[Autocomplete] Use hash_equals() to compare the extra_options checksum#3565
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validateChecksum() compared the client-supplied checksum against the server-computed HMAC with `!==`, which short-circuits on the first differing byte and is therefore not constant-time (CWE-208). The checksum guards the integrity of `extra_options`, which the controller feeds into the autocompleter as form-creation options, so the comparison should be timing-safe. Switch to hash_equals() with the known value as the first argument. LiveComponent already does this in LiveComponentHydrator::verifyChecksum() — this aligns Autocomplete with it.
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hash_equals() to compare the extra_options checksum
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Thank you @Amoifr. |
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validateChecksum()compared the client-supplied checksum against theserver-computed HMAC with
!==, which short-circuits on the firstdiffering byte and is therefore not constant-time (CWE-208).
The checksum guards the integrity of
extra_options, which thecontroller feeds into the autocompleter as form-creation options, so the
comparison should be timing-safe. Switch to hash_equals() with the
known value as the first argument. LiveComponent already does this in
LiveComponentHydrator::verifyChecksum() — this aligns Autocomplete with
it.