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/extract-ikconfig | 69 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100755 scripts/extract-ikconfig (limited to 'scripts/extract-ikconfig') diff --git a/scripts/extract-ikconfig b/scripts/extract-ikconfig new file mode 100755 index 000000000..8df33e7d6 --- /dev/null +++ b/scripts/extract-ikconfig @@ -0,0 +1,69 @@ +#!/bin/sh +# ---------------------------------------------------------------------- +# extract-ikconfig - Extract the .config file from a kernel image +# +# This will only work when the kernel was compiled with CONFIG_IKCONFIG. +# +# The obscure use of the "tr" filter is to work around older versions of +# "grep" that report the byte offset of the line instead of the pattern. +# +# (c) 2009,2010 Dick Streefland +# Licensed under the terms of the GNU General Public License. +# ---------------------------------------------------------------------- + +cf1='IKCFG_ST\037\213\010' +cf2='0123456789' + +dump_config() +{ + if pos=`tr "$cf1\n$cf2" "\n$cf2=" < "$1" | grep -abo "^$cf2"` + then + pos=${pos%%:*} + tail -c+$(($pos+8)) "$1" | zcat > $tmp1 2> /dev/null + if [ $? != 1 ] + then # exit status must be 0 or 2 (trailing garbage warning) + cat $tmp1 + exit 0 + fi + fi +} + +try_decompress() +{ + for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` + do + pos=${pos%%:*} + tail -c+$pos "$img" | $3 > $tmp2 2> /dev/null + dump_config $tmp2 + done +} + +# Check invocation: +me=${0##*/} +img=$1 +if [ $# -ne 1 -o ! -s "$img" ] +then + echo "Usage: $me " >&2 + exit 2 +fi + +# Prepare temp files: +tmp1=/tmp/ikconfig$$.1 +tmp2=/tmp/ikconfig$$.2 +trap "rm -f $tmp1 $tmp2" 0 + +# Initial attempt for uncompressed images or objects: +dump_config "$img" + +# That didn't work, so retry after decompression. +try_decompress '\037\213\010' xy gunzip +try_decompress '\3757zXZ\000' abcde unxz +try_decompress 'BZh' xy bunzip2 +try_decompress '\135\0\0\0' xxx unlzma +try_decompress '\211\114\132' xy 'lzop -d' +try_decompress '\002\041\114\030' xyy 'lz4 -d -l' +try_decompress '\050\265\057\375' xxx unzstd + +# Bail out: +echo "$me: Cannot find kernel config." >&2 +exit 1 -- cgit v1.3.1