sf_path_from_dentry: null pointer deference on failed kmalloc allocation

[ColinIanKing]

Function sf_path_from_dentry in src/VBox/Additions/linux/sharedfolders/utils.c is allocating a buffer using kmalloc but it does not check if the allocation failed:

        out_bound_len = PATH_MAX;
        out = kmalloc(out_bound_len, GFP_KERNEL);
        name = out;

..and later it is dereferenced leading to a potential NULL pointer dereference crash.

        LogFunc(("result(%d) = %.*s\n", len, len, name));
        *out = 0;

I suggest that the kmalloc failure case needs to be handled correctly.

[Frank Mehnert]

That case is handled here:

    if (name != d_name)
        kfree(name);