CVE-2025-37738

In the Linux kernel, the following vulnerability has been resolved:

ext4: ignore xattrs past end

Once inside 'ext4_xattr_inode_dec_ref_all' we should

ignore xattrs entries past the 'end' entry.

This fixes the following KASAN reported issue:

==================================================================

BUG: KASAN: slab-use-after-free in ext4_xattr_inode_dec_ref_all+0xb8c/0xe90

Read of size 4 at addr ffff888012c120c4 by task repro/2065

CPU: 1 UID: 0 PID: 2065 Comm: repro Not tainted 6.13.0-rc2+ #11

Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014

Call Trace:

<TASK>

dump_stack_lvl+0x1fd/0x300

? tcp_gro_dev_warn+0x260/0x260

? _printk+0xc0/0x100

? read_lock_is_recursive+0x10/0x10

? irq_work_queue+0x72/0xf0

? __virt_addr_valid+0x17b/0x4b0

print_address_description+0x78/0x390

print_report+0x107/0x1f0

? __virt_addr_valid+0x17b/0x4b0

? __virt_addr_valid+0x3ff/0x4b0

? __phys_addr+0xb5/0x160

? ext4_xattr_inode_dec_ref_all+0xb8c/0xe90

kasan_report+0xcc/0x100

? ext4_xattr_inode_dec_ref_all+0xb8c/0xe90

ext4_xattr_inode_dec_ref_all+0xb8c/0xe90

? ext4_xattr_delete_inode+0xd30/0xd30

? __ext4_journal_ensure_credits+0x5f0/0x5f0

? __ext4_journal_ensure_credits+0x2b/0x5f0

? inode_update_timestamps+0x410/0x410

ext4_xattr_delete_inode+0xb64/0xd30

? ext4_truncate+0xb70/0xdc0

? ext4_expand_extra_isize_ea+0x1d20/0x1d20

? __ext4_mark_inode_dirty+0x670/0x670

? ext4_journal_check_start+0x16f/0x240

? ext4_inode_is_fast_symlink+0x2f2/0x3a0

ext4_evict_inode+0xc8c/0xff0

? ext4_inode_is_fast_symlink+0x3a0/0x3a0

? do_raw_spin_unlock+0x53/0x8a0

? ext4_inode_is_fast_symlink+0x3a0/0x3a0

evict+0x4ac/0x950

? proc_nr_inodes+0x310/0x310

? trace_ext4_drop_inode+0xa2/0x220

? _raw_spin_unlock+0x1a/0x30

? iput+0x4cb/0x7e0

do_unlinkat+0x495/0x7c0

? try_break_deleg+0x120/0x120

? 0xffffffff81000000

? __check_object_size+0x15a/0x210

? strncpy_from_user+0x13e/0x250

? getname_flags+0x1dc/0x530

__x64_sys_unlinkat+0xc8/0xf0

do_syscall_64+0x65/0x110

entry_SYSCALL_64_after_hwframe+0x67/0x6f

RIP: 0033:0x434ffd

Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 8

RSP: 002b:00007ffc50fa7b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000107

RAX: ffffffffffffffda RBX: 00007ffc50fa7e18 RCX: 0000000000434ffd

RDX: 0000000000000000 RSI: 0000000020000240 RDI: 0000000000000005

RBP: 00007ffc50fa7be0 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001

R13: 00007ffc50fa7e08 R14: 00000000004bbf30 R15: 0000000000000001

</TASK>

The buggy address belongs to the object at ffff888012c12000

which belongs to the cache filp of size 360

The buggy address is located 196 bytes inside of

freed 360-byte region [ffff888012c12000, ffff888012c12168)

The buggy address belongs to the physical page:

page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x12c12

head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0

flags: 0x40(head|node=0|zone=0)

page_type: f5(slab)

raw: 0000000000000040 ffff888000ad7640 ffffea0000497a00 dead000000000004

raw: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000

head: 0000000000000040 ffff888000ad7640 ffffea0000497a00 dead000000000004

head: 0000000000000000 0000000000100010 00000001f5000000 0000000000000000

head: 0000000000000001 ffffea00004b0481 ffffffffffffffff 0000000000000000

head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff888012c11f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

ffff888012c12000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

> ffff888012c12080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^

ffff888012c12100: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc

ffff888012c12180: fc fc fc fc fc fc fc fc fc

---truncated---