single executable applications with warning

[waitingsong]

CentOS 8

[admin tmp]$ uname -a
Linux git 4.18.0-348.7.1.el8_5.x86_64 #1 SMP Wed Dec 22 13:25:12 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

[admin tmp]$ node -v
v18.16.0
[admins tmp]$ npm -v
9.5.1

[admin tmp]$ node hello.js
Hello, undefined!

[admin tmp]$ node hello.js foo
Hello, foo!

got error:

[admin tmp]$ npx postject hello NODE_JS_CODE hello.js \
>     --sentinel-fuse NODE_JS_FUSE_fce680ab2cc467b6e072b8b5df1996b2

Need to install the following packages:
  postject@1.0.0-alpha.5
Ok to proceed? (y)
Start injection of NODE_JS_CODE in hello...
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'

[RaisinTen]

Could you run echo $? after running postject to check the exit code of the process?
Also, what happens when you run ./hello foo?

[waitingsong]

echo 'console.log(`Hello, ${process.argv[2]}!`);' > hello.js

cp $(command -v node) hello

npx postject hello NODE_JS_CODE hello.js \
    --sentinel-fuse NODE_JS_FUSE_fce680ab2cc467b6e072b8b5df1996b2

got:

Start injection of NODE_JS_CODE in hello...
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
warning: Can't find string offset for section name '.note.100'
💉 Injection done!

And then:

[admins foo]$ echo $?
0

It seems work:

[admin foo]$ ./hello world
Hello, world!
(node:1468169) ExperimentalWarning: Single executable application is an experimental feature and might change at any time
(Use `hello --trace-warnings ...` to show where the warning was created)

[RaisinTen]

Okay, so it works! I was curious about the exit code because your original logs didn't contain the 💉 Injection done! part. The other logs are just warnings, so those can be ignored for now.

FWIW, these warnings are coming from the primary dependency, LIEF, from here - https://github.com/lief-project/LIEF/blob/f8f38b60757c0f0401df347de1266c0ecb88055b/src/ELF/Builder.tcc#L667. We intentionally preserved the warnings, so that in case this unexpectedly fails, it would be easier to diagnose what's going on.

[waitingsong]

thanks

[paskozdilar]

Running eu-elflint on hello binary (node v22.12.0) gives quite a few complaints (not counting ones that it raised on vanilla binary):

dynamic section size mismatch in program and section header
phdr[10]: unknown object file note type 0 with owner name '' at offset 284
phdr[10]: unknown object file note type 0 with owner name 'NODE_SEA_BLOB' at offset 472
zeroth section has nonzero name
section [ 5] '.dynsym': 'st_name' in zeroth entry not zero
[...]
section [38] '.symtab': 'st_name' in zeroth entry not zero
section [38] '.symtab': symbol 2 (): st_value out of bounds
section [38] '.symtab': symbol 3 (): st_value out of bounds
[...]
section [42] '': cannot get content of note section
section [43] '': cannot get content of note section
section [44] '': cannot get content of note section
section [45] '': extra 20 bytes after last note
section [46] '': unknown object file note type 0 with owner name '' at offset 24
section [46] '': extra 20 bytes after last note
section [47] '': extra 12 bytes after last note
section [48] '': extra 8 bytes after last note
section [49] '': extra 16 bytes after last note

I found this out when another tool I was using complained that "the header space is insufficient" on binaries created via Node SEA.