{ "schema_version": "1.6.1", "id": "RPI-CVE-2025-40082", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2025-40082" ], "published": "2025-10-28T11:50:45Z", "summary": "hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nhfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()\n\nBUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186\nRead of size 2 at addr ffff8880289ef218 by task syz.6.248/14290\n\nCPU: 0 UID: 0 PID: 14290 Comm: syz.6.248 Not tainted 6.16.4 #1 PREEMPT(full)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nCall Trace:\n \n __dump_stack lib/dump_stack.c:94 [inline]\n dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xca/0x5f0 mm/kasan/report.c:482\n kasan_report+0xca/0x100 mm/kasan/report.c:595\n hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186\n hfsplus_listxattr+0x5b6/0xbd0 fs/hfsplus/xattr.c:738\n vfs_listxattr+0xbe/0x140 fs/xattr.c:493\n listxattr+0xee/0x190 fs/xattr.c:924\n filename_listxattr fs/xattr.c:958 [inline]\n path_listxattrat+0x143/0x360 fs/xattr.c:988\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7fe0e9fae16d\nCode: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007fe0eae67f98 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3\nRAX: ffffffffffffffda RBX: 00007fe0ea205fa0 RCX: 00007fe0e9fae16d\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000\nRBP: 00007fe0ea0480f0 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 00007fe0ea206038 R14: 00007fe0ea205fa0 R15: 00007fe0eae48000\n \n\nAllocated by task 14290:\n kasan_save_stack+0x24/0x50 mm/kasan/common.c:47\n kasan_save_track+0x14/0x30 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:377 [inline]\n __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394\n kasan_kmalloc include/linux/kasan.h:260 [inline]\n __do_kmalloc_node mm/slub.c:4333 [inline]\n __kmalloc_noprof+0x219/0x540 mm/slub.c:4345\n kmalloc_noprof include/linux/slab.h:909 [inline]\n hfsplus_find_init+0x95/0x1f0 fs/hfsplus/bfind.c:21\n hfsplus_listxattr+0x331/0xbd0 fs/hfsplus/xattr.c:697\n vfs_listxattr+0xbe/0x140 fs/xattr.c:493\n listxattr+0xee/0x190 fs/xattr.c:924\n filename_listxattr fs/xattr.c:958 [inline]\n path_listxattrat+0x143/0x360 fs/xattr.c:988\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nWhen hfsplus_uni2asc is called from hfsplus_listxattr,\nit actually passes in a struct hfsplus_attr_unistr*.\nThe size of the corresponding structure is different from that of hfsplus_unistr,\nso the previous fix (94458781aee6) is insufficient.\nThe pointer on the unicode buffer is still going beyond the allocated memory.\n\nThis patch introduces two warpper functions hfsplus_uni2asc_xattr_str and\nhfsplus_uni2asc_str to process two unicode buffers,\nstruct hfsplus_attr_unistr* and struct hfsplus_unistr* respectively.\nWhen ustrlen value is bigger than the allocated memory size,\nthe ustrlen value is limited to an safe size.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.47-1+rpt1~bookworm", "1:6.12.62-1+rpt1~bookworm" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v6", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7l", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-2712", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v6", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v7", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v7l", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8-rt", "binary_version": "1:6.12.62-1+rpt1~bookworm" } ] }, "database_specific": { "per_version": { "1:6.12.47-1+rpt1~bookworm": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.70" }, "1:6.12.62-1+rpt1~bookworm": { "linux_commit": "a1073743767f9e7fdc7017ababd2a07ea0c97c1c", "upstream_version": "6.12.62", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.70" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.47-1+rpt1", "1:6.12.62-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v6", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v7", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-2712", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v6", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v7", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8-rt", "binary_version": "1:6.12.62-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.47-1+rpt1": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.70" }, "1:6.12.62-1+rpt1": { "linux_commit": "a1073743767f9e7fdc7017ababd2a07ea0c97c1c", "upstream_version": "6.12.62", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.70" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2025-40082" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/343fe375a8dd6ee51a193a1c233b999f5ea4d479" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/782acde47e127c98a113726e2ff8024bd65c0454" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/c3db89ea1ed3d540eebe8f3c36e806fb75ee4a1e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/5b5228964619b180f366940505b77255b1a03929" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/857aefc70d4ae3b9bf1ae67434d27d0f79f80c9e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/bea3e1d4467bcf292c8e54f080353d556d355e26" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T12:19:11Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.1, "cvss_v3_severity": "High", "scenario": "AV:L - The attacker-controlled input is an on-disk HFS+ attributes B-tree key, and the vulnerable conversion is reached through the ordinary local `listxattr()`/`llistxattr()` syscall on a mounted volume; there is no network or remote-peer input path. Local rather than Physical because the volume can be attached locally via a loop device and the trigger is a plain local syscall.\nAC:L - The `length` field of the `hfsplus_attr_unistr` key name is written verbatim by the attacker in the crafted image and was clamped to 255 instead of 127, so the 256-byte overread fires deterministically on the first `listxattr()` call. No race, no heap grooming, and no condition outside the attacker's control.\nPR:L - Nothing on the `path_listxattrat` \u2192 `vfs_listxattr` \u2192 `hfsplus_listxattr` \u2192 `hfsplus_uni2asc` path performs any capability check \u2014 the only `capable(CAP_SYS_ADMIN)` test (`can_list()`) runs after the out-of-bounds conversion and merely filters `trusted.*` names. Any unprivileged local user who can traverse an HFS+ volume (e.g. one udisks2-automounted from attacker-supplied removable media) triggers it.\nUI:N - In the automount/kiosk scenario the volume is mounted by the system on device insertion with no victim action, and the attacker then issues the `listxattr()` himself; likewise an attacker with loop-mount access performs every step. Choosing the higher-severity option where the mount could otherwise be attributed to a victim.\nS:U - The out-of-bounds read, the leaked bytes, and any resulting fault all stay within the kernel's own security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - This is not a bounded few-byte read: up to 256 bytes past the `kzalloc(536)` key allocation are consumed, NLS-converted into `strbuf`, and copied out to userspace by `copy_name()` plus the `copy_to_user()` in `listxattr()`, giving a direct kernel-heap disclosure channel rather than a mere oracle. On slub_debug/KASAN/KFENCE and hardened configurations those bytes are live redzone/stale slab content adjacent to the allocation.\nI:N - `hfsplus_uni2asc()` only dereferences and converts the input; the output writes are bounded by `*len_p` via `nls->uni2char()` returning `-ENAMETOOLONG`. There is no out-of-bounds write, no type confusion, and no mechanism to modify kernel memory or hijack control flow.\nA:H - The slab out-of-bounds read is a guaranteed KASAN/KFENCE report and, with `panic_on_warn`/`panic_on_oops`, a kernel panic; where the overread crosses a KFENCE guard page it faults outright. It also leaves the xattr listing returning `-EIO`/garbage, rendering the volume's attribute handling unusable, and is repeatable at will by an unprivileged user." } } }