Vulnerability CVE-2024-27066
Published: 2024-05-01

Description:
In the Linux kernel, the following vulnerability has been resolved:

virtio: packed: fix unmap leak for indirect desc table

When use_dma_api and premapped are true, then the do_unmap is false.

Because the do_unmap is false, vring_unmap_extra_packed is not called by
detach_buf_packed.

if (unlikely(vq->do_unmap)) {
curr = id;
for (i = 0; i < state->num; i++) {
vring_unmap_extra_packed(vq,
&vq->packed.desc_extra[curr]);
curr = vq->packed.desc_extra[curr].next;
}
}

So the indirect desc table is not unmapped. This causes the unmap leak.

So here, we check vq->use_dma_api instead. Synchronously, dma info is
updated based on use_dma_api judgment

This bug does not occur, because no driver use the premapped with
indirect.

 References:
https://git.kernel.org/stable/c/e142169aca5546ae6619c39a575cda8105362100
https://git.kernel.org/stable/c/75450ff8c6fe8755bf5b139b238eaf9739cfd64e
https://git.kernel.org/stable/c/51bacd9d29bf98c3ebc65e4a0477bb86306b4140
https://git.kernel.org/stable/c/d5c0ed17fea60cca9bc3bf1278b49ba79242bbcd
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