From 33a154a96e71a34a1bcca9f40da343dbbf7b38b4 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 1 Oct 2026 14:52:55 +0000 Subject: selftests/bpf: Test packet range of pointers sharing an id Add tests where two packet pointers share an id and tightening one pointer's umax from its var_off would put it less than their constant distance from the other's umax: with an index & 0x38 capped at 50, the base pointer keeps umax 50, so the pointer 8 bytes further on must keep umax 58, even though its known bits allow at most 56. These refused a valid program or accepted an out-of-bounds access before the fix: - check the advanced copy, load through the base: valid, was refused; - check the base, load the byte at base + 1 through a copy advanced by 8: was accepted; - check base + 4, load 4 bytes at base + 2 through base + 8: reads two bytes past the checked range, was accepted; - the same as the second with data_meta pointers checked against data: was accepted. These pass with and without the fix and cover nearby paths: - subtract an unknown scalar from a checked pointer and load below it (the range is kept across a new id); - reach a load through two paths whose checks cover 8 and 7 bytes after the loaded pointer; the second path must not be pruned by the first; - spill a copy of a pointer, check the pointer, fill the copy and load one byte past the checked range: the load is refused, and the copy has the range of the check. Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi --- lib/netdev-notifier-error-inject.c | 56 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 lib/netdev-notifier-error-inject.c (limited to 'lib/netdev-notifier-error-inject.c') diff --git a/lib/netdev-notifier-error-inject.c b/lib/netdev-notifier-error-inject.c new file mode 100644 index 000000000..bb930f279 --- /dev/null +++ b/lib/netdev-notifier-error-inject.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include +#include + +#include "notifier-error-inject.h" + +static int priority; +module_param(priority, int, 0); +MODULE_PARM_DESC(priority, "specify netdevice notifier priority"); + +static struct notifier_err_inject netdev_notifier_err_inject = { + .actions = { + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_REGISTER) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGEMTU) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGENAME) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_UP) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRE_TYPE_CHANGE) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_POST_INIT) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEMTU) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_PRECHANGEUPPER) }, + { NOTIFIER_ERR_INJECT_ACTION(NETDEV_CHANGEUPPER) }, + {} + } +}; + +static struct dentry *dir; + +static int netdev_err_inject_init(void) +{ + int err; + + dir = notifier_err_inject_init("netdev", notifier_err_inject_dir, + &netdev_notifier_err_inject, priority); + if (IS_ERR(dir)) + return PTR_ERR(dir); + + err = register_netdevice_notifier(&netdev_notifier_err_inject.nb); + if (err) + debugfs_remove_recursive(dir); + + return err; +} + +static void netdev_err_inject_exit(void) +{ + unregister_netdevice_notifier(&netdev_notifier_err_inject.nb); + debugfs_remove_recursive(dir); +} + +module_init(netdev_err_inject_init); +module_exit(netdev_err_inject_exit); + +MODULE_DESCRIPTION("Netdevice notifier error injection module"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Nikolay Aleksandrov "); -- cgit v1.3.1