[Reflection] Fix overrun when reading field records of nonstandard size.#88628
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mikeash merged 1 commit intoMay 15, 2026
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When we read field descriptors, we compute the size of each one and bail out if it goes past the end of the section. The size consists of the header, plus record size multiplied by count. However, when we iterate, we ignore the record size and just iterate using the known standard size. If the record size field is smaller than standard, especially zero, we can go off the end of the section. This only happens with corrupt data, but we do want to gracefully handle corrupt data. rdar://175435261
al45tair
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May 14, 2026
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@swift-ci please test |
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@swift-ci please test windows platform |
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When we read field descriptors, we compute the size of each one and bail out if it goes past the end of the section. The size consists of the header, plus record size multiplied by count. However, when we iterate, we ignore the record size and just iterate using the known standard size. If the record size field is smaller than standard, especially zero, we can go off the end of the section. This only happens with corrupt data, but we do want to gracefully handle corrupt data.
rdar://175435261