From: Lizhi Xu <lizhi.xu@windriver.com> mainline inclusion from mainline-v6.17-rc1 commit 8282013b56059c34590ac0245c74ea7ed7642924 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ICU6HC CVE: CVE-2025-38611 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The reproducer executes the host's unlocked_ioctl call in two different tasks. When init_context fails, the struct vmci_event_ctx is not fully initialized when executing vmci_datagram_dispatch() to send events to all vm contexts. This affects the datagram taken from the datagram queue of its context by another task, because the datagram payload is not initialized according to the size payload_size, which causes the kernel data to leak to the user space. Before dispatching the datagram, and before setting the payload content, explicitly set the payload content to 0 to avoid data leakage caused by incomplete payload initialization. To avoid the oob check failure when executing __compiletime_lessthan() in memset(), directly use the address of the vmci_event_ctx instance ev to replace ev.msg.hdr, because their addresses are the same. Fixes: 28d6692cd8fb ("VMCI: context implementation.") Reported-by: syzbot+9b9124ae9b12d5af5d95@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9b9124ae9b12d5af5d95 Tested-by: syzbot+9b9124ae9b12d5af5d95@syzkaller.appspotmail.com Signed-off-by: Lizhi Xu <lizhi.xu@windriver.com> Link: https://lore.kernel.org/r/20250703075334.856445-1-lizhi.xu@windriver.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Pan Taixi <pantaixi1@huawei.com> --- drivers/misc/vmw_vmci/vmci_context.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/misc/vmw_vmci/vmci_context.c b/drivers/misc/vmw_vmci/vmci_context.c index f22b44827e92..034a971de551 100644 --- a/drivers/misc/vmw_vmci/vmci_context.c +++ b/drivers/misc/vmw_vmci/vmci_context.c @@ -251,6 +251,8 @@ static int ctx_fire_notification(u32 context_id, u32 priv_flags) ev.msg.hdr.src = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID, VMCI_CONTEXT_RESOURCE_ID); ev.msg.hdr.payload_size = sizeof(ev) - sizeof(ev.msg.hdr); + memset((char*)&ev + sizeof(ev.msg.hdr), 0, + ev.msg.hdr.payload_size); ev.msg.event_data.event = VMCI_EVENT_CTX_REMOVED; ev.payload.context_id = context_id; -- 2.34.1