#syz test
---
fs/ntfs3/index.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 1bf2a6593dec..15f3a711ea0a 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -478,6 +478,7 @@ static int indx_find_free(struct ntfs_index *indx,
struct ntfs_inode *ni,
struct ATTR_LIST_ENTRY *le = NULL;
const struct INDEX_NAMES *in = &s_index_names[indx->type];
int err;
+ u64 bm_size;
b = ni_find_attr(ni, NULL, &le, ATTR_BITMAP, in->name, in->name_len,
NULL, NULL);
@@ -488,6 +489,17 @@ static int indx_find_free(struct ntfs_index
*indx, struct ntfs_inode *ni,
*bitmap = b;
*bit = MINUS_ONE_T;
+ bm_size = b->non_res ? le64_to_cpu(b->nres.valid_size) :
+ le32_to_cpu(b->res.data_size);
+
+ /*
+ * Allocated index blocks require $BITMAP to contain at least
+ * one bit for usage tracking. A zero-length bitmap in this
+ * case indicates a malformed on-disk structure and cannot be used.
+ */
+ if (unlikely(bm_size == 0 && indx->alloc_run.count))
+ return -EINVAL;
+
if (!b->non_res) {
u32 nbits = 8 * le32_to_cpu(b->res.data_size);
size_t pos = find_next_zero_bit_le(resident_data(b), nbits, 0);
--
On Tue, Jul 8, 2025 at 1:13 AM syzbot
<syzbot+b0373017f711c06ada64@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
> WARNING in ni_rename
>
> loop0: detected capacity change from 0 to 4096
> ------------[ cut here ]------------
> WARNING: fs/ntfs3/frecord.c:3030 at ni_rename+0xee/0x100 fs/ntfs3/frecord.c:3029, CPU#1: syz.0.16/6620
> Modules linked in:
> CPU: 1 UID: 0 PID: 6620 Comm: syz.0.16 Not tainted 6.16.0-rc4-next-20250704-syzkaller-07381-g26ffb3d6f02c-dirty #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
> RIP: 0010:ni_rename+0xee/0x100 fs/ntfs3/frecord.c:3029
> Code: 8b 05 b6 5d 9a 0f 48 3b 44 24 10 75 22 44 89 e0 48 83 c4 18 5b 41 5c 41 5d 41 5e 41 5f 5d e9 d9 a6 6c 08 cc e8 f3 7d b9 fe 90 <0f> 0b 90 eb c5 e8 68 cc 69 08 0f 1f 84 00 00 00 00 00 90 90 90 90
> RSP: 0018:ffffc900033e7ab8 EFLAGS: 00010293
> RAX: ffffffff8306228d RBX: 00000000fffffffe RCX: ffff888021723c00
> RDX: 0000000000000000 RSI: 00000000fffffffe RDI: 0000000000000000
> RBP: 00000000fffffffe R08: ffffffff8fa18a37 R09: 1ffffffff1f43146
> R10: dffffc0000000000 R11: fffffbfff1f43147 R12: 0000000000000000
> R13: ffff88802f30d500 R14: ffff88806d04d0c8 R15: ffff88806d04b368
> FS: 00007f1edd33f6c0(0000) GS:ffff888125d18000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000200000001060 CR3: 000000007c546000 CR4: 00000000003526f0
> Call Trace:
> <TASK>
> ntfs_rename+0x6e2/0xb40 fs/ntfs3/namei.c:316
> vfs_rename+0xbd7/0xf00 fs/namei.c:5129
> do_renameat2+0x6ce/0xa80 fs/namei.c:5278
> __do_sys_rename fs/namei.c:5325 [inline]
> __se_sys_rename fs/namei.c:5323 [inline]
> __x64_sys_rename+0x82/0x90 fs/namei.c:5323
> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
> do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
> entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f1edc58e929
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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
> RSP: 002b:00007f1edd33f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
> RAX: ffffffffffffffda RBX: 00007f1edc7b5fa0 RCX: 00007f1edc58e929
> RDX: 0000000000000000 RSI: 0000200000001040 RDI: 0000200000000280
> RBP: 00007f1edc610b39 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007f1edc7b5fa0 R15: 00007ffcb3616c48
> </TASK>
>
>
> Tested on:
>
> commit: 26ffb3d6 Add linux-next specific files for 20250704
> git tree: linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=16c95582580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=59817f9ef599726c
> dashboard link: https://syzkaller.appspot.com/bug?extid=b0373017f711c06ada64
> compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
> patch: https://syzkaller.appspot.com/x/patch.diff?x=175edf70580000
>
> --
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