Compression.ZipFile support for Unix Permissions

src/libraries/System.IO.Compression.ZipFile/src/System.IO.Compression.ZipFile.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <TargetFrameworks>$(NetCoreAppCurrent)</TargetFrameworks>
+    <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent)-Unix</TargetFrameworks>
     <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
@@ -14,10 +14,24 @@
     <Compile Include="$(CommonPath)System\IO\PathInternal.CaseSensitivity.cs"
              Link="Common\System\IO\PathInternal.CaseSensitivity.cs" />
   </ItemGroup>
+  <!-- Unix specific files -->
+  <ItemGroup Condition=" '$(TargetsUnix)' == 'true'">
+    <Compile Include="System\IO\Compression\ZipFileExtensions.ZipArchive.Create.Unix.cs" />
+    <Compile Include="System\IO\Compression\ZipFileExtensions.ZipArchiveEntry.Extract.Unix.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\Interop.Libraries.cs"
+             Link="Common\Interop\Unix\Interop.Libraries.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\Interop.Errors.cs"
+             Link="Common\Interop\Unix\System.Native\Interop.Errors.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.FChMod.cs"
+             Link="Common\Interop\Unix\System.Native\Interop.FChMod.cs" />
+    <Compile Include="$(CommonPath)Interop\Unix\System.Native\Interop.Stat.cs"
+             Link="Common\Interop\Unix\System.Native\Interop.Stat.cs" />
+  </ItemGroup>
   <ItemGroup>
     <Reference Include="System.IO.Compression" />
     <Reference Include="System.IO.FileSystem" />
     <Reference Include="System.Runtime" />
     <Reference Include="System.Runtime.Extensions" />
+    <Reference Include="System.Runtime.InteropServices" />
   </ItemGroup>
 </Project>

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFileExtensions.ZipArchive.Create.Unix.cs

@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.IO.Compression
+{
+    public static partial class ZipFileExtensions
+    {
+        static partial void SetExternalAttributes(FileStream fs, ZipArchiveEntry entry)
+        {
+            Interop.Sys.FileStatus status;
+            if (Interop.Sys.FStat(fs.SafeFileHandle, out status) != 0)
+            {
+                Interop.ErrorInfo error = Interop.Sys.GetLastErrorInfo();
+                throw new IOException(error.GetErrorMessage(), error.RawErrno);
+            }
+
+            entry.ExternalAttributes |= status.Mode << 16;
+        }
+    }
+}

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFileExtensions.ZipArchive.Create.cs

@@ -94,7 +94,7 @@ internal static ZipArchiveEntry DoCreateEntryFromFile(this ZipArchive destinatio
 
             // Argument checking gets passed down to FileStream's ctor and CreateEntry
 
-            using (Stream fs = new FileStream(sourceFileName, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 0x1000, useAsync: false))
+            using (FileStream fs = new FileStream(sourceFileName, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 0x1000, useAsync: false))
             {
                 ZipArchiveEntry entry = compressionLevel.HasValue
                                     ? destination.CreateEntry(entryName, compressionLevel.Value)
@@ -109,11 +109,15 @@ internal static ZipArchiveEntry DoCreateEntryFromFile(this ZipArchive destinatio
 
                 entry.LastWriteTime = lastWrite;
 
+                SetExternalAttributes(fs, entry);
+
                 using (Stream es = entry.Open())
                     fs.CopyTo(es);
 
                 return entry;
             }
         }
+
+        static partial void SetExternalAttributes(FileStream fs, ZipArchiveEntry entry);
     }
 }

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFileExtensions.ZipArchiveEntry.Extract.Unix.cs

@@ -0,0 +1,33 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.IO.Compression
+{
+    public static partial class ZipFileExtensions
+    {
+        static partial void ExtractExternalAttributes(FileStream fs, ZipArchiveEntry entry)
+        {
+            // Only extract USR, GRP, and OTH file permissions, and ignore
+            // S_ISUID, S_ISGID, and S_ISVTX bits. This matches unzip's default behavior.
+            // It is off by default because of this comment:
+
+            // "It's possible that a file in an archive could have one of these bits set
+            // and, unknown to the person unzipping, could allow others to execute the
+            // file as the user or group. The new option -K bypasses this check."
+            const int ExtractPermissionMask = 0x1FF;
+            int permissions = (entry.ExternalAttributes >> 16) & ExtractPermissionMask;
+
+            // If the permissions weren't set at all, don't write the file's permissions,
+            // since the .zip could have been made using a previous version of .NET, which didn't
+            // include the permissions, or was made on Windows.
+            if (permissions != 0)
+            {
+                if (Interop.Sys.FChMod(fs.SafeFileHandle, permissions) != 0)
+                {
+                    Interop.ErrorInfo error = Interop.Sys.GetLastErrorInfo();
+                    throw new IOException(error.GetErrorMessage(), error.RawErrno);
+                }
+            }
+        }
+    }
+}

src/libraries/System.IO.Compression.ZipFile/src/System/IO/Compression/ZipFileExtensions.ZipArchiveEntry.Extract.cs

@@ -1,8 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.ComponentModel;
-
 namespace System.IO.Compression
 {
     public static partial class ZipFileExtensions
@@ -75,15 +73,19 @@ public static void ExtractToFile(this ZipArchiveEntry source, string destination
             // Rely on FileStream's ctor for further checking destinationFileName parameter
             FileMode fMode = overwrite ? FileMode.Create : FileMode.CreateNew;
 
-            using (Stream fs = new FileStream(destinationFileName, fMode, FileAccess.Write, FileShare.None, bufferSize: 0x1000, useAsync: false))
+            using (FileStream fs = new FileStream(destinationFileName, fMode, FileAccess.Write, FileShare.None, bufferSize: 0x1000, useAsync: false))
             {
                 using (Stream es = source.Open())
                     es.CopyTo(fs);
+
+                ExtractExternalAttributes(fs, source);
             }
 
             File.SetLastWriteTime(destinationFileName, source.LastWriteTime.DateTime);
         }
 
+        static partial void ExtractExternalAttributes(FileStream fs, ZipArchiveEntry entry);
+
         internal static void ExtractRelativeToDirectory(this ZipArchiveEntry source, string destinationDirectoryName) =>
             ExtractRelativeToDirectory(source, destinationDirectoryName, overwrite: false);