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/extract-fwblobs | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100755 scripts/extract-fwblobs (limited to 'scripts/extract-fwblobs') diff --git a/scripts/extract-fwblobs b/scripts/extract-fwblobs new file mode 100755 index 000000000..53729124e --- /dev/null +++ b/scripts/extract-fwblobs @@ -0,0 +1,30 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# ----------------------------------------------------------------------------- +# Extracts the vmlinux built-in firmware blobs - requires a non-stripped image +# ----------------------------------------------------------------------------- + +if [ -z "$1" ]; then + echo "Must provide a non-stripped vmlinux as argument" + exit 1 +fi + +read -r RD_ADDR_HEX RD_OFF_HEX <<< "$( readelf -SW "$1" |\ +grep -w rodata | awk '{print "0x"$5" 0x"$6}' )" + +FW_SYMS="$(readelf -sW "$1" |\ +awk -n '/fw_end/ { end=$2 ; print name " 0x" start " 0x" end; } { start=$2; name=$8; }')" + +while IFS= read -r entry; do + read -r FW_NAME FW_ADDR_ST_HEX FW_ADDR_END_HEX <<< "$entry" + + # Notice kernel prepends _fw_ and appends _bin to the FW name + # in rodata; hence we hereby filter that out. + FW_NAME=${FW_NAME:4:-4} + + FW_OFFSET="$(printf "%d" $((FW_ADDR_ST_HEX - RD_ADDR_HEX + RD_OFF_HEX)))" + FW_SIZE="$(printf "%d" $((FW_ADDR_END_HEX - FW_ADDR_ST_HEX)))" + + dd if="$1" of="./${FW_NAME}" bs="${FW_SIZE}" count=1 iflag=skip_bytes skip="${FW_OFFSET}" +done <<< "${FW_SYMS}" -- cgit v1.3.1