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Harry Sintonen

@harrysintonen@infosec.exchange View on infosec.exchange

Infosec consultant at REVƎЯSEC reversec.com - Coding, Research + various other interests

PGP
sintonen.fi/pgpkey.txt
Research
sintonen.fi/advisories/ Link checked on 2026-10-28
Github
github.com/piru Link checked on 2026-10-28
  • 3 posts
Harry Sintonen @harrysintonen@infosec.exchange

Motorola 68010 is an interesting CPU. It has a 2-instruction cache for a specific opcode: DBcc. When a cacheable 2-byte instruction is combined with DBcc that loops back to this instruction, the 68010 automatically enters a loop mode. In this mode, the instructions don't need to be fetched, leading to a performance boost over the 68000.

As a practical example, I came up with this strlen() implementation that (as far as I can tell) is the fastest way strlen() can be implemented on a 68010 CPU.

#assembly #m68k

strlen: moveq #-1,d0 .loop: tst.b (a0)+ dbeq d0,.loop tst.b -1(a0) beq.b .done sub.l #$10000,d0 bra.b .loop .done: not.l d0 rts

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Harry Sintonen @harrysintonen@infosec.exchange

Rest in peace Patrick Stewart

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Harry Sintonen @harrysintonen@infosec.exchange

With this #GitHub runner vulnerability in place, dependencies could have been tampered with and malicious payloads injected into the built software. Any software built with these runners since the #eMudhra was made public and until the runners are fixed must be considered compromised.

infosec.exchange/@yossarian/11

yossarian @yossarian@infosec.exchange · open

GitHub's macOS runners are unfortunately still vulnerable to the eMudhra CA compromise, meaning that any TLS traffic that goes through the system Git, curl, etc. is MITMable.

(success in the CI matrix below means the runner made a TLS connection that it absolutely should not have.)

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