lib/vfscore: Fix crash in fstatat on NULL args

This change makes fstatat gracefully handle NULL arguments by returning
-EFAULT, preventing a hard crash.

Signed-off-by: Andrei Tatar <andrei@unikraft.io>
Reviewed-by: Simon Kuenzer <simon@unikraft.io>
Approved-by: Simon Kuenzer <simon@unikraft.io>
GitHub-Closes: #1155

diff --git a/lib/vfscore/main.c b/lib/vfscore/main.c
index fdcb1226f601eb2c4df79512c0ad9fd60c298a4f..e0974feeaf80559407d66a0a968e584f2e233747 100644 (file)
--- a/lib/vfscore/main.c
+++ b/lib/vfscore/main.c
@@ -1856,6 +1856,8 @@ UK_SYSCALL_R_DEFINE(int, lstat, const char*, pathname, struct stat*, st)
 static int __fxstatat_helper(int ver __unused, int dirfd, const char *pathname,
                struct stat *st, int flags)
 {
+       if (!pathname || !st)
+               return -EFAULT;
        if (pathname[0] == '/' || dirfd == AT_FDCWD) {
                return uk_syscall_r_stat((long) pathname, (long) st);
        }