CVE-2024-47701

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ext4: avoid OOB when system.data xattr changes underneath the filesystem<br /> <br /> When looking up for an entry in an inlined directory, if e_value_offs is<br /> changed underneath the filesystem by some change in the block device, it<br /> will lead to an out-of-bounds access that KASAN detects as an UAF.<br /> <br /> EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.<br /> loop0: detected capacity change from 2048 to 2047<br /> ==================================================================<br /> BUG: KASAN: use-after-free in ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500<br /> Read of size 1 at addr ffff88803e91130f by task syz-executor269/5103<br /> <br /> CPU: 0 UID: 0 PID: 5103 Comm: syz-executor269 Not tainted 6.11.0-rc4-syzkaller #0<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014<br /> Call Trace:<br /> <br /> __dump_stack lib/dump_stack.c:93 [inline]<br /> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119<br /> print_address_description mm/kasan/report.c:377 [inline]<br /> print_report+0x169/0x550 mm/kasan/report.c:488<br /> kasan_report+0x143/0x180 mm/kasan/report.c:601<br /> ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500<br /> ext4_find_inline_entry+0x4be/0x5e0 fs/ext4/inline.c:1697<br /> __ext4_find_entry+0x2b4/0x1b30 fs/ext4/namei.c:1573<br /> ext4_lookup_entry fs/ext4/namei.c:1727 [inline]<br /> ext4_lookup+0x15f/0x750 fs/ext4/namei.c:1795<br /> lookup_one_qstr_excl+0x11f/0x260 fs/namei.c:1633<br /> filename_create+0x297/0x540 fs/namei.c:3980<br /> do_symlinkat+0xf9/0x3a0 fs/namei.c:4587<br /> __do_sys_symlinkat fs/namei.c:4610 [inline]<br /> __se_sys_symlinkat fs/namei.c:4607 [inline]<br /> __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:4607<br /> do_syscall_x64 arch/x86/entry/common.c:52 [inline]<br /> do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83<br /> entry_SYSCALL_64_after_hwframe+0x77/0x7f<br /> RIP: 0033:0x7f3e73ced469<br /> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48<br /> RSP: 002b:00007fff4d40c258 EFLAGS: 00000246 ORIG_RAX: 000000000000010a<br /> RAX: ffffffffffffffda RBX: 0032656c69662f2e RCX: 00007f3e73ced469<br /> RDX: 0000000020000200 RSI: 00000000ffffff9c RDI: 00000000200001c0<br /> RBP: 0000000000000000 R08: 00007fff4d40c290 R09: 00007fff4d40c290<br /> R10: 0023706f6f6c2f76 R11: 0000000000000246 R12: 00007fff4d40c27c<br /> R13: 0000000000000003 R14: 431bde82d7b634db R15: 00007fff4d40c2b0<br /> <br /> <br /> Calling ext4_xattr_ibody_find right after reading the inode with<br /> ext4_get_inode_loc will lead to a check of the validity of the xattrs,<br /> avoiding this problem.