Fix bounds check in OLE2 decryption #1458
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The bounds check for the loop iterating an OLE2 block during decryption may have an integer unerflow if the `leftover + bytesToWrite` is less than 16. That results in a significant buffer over read and a segfault. The fix is simply to do addition on the left side of the check instead of subtraction on the right. Fixes https://issues.oss-fuzz.com/issues/372544101
tj-cisco
approved these changes
Feb 24, 2025
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The bounds check for the loop iterating an OLE2 block during decryption may have an integer underflow if the
leftover + bytesToWriteis less than 16. That results in a significant buffer over read and a segfault.The fix is simply to do addition on the left side of the check instead of subtraction on the right.
Fixes https://issues.oss-fuzz.com/issues/372544101
Note: This is the fix from 1.4.2 and 1.0.8 (e.g. a copy of 935b2fe) for main / 1.5.