LibC: Make the syscall wrappers for stat/lstat/chdir return EFAULT

If we pass a null path to these syscall wrappers, just return EFAULT
directly from the wrapper instead of segfaulting by calling strlen().
This is a compromise, since we now have to pass the path length to the
kernel, so we can't rely on the kernel to tell us that the path is at
a bad memory address.

1 files changed, 12 insertions, 0 deletions

diff --git a/Libraries/LibC/unistd.cpp b/Libraries/LibC/unistd.cpp
index 8c0f093f3f..70cd0f7e8e 100644
--- a/Libraries/LibC/unistd.cpp
+++ b/Libraries/LibC/unistd.cpp
@@ -227,12 +227,20 @@ pid_t waitpid(pid_t waitee, int* wstatus, int options)
 
 int lstat(const char* path, struct stat* statbuf)
 {
+    if (!path) {
+        errno = EFAULT;
+        return -1;
+    }
     int rc = syscall(SC_lstat, path, strlen(path), statbuf);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
 int stat(const char* path, struct stat* statbuf)
 {
+    if (!path) {
+        errno = EFAULT;
+        return -1;
+    }
     int rc = syscall(SC_stat, path, strlen(path), statbuf);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
@@ -245,6 +253,10 @@ int fstat(int fd, struct stat* statbuf)
 
 int chdir(const char* path)
 {
+    if (!path) {
+        errno = EFAULT;
+        return -1;
+    }
     int rc = syscall(SC_chdir, path, strlen(path));
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }