Alma Linux: CVE-2024-35944: Important: kernel security update (Multiple Advisories)

Alma Linux: CVE-2024-35944: Important: kernel security update (Multiple Advisories)

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

05/19/2024

Created

09/27/2024

Added

09/26/2024

Modified

09/26/2024

Description

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."

Solution(s)

• alma-upgrade-bpftool
• alma-upgrade-kernel
• alma-upgrade-kernel-abi-stablelists
• alma-upgrade-kernel-core
• alma-upgrade-kernel-cross-headers
• alma-upgrade-kernel-debug
• alma-upgrade-kernel-debug-core
• alma-upgrade-kernel-debug-devel
• alma-upgrade-kernel-debug-modules
• alma-upgrade-kernel-debug-modules-extra
• alma-upgrade-kernel-devel
• alma-upgrade-kernel-doc
• alma-upgrade-kernel-headers
• alma-upgrade-kernel-modules
• alma-upgrade-kernel-modules-extra
• alma-upgrade-kernel-rt
• alma-upgrade-kernel-rt-core
• alma-upgrade-kernel-rt-debug
• alma-upgrade-kernel-rt-debug-core
• alma-upgrade-kernel-rt-debug-devel
• alma-upgrade-kernel-rt-debug-kvm
• alma-upgrade-kernel-rt-debug-modules
• alma-upgrade-kernel-rt-debug-modules-extra
• alma-upgrade-kernel-rt-devel
• alma-upgrade-kernel-rt-kvm
• alma-upgrade-kernel-rt-modules
• alma-upgrade-kernel-rt-modules-extra
• alma-upgrade-kernel-tools
• alma-upgrade-kernel-tools-libs
• alma-upgrade-kernel-tools-libs-devel
• alma-upgrade-kernel-zfcpdump
• alma-upgrade-kernel-zfcpdump-core
• alma-upgrade-kernel-zfcpdump-devel
• alma-upgrade-kernel-zfcpdump-modules
• alma-upgrade-kernel-zfcpdump-modules-extra
• alma-upgrade-perf
• alma-upgrade-python3-perf

References

• https://attackerkb.com/topics/cve-2024-35944
• CVE - 2024-35944
• https://errata.almalinux.org/8/ALSA-2024-7000.html
• https://errata.almalinux.org/8/ALSA-2024-7001.html