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lib: handle windows reserved device names on UNC #59286

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Merged
merged 4 commits into from
Aug 9, 2025
Merged

lib: handle windows reserved device names on UNC #59286

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1dade18
lib: handle windows reserved device names on UNC
RafaelGSS Jul 30, 2025
6ada607
fixup! lib: handle windows reserved device names on UNC
RafaelGSS Jul 30, 2025
3bfea8f
fixup! fixup! lib: handle windows reserved device names on UNC
RafaelGSS Jul 31, 2025
a2ad295
fixup! fixup! fixup! lib: handle windows reserved device names on UNC
RafaelGSS Aug 7, 2025
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15 changes: 15 additions & 0 deletions lib/path.js
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Original file line number Diff line number Diff line change
Expand Up @@ -398,6 +398,12 @@ const win32 = {
// We matched a device root (e.g. \\\\.\\PHYSICALDRIVE0)
device = `\\\\${firstPart}`;
rootEnd = 4;
// Special case: handle \\?\COM1: or similar reserved device paths
const possibleDevice = StringPrototypeSlice(path, 4, path.indexOf(':') + 1);
if (isWindowsReservedName(possibleDevice, possibleDevice.length - 1)) {
device = `\\\\?\\${possibleDevice}`;
rootEnd = 4 + possibleDevice.length;
}
} else if (j === len) {
// We matched a UNC root only
// Return the normalized version of the UNC root since there
Expand Down Expand Up @@ -556,6 +562,15 @@ const win32 = {
joined = `\\${StringPrototypeSlice(joined, slashCount)}`;
}

// Skip normalization when reserved device names are present
const parts = joined.split(/\\+/);
if (parts.some((p) => {
const colonIndex = p.indexOf(':');
return colonIndex !== -1 && isWindowsReservedName(p, colonIndex);
})) {
return joined.replace(/\//g, '\\');
}

return win32.normalize(joined);
},

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8 changes: 8 additions & 0 deletions test/parallel/test-path-join.js
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Expand Up @@ -110,6 +110,14 @@ joinTests.push([
[['c:.', 'file'], 'c:file'],
[['c:', '/'], 'c:\\'],
[['c:', 'file'], 'c:\\file'],
// UNC path join tests (Windows)
[['\\server\\share', 'file.txt'], '\\server\\share\\file.txt'],
[['\\server\\share', 'folder', 'another.txt'], '\\server\\share\\folder\\another.txt'],
[['\\server\\share', 'COM1:'], '\\server\\share\\COM1:'],
[['\\server\\share', 'path', 'LPT1:'], '\\server\\share\\path\\LPT1:'],
[['\\fileserver\\public\\uploads', 'CON:..\\..\\..\\private\\db.conf'],
'\\fileserver\\public\\uploads\\CON:..\\..\\..\\private\\db.conf'],

// Path traversal in previous versions of Node.js.
[['./upload', '/../C:/Windows'], '.\\C:\\Windows'],
[['upload', '../', 'C:foo'], '.\\C:foo'],
Expand Down
15 changes: 15 additions & 0 deletions test/parallel/test-path-win32-normalize-device-names.js
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Expand Up @@ -9,6 +9,19 @@ if (!common.isWindows) {
}

const normalizeDeviceNameTests = [
// UNC paths: \\server\share\... is a Windows UNC path, where 'server' is the network server name and 'share'
// is the shared folder. These are used for network file access and are subject to reserved device name
// checks after the share.
{ input: '\\\\server\\share\\COM1:', expected: '\\\\server\\share\\COM1:' },
{ input: '\\\\server\\share\\PRN:', expected: '\\\\server\\share\\PRN:' },
{ input: '\\\\server\\share\\AUX:', expected: '\\\\server\\share\\AUX:' },
{ input: '\\\\server\\share\\LPT1:', expected: '\\\\server\\share\\LPT1:' },
{ input: '\\\\server\\share\\COM1:\\foo\\bar', expected: '\\\\server\\share\\COM1:\\foo\\bar' },
{ input: '\\\\server\\share\\path\\COM1:', expected: '\\\\server\\share\\path\\COM1:' },
{ input: '\\\\server\\share\\COM1:..\\..\\..\\..\\Windows', expected: '\\\\server\\share\\Windows' },
{ input: '\\\\server\\share\\path\\to\\LPT9:..\\..\\..\\..\\..\\..\\..\\..\\..\\file.txt',
expected: '\\\\server\\share\\file.txt' },

{ input: 'CON', expected: 'CON' },
{ input: 'con', expected: 'con' },
{ input: 'CON:', expected: '.\\CON:.' },
Expand Down Expand Up @@ -73,6 +86,8 @@ const normalizeDeviceNameTests = [
// Test cases from original vulnerability reports or similar scenarios
{ input: 'COM1:.\\..\\..\\foo.js', expected: '.\\COM1:..\\..\\foo.js' },
{ input: 'LPT1:.\\..\\..\\another.txt', expected: '.\\LPT1:..\\..\\another.txt' },
// UNC paths
{ input: '\\\\?\\COM1:.\\..\\..\\foo2.js', expected: '\\\\?\\COM1:\\foo2.js' },

// Paths with device names not at the beginning
{ input: 'C:\\CON', expected: 'C:\\CON' },
Expand Down
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