https://github.com/raehik/elf-data-injector

Inject data into ELFs and patch over references to use them, automatically
https://github.com/raehik/elf-data-injector

Last synced: 12 days ago
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Inject data into ELFs and patch over references to use them, automatically

• Host: GitHub
• URL: https://github.com/raehik/elf-data-injector
• Owner: raehik
• Created: 2022-05-02T13:13:43.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-05-02T13:13:55.000Z (over 2 years ago)
• Last Synced: 2024-11-13T16:34:21.202Z (2 months ago)
• Language: Haskell
• Homepage:
• Size: 11.7 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md

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README

        
# ELF data injector

Inject data into ELFs and patch over references to use them.

Intended primarily for the awkward task of replacing a string literal with an

arbitrarily longer one. Replacing a string with another string of the same

shorter length is easy; longer is challenging. This tool appends a new segment

to the ELF, amends headers and offsets, and patches offsets to replace

references to the old data with references to the new data.

## Rough notes

  * Lay out data and create blablabla

  * PH: Increment file offsets. Everything shifts by `e_phentsize * 1 = 0x20`.

  * PH: Insert new segment *before* the weird empty one. If it comes after,

    raehik's device immediately reboots.

    * `p_flags` is a bitmask. 4 is R, 5 is RW. Both work. Make it read-only,

      until we need to add our own global data for some reason.

    * Need to know total size, vaddr

  * FH: Increment `e_phnum`.

## To-dos

  * I talk about paddr where ELF talks about offset. I don't mean paddr in

    memory, I mean in ELF file. That's bad, should fix