Kernel: Pass path+length to mkdir(), rmdir() and chmod()

Kernel/Process.cpp

@@ -2333,17 +2333,12 @@ int Process::sys$setgroups(ssize_t count, const gid_t* gids)
     return 0;
 }
 
-int Process::sys$mkdir(const char* pathname, mode_t mode)
+int Process::sys$mkdir(const char* user_path, size_t path_length, mode_t mode)
 {
-    SmapDisabler disabler;
-    if (!validate_read_str(pathname))
-        return -EFAULT;
-    size_t pathname_length = strlen(pathname);
-    if (pathname_length == 0)
-        return -EINVAL;
-    if (pathname_length >= 255)
-        return -ENAMETOOLONG;
-    return VFS::the().mkdir(StringView(pathname, pathname_length), mode & ~umask(), current_directory());
+    auto path = get_syscall_path_argument(user_path, path_length);
+    if (path.is_error())
+        return path.error();
+    return VFS::the().mkdir(path.value(), mode & ~umask(), current_directory());
 }
 
 int Process::sys$realpath(const char* pathname, char* buffer, size_t size)
@@ -2574,20 +2569,31 @@ int Process::sys$symlink(const char* target, const char* linkpath)
     return VFS::the().symlink(StringView(target), StringView(linkpath), current_directory());
 }
 
-int Process::sys$rmdir(const char* pathname)
+KResultOr<String> Process::get_syscall_path_argument(const char* user_path, size_t path_length)
 {
-    SmapDisabler disabler;
-    if (!validate_read_str(pathname))
-        return -EFAULT;
-    return VFS::the().rmdir(StringView(pathname), current_directory());
+    if (path_length == 0)
+        return KResult(-EINVAL);
+    if (path_length > PATH_MAX)
+        return KResult(-ENAMETOOLONG);
+    if (!validate_read(user_path, path_length))
+        return KResult(-EFAULT);
+    return copy_string_from_user(user_path, path_length);
 }
 
-int Process::sys$chmod(const char* pathname, mode_t mode)
+int Process::sys$rmdir(const char* user_path, size_t path_length)
 {
-    SmapDisabler disabler;
-    if (!validate_read_str(pathname))
-        return -EFAULT;
-    return VFS::the().chmod(StringView(pathname), mode, current_directory());
+    auto path = get_syscall_path_argument(user_path, path_length);
+    if (path.is_error())
+        return path.error();
+    return VFS::the().rmdir(path.value(), current_directory());
+}
+
+int Process::sys$chmod(const char* user_path, size_t path_length, mode_t mode)
+{
+    auto path = get_syscall_path_argument(user_path, path_length);
+    if (path.is_error())
+        return path.error();
+    return VFS::the().chmod(path.value(), mode, current_directory());
 }
 
 int Process::sys$fchmod(int fd, mode_t mode)

Kernel/Process.h

@@ -174,16 +174,16 @@ public:
     int sys$access(const char* pathname, size_t path_length, int mode);
     int sys$fcntl(int fd, int cmd, u32 extra_arg);
     int sys$ioctl(int fd, unsigned request, unsigned arg);
-    int sys$mkdir(const char* pathname, mode_t mode);
+    int sys$mkdir(const char* pathname, size_t path_length, mode_t mode);
     clock_t sys$times(tms*);
     int sys$utime(const char* pathname, const struct utimbuf*);
     int sys$link(const char* old_path, const char* new_path);
     int sys$unlink(const char* pathname);
     int sys$symlink(const char* target, const char* linkpath);
-    int sys$rmdir(const char* pathname);
+    int sys$rmdir(const char* pathname, size_t path_length);
     int sys$mount(const char* device, const char* mountpoint, const char* fstype);
     int sys$umount(const char* mountpoint);
-    int sys$chmod(const char* pathname, mode_t);
+    int sys$chmod(const char* pathname, size_t path_length, mode_t);
     int sys$fchmod(int fd, mode_t);
     int sys$chown(const char* pathname, uid_t, gid_t);
     int sys$fchown(int fd, uid_t, gid_t);
@@ -329,6 +329,8 @@ private:
     KResult do_kill(Process&, int signal);
     KResult do_killpg(pid_t pgrp, int signal);
 
+    KResultOr<String> get_syscall_path_argument(const char* user_path, size_t path_length);
+
     RefPtr<PageDirectory> m_page_directory;
 
     Process* m_prev { nullptr };

Libraries/LibC/stat.cpp

@@ -2,6 +2,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <stdio.h>
+#include <string.h>
 #include <sys/stat.h>
 
 extern "C" {
@@ -13,13 +14,21 @@ mode_t umask(mode_t mask)
 
 int mkdir(const char* pathname, mode_t mode)
 {
-    int rc = syscall(SC_mkdir, pathname, mode);
+    if (!pathname) {
+        errno = EFAULT;
+        return -1;
+    }
+    int rc = syscall(SC_mkdir, pathname, strlen(pathname), mode);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
 int chmod(const char* pathname, mode_t mode)
 {
-    int rc = syscall(SC_chmod, pathname, mode);
+    if (!pathname) {
+        errno = EFAULT;
+        return -1;
+    }
+    int rc = syscall(SC_chmod, pathname, strlen(pathname), mode);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 

Libraries/LibC/unistd.cpp

@@ -331,7 +331,11 @@ int symlink(const char* target, const char* linkpath)
 
 int rmdir(const char* pathname)
 {
-    int rc = syscall(SC_rmdir, pathname);
+    if (!pathname) {
+        errno = EFAULT;
+        return -1;
+    }
+    int rc = syscall(SC_rmdir, pathname, strlen(pathname));
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }