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 --- include/net/dropreason.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 include/net/dropreason.h (limited to 'include/net/dropreason.h') diff --git a/include/net/dropreason.h b/include/net/dropreason.h new file mode 100644 index 000000000..1df60645f --- /dev/null +++ b/include/net/dropreason.h @@ -0,0 +1,49 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#ifndef _LINUX_DROPREASON_H +#define _LINUX_DROPREASON_H +#include + +/** + * enum skb_drop_reason_subsys - subsystem tag for (extended) drop reasons + */ +enum skb_drop_reason_subsys { + /** @SKB_DROP_REASON_SUBSYS_CORE: core drop reasons defined above */ + SKB_DROP_REASON_SUBSYS_CORE, + + /** + * @SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE: mac80211 drop reasons + * for unusable frames, see net/mac80211/drop.h + */ + SKB_DROP_REASON_SUBSYS_MAC80211_UNUSABLE, + + /** + * @SKB_DROP_REASON_SUBSYS_OPENVSWITCH: openvswitch drop reasons, + * see net/openvswitch/drop.h + */ + SKB_DROP_REASON_SUBSYS_OPENVSWITCH, + + /** + * @SKB_DROP_REASON_SUBSYS_QDISC: TC qdisc drop reasons, + * see include/net/dropreason-qdisc.h + */ + SKB_DROP_REASON_SUBSYS_QDISC, + + /** @SKB_DROP_REASON_SUBSYS_NUM: number of subsystems defined */ + SKB_DROP_REASON_SUBSYS_NUM +}; + +struct drop_reason_list { + const char * const *reasons; + size_t n_reasons; +}; + +/* Note: due to dynamic registrations, access must be under RCU */ +extern const struct drop_reason_list __rcu * +drop_reasons_by_subsys[SKB_DROP_REASON_SUBSYS_NUM]; + +void drop_reasons_register_subsys(enum skb_drop_reason_subsys subsys, + const struct drop_reason_list *list); +void drop_reasons_unregister_subsys(enum skb_drop_reason_subsys subsys); + +#endif -- cgit v1.3.1