Описание
In the Linux kernel, the following vulnerability has been resolved:
VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host()
Syzkaller hit 'WARNING in dg_dispatch_as_host' bug.
memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg"
at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24)
WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237
dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237
Some code commentry, based on my understanding:
544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size)
/// This is 24 + payload_size
memcpy(&dg_info->msg, dg, dg_size);
Destination = dg_info->msg ---> this is a 24 byte
structure(struct vmci_datagram)
Source = dg --> this is a 24 byte structure (struct vmci_datagram)
Size = dg_size = 24 + payload_size
{payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32.
35 struct delayed_datagram_info {
36 struct datagram_entry entry;
37 struct work_struct work;
38 bool in_dg_host_queue;
39 / msg and msg_payload must be together. */
40 struct vmci_datagram msg;
41 u8 msg_payload[];
42 };
So those extra bytes of payload are copied into msg_payload[], a run time
warning is seen while fuzzing with Syzkaller.
One possible way to fix the warning is to split the memcpy() into
two parts -- one -- direct assignment of msg and second taking care of payload.
Gustavo quoted:
"Under FORTIFY_SOURCE we should not copy data across multiple members
in a structure."
In the Linux kernel, the following vulnerability has been resolved:
VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host()
The Linux kernel CVE team has assigned CVE-2024-35944 to this issue.
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2024051920-CVE-2024-35944-a860@gregkh/T
Отчет
This vulnerability is rated with a Low severity because it requires local access to interact with the VMware VMCI interface and primarily triggers a fortification runtime check rather than causing arbitrary out-of-bounds memory corruption. Exposure is restricted to virtualized environments running on VMware platforms where the VMCI driver is actively loaded. Because the flaw involves copying datagram contents across contiguous structure members into an adjacent flexible array buffer, the operational blast radius is limited to kernel diagnostic warnings or a potential local denial of service under fortified kernel configurations.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2024:7001 | 24.09.2024 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2024:7000 | 24.09.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:9315 | 12.11.2024 |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2024:9315 | 12.11.2024 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | kernel | Fixed | RHSA-2025:4342 | 30.04.2025 |
| RHOAI-2.13-RHEL-8 | rhoai/odh-codeflare-operator-rhel8 | Fixed | RHBA-2024:8413 | 24.10.2024 |
| RHOAI-2.13-RHEL-8 | rhoai/odh-dashboard-rhel8 | Fixed | RHBA-2024:8413 | 24.10.2024 |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg" at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24) WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237 dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237 Some code commentry, based on my understanding: 544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size) /// This is 24 + payload_size memcpy(&dg_info->msg, dg, dg_size); Destination = dg_info->msg ---> this is a 24 byte structure(struct vmci_datagram) Source = dg --> this is a 24 byte structure (struct vmci_datagram) Size = dg_size = 24 + payload_size {payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32. 35 struct delayed_datagram_info { 36 struct datagram_entry *entry; 37 ...
In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg" at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24) WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237 dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237 Some code commentry, based on my understanding: 544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size) /// This is 24 + payload_size memcpy(&dg_info->msg, dg, dg_size); Destination = dg_info->msg ---> this is a 24 byte structure(struct vmci_datagram) Source = dg --> this is a 24 byte structure (struct vmci_datagram) Size = dg_size = 24 + payload_size {payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32. 35 struct delayed_datagram_info { 36 struct datagram_entry
In the Linux kernel, the following vulnerability has been resolved: V ...
In the Linux kernel, the following vulnerability has been resolved: VMCI: Fix memcpy() run-time warning in dg_dispatch_as_host() Syzkaller hit 'WARNING in dg_dispatch_as_host' bug. memcpy: detected field-spanning write (size 56) of single field "&dg_info->msg" at drivers/misc/vmw_vmci/vmci_datagram.c:237 (size 24) WARNING: CPU: 0 PID: 1555 at drivers/misc/vmw_vmci/vmci_datagram.c:237 dg_dispatch_as_host+0x88e/0xa60 drivers/misc/vmw_vmci/vmci_datagram.c:237 Some code commentry, based on my understanding: 544 #define VMCI_DG_SIZE(_dg) (VMCI_DG_HEADERSIZE + (size_t)(_dg)->payload_size) /// This is 24 + payload_size memcpy(&dg_info->msg, dg, dg_size); Destination = dg_info->msg ---> this is a 24 byte structure(struct vmci_datagram) Source = dg --> this is a 24 byte structure (struct vmci_datagram) Size = dg_size = 24 + payload_size {payload_size = 56-24 =32} -- Syzkaller managed to set payload_size to 32. 35 struct delayed_datagram_info { 36 struct datagram_en...
Уязвимость компонента VMCI ядра операционной системы Linux, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5.5 Medium
CVSS3