From 836b2fe544a5e9b5ce116622cb36fba33838c6fd Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 01:33:23 -0700 Subject: selftests/bpf: Check that JMP32 pointer vs zero jumps are not predicted Add jmp32_ptr_vs_zero_jne: the fall-through of the 32-bit compare, which the verifier used to skip, contains an out of bounds map value access, hence w/o the previous patch the program is accepted. See previous patch for detailed description. Reported-by: Nicholas Carlini Suggested-by: Nicholas Carlini Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/bpf/20260904083325.2083493-6-eddyz87@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- drivers/tty/n_null.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 drivers/tty/n_null.c (limited to 'drivers/tty/n_null.c') diff --git a/drivers/tty/n_null.c b/drivers/tty/n_null.c new file mode 100644 index 000000000..5a429d923 --- /dev/null +++ b/drivers/tty/n_null.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include + +/* + * n_null.c - Null line discipline used in the failure path + * + * Copyright (C) Intel 2017 + */ + +static ssize_t n_null_read(struct tty_struct *tty, struct file *file, u8 *buf, + size_t nr, void **cookie, unsigned long offset) +{ + return -EOPNOTSUPP; +} + +static ssize_t n_null_write(struct tty_struct *tty, struct file *file, + const u8 *buf, size_t nr) +{ + return -EOPNOTSUPP; +} + +static struct tty_ldisc_ops null_ldisc = { + .owner = THIS_MODULE, + .num = N_NULL, + .name = "n_null", + .read = n_null_read, + .write = n_null_write, +}; + +static int __init n_null_init(void) +{ + BUG_ON(tty_register_ldisc(&null_ldisc)); + return 0; +} + +static void __exit n_null_exit(void) +{ + tty_unregister_ldisc(&null_ldisc); +} + +module_init(n_null_init); +module_exit(n_null_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Alan Cox"); +MODULE_ALIAS_LDISC(N_NULL); +MODULE_DESCRIPTION("Null ldisc driver"); -- cgit v1.3.1