Shell Code

Assembly codes
Inject into kernel after compiling.

Shell Code is the key place why we patch kernel or what do we patch kernel for.

DualBoot ShellCodes

• For DualBoot feature, here provided several sources:

  • DummyHead.S

    • PlaceHolders of Linux Kernel hdr.(refer kernel64_hdr struct in Qualcomm ABL)
    • This part will not be injected into Linux kernel.

  • ShellCode.xxx.S

    • Read flags in memory or do other check.
    • Once the conditions are met, will jump to _UEFI, otherwise continue next instruction.

  • CommonTail.S

    • First instruction is jumping to linux, that happen when condition in ShellCode.xxx.S not meet.
    • Provide _UEFIlabel, ShellCode.xxx.S will jump here after conditions.
    • Handles unexceptional behavior in the end.

DTB Wrapper

• Comming soon.