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doc: Provide a warning around child_process.exec() #10466

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doc: Provide a warning around child_process.exec() #10466

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mjg59
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@mjg59 mjg59 commented Dec 26, 2016 •
edited by sam-github
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child_process.exec() allows trivial arbitrary command execution if code
passes unsanitised user input to it. Add a warning in the docs to make that
clear.

Checklist
  • documentation is changed or added
  • commit message follows commit guidelines
Affected core subsystem(s)

doc

Description of change

@nodejs-github-bot nodejs-github-bot added child_process Issues and PRs related to the child_process subsystem. doc Issues and PRs related to the documentations. lts-watch-v6.x labels Dec 26, 2016
@MylesBorins
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/cc @nodejs/security

@MylesBorins
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Should this perhaps be a general message for all child process commands?

@mjg59
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mjg59 commented Dec 27, 2016

@thealphanerd It's much less true for the others in the family that don't launch shells.

jasnell
jasnell approved these changes Dec 27, 2016
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doc/api/child_process.md
@@ -149,6 +149,9 @@ added: v0.1.90
Spawns a shell then executes the `command` within that shell, buffering any
generated output.

**Note: Never pass unsanitised user input to this function, as otherwise
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I would suggest rephrasing slightly...

*Note*: Passing unsanitized user input containing shell metacharacters can be
used to trigger arbitrary command execution.

LGTM either way tho.

@Trott
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Trott commented Dec 27, 2016

@nodejs/documentation

cjihrig
cjihrig requested changes Dec 28, 2016
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This isn't the only function that spawns a shell. If we include this, it should probably be in top level text.

@mjg59
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mjg59 commented Dec 28, 2016

People will frequently look at function documentation without reading top level text. Adding it to all relevant calls seems reasonable?

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mjg59 commented Dec 28, 2016

Ok I've added the same warning to execSync(). I don't think it's as relevant for the spawn() family.

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cjihrig commented Dec 28, 2016

I don't think it's as relevant for the spawn() family.

What about with the shell: true option?

@mjg59
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mjg59 commented Dec 29, 2016

If the arguments are passed as an array rather than being passed as a single argument to the shell, they won't be interpreted by the shell.

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mjg59 commented Dec 29, 2016

Hm actually this may not be true - sorry, I'm making assumptions about how Unix handles exec(), which is exactly the problem in the first place! Let me look a little more at exactly what child_process does here.

sam-github
sam-github suggested changes Dec 29, 2016
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spawn doesn't use the shell by default, exec does use shell by default, execFile never uses the shell, sync vs. async is not relevant here

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mjg59 commented Dec 29, 2016

Added warnings to spawn() and spawnSync() as well.

sam-github
sam-github reviewed Dec 29, 2016
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doc/api/child_process.md
@@ -149,6 +149,10 @@ added: v0.1.90
Spawns a shell then executes the `command` within that shell, buffering any
generated output.

**Note: Never pass unsanitised user input to this function. Any input
containing shell metacharacters may be used to trigger arbitrary command
execution**
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Missing . at end of sentence

sam-github
sam-github suggested changes Dec 29, 2016
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I updated the PR description for you, please follow directions in the template next time.

The commit message is now inaccurate since the scope expanded.

I suggest

test: warn about shell metas in child_process

or something of the like.

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mjg59 commented Dec 29, 2016

Thanks - fixed up the commit message and added the missing full stops.

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Landed in f60aba2, thanks.

@sam-github sam-github closed this Dec 30, 2016
sam-github pushed a commit that referenced this pull request Dec 30, 2016
@sam-github
doc: warn about unvalidated input in child_process
f60aba2 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
@ChALkeR ChALkeR added the security Issues and PRs related to security. label Dec 31, 2016
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ChALkeR commented Dec 31, 2016

Thanks for doing this! 👍

@evanlucas evanlucas mentioned this pull request Jan 3, 2017
Merged
evanlucas pushed a commit that referenced this pull request Jan 3, 2017
@evanlucas
doc: warn about unvalidated input in child_process
a1464a4 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
evanlucas pushed a commit that referenced this pull request Jan 4, 2017
@evanlucas
doc: warn about unvalidated input in child_process
deb0917 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Jan 23, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
f720bc8 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Jan 23, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
692dce7 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Jan 23, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
678c563 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Jan 24, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
394e85e 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Jan 24, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
6317567 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
This was referenced Jan 24, 2017
Merged
Merged
MylesBorins pushed a commit that referenced this pull request Jan 31, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
c3882f4 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
MylesBorins pushed a commit that referenced this pull request Feb 1, 2017
@MylesBorins
doc: warn about unvalidated input in child_process
c7378c4 
child_process.exec*() and child_process.spawn*() (if options.shell is
true) allow trivial arbitrary command execution if code passes
unsanitised user input to it. Add warnings in the docs to make that
clear.

PR-URL: #10466
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
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@gibfahn gibfahn gibfahn approved these changes

@cjihrig cjihrig cjihrig approved these changes

@jasnell jasnell jasnell approved these changes

@sam-github sam-github sam-github approved these changes

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