[syzbot] [net?] [nfc?] KMSAN: uninit-value in nci_ntf_packet (3)

[syzbot] [net?] [nfc?] KMSAN: uninit-value in nci_ntf_packet (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    614da38e2f7a Merge tag 'hid-for-linus-2024051401' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1125e6fe980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f5d2cbf33633f507
dashboard link: https://syzkaller.appspot.com/bug?extid=3f8fa0edaa75710cd66e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/89eafb874b71/disk-614da38e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/356000512ad9/vmlinux-614da38e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/839c73939115/bzImage-614da38e.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com

nci: nci_rf_discover_ntf_packet: unsupported rf_tech_and_mode 0x6e
=====================================================
BUG: KMSAN: uninit-value in nci_rf_discover_ntf_packet net/nfc/nci/ntf.c:386 [inline]
BUG: KMSAN: uninit-value in nci_ntf_packet+0x2ac8/0x39c0 net/nfc/nci/ntf.c:798
 nci_rf_discover_ntf_packet net/nfc/nci/ntf.c:386 [inline]
 nci_ntf_packet+0x2ac8/0x39c0 net/nfc/nci/ntf.c:798
 nci_rx_work+0x288/0x5d0 net/nfc/nci/core.c:1532
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0xa81/0x1bd0 kernel/workqueue.c:3348
 worker_thread+0xea5/0x1560 kernel/workqueue.c:3429
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:3877 [inline]
 slab_alloc_node mm/slub.c:3918 [inline]
 kmem_cache_alloc_node+0x622/0xc90 mm/slub.c:3961
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577
 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1319 [inline]
 virtual_ncidev_write+0x6d/0x290 drivers/nfc/virtual_ncidev.c:120
 vfs_write+0x497/0x14d0 fs/read_write.c:588
 ksys_write+0x20f/0x4c0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:652
 x64_sys_call+0x3062/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 PID: 2431 Comm: kworker/u8:8 Not tainted 6.9.0-syzkaller-02707-g614da38e2f7a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
Workqueue: nfc2_nci_rx_wq nci_rx_work
=====================================================


---
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If the report is already addressed, let syzbot know by replying with:
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#syz undup

Re: [syzbot] [net?] [nfc?] KMSAN: uninit-value in nci_ntf_packet (3)

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    8f602276d390 Merge tag 'bcachefs-2024-10-05' of git://evil..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=148c27d0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d302f14701986aa0
dashboard link: https://syzkaller.appspot.com/bug?extid=3f8fa0edaa75710cd66e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1367f307980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14c98327980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/241996bfa3de/disk-8f602276.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/417de1b4ca32/vmlinux-8f602276.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2c793c19b953/bzImage-8f602276.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com

nci: nci_rf_discover_ntf_packet: unsupported rf_tech_and_mode 0xe6
=====================================================
BUG: KMSAN: uninit-value in nci_rf_discover_ntf_packet net/nfc/nci/ntf.c:386 [inline]
BUG: KMSAN: uninit-value in nci_ntf_packet+0x2ac6/0x39c0 net/nfc/nci/ntf.c:798
 nci_rf_discover_ntf_packet net/nfc/nci/ntf.c:386 [inline]
 nci_ntf_packet+0x2ac6/0x39c0 net/nfc/nci/ntf.c:798
 nci_rx_work+0x408/0x6f0 net/nfc/nci/core.c:1544
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xae0/0x1c40 kernel/workqueue.c:3310
 worker_thread+0xea7/0x14f0 kernel/workqueue.c:3391
 kthread+0x3e2/0x540 kernel/kthread.c:389
 ret_from_fork+0x6d/0x90 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4091 [inline]
 slab_alloc_node mm/slub.c:4134 [inline]
 kmem_cache_alloc_node_noprof+0x6bf/0xb80 mm/slub.c:4186
 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
 alloc_skb include/linux/skbuff.h:1322 [inline]
 virtual_ncidev_write+0x67/0x380 drivers/nfc/virtual_ncidev.c:120
 vfs_write+0x487/0x1540 fs/read_write.c:681
 ksys_write+0x24f/0x4c0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:748 [inline]
 __se_sys_write fs/read_write.c:745 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:745
 x64_sys_call+0x306a/0x3ba0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 2937 Comm: kworker/u8:9 Not tainted 6.12.0-rc1-syzkaller-00349-g8f602276d390 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: nfc2_nci_rx_wq nci_rx_work
=====================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [net?] [nfc?] KMSAN: uninit-value in nci_ntf_packet (3)

[Qianqiang Liu]

#syz test

diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index 6b89d596ba9a..31da26287327 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -117,7 +117,7 @@ static ssize_t virtual_ncidev_write(struct file *file,
 	struct virtual_nci_dev *vdev = file->private_data;
 	struct sk_buff *skb;
 
-	skb = alloc_skb(count, GFP_KERNEL);
+	skb = alloc_skb(count, GFP_KERNEL | __GFP_ZERO);
 	if (!skb)
 		return -ENOMEM;
 
-- 
Best,
Qianqiang Liu

Re: [syzbot] [net?] [nfc?] KMSAN: uninit-value in nci_ntf_packet (3)

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com
Tested-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com

Tested on:

commit:         7234e2ea Merge tag 'scsi-fixes' of git://git.kernel.or..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11b63fd0580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=981fe2ff8a1e457a
dashboard link: https://syzkaller.appspot.com/bug?extid=3f8fa0edaa75710cd66e
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14f87b27980000

Note: testing is done by a robot and is best-effort only.

[PATCH] nfc/nci: Fix uninit-value issue in nci_ntf_packet

[Qianqiang Liu]

When an unsupported rf_tech_and_mode (0xe6) occurs in nci_rf_discover_ntf_packet,
the ntf.ntf_type may be assigned an uninitialized value.

To resolve this, use the __GFP_ZERO flag when calling alloc_skb(),
ensuring that skb->data is properly initialized.

Reported-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3f8fa0edaa75710cd66e
Tested-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com
Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>
---
 drivers/nfc/virtual_ncidev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index 6b89d596ba9a..31da26287327 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -117,7 +117,7 @@ static ssize_t virtual_ncidev_write(struct file *file,
 	struct virtual_nci_dev *vdev = file->private_data;
 	struct sk_buff *skb;
 
-	skb = alloc_skb(count, GFP_KERNEL);
+	skb = alloc_skb(count, GFP_KERNEL | __GFP_ZERO);
 	if (!skb)
 		return -ENOMEM;
 
-- 
2.47.0

Re: [PATCH] nfc/nci: Fix uninit-value issue in nci_ntf_packet

[Krzysztof Kozlowski]

On 12/10/2024 20:47, Qianqiang Liu wrote:
> When an unsupported rf_tech_and_mode (0xe6) occurs in nci_rf_discover_ntf_packet,
> the ntf.ntf_type may be assigned an uninitialized value.
> 
> To resolve this, use the __GFP_ZERO flag when calling alloc_skb(),
> ensuring that skb->data is properly initialized.
> 
> Reported-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=3f8fa0edaa75710cd66e
> Tested-by: syzbot+3f8fa0edaa75710cd66e@syzkaller.appspotmail.com
> Signed-off-by: Qianqiang Liu <qianqiang.liu@163.com>

Do not attach (thread) your patchsets to some other threads (unrelated
or older versions). This buries them deep in the mailbox and might
interfere with applying entire sets.

> ---
>  drivers/nfc/virtual_ncidev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
> index 6b89d596ba9a..31da26287327 100644
> --- a/drivers/nfc/virtual_ncidev.c
> +++ b/drivers/nfc/virtual_ncidev.c
> @@ -117,7 +117,7 @@ static ssize_t virtual_ncidev_write(struct file *file,
>  	struct virtual_nci_dev *vdev = file->private_data;
>  	struct sk_buff *skb;
>  
> -	skb = alloc_skb(count, GFP_KERNEL);
> +	skb = alloc_skb(count, GFP_KERNEL | __GFP_ZERO);
>  	if (!skb)
>  		return -ENOMEM;

Same comments as before:

https://lore.kernel.org/all/20240803121817.383567-1-zhanghao1@kylinos.cn/

Respond to existing feedback, please.

Best regards,
Krzysztof

Re: [PATCH] nfc/nci: Fix uninit-value issue in nci_ntf_packet

[Qianqiang Liu]

On Wed, Oct 16, 2024 at 09:58:53AM +0200, Krzysztof Kozlowski wrote:
> 
> Same comments as before:
> 
> https://lore.kernel.org/all/20240803121817.383567-1-zhanghao1@kylinos.cn/
> 
> Respond to existing feedback, please.
> 
> Best regards,
> Krzysztof

Got it, thanks!

-- 
Best,
Qianqiang Liu