wolfSSL_PEM_X509_X509_CRL_X509_PKEY_read_bio: avoid quadratic PEM marker scanning - #11405
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per-allansson wants to merge 1 commit into
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wolfSSL_PEM_X509_X509_CRL_X509_PKEY_read_bio: avoid quadratic PEM marker scanning#11405per-allansson wants to merge 1 commit into
per-allansson wants to merge 1 commit into
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…ker scanning The PEM reader rescanned previously examined data after each byte read, causing quadratic scanning time for large PEM objects. Track the search position for BEGIN and END markers, retaining enough overlap to detect markers split across reads. Also check the buffer bound before reading the newline after the header.
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🟢 Approval recommended
The changes are localized, consistent with existing parsing logic, and address both performance and a concrete buffer-bound safety check without altering the PEM parsing contract.
Pull request overview
This PR optimizes wolfSSL_PEM_X509_X509_CRL_X509_PKEY_read_bio()’s PEM header/footer detection to avoid repeated rescanning of already-processed bytes, preventing quadratic-time behavior when reading large PEM objects from a BIO.
Changes:
- Track and advance a
searchPosoffset so-----BEGIN/-----ENDmarker searches only scan a small overlapping window instead of the entire accumulated buffer. - Add an explicit
i >= lbound check before reading the post-header newline byte.
File summaries
| File | Description |
|---|---|
src/x509.c |
Makes PEM marker scanning linear-time by keeping search position state and hardens the newline read with a buffer bound check. |
Review details
- Files reviewed: 1/1 changed files
- Comments generated: 0
- Review effort level: Lite
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The PEM reader rescanned previously examined data after each byte read, causing quadratic scanning time for large PEM objects.
Track the search position for BEGIN and END markers, retaining enough overlap to detect markers split across reads.
Also check the buffer bound before reading the newline after the header.