PVA: harden handling of protocol sizes#3878
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July 10, 2026 13:48
Protocol handling was prone to memory exhaustion because of this pattern: ``` int count = buffer.getInteger(); Whatever[] data = new Whatever[count]; .. then read data from buffer ``` A misconfigured package can contain a huge `count`. This update checks the `count` against the remaining package size, refusing packets that are obviously too small or rather the `count` is obviously too large for the packet size. Along the same lines, one could introduce an upper packet size limit similar to `EPICS_CA_MAX_ARRAY_BYTES` in channel access, but at this time, confirmed in a 2026-07-10 EPICS core telecon, PVA does not impose any such size limits, using all available memory.
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Protocol handling was prone to memory exhaustion because of this pattern:
A misconfigured package can contain a huge
count. This update checks thecountagainst the remaining package size, refusing packets that are obviously too small or rather thecountis obviously too large for the packet size.Along the same lines, one could introduce an upper packet size limit similar to
EPICS_CA_MAX_ARRAY_BYTESin channel access, but at this time, confirmed in a 2026-07-10 EPICS core telecon, PVA does not impose any such size limits, using all available memory.