From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- scripts/Makefile.ubsan | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 scripts/Makefile.ubsan (limited to 'scripts/Makefile.ubsan') diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan new file mode 100644 index 000000000..734a102e6 --- /dev/null +++ b/scripts/Makefile.ubsan @@ -0,0 +1,28 @@ +# SPDX-License-Identifier: GPL-2.0 + +# Shared with KVM/arm64. +export CFLAGS_UBSAN_TRAP := $(call cc-option,-fsanitize-trap=undefined,-fsanitize-undefined-trap-on-error) + +# Enable available and selected UBSAN features. +ubsan-cflags-$(CONFIG_UBSAN_ALIGNMENT) += -fsanitize=alignment +ubsan-cflags-$(CONFIG_UBSAN_BOUNDS_STRICT) += -fsanitize=bounds-strict +ubsan-cflags-$(CONFIG_UBSAN_ARRAY_BOUNDS) += -fsanitize=array-bounds +ubsan-cflags-$(CONFIG_UBSAN_LOCAL_BOUNDS) += -fsanitize=local-bounds +ubsan-cflags-$(CONFIG_UBSAN_SHIFT) += -fsanitize=shift +ubsan-cflags-$(CONFIG_UBSAN_DIV_ZERO) += -fsanitize=integer-divide-by-zero +ubsan-cflags-$(CONFIG_UBSAN_UNREACHABLE) += -fsanitize=unreachable +ubsan-cflags-$(CONFIG_UBSAN_BOOL) += -fsanitize=bool +ubsan-cflags-$(CONFIG_UBSAN_ENUM) += -fsanitize=enum +ubsan-cflags-$(CONFIG_UBSAN_TRAP) += $(CFLAGS_UBSAN_TRAP) + +export CFLAGS_UBSAN := $(ubsan-cflags-y) + +ubsan-integer-wrap-cflags-$(CONFIG_UBSAN_INTEGER_WRAP) += \ + -DINTEGER_WRAP \ + -fsanitize-undefined-ignore-overflow-pattern=all \ + -fsanitize=signed-integer-overflow \ + -fsanitize=unsigned-integer-overflow \ + -fsanitize=implicit-signed-integer-truncation \ + -fsanitize=implicit-unsigned-integer-truncation \ + -fsanitize-ignorelist=$(srctree)/scripts/integer-wrap-ignore.scl +export CFLAGS_UBSAN_INTEGER_WRAP := $(ubsan-integer-wrap-cflags-y) -- cgit v1.3.1