "url": "https://git.kernel.org/stable/c/f68caedf264a95c0b02dfd0d9f92ac2637d5848a" }, { "url": "https://git.kernel.org/stable/c/0748a0f7dcb9d9dddc80302d73ebcecef6782ef0" }, { "url": "https://git.kernel.org/stable/c/c12765e3f129b144421c80d3383df885f85ee290" }, { "url": "https://git.kernel.org/stable/c/f41ee8b91c00770d718be2ff4852a80017ae9ab3" } ], "title": "f2fs: fix to do sanity check on curseg->alloc_type", "x_generator": { "engine": "bippy-1.2.0" } } } }