Kernel: Make O_RDONLY non-zero

Sergey suggested that having a non-zero O_RDONLY would make some things
less confusing, and it seems like he's right about that.

We can now easily check read/write permissions separately instead of
dancing around with the bits.

This patch also fixes unveil() validation for O_RDWR which previously
forgot to check for "r" permission.

5 files changed, 21 insertions, 30 deletions

diff --git a/Kernel/FileSystem/FileDescription.h b/Kernel/FileSystem/FileDescription.h
index e907545d9b..4638f00028 100644
--- a/Kernel/FileSystem/FileDescription.h
+++ b/Kernel/FileSystem/FileDescription.h
@@ -59,16 +59,8 @@ public:
 
     void set_rw_mode(int options)
     {
-        if (options & O_WRONLY) {
-            set_readable(false);
-            set_writable(true);
-        } else if (options & O_RDWR) {
-            set_readable(true);
-            set_writable(true);
-        } else {
-            set_readable(true);
-            set_writable(false);
-        }
+        set_readable(options & O_RDONLY);
+        set_writable(options & O_WRONLY);
     }
 
     int close();
diff --git a/Kernel/FileSystem/VirtualFileSystem.cpp b/Kernel/FileSystem/VirtualFileSystem.cpp
index d87e70c28b..6b4ba042eb 100644
--- a/Kernel/FileSystem/VirtualFileSystem.cpp
+++ b/Kernel/FileSystem/VirtualFileSystem.cpp
@@ -239,13 +239,10 @@ KResultOr<NonnullRefPtr<FileDescription>> VFS::open(StringView path, int options
 
     bool should_truncate_file = false;
 
-    // NOTE: Read permission is a bit weird, since O_RDONLY == 0,
-    //       so we check if (NOT write_only OR read_and_write)
-    if (!(options & O_WRONLY) || (options & O_RDWR)) {
-        if (!metadata.may_read(current->process()))
-            return KResult(-EACCES);
-    }
-    if ((options & O_WRONLY) || (options & O_RDWR)) {
+    if ((options & O_RDONLY) && !metadata.may_read(current->process()))
+        return KResult(-EACCES);
+
+    if (options & O_WRONLY) {
         if (!metadata.may_write(current->process()))
             return KResult(-EACCES);
         if (metadata.is_directory())
@@ -748,21 +745,23 @@ KResult VFS::validate_path_against_process_veil(StringView path, int options)
         }
         return KSuccess;
     }
-    if ((options & O_RDWR) || (options & O_WRONLY)) {
+    if (options & O_RDONLY) {
+        if (!(unveiled_path->permissions & UnveiledPath::Access::Read)) {
+            dbg() << *current << " rejecting path '" << path << "' since it hasn't been unveiled with 'r' permission.";
+            return KResult(-EACCES);
+        }
+    }
+    if (options & O_WRONLY) {
         if (!(unveiled_path->permissions & UnveiledPath::Access::Write)) {
             dbg() << *current << " rejecting path '" << path << "' since it hasn't been unveiled with 'w' permission.";
             return KResult(-EACCES);
         }
-    } else if (options & O_EXEC) {
+    }
+    if (options & O_EXEC) {
         if (!(unveiled_path->permissions & UnveiledPath::Access::Execute)) {
             dbg() << *current << " rejecting path '" << path << "' since it hasn't been unveiled with 'x' permission.";
             return KResult(-EACCES);
         }
-    } else {
-        if (!(unveiled_path->permissions & UnveiledPath::Access::Read)) {
-            dbg() << *current << " rejecting path '" << path << "' since it hasn't been unveiled with 'r' permission.";
-            return KResult(-EACCES);
-        }
     }
     return KSuccess;
 }
diff --git a/Kernel/FileSystem/VirtualFileSystem.h b/Kernel/FileSystem/VirtualFileSystem.h
index 27fcc172dc..3984f9eb3a 100644
--- a/Kernel/FileSystem/VirtualFileSystem.h
+++ b/Kernel/FileSystem/VirtualFileSystem.h
@@ -38,9 +38,9 @@
 #include <Kernel/FileSystem/InodeMetadata.h>
 #include <Kernel/KResult.h>
 
-#define O_RDONLY 0
-#define O_WRONLY 1
-#define O_RDWR 2
+#define O_RDONLY 1
+#define O_WRONLY 2
+#define O_RDWR 3
 #define O_EXEC 4
 #define O_CREAT 0100
 #define O_EXCL 0200
diff --git a/Kernel/Net/LocalSocket.cpp b/Kernel/Net/LocalSocket.cpp
index 12269b83fa..0c59ba14f8 100644
--- a/Kernel/Net/LocalSocket.cpp
+++ b/Kernel/Net/LocalSocket.cpp
@@ -111,7 +111,7 @@ KResult LocalSocket::bind(const sockaddr* user_address, socklen_t address_size)
 
     mode_t mode = S_IFSOCK | (m_prebind_mode & 04777);
     UidAndGid owner { m_prebind_uid, m_prebind_gid };
-    auto result = VFS::the().open(path, O_RDWR | O_CREAT | O_EXCL | O_NOFOLLOW_NOERROR, mode, current->process().current_directory(), owner);
+    auto result = VFS::the().open(path, O_CREAT | O_EXCL | O_NOFOLLOW_NOERROR, mode, current->process().current_directory(), owner);
     if (result.is_error()) {
         if (result.error() == -EEXIST)
             return KResult(-EADDRINUSE);
diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 6be807edaa..56dc3ea059 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -1945,9 +1945,9 @@ int Process::sys$open(const Syscall::SC_open_params* user_params)
     if (options & O_UNLINK_INTERNAL)
         return -EINVAL;
 
-    if ((options & O_RDWR) || (options & O_WRONLY))
+    if (options & O_WRONLY)
         REQUIRE_PROMISE(wpath);
-    else
+    else if (options & O_RDONLY)
         REQUIRE_PROMISE(rpath);
 
     if (options & O_CREAT)