[syzbot] [ntfs3?] WARNING in indx_insert_into_buffer (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 6093a688a07d Merge tag 'char-misc-6.18-rc1' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13962458580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e654219ed2546322
dashboard link: https://syzkaller.appspot.com/bug?extid=3a1878433bc1cb97b42a
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=104b692f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17962458580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/660883fc9bdb/disk-6093a688.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/29f543ec9187/vmlinux-6093a688.xz
kernel image: https://storage.googleapis.com/syzbot-assets/456918818f89/bzImage-6093a688.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/dc6369359d19/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3a1878...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 4096
------------[ cut here ]------------
memcpy: detected field-spanning write (size 3656) of single field "hdr1" at fs/ntfs3/index.c:1927 (size 16)
WARNING: CPU: 0 PID: 6065 at fs/ntfs3/index.c:1927 indx_insert_into_buffer.isra.0+0x1041/0x12a0 fs/ntfs3/index.c:1927
Modules linked in:
CPU: 0 UID: 0 PID: 6065 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:indx_insert_into_buffer.isra.0+0x1041/0x12a0 fs/ntfs3/index.c:1927
Code: b5 ed a3 fe c6 05 52 41 31 0d 01 90 48 8b 74 24 68 b9 10 00 00 00 48 c7 c2 20 53 a7 8b 48 c7 c7 80 53 a7 8b e8 a0 74 62 fe 90 <0f> 0b 90 90 e9 df fd ff ff e8 71 6d 0b ff e9 4d f4 ff ff e8 67 6d
RSP: 0018:ffffc900039af748 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 00000000ffffffe4 RCX: ffffffff81799b88
RDX: ffff88802ed50000 RSI: ffffffff81799b95 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888146f46800
R13: ffff888069637800 R14: 0000000000000e48 R15: ffff88807ae74018
FS: 0000555563ff7500(0000) GS:ffff888124e6a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fdbd7fd4286 CR3: 0000000069517000 CR4: 0000000000350ef0
Call Trace:
<TASK>
indx_insert_entry+0x1a0/0x460 fs/ntfs3/index.c:1996
ni_add_name+0x4dd/0x820 fs/ntfs3/frecord.c:2995
ni_rename+0x98/0x170 fs/ntfs3/frecord.c:3026
ntfs_rename+0xab9/0xf00 fs/ntfs3/namei.c:332
vfs_rename+0xfa3/0x2290 fs/namei.c:5216
do_renameat2+0x7d8/0xc20 fs/namei.c:5364
__do_sys_rename fs/namei.c:5411 [inline]
__se_sys_rename fs/namei.c:5409 [inline]
__x64_sys_rename+0x7d/0xa0 fs/namei.c:5409
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f780118eec9
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:00007ffcbf706748 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f78013e5fa0 RCX: 00007f780118eec9
RDX: 0000000000000000 RSI: 0000200000000f40 RDI: 00002000000003c0
RBP: 00007f7801211f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f78013e5fa0 R14: 00007f78013e5fa0 R15: 0000000000000002
</TASK>


---
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[syzbot]

syzbot has bisected this issue to:

commit acdbd67bf939577d6f9e3cf796a005c31cec52d8
Author: Konstantin Komarov <almaz.ale...@paragon-software.com>
Date: Fri Jun 28 15:27:46 2024 +0000

fs/ntfs3: Optimize large writes into sparse file

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=147995cd980000
start commit: 6093a688a07d Merge tag 'char-misc-6.18-rc1' of git://git.k..
git tree: upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=167995cd980000
console output: https://syzkaller.appspot.com/x/log.txt?x=127995cd980000

kernel config: https://syzkaller.appspot.com/x/.config?x=e654219ed2546322
dashboard link: https://syzkaller.appspot.com/bug?extid=3a1878433bc1cb97b42a

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=104b692f980000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17962458580000

Reported-by: syzbot+3a1878...@syzkaller.appspotmail.com
Fixes: acdbd67bf939 ("fs/ntfs3: Optimize large writes into sparse file")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject:
Author: jkoo...@xs4all.nl

#syz test


fs/ntfs3/index.c | 10 +++++-----
fs/ntfs3/ntfs.h | 5 ++++-
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 6d1bf890929d..2e512abc7000 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -1808,7 +1808,7 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
CLST new_vbn;
__le64 t_vbn, *sub_vbn;
u16 sp_size;
- void *hdr1_saved = NULL;
+ void *blk1_saved = NULL;

/* Try the most easy case. */
e = fnd->level - 1 == level ? fnd->de[level] : NULL;
@@ -1842,8 +1842,8 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
memcpy(up_e, sp, sp_size);

used1 = le32_to_cpu(hdr1->used);
- hdr1_saved = kmemdup(hdr1, used1, GFP_NOFS);
- if (!hdr1_saved) {
+ blk1_saved = kmemdup(&n1->index->blk, used1, GFP_NOFS);
+ if (!blk1_saved) {
err = -ENOMEM;
goto out;
}
@@ -1924,13 +1924,13 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,
* Undo critical operations.
*/
indx_mark_free(indx, ni, new_vbn >> indx->idx2vbn_bits);
- memcpy(hdr1, hdr1_saved, used1);
+ memcpy(&n1->index->blk, blk1_saved, used1);
indx_write(indx, ni, n1, 0);
}

out:
kfree(up_e);
- kfree(hdr1_saved);
+ kfree(blk1_saved);

return err;
}
diff --git a/fs/ntfs3/ntfs.h b/fs/ntfs3/ntfs.h
index 552b97905813..d5e2b22eacd7 100644
--- a/fs/ntfs3/ntfs.h
+++ b/fs/ntfs3/ntfs.h
@@ -754,7 +754,10 @@ static inline bool hdr_has_subnode(const struct INDEX_HDR *hdr)
struct INDEX_BUFFER {
struct NTFS_RECORD_HEADER rhdr; // 'INDX'
__le64 vbn; // 0x10: vcn if index >= cluster or vsn id index < cluster
- struct INDEX_HDR ihdr; // 0x18:
+ struct_group(blk,
+ struct INDEX_HDR ihdr; // 0x18:
+ u8 data[]; // NTFS_DE entries
+ );
};

static_assert(sizeof(struct INDEX_BUFFER) == 0x28);
--
2.51.0

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in indx_insert_into_buffer

loop0: detected capacity change from 0 to 4096
------------[ cut here ]------------

memcpy: detected field-spanning write (size 3656) of single field "&n1->index->blk" at fs/ntfs3/index.c:1927 (size 16)
WARNING: CPU: 1 PID: 6418 at fs/ntfs3/index.c:1927 indx_insert_into_buffer.isra.0+0x109a/0x1320 fs/ntfs3/index.c:1927
Modules linked in:
CPU: 1 UID: 0 PID: 6418 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025

RIP: 0010:indx_insert_into_buffer.isra.0+0x109a/0x1320 fs/ntfs3/index.c:1927
Code: 0c d5 a3 fe c6 05 3a ad 30 0d 01 90 48 8b 74 24 68 b9 10 00 00 00 48 c7 c2 60 68 a7 8b 48 c7 c7 c0 68 a7 8b e8 87 5b 62 fe 90 <0f> 0b 90 90 e9 b0 fd ff ff e8 38 56 0b ff e9 f4 f3 ff ff e8 2e 56
RSP: 0018:ffffc90003a0f748 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 00000000ffffffe4 RCX: ffffffff817a4b08
RDX: ffff888025980000 RSI: ffffffff817a4b15 RDI: 0000000000000001

RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000

R10: 0000000000000001 R11: 0000000000000000 R12: ffff88807927e800
R13: ffff88805862a800 R14: dffffc0000000000 R15: 0000000000000e48
FS: 00007f94fb6426c0(0000) GS:ffff888124f62000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f3ee058dd30 CR3: 00000000616dd000 CR4: 0000000000350ef0

Call Trace:
<TASK>
indx_insert_entry+0x1a0/0x460 fs/ntfs3/index.c:1996
ni_add_name+0x4dd/0x820 fs/ntfs3/frecord.c:2995
ni_rename+0x98/0x170 fs/ntfs3/frecord.c:3026
ntfs_rename+0xab9/0xf00 fs/ntfs3/namei.c:332
vfs_rename+0xfa3/0x2290 fs/namei.c:5216
do_renameat2+0x7d8/0xc20 fs/namei.c:5364
__do_sys_rename fs/namei.c:5411 [inline]
__se_sys_rename fs/namei.c:5409 [inline]
__x64_sys_rename+0x7d/0xa0 fs/namei.c:5409
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f94fa78eec9

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:00007f94fb642038 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007f94fa9e5fa0 RCX: 00007f94fa78eec9

RDX: 0000000000000000 RSI: 0000200000000f40 RDI: 00002000000003c0

RBP: 00007f94fa811f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f94fa9e6038 R14: 00007f94fa9e5fa0 R15: 00007ffce10dde88
</TASK>


Tested on:

commit: a8cdf51c Merge tag 'hardening-fix1-v6.18-rc1' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16277334580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7e89ecd5e8107dd4

dashboard link: https://syzkaller.appspot.com/bug?extid=3a1878433bc1cb97b42a
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=14a8e892580000

[Lizhi Xu]

There are more entries after the structure, use unsafe_memcpy() to avoid
this warning.

syzbot reported:

memcpy: detected field-spanning write (size 3656) of single field "hdr1" at fs/ntfs3/index.c:1927 (size 16)

Call Trace:

indx_insert_entry+0x1a0/0x460 fs/ntfs3/index.c:1996
ni_add_name+0x4dd/0x820 fs/ntfs3/frecord.c:2995
ni_rename+0x98/0x170 fs/ntfs3/frecord.c:3026
ntfs_rename+0xab9/0xf00 fs/ntfs3/namei.c:332

Reported-by: syzbot+3a1878...@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3a1878433bc1cb97b42a
Signed-off-by: Lizhi Xu <lizh...@windriver.com>
---
fs/ntfs3/index.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/index.c b/fs/ntfs3/index.c
index 6d1bf890929d..7157cfd70fdc 100644
--- a/fs/ntfs3/index.c
+++ b/fs/ntfs3/index.c
@@ -1924,7 +1924,8 @@ indx_insert_into_buffer(struct ntfs_index *indx, struct ntfs_inode *ni,

* Undo critical operations.
*/
indx_mark_free(indx, ni, new_vbn >> indx->idx2vbn_bits);
- memcpy(hdr1, hdr1_saved, used1);

+ unsafe_memcpy(hdr1, hdr1_saved, used1,
+ "There are entries after the structure");
indx_write(indx, ni, n1, 0);
}

--
2.43.0

[Konstantin Komarov]

Thanks for the patch. Applied.

Regards,
Konstantin