A stack based buffer overflow was found in the virtio-net device of QEMU. This issue occurs when flushing TX in the virtio_net_flush_tx function if guest features VIRTIO_NET_F_HASH_REPORT, VIRTIO_F_VERSION_1 and VIRTIO_NET_F_MRG_RXBUF are enabled. This could allow a malicious user to overwrite local variables allocated on the stack. Specifically, the out_sg variable could be used to read a part of process memory and send it to the wire, causing an information leak.
Weakness
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
Affected Software
| Name |
Vendor |
Start Version |
End Version |
| Qemu |
Qemu |
* |
8.2.1 (excluding) |
| Red Hat Enterprise Linux 8 |
RedHat |
virt-devel:rhel-8100020240314161907.e155f54d |
* |
| Red Hat Enterprise Linux 8 |
RedHat |
virt:rhel-8100020240314161907.e155f54d |
* |
| Qemu |
Ubuntu |
bionic |
* |
| Qemu |
Ubuntu |
jammy |
* |
| Qemu |
Ubuntu |
lunar |
* |
| Qemu |
Ubuntu |
mantic |
* |
| Qemu |
Ubuntu |
trusty |
* |
| Qemu |
Ubuntu |
upstream |
* |
| Qemu |
Ubuntu |
xenial |
* |
Potential Mitigations
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
- D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
- Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
- For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
References