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Override `child_process.execFile` asar patch for `child_process.exec`

NodeJS implements `child_process.exec` by simply passing the whole
command to `child_process.execFile`. See:

- https://github.com/nodejs/node/blob/master/lib/child_process.js#L90
- https://github.com/nodejs/node/blob/master/lib/child_process.js#L99

Electron patches `child_process.execFile` to add support for `asar`
archives by injecting logic that extracts the required files from the
`asar` to a temporary location before delegating the work to the
original `child_process.execFile`.

In order to decide whether to inject the custom `asar` extracting logic,
Electron makes use of a helper function called `splitPath()`. See:

- https://github.com/electron/electron/blob/master/lib/common/asar.js#L37

If the first argument of the returned array equals `true`, means that
the path is considered to be an `asar` archive, and thus the extraction
logic takes place. The problem is that if the command passed to
`child_process.execFile` *contains* a path to an asar archive, padded
with other commands/arguments, `splitPath()` will consider it to be an
`asar` archive, and will try to extract it, throwing a rightfully
`Invalid package` error.

Fixes: #5571
Signed-off-by: Juan Cruz Viotti <jviottidc@gmail.com>
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Juan Cruz Viotti
Juan Cruz Viotti committed May 19, 2016
1 parent 242508e commit 1a27ecdad41ba0854a8a890774e1ec67c83ee427
Showing with 41 additions and 0 deletions.
  1. +17 −0 lib/common/asar.js
  2. +24 −0 spec/asar-spec.js
@@ -589,6 +589,23 @@
return mkdirSync(p, mode)
}
}

// Executing a command string containing a path to an asar
// archive confuses `child_process.execFile`, which is internally
// called by `child_process.{exec,execSync}`, causing
// Electron to consider the full command as a single path
// to an archive.
[ 'exec', 'execSync' ].forEach(function (functionName) {
var old = child_process[functionName]
child_process[functionName] = function () {
var processNoAsarOriginalValue = process.noAsar
process.noAsar = true
var result = old.apply(this, arguments)
process.noAsar = processNoAsarOriginalValue
return result
}
})

overrideAPI(fs, 'open')
overrideAPI(child_process, 'execFile')
overrideAPISync(process, 'dlopen', 1)
@@ -555,6 +555,30 @@ describe('asar package', function () {
})
})

describe('child_process.exec', function () {
var child_process = require('child_process');
var echo = path.join(fixtures, 'asar', 'echo.asar', 'echo')

it('should not try to extract the command if there is a reference to a file inside an .asar', function (done) {
child_process.exec('echo ' + echo + ' foo bar', function (error, stdout) {
assert.equal(error, null)
assert.equal(stdout.toString().replace(/\r/g, ''), echo + ' foo bar\n')
done()
})
})
})

describe('child_process.execSync', function () {
var child_process = require('child_process');
var echo = path.join(fixtures, 'asar', 'echo.asar', 'echo')

it('should not try to extract the command if there is a reference to a file inside an .asar', function (done) {
var stdout = child_process.execSync('echo ' + echo + ' foo bar')
assert.equal(stdout.toString().replace(/\r/g, ''), echo + ' foo bar\n')
done()
})
})

describe('child_process.execFile', function () {
var echo, execFile, execFileSync, ref2
if (process.platform !== 'darwin') {

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