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 --- scripts/makelst | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100755 scripts/makelst (limited to 'scripts/makelst') diff --git a/scripts/makelst b/scripts/makelst new file mode 100755 index 000000000..e432af073 --- /dev/null +++ b/scripts/makelst @@ -0,0 +1,32 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# A script to dump mixed source code & assembly +# with correct relocations from System.map +# Requires the following lines in makefile: +#%.lst: %.c +# $(CC) $(c_flags) -g -c -o $*.o $< && +# $(srctree)/scripts/makelst $*.o System.map $(OBJDUMP) > $@ +# +# Copyright (C) 2000 IBM Corporation +# Author(s): DJ Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) +# William Stearns +# + +# awk style field access +field() { + shift $1 ; echo $1 +} + +t1=`$3 --syms $1 | grep .text | grep -m1 " F "` +if [ -n "$t1" ]; then + t2=`field 6 $t1` + if [ ! -r $2 ]; then + echo "No System.map" >&2 + else + t3=`grep $t2 $2` + t4=`field 1 $t3` + t5=`field 1 $t1` + t6=`printf "%lu" $((0x$t4 - 0x$t5))` + fi +fi +$3 -r --source --adjust-vma=${t6:-0} $1 -- cgit v1.3.1