[mysqlnd] Fix result set field metadata length buffer over-read - #289
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[mysqlnd] Fix result set field metadata length buffer over-read#289iliaal wants to merge 1 commit into
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The rset_field metadata reader trusted each length-encoded string size: a hostile server could send a length marker at the end of a field packet whose value exceeds the remaining payload, advancing p past header.size and past the command buffer before the next dereference, and recording attacker-controlled lengths on pointers outside the packet that later feed memcpy() into the field memory pool. Bound each metadata string by bailing once p leaves the payload and rejecting lengths larger than the remaining bytes, mirroring the hardening applied to php_mysqlnd_ok_read() and the other packet readers by GHSA-h35g-vwh6-m678; an audit found no other users of the READ_RSET_FIELD macro and the trailing default-value check never dereferences its length.
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php_mysqlnd_rset_field_read() trusted the length-encoded string sizes sent by the server: a hostile server can place a length marker at the end of a field metadata packet whose value exceeds the remaining payload, so p advances past header.size and the command buffer before the next dereference, and attacker-controlled lengths get attached to pointers outside the packet that later feed memcpy() into the field memory pool. Each metadata string is now bounded by bailing out once p leaves the payload and rejecting lengths larger than the remaining bytes, mirroring the hardening already applied to php_mysqlnd_ok_read() and the other packet readers by GHSA-h35g-vwh6-m678. An audit of sibling readers found no other users of the READ_RSET_FIELD macro, and the trailing default-value check never dereferences its length; a hostile-server phpt test fails on the unpatched build with a bogus protocol warning from the over-read and passes after the fix.