Messages in this thread | | | Date | Wed, 13 Mar 2024 10:01:27 +0100 | Subject | Re: [PATCH net] nfc: nci: Fix uninit-value in nci_dev_up | From | Krzysztof Kozlowski <> |
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On 12/03/2024 15:56, Ryosuke Yasuoka wrote: > syzbot reported the following unitit-value access issue [1]:
If there is going to be any new version then: typo, uninit-value > > nci_ntf_packet() calls each ntf operation parsed from skb->data. When > the payload length is zero, each operation handler reads uninitialized > payload and KMSAN detects this issue. Such notification packet should be > silently discarded since it is unexpected for any notification handlers. > > This patch resolved this issue by checking payload size before calling > each notification handler codes. > > BUG: KMSAN: uninit-value in nci_init_req net/nfc/nci/core.c:177 [inline] > BUG: KMSAN: uninit-value in __nci_request net/nfc/nci/core.c:108 [inline] > BUG: KMSAN: uninit-value in nci_open_device net/nfc/nci/core.c:521 [inline] > BUG: KMSAN: uninit-value in nci_dev_up+0xfec/0x1b10 net/nfc/nci/core.c:632 > nci_init_req net/nfc/nci/core.c:177 [inline] > __nci_request net/nfc/nci/core.c:108 [inline] > nci_open_device net/nfc/nci/core.c:521 [inline] > nci_dev_up+0xfec/0x1b10 net/nfc/nci/core.c:632 > nfc_dev_up+0x26e/0x440 net/nfc/core.c:118 > nfc_genl_dev_up+0xfe/0x1d0 net/nfc/netlink.c:770 > genl_family_rcv_msg_doit net/netlink/genetlink.c:972 [inline] > genl_family_rcv_msg net/netlink/genetlink.c:1052 [inline] > genl_rcv_msg+0x11ec/0x1290 net/netlink/genetlink.c:1067 > netlink_rcv_skb+0x371/0x650 net/netlink/af_netlink.c:2545 > genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076 > netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] > netlink_unicast+0xf47/0x1250 net/netlink/af_netlink.c:1368 > netlink_sendmsg+0x1238/0x13d0 net/netlink/af_netlink.c:1910 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg net/socket.c:745 [inline] > ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2584 > ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 > __sys_sendmsg net/socket.c:2667 [inline] > __do_sys_sendmsg net/socket.c:2676 [inline] > __se_sys_sendmsg net/socket.c:2674 [inline] > __x64_sys_sendmsg+0x307/0x490 net/socket.c:2674 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > Uninit was stored to memory at: > nci_core_reset_ntf_packet net/nfc/nci/ntf.c:36 [inline] > nci_ntf_packet+0x19dc/0x39c0 net/nfc/nci/ntf.c:782 > nci_rx_work+0x213/0x500 net/nfc/nci/core.c:1522 > process_one_work kernel/workqueue.c:2633 [inline] > process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2706 > worker_thread+0xf45/0x1490 kernel/workqueue.c:2787 > kthread+0x3ed/0x540 kernel/kthread.c:388 > ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242 > > Uninit was created at: > slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768 > slab_alloc_node mm/slub.c:3478 [inline] > kmem_cache_alloc_node+0x5e9/0xb10 mm/slub.c:3523 > kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:560 > __alloc_skb+0x318/0x740 net/core/skbuff.c:651 > alloc_skb include/linux/skbuff.h:1286 [inline] > virtual_ncidev_write+0x6d/0x280 drivers/nfc/virtual_ncidev.c:120 > vfs_write+0x48b/0x1200 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+0x93/0xd0 fs/read_write.c:652 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x6d/0x140 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > > CPU: 1 PID: 5012 Comm: syz-executor935 Not tainted 6.7.0-syzkaller-00562-g9f8413c4a66f #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
These two lines are not really relevant, it's a virtual platform, so whether this is Google or Amazon it does not matter, and your log paste is already quite long. If there is going to be any resend, I propose to drop.
> > Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation") > Reported-and-tested-by: syzbot+7ea9413ea6749baf5574@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=7ea9413ea6749baf5574 [1] > Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com> > --- > net/nfc/nci/ntf.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/nfc/nci/ntf.c b/net/nfc/nci/ntf.c > index 994a0a1efb58..56624387e253 100644 > --- a/net/nfc/nci/ntf.c > +++ b/net/nfc/nci/ntf.c > @@ -765,6 +765,9 @@ void nci_ntf_packet(struct nci_dev *ndev, struct sk_buff *skb) > nci_opcode_oid(ntf_opcode), > nci_plen(skb->data)); > > + if (!nci_plen(skb->data)) > + goto end;
Looks reasonable, however wouldn't there be the same issue in nci_rsp_packet() and other cases from nci_rx_work()? I wonder why only NTF packets could be constructed without payload.
Best regards, Krzysztof
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