xfs: Check Permissions

Implemented the xfs_access hook and we now check for permissions where
required.

Change-Id: Idaa71f300e0a73951d13073b66cb9ff37dbfa3ec
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3151
Reviewed-by: Adrien Destugues <[email protected]>

src/add-ons/kernel/file_systems/xfs/Inode.cpp

@@ -181,6 +181,18 @@ Inode::HasFileTypeField() const
 }
 
 
+status_t
+Inode::CheckPermissions(int accessMode) const
+{
+	// you never have write access to a read-only volume
+	if ((accessMode & W_OK) != 0 && fVolume->IsReadOnly())
+		return B_READ_ONLY_DEVICE;
+
+	return check_access_permissions(accessMode, Mode(),
+		(uint32)fNode->GroupId(), (uint32)fNode->UserId());
+}
+
+
 status_t
 Inode::GetFromDisk()
 {

src/add-ons/kernel/file_systems/xfs/Inode.h

@@ -189,6 +189,7 @@ public:
 			void				GetAccessTime(struct timespec& timestamp) const
 								{ fNode->GetAccessTime(timestamp); }
 
+			status_t			CheckPermissions(int accessMode) const;
 			uint32				UserId() const { return fNode->UserId(); }
 			uint32				GroupId() const { return fNode->GroupId(); }
 			bool				HasFileTypeField() const;

src/add-ons/kernel/file_systems/xfs/kernel_interface.cpp

@@ -211,14 +211,16 @@ xfs_lookup(fs_volume *_volume, fs_vnode *_directory, const char *name,
 	if (!directory->IsDirectory())
 		return B_NOT_A_DIRECTORY;
 
-	//TODO: pretend everything is accessible. We should actually checking
-	//for permission here.
+	status_t status = directory->CheckPermissions(X_OK);
+	if (status < B_OK)
+		return status;
+
 	DirectoryIterator* iterator =
 		new(std::nothrow) DirectoryIterator(directory);
 	if (iterator == NULL)
 		return B_NO_MEMORY;
 
-	status_t status = iterator->Init();
+	status = iterator->Init();
 	if (status != B_OK) {
 		delete iterator;
 		return status;
@@ -308,9 +310,8 @@ xfs_free_cookie(fs_volume *_volume, fs_vnode *_node, void *_cookie)
 static status_t
 xfs_access(fs_volume *_volume, fs_vnode *_node, int accessMode)
 {
-	//TODO: pretend everything is accessible. We should actually checking
-	//for permission here.
-	return B_OK;
+	Inode* inode = (Inode*)_node->private_node;
+	return inode->CheckPermissions(accessMode);
 }
 
 
@@ -353,6 +354,10 @@ xfs_open_dir(fs_volume * /*_volume*/, fs_vnode *_node, void **_cookie)
 	Inode* inode = (Inode*)_node->private_node;
 	TRACE("XFS_OPEN_DIR: (%ld)\n", inode->ID());
 
+	status_t status = inode->CheckPermissions(R_OK);
+	if (status < B_OK)
+		return status;
+
 	if (!inode->IsDirectory())
 		return B_NOT_A_DIRECTORY;
 
@@ -361,7 +366,7 @@ xfs_open_dir(fs_volume * /*_volume*/, fs_vnode *_node, void **_cookie)
 		delete iterator;
 		return B_NO_MEMORY;
 	}
-	status_t status = iterator->Init();
+	status = iterator->Init();
 	*_cookie = iterator;
 	return status;
 }