Dear Linux kernel developers and maintainers, We would like to report a new kernel bug found by our tool. The issue is a WARNING in ext4_fill_super. Details are as follows.
Kernel commit: v6.18.2 Kernel config: see attachment report: see attachment We are currently analyzing the root cause and working on a reproducible PoC. We will provide further updates in this thread as soon as we have more information. Best regards, Longxing Li loop4: detected capacity change from 0 to 514 ------------[ cut here ]------------ strnlen: detected buffer overflow: 65 byte read of buffer size 64 WARNING: CPU: 0 PID: 12320 at lib/string_helpers.c:1035 __fortify_report+0x9c/0xd0 lib/string_helpers.c:1035 Modules linked in: CPU: 0 UID: 0 PID: 12320 Comm: syz.4.59 Not tainted 6.18.2 #1 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__fortify_report+0x9c/0xd0 lib/string_helpers.c:1035 Code: ed 48 c7 c0 80 c8 cf 8b 48 0f 44 d8 e8 cd dd 17 fd 4d 89 e0 48 89 ea 4c 89 f6 48 89 d9 48 c7 c7 00 c9 cf 8b e8 b5 57 d6 fc 90 <0f> 0b 90 90 5b 5d 41 5c 41 5d 41 5e c3 cc cc cc cc 48 89 de 48 c7 RSP: 0018:ffffc90011f9fa18 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffffffff8bcfc880 RCX: ffffffff817afc38 RDX: ffff8881095eca80 RSI: ffffffff817afc45 RDI: 0000000000000001 RBP: 0000000000000041 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000040 R13: 0000000000000000 R14: ffffffff8bcfd240 R15: ffff88803c484400 FS: 00007f9e5f45c640(0000) GS:ffff8880cf053000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000123400000 CR4: 0000000000752ef0 PKRU: 80000000 Call Trace: <TASK> __fortify_panic+0x23/0x30 lib/string_helpers.c:1042 strnlen include/linux/fortify-string.h:235 [inline] sized_strscpy include/linux/fortify-string.h:309 [inline] parse_apply_sb_mount_options fs/ext4/super.c:2486 [inline] __ext4_fill_super fs/ext4/super.c:5306 [inline] ext4_fill_super+0x3972/0xaf70 fs/ext4/super.c:5736 get_tree_bdev_flags+0x38c/0x620 fs/super.c:1698 vfs_get_tree+0x8e/0x340 fs/super.c:1758 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3642 [inline] do_new_mount fs/namespace.c:3718 [inline] path_mount+0x7b9/0x23a0 fs/namespace.c:4028 do_mount fs/namespace.c:4041 [inline] __do_sys_mount fs/namespace.c:4229 [inline] __se_sys_mount fs/namespace.c:4206 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4206 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x56755e Code: 48 c7 c0 ff ff ff ff eb aa e8 3e 1c 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f9e5f45bdf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f9e5f45be80 RCX: 000000000056755e RDX: 0000000020000140 RSI: 0000000020000440 RDI: 00007f9e5f45be40 RBP: 0000000020000140 R08: 00007f9e5f45be80 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000440 R13: 00007f9e5f45be40 R14: 00000000000003d5 R15: 0000000020000200 </TASK> https://drive.google.com/file/d/12W8B3IU88RBdBpV4nMcAj9TVOzlx6xL-/view?usp=drive_link https://drive.google.com/file/d/1efTUJTmSTMuJqSpCq686RjXdUzhyEJDL/view?usp=drive_link
