virtio: packed: fix unmap leak for indirect desc table

Vulnerability 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