Re: CVE-2018-20124 QEMU: rdma: OOB access when building scatter-gather array

[P J P <ppandit () redhat com>]

+-- On Tue, 18 Dec 2018, saar amar wrote --+
| I'm wondering why it says "DOS" and not "execute arbitrary code on the host, 
| in the context of the QEMU process"? I have stack overflow, it pretty clear 
| I could gain more than simple DOS:)
| 
| What do your day?

IIUC, it's likely to corrupt adjacent stack variables and/or hit stack canary 
resulting in DoS. The scatter/gather entry object(struct ibv_sge) holds buffer 
address/length attributes used during r/w operations. If their values are 
astray, the following call to ibv_post_send() may suffer/return an error.

Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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