Extremely simple wall-hack achieved by patching a single byte.
LINUX ONLY: THIS WILL NOT WORK ON ANYTHING BUT LINUX.
Patching the test instruction, in the IsOtherEnemy function, results in returning false for every call.
The game treats every player as a friendly. This means the game shows the overhead indicator and spectator glow on enemies.
IsOtherEnemy (at least this one) is not used by any other relevant functions so the game does not break because of this.
bool IsOtherEnemy(C_BaseEntity* player1, C_BaseEntity* player2)
31 c0 XOR EAX,EAX ; clears return value
48 85 f6 TEST RSI,RSI ; check if player2 is null
0f 84 85 JZ LABEL_EXIT_EARLY ; return cleared return value => return false;
00 00 00
55 PUSH RBP ; Normal function prologue
48 89 e5 MOV RBP,RSP
41 54 PUSH R12
49 89 fc MOV R12,RDI
53 PUSH RBX
; and so on...
LABEL_EXIT_EARLY:
c3 RET