Guard against short server scramble in sha256_password auth#22356
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iliaal wants to merge 1 commit into
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Guard against short server scramble in sha256_password auth#22356iliaal wants to merge 1 commit into
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morrisonlevi
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The code looks okay but... how would we test it to be sure?
mysqlnd_sha256_auth_get_auth_data() XORs SCRAMBLE_LENGTH bytes of the server-supplied scramble into the password without checking the scramble is at least that long, unlike the native and caching_sha2 plugins which reject a short scramble with CR_MALFORMED_PACKET. A server reporting a scramble shorter than 20 bytes shrinks the heap buffer the scramble is copied into, so the XOR reads past it. Add the same length guard the sibling plugins use.
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Added a regression test (a |
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mysqlnd_sha256_auth_get_auth_data() XORs SCRAMBLE_LENGTH (20) bytes of the server-supplied scramble into the password without checking the scramble is at least that long, unlike the native and caching_sha2 plugins which reject a short scramble with CR_MALFORMED_PACKET. A server reporting a scramble shorter than 20 bytes shrinks the heap buffer the scramble is copied into, so the XOR reads past it. Add the same length guard the sibling plugins use.